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+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<chapter id='extendpoky'>
+
+<title>Common Tasks</title>
+    <para>
+        This chapter describes fundamental procedures such as creating layers,
+        adding new software packages, extending or customizing images,
+        porting work to new hardware (adding a new machine), and so forth.
+        You will find that the procedures documented here occur often in the
+        development cycle using the Yocto Project.
+    </para>
+
+    <section id="understanding-and-creating-layers">
+        <title>Understanding and Creating Layers</title>
+
+        <para>
+            The OpenEmbedded build system supports organizing
+            <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink> into
+            multiple layers.
+            Layers allow you to isolate different types of customizations from
+            each other.
+            For introductory information on the Yocto Project Layer Model,
+            see the
+            "<ulink url='&YOCTO_DOCS_OM_URL;#the-yocto-project-layer-model'>The Yocto Project Layer Model</ulink>"
+            section in the Yocto Project Overview and Concepts Manual.
+        </para>
+
+        <section id='creating-your-own-layer'>
+            <title>Creating Your Own Layer</title>
+
+            <para>
+                It is very easy to create your own layers to use with the
+                OpenEmbedded build system.
+                The Yocto Project ships with tools that speed up creating
+                layers.
+                This section describes the steps you perform by hand to create
+                layers so that you can better understand them.
+                For information about the layer-creation tools, see the
+                "<ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-bitbake-layers-script'>Creating a New BSP Layer Using the <filename>bitbake-layers</filename> Script</ulink>"
+                section in the Yocto Project Board Support Package (BSP)
+                Developer's Guide and the
+                "<link linkend='creating-a-general-layer-using-the-bitbake-layers-script'>Creating a General Layer Using the <filename>bitbake-layers</filename> Script</link>"
+                section further down in this manual.
+            </para>
+
+            <para>
+                Follow these general steps to create your layer without using
+                tools:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Check Existing Layers:</emphasis>
+                        Before creating a new layer, you should be sure someone
+                        has not already created a layer containing the Metadata
+                        you need.
+                        You can see the
+                        <ulink url='http://layers.openembedded.org/layerindex/layers/'>OpenEmbedded Metadata Index</ulink>
+                        for a list of layers from the OpenEmbedded community
+                        that can be used in the Yocto Project.
+                        You could find a layer that is identical or close to
+                        what you need.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create a Directory:</emphasis>
+                        Create the directory for your layer.
+                        When you create the layer, be sure to create the
+                        directory in an area not associated with the
+                        Yocto Project
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                        (e.g. the cloned <filename>poky</filename> repository).
+                        </para>
+
+                        <para>While not strictly required, prepend the name of
+                        the directory with the string "meta-".
+                        For example:
+                        <literallayout class='monospaced'>
+     meta-mylayer
+     meta-GUI_xyz
+     meta-mymachine
+                        </literallayout>
+                        With rare exceptions, a layer's name follows this
+                        form:
+                        <literallayout class='monospaced'>
+     meta-<replaceable>root_name</replaceable>
+                        </literallayout>
+                        Following this layer naming convention can
+                        save you trouble later when tools, components, or
+                        variables "assume" your layer name begins with "meta-".
+                        A notable example is in configuration files as
+                        shown in the following step where layer names without
+                        the "meta-" string are appended
+                        to several variables used in the configuration.
+                        </para></listitem>
+                    <listitem><para id='dev-layer-config-file-description'>
+                        <emphasis>Create a Layer Configuration File:</emphasis>
+                        Inside your new layer folder, you need to create a
+                        <filename>conf/layer.conf</filename> file.
+                        It is easiest to take an existing layer configuration
+                        file and copy that to your layer's
+                        <filename>conf</filename> directory and then modify the
+                        file as needed.</para>
+
+                        <para>The
+                        <filename>meta-yocto-bsp/conf/layer.conf</filename> file
+                        in the Yocto Project
+                        <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/poky/tree/meta-yocto-bsp/conf'>Source Repositories</ulink>
+                        demonstrates the required syntax.
+                        For your layer, you need to replace "yoctobsp" with
+                        a unique identifier for your layer (e.g. "machinexyz"
+                        for a layer named "meta-machinexyz"):
+                        <literallayout class='monospaced'>
+     # We have a conf and classes directory, add to BBPATH
+     BBPATH .= ":${LAYERDIR}"
+
+     # We have recipes-* directories, add to BBFILES
+     BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
+                 ${LAYERDIR}/recipes-*/*/*.bbappend"
+
+     BBFILE_COLLECTIONS += "yoctobsp"
+     BBFILE_PATTERN_yoctobsp = "^${LAYERDIR}/"
+     BBFILE_PRIORITY_yoctobsp = "5"
+     LAYERVERSION_yoctobsp = "4"
+     LAYERSERIES_COMPAT_yoctobsp = "&DISTRO_NAME_NO_CAP;"
+                        </literallayout>
+                        Following is an explanation of the layer configuration
+                        file:
+                        <itemizedlist>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBPATH'><filename>BBPATH</filename></ulink>:
+                                Adds the layer's root directory to BitBake's
+                                search path.
+                                Through the use of the
+                                <filename>BBPATH</filename> variable, BitBake
+                                locates class files
+                                (<filename>.bbclass</filename>),
+                                configuration files, and files that are
+                                included with <filename>include</filename> and
+                                <filename>require</filename> statements.
+                                For these cases, BitBake uses the first file
+                                that matches the name found in
+                                <filename>BBPATH</filename>.
+                                This is similar to the way the
+                                <filename>PATH</filename> variable is used for
+                                binaries.
+                                It is recommended, therefore, that you use
+                                unique class and configuration filenames in
+                                your custom layer.
+                                </para></listitem>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILES'><filename>BBFILES</filename></ulink>:
+                                Defines the location for all recipes in the
+                                layer.
+                                </para></listitem>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_COLLECTIONS'><filename>BBFILE_COLLECTIONS</filename></ulink>:
+                                Establishes the current layer through a
+                                unique identifier that is used throughout the
+                                OpenEmbedded build system to refer to the layer.
+                                In this example, the identifier "yoctobsp" is
+                                the representation for the container layer
+                                named "meta-yocto-bsp".
+                                </para></listitem>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_PATTERN'><filename>BBFILE_PATTERN</filename></ulink>:
+                                Expands immediately during parsing to
+                                provide the directory of the layer.
+                                </para></listitem>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_PRIORITY'><filename>BBFILE_PRIORITY</filename></ulink>:
+                                Establishes a priority to use for
+                                recipes in the layer when the OpenEmbedded build
+                                finds recipes of the same name in different
+                                layers.
+                                </para></listitem>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERVERSION'><filename>LAYERVERSION</filename></ulink>:
+                                Establishes a version number for the layer.
+                                You can use this version number to specify this
+                                exact version of the layer as a dependency when
+                                using the
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERDEPENDS'><filename>LAYERDEPENDS</filename></ulink>
+                                variable.
+                                </para></listitem>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERDEPENDS'><filename>LAYERDEPENDS</filename></ulink>:
+                                Lists all layers on which this layer depends (if any).
+                                </para></listitem>
+                            <listitem><para>
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-LAYERSERIES_COMPAT'><filename>LAYERSERIES_COMPAT</filename></ulink>:
+                                Lists the
+                                <ulink url='&YOCTO_WIKI_URL;/wiki/Releases'>Yocto Project</ulink>
+                                releases for which the current version is
+                                compatible.
+                                This variable is a good way to indicate if
+                                your particular layer is current.
+                                </para></listitem>
+                        </itemizedlist>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Add Content:</emphasis>
+                        Depending on the type of layer, add the content.
+                        If the layer adds support for a machine, add the machine
+                        configuration in a <filename>conf/machine/</filename>
+                        file within the layer.
+                        If the layer adds distro policy, add the distro
+                        configuration in a <filename>conf/distro/</filename>
+                        file within the layer.
+                        If the layer introduces new recipes, put the recipes
+                        you need in <filename>recipes-*</filename>
+                        subdirectories within the layer.
+                        <note>
+                            For an explanation of layer hierarchy that
+                            is compliant with the Yocto Project, see
+                            the
+                            "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-filelayout'>Example Filesystem Layout</ulink>"
+                            section in the Yocto Project Board
+                            Support Package (BSP) Developer's Guide.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Optionally Test for Compatibility:</emphasis>
+                        If you want permission to use the Yocto Project
+                        Compatibility logo with your layer or application that
+                        uses your layer, perform the steps to apply for
+                        compatibility.
+                        See the
+                        "<link linkend='making-sure-your-layer-is-compatible-with-yocto-project'>Making Sure Your Layer is Compatible With Yocto Project</link>"
+                        section for more information.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+
+        <section id='best-practices-to-follow-when-creating-layers'>
+            <title>Following Best Practices When Creating Layers</title>
+
+            <para>
+                To create layers that are easier to maintain and that will
+                not impact builds for other machines, you should consider the
+                information in the following list:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Avoid "Overlaying" Entire Recipes from Other Layers in Your Configuration:</emphasis>
+                        In other words, do not copy an entire recipe into your
+                        layer and then modify it.
+                        Rather, use an append file
+                        (<filename>.bbappend</filename>) to override only those
+                        parts of the original recipe you need to modify.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Avoid Duplicating Include Files:</emphasis>
+                        Use append files (<filename>.bbappend</filename>)
+                        for each recipe that uses an include file.
+                        Or, if you are introducing a new recipe that requires
+                        the included file, use the path relative to the
+                        original layer directory to refer to the file.
+                        For example, use
+                        <filename>require recipes-core/</filename><replaceable>package</replaceable><filename>/</filename><replaceable>file</replaceable><filename>.inc</filename>
+                        instead of
+                        <filename>require </filename><replaceable>file</replaceable><filename>.inc</filename>.
+                        If you're finding you have to overlay the include file,
+                        it could indicate a deficiency in the include file in
+                        the layer to which it originally belongs.
+                        If this is the case, you should try to address that
+                        deficiency instead of overlaying the include file.
+                        For example, you could address this by getting the
+                        maintainer of the include file to add a variable or
+                        variables to make it easy to override the parts needing
+                        to be overridden.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Structure Your Layers:</emphasis>
+                        Proper use of overrides within append files and
+                        placement of machine-specific files within your layer
+                        can ensure that a build is not using the wrong Metadata
+                        and negatively impacting a build for a different
+                        machine.
+                        Following are some examples:
+                        <itemizedlist>
+                            <listitem><para>
+                                <emphasis>Modify Variables to Support a
+                                Different Machine:</emphasis>
+                                Suppose you have a layer named
+                                <filename>meta-one</filename> that adds support
+                                for building machine "one".
+                                To do so, you use an append file named
+                                <filename>base-files.bbappend</filename> and
+                                create a dependency on "foo" by altering the
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                                variable:
+                                <literallayout class='monospaced'>
+     DEPENDS = "foo"
+                                </literallayout>
+                                The dependency is created during any build that
+                                includes the layer
+                                <filename>meta-one</filename>.
+                                However, you might not want this dependency
+                                for all machines.
+                                For example, suppose you are building for
+                                machine "two" but your
+                                <filename>bblayers.conf</filename> file has the
+                                <filename>meta-one</filename> layer included.
+                                During the build, the
+                                <filename>base-files</filename> for machine
+                                "two" will also have the dependency on
+                                <filename>foo</filename>.</para>
+                                <para>To make sure your changes apply only when
+                                building machine "one", use a machine override
+                                with the <filename>DEPENDS</filename> statement:
+                                <literallayout class='monospaced'>
+     DEPENDS_one = "foo"
+                                </literallayout>
+                                You should follow the same strategy when using
+                                <filename>_append</filename> and
+                                <filename>_prepend</filename> operations:
+                                <literallayout class='monospaced'>
+     DEPENDS_append_one = " foo"
+     DEPENDS_prepend_one = "foo "
+                                </literallayout>
+                                As an actual example, here's a snippet from the
+                                generic kernel include file
+                                <filename>linux-yocto.inc</filename>,
+                                wherein the kernel compile and link options are
+                                adjusted in the case of a subset of the supported
+                                architectures:
+                                <literallayout class='monospaced'>
+     DEPENDS_append_aarch64 = " libgcc"
+     KERNEL_CC_append_aarch64 = " ${TOOLCHAIN_OPTIONS}"
+     KERNEL_LD_append_aarch64 = " ${TOOLCHAIN_OPTIONS}"
+
+     DEPENDS_append_nios2 = " libgcc"
+     KERNEL_CC_append_nios2 = " ${TOOLCHAIN_OPTIONS}"
+     KERNEL_LD_append_nios2 = " ${TOOLCHAIN_OPTIONS}"
+
+     DEPENDS_append_arc = " libgcc"
+     KERNEL_CC_append_arc = " ${TOOLCHAIN_OPTIONS}"
+     KERNEL_LD_append_arc = " ${TOOLCHAIN_OPTIONS}"
+
+     KERNEL_FEATURES_append_qemuall=" features/debug/printk.scc"
+                                </literallayout>
+                                <note>
+                                    Avoiding "+=" and "=+" and using
+                                    machine-specific
+                                    <filename>_append</filename>
+                                    and <filename>_prepend</filename> operations
+                                    is recommended as well.
+                                </note>
+                                </para></listitem>
+                            <listitem><para>
+                                <emphasis>Place Machine-Specific Files in
+                                Machine-Specific Locations:</emphasis>
+                                When you have a base recipe, such as
+                                <filename>base-files.bb</filename>, that
+                                contains a
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                                statement to a file, you can use an append file
+                                to cause the build to use your own version of
+                                the file.
+                                For example, an append file in your layer at
+                                <filename>meta-one/recipes-core/base-files/base-files.bbappend</filename>
+                                could extend
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESPATH'><filename>FILESPATH</filename></ulink>
+                                using
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                                as follows:
+                                <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${BPN}:"
+                                </literallayout>
+                                The build for machine "one" will pick up your
+                                machine-specific file as long as you have the
+                                file in
+                                <filename>meta-one/recipes-core/base-files/base-files/</filename>.
+                                However, if you are building for a different
+                                machine and the
+                                <filename>bblayers.conf</filename> file includes
+                                the <filename>meta-one</filename> layer and
+                                the location of your machine-specific file is
+                                the first location where that file is found
+                                according to <filename>FILESPATH</filename>,
+                                builds for all machines will also use that
+                                machine-specific file.</para>
+                                <para>You can make sure that a machine-specific
+                                file is used for a particular machine by putting
+                                the file in a subdirectory specific to the
+                                machine.
+                                For example, rather than placing the file in
+                                <filename>meta-one/recipes-core/base-files/base-files/</filename>
+                                as shown above, put it in
+                                <filename>meta-one/recipes-core/base-files/base-files/one/</filename>.
+                                Not only does this make sure the file is used
+                                only when building for machine "one", but the
+                                build process locates the file more quickly.</para>
+                                <para>In summary, you need to place all files
+                                referenced from <filename>SRC_URI</filename>
+                                in a machine-specific subdirectory within the
+                                layer in order to restrict those files to
+                                machine-specific builds.
+                                </para></listitem>
+                        </itemizedlist>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Perform Steps to Apply for Yocto Project Compatibility:</emphasis>
+                        If you want permission to use the
+                        Yocto Project Compatibility logo with your layer
+                        or application that uses your layer, perform the
+                        steps to apply for compatibility.
+                        See the
+                        "<link linkend='making-sure-your-layer-is-compatible-with-yocto-project'>Making Sure Your Layer is Compatible With Yocto Project</link>"
+                        section for more information.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Follow the Layer Naming Convention:</emphasis>
+                        Store custom layers in a Git repository that use the
+                        <filename>meta-<replaceable>layer_name</replaceable></filename>
+                        format.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Group Your Layers Locally:</emphasis>
+                        Clone your repository alongside other cloned
+                        <filename>meta</filename> directories from the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='making-sure-your-layer-is-compatible-with-yocto-project'>
+            <title>Making Sure Your Layer is Compatible With Yocto Project</title>
+
+            <para>
+                When you create a layer used with the Yocto Project, it is
+                advantageous to make sure that the layer interacts well with
+                existing Yocto Project layers (i.e. the layer is compatible
+                with the Yocto Project).
+                Ensuring compatibility makes the layer easy to be consumed
+                by others in the Yocto Project community and could allow you
+                permission to use the Yocto Project Compatible Logo.
+                <note>
+                    Only Yocto Project member organizations are permitted to
+                    use the Yocto Project Compatible Logo.
+                    The logo is not available for general use.
+                    For information on how to become a Yocto Project member
+                    organization, see the
+                    <ulink url='&YOCTO_HOME_URL;'>Yocto Project Website</ulink>.
+                </note>
+            </para>
+
+            <para>
+                The Yocto Project Compatibility Program consists of a layer
+                application process that requests permission to use the Yocto
+                Project Compatibility Logo for your layer and application.
+                The process consists of two parts:
+                <orderedlist>
+                    <listitem><para>
+                        Successfully passing a script
+                        (<filename>yocto-check-layer</filename>) that
+                        when run against your layer, tests it against
+                        constraints based on experiences of how layers have
+                        worked in the real world and where pitfalls have been
+                        found.
+                        Getting a "PASS" result from the script is required for
+                        successful compatibility registration.
+                        </para></listitem>
+                    <listitem><para>
+                        Completion of an application acceptance form, which
+                        you can find at
+                        <ulink url='https://www.yoctoproject.org/webform/yocto-project-compatible-registration'></ulink>.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                To be granted permission to use the logo, you need to satisfy
+                the following:
+                <itemizedlist>
+                    <listitem><para>
+                        Be able to check the box indicating that you
+                        got a "PASS" when running the script against your
+                        layer.
+                        </para></listitem>
+                    <listitem><para>
+                        Answer "Yes" to the questions on the form or have an
+                        acceptable explanation for any questions answered "No".
+                        </para></listitem>
+                    <listitem><para>
+                        Be a Yocto Project Member Organization.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                The remainder of this section presents information on the
+                registration form and on the
+                <filename>yocto-check-layer</filename> script.
+            </para>
+
+            <section id='yocto-project-compatible-program-application'>
+                <title>Yocto Project Compatible Program Application</title>
+
+                <para>
+                    Use the form to apply for your layer's approval.
+                    Upon successful application, you can use the Yocto
+                    Project Compatibility Logo with your layer and the
+                    application that uses your layer.
+                </para>
+
+                <para>
+                    To access the form, use this link:
+                    <ulink url='https://www.yoctoproject.org/webform/yocto-project-compatible-registration'></ulink>.
+                    Follow the instructions on the form to complete your
+                    application.
+                </para>
+
+                <para>
+                    The application consists of the following sections:
+                    <itemizedlist>
+                        <listitem><para>
+                            <emphasis>Contact Information:</emphasis>
+                            Provide your contact information as the fields
+                            require.
+                            Along with your information, provide the
+                            released versions of the Yocto Project for which
+                            your layer is compatible.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Acceptance Criteria:</emphasis>
+                            Provide "Yes" or "No" answers for each of the
+                            items in the checklist.
+                            Space exists at the bottom of the form for any
+                            explanations for items for which you answered "No".
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Recommendations:</emphasis>
+                            Provide answers for the questions regarding Linux
+                            kernel use and build success.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='yocto-check-layer-script'>
+                <title><filename>yocto-check-layer</filename> Script</title>
+
+                <para>
+                    The <filename>yocto-check-layer</filename> script
+                    provides you a way to assess how compatible your layer is
+                    with the Yocto Project.
+                    You should run this script prior to using the form to
+                    apply for compatibility as described in the previous
+                    section.
+                    You need to achieve a "PASS" result in order to have
+                    your application form successfully processed.
+                </para>
+
+                <para>
+                    The script divides tests into three areas: COMMON, BSP,
+                    and DISTRO.
+                    For example, given a distribution layer (DISTRO), the
+                    layer must pass both the COMMON and DISTRO related tests.
+                    Furthermore, if your layer is a BSP layer, the layer must
+                    pass the COMMON and BSP set of tests.
+                </para>
+
+                <para>
+                    To execute the script, enter the following commands from
+                    your build directory:
+                    <literallayout class='monospaced'>
+     $ source oe-init-build-env
+     $ yocto-check-layer <replaceable>your_layer_directory</replaceable>
+                    </literallayout>
+                    Be sure to provide the actual directory for your layer
+                    as part of the command.
+                </para>
+
+                <para>
+                    Entering the command causes the script to determine the
+                    type of layer and then to execute a set of specific
+                    tests against the layer.
+                    The following list overviews the test:
+                    <itemizedlist>
+                        <listitem><para>
+                            <filename>common.test_readme</filename>:
+                            Tests if a <filename>README</filename> file
+                            exists in the layer and the file is not empty.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>common.test_parse</filename>:
+                            Tests to make sure that BitBake can parse the
+                            files without error (i.e.
+                            <filename>bitbake -p</filename>).
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>common.test_show_environment</filename>:
+                            Tests that the global or per-recipe environment
+                            is in order without errors (i.e.
+                            <filename>bitbake -e</filename>).
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>common.test_world</filename>:
+                            Verifies that <filename>bitbake world</filename> works.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>common.test_signatures</filename>:
+                            Tests to be sure that BSP and DISTRO layers do not
+                            come with recipes that change signatures.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>common.test_layerseries_compat</filename>:
+                            Verifies layer compatibility is set properly.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>bsp.test_bsp_defines_machines</filename>:
+                            Tests if a BSP layer has machine configurations.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>bsp.test_bsp_no_set_machine</filename>:
+                            Tests to ensure a BSP layer does not set the
+                            machine when the layer is added.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>bsp.test_machine_world</filename>:
+                            Verifies that <filename>bitbake world</filename>
+                            works regardless of which machine is selected.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>bsp.test_machine_signatures</filename>:
+                            Verifies that building for a particular machine
+                            affects only the signature of tasks specific to that
+                            machine.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>distro.test_distro_defines_distros</filename>:
+                            Tests if a DISTRO layer has distro configurations.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>distro.test_distro_no_set_distros</filename>:
+                            Tests to ensure a DISTRO layer does not set the
+                            distribution when the layer is added.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+        </section>
+
+        <section id='enabling-your-layer'>
+            <title>Enabling Your Layer</title>
+
+            <para>
+                Before the OpenEmbedded build system can use your new layer,
+                you need to enable it.
+                To enable your layer, simply add your layer's path to the
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BBLAYERS'>BBLAYERS</ulink></filename>
+                variable in your <filename>conf/bblayers.conf</filename> file,
+                which is found in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                The following example shows how to enable a layer named
+                <filename>meta-mylayer</filename>:
+                <literallayout class='monospaced'>
+     # POKY_BBLAYERS_CONF_VERSION is increased each time build/conf/bblayers.conf
+     # changes incompatibly
+     POKY_BBLAYERS_CONF_VERSION = "2"
+
+     BBPATH = "${TOPDIR}"
+     BBFILES ?= ""
+
+     BBLAYERS ?= " \
+       /home/<replaceable>user</replaceable>/poky/meta \
+       /home/<replaceable>user</replaceable>/poky/meta-poky \
+       /home/<replaceable>user</replaceable>/poky/meta-yocto-bsp \
+       /home/<replaceable>user</replaceable>/poky/meta-mylayer \
+       "
+                </literallayout>
+            </para>
+
+            <para>
+                BitBake parses each <filename>conf/layer.conf</filename> file
+                from the top down as specified in the
+                <filename>BBLAYERS</filename> variable
+                within the <filename>conf/bblayers.conf</filename> file.
+                During the processing of each
+                <filename>conf/layer.conf</filename> file, BitBake adds the
+                recipes, classes and configurations contained within the
+                particular layer to the source directory.
+            </para>
+        </section>
+
+        <section id='using-bbappend-files'>
+            <title>Using .bbappend Files in Your Layer</title>
+
+            <para>
+                A recipe that appends Metadata to another recipe is called a
+                BitBake append file.
+                A BitBake append file uses the <filename>.bbappend</filename>
+                file type suffix, while the corresponding recipe to which
+                Metadata is being appended uses the <filename>.bb</filename>
+                file type suffix.
+            </para>
+
+            <para>
+                You can use a <filename>.bbappend</filename> file in your
+                layer to make additions or changes to the content of another
+                layer's recipe without having to copy the other layer's
+                recipe into your layer.
+                Your <filename>.bbappend</filename> file resides in your layer,
+                while the main <filename>.bb</filename> recipe file to
+                which you are appending Metadata resides in a different layer.
+            </para>
+
+            <para>
+                Being able to append information to an existing recipe not only
+                avoids duplication, but also automatically applies recipe
+                changes from a different layer into your layer.
+                If you were copying recipes, you would have to manually merge
+                changes as they occur.
+            </para>
+
+            <para>
+                When you create an append file, you must use the same root
+                name as the corresponding recipe file.
+                For example, the append file
+                <filename>someapp_&DISTRO;.bbappend</filename> must apply to
+                <filename>someapp_&DISTRO;.bb</filename>.
+                This means the original recipe and append file names are
+                version number-specific.
+                If the corresponding recipe is renamed to update to a newer
+                version, you must also rename and possibly update
+                the corresponding <filename>.bbappend</filename> as well.
+                During the build process, BitBake displays an error on starting
+                if it detects a <filename>.bbappend</filename> file that does
+                not have a corresponding recipe with a matching name.
+                See the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BB_DANGLINGAPPENDS_WARNONLY'><filename>BB_DANGLINGAPPENDS_WARNONLY</filename></ulink>
+                variable for information on how to handle this error.
+            </para>
+
+            <para>
+                As an example, consider the main formfactor recipe and a
+                corresponding formfactor append file both from the
+                <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
+                Here is the main formfactor recipe, which is named
+                <filename>formfactor_0.0.bb</filename> and located in the
+                "meta" layer at
+                <filename>meta/recipes-bsp/formfactor</filename>:
+                <literallayout class='monospaced'>
+     SUMMARY = "Device formfactor information"
+     SECTION = "base"
+     LICENSE = "MIT"
+     LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
+     PR = "r45"
+
+     SRC_URI = "file://config file://machconfig"
+     S = "${WORKDIR}"
+
+     PACKAGE_ARCH = "${MACHINE_ARCH}"
+     INHIBIT_DEFAULT_DEPS = "1"
+
+     do_install() {
+	     # Install file only if it has contents
+             install -d ${D}${sysconfdir}/formfactor/
+             install -m 0644 ${S}/config ${D}${sysconfdir}/formfactor/
+	     if [ -s "${S}/machconfig" ]; then
+	             install -m 0644 ${S}/machconfig ${D}${sysconfdir}/formfactor/
+	     fi
+     }                </literallayout>
+                In the main recipe, note the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                variable, which tells the OpenEmbedded build system where to
+                find files during the build.
+            </para>
+
+            <para>
+                Following is the append file, which is named
+                <filename>formfactor_0.0.bbappend</filename> and is from the
+                Raspberry Pi BSP Layer named
+                <filename>meta-raspberrypi</filename>.
+                The file is in the layer at
+                <filename>recipes-bsp/formfactor</filename>:
+                <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+                </literallayout>
+            </para>
+
+            <para>
+                By default, the build system uses the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESPATH'><filename>FILESPATH</filename></ulink>
+                variable to locate files.
+                This append file extends the locations by setting the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                variable.
+                Setting this variable in the <filename>.bbappend</filename>
+                file is the most reliable and recommended method for adding
+                directories to the search path used by the build system
+                to find files.
+            </para>
+
+            <para>
+                The statement in this example extends the directories to
+                include
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-THISDIR'><filename>THISDIR</filename></ulink><filename>}/${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>,
+                which resolves to a directory named
+                <filename>formfactor</filename> in the same directory
+                in which the append file resides (i.e.
+                <filename>meta-raspberrypi/recipes-bsp/formfactor</filename>.
+                This implies that you must have the supporting directory
+                structure set up that will contain any files or patches you
+                will be including from the layer.
+            </para>
+
+            <para>
+                Using the immediate expansion assignment operator
+                <filename>:=</filename> is important because of the reference
+                to <filename>THISDIR</filename>.
+                The trailing colon character is important as it ensures that
+                items in the list remain colon-separated.
+                <note>
+                    <para>
+                        BitBake automatically defines the
+                        <filename>THISDIR</filename> variable.
+                        You should never set this variable yourself.
+                        Using "_prepend" as part of the
+                        <filename>FILESEXTRAPATHS</filename> ensures your path
+                        will be searched prior to other paths in the final
+                        list.
+                    </para>
+
+                    <para>
+                        Also, not all append files add extra files.
+                        Many append files simply exist to add build options
+                        (e.g. <filename>systemd</filename>).
+                        For these cases, your append file would not even
+                        use the <filename>FILESEXTRAPATHS</filename> statement.
+                    </para>
+                </note>
+            </para>
+        </section>
+
+        <section id='prioritizing-your-layer'>
+            <title>Prioritizing Your Layer</title>
+
+            <para>
+                Each layer is assigned a priority value.
+                Priority values control which layer takes precedence if there
+                are recipe files with the same name in multiple layers.
+                For these cases, the recipe file from the layer with a higher
+                priority number takes precedence.
+                Priority values also affect the order in which multiple
+                <filename>.bbappend</filename> files for the same recipe are
+                applied.
+                You can either specify the priority manually, or allow the
+                build system to calculate it based on the layer's dependencies.
+            </para>
+
+            <para>
+                To specify the layer's priority manually, use the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_PRIORITY'><filename>BBFILE_PRIORITY</filename></ulink>
+                variable and append the layer's root name:
+                <literallayout class='monospaced'>
+     BBFILE_PRIORITY_mylayer = "1"
+                </literallayout>
+            </para>
+
+            <note>
+                <para>It is possible for a recipe with a lower version number
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+                in a layer that has a higher priority to take precedence.</para>
+                <para>Also, the layer priority does not currently affect the
+                precedence order of <filename>.conf</filename>
+                or <filename>.bbclass</filename> files.
+                Future versions of BitBake might address this.</para>
+            </note>
+        </section>
+
+        <section id='managing-layers'>
+            <title>Managing Layers</title>
+
+            <para>
+                You can use the BitBake layer management tool
+                <filename>bitbake-layers</filename> to provide a view
+                into the structure of recipes across a multi-layer project.
+                Being able to generate output that reports on configured layers
+                with their paths and priorities and on
+                <filename>.bbappend</filename> files and their applicable
+                recipes can help to reveal potential problems.
+            </para>
+
+            <para>
+                For help on the BitBake layer management tool, use the
+                following command:
+                <literallayout class='monospaced'>
+     $ bitbake-layers --help
+     NOTE: Starting bitbake server...
+     usage: bitbake-layers [-d] [-q] [-F] [--color COLOR] [-h] &lt;subcommand&gt; ...
+
+     BitBake layers utility
+
+     optional arguments:
+       -d, --debug           Enable debug output
+       -q, --quiet           Print only errors
+       -F, --force           Force add without recipe parse verification
+       --color COLOR         Colorize output (where COLOR is auto, always, never)
+       -h, --help            show this help message and exit
+
+     subcommands:
+       &lt;subcommand&gt;
+         show-layers         show current configured layers.
+         show-overlayed      list overlayed recipes (where the same recipe exists
+                             in another layer)
+         show-recipes        list available recipes, showing the layer they are
+                             provided by
+         show-appends        list bbappend files and recipe files they apply to
+         show-cross-depends  Show dependencies between recipes that cross layer
+                             boundaries.
+         add-layer           Add one or more layers to bblayers.conf.
+         remove-layer        Remove one or more layers from bblayers.conf.
+         flatten             flatten layer configuration into a separate output
+                             directory.
+         layerindex-fetch    Fetches a layer from a layer index along with its
+                             dependent layers, and adds them to conf/bblayers.conf.
+         layerindex-show-depends
+                             Find layer dependencies from layer index.
+         create-layer        Create a basic layer
+
+     Use bitbake-layers &lt;subcommand&gt; --help to get help on a specific command
+                </literallayout>
+            </para>
+
+            <para>
+                The following list describes the available commands:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis><filename>help:</filename></emphasis>
+                        Displays general help or help on a specified command.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>show-layers:</filename></emphasis>
+                        Shows the current configured layers.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>show-overlayed:</filename></emphasis>
+                        Lists overlayed recipes.
+                        A recipe is overlayed when a recipe with the same name
+                        exists in another layer that has a higher layer
+                        priority.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>show-recipes:</filename></emphasis>
+                        Lists available recipes and the layers that provide them.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>show-appends:</filename></emphasis>
+                        Lists <filename>.bbappend</filename> files and the
+                        recipe files to which they apply.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>show-cross-depends:</filename></emphasis>
+                        Lists dependency relationships between recipes that
+                        cross layer boundaries.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>add-layer:</filename></emphasis>
+                        Adds a layer to <filename>bblayers.conf</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>remove-layer:</filename></emphasis>
+                        Removes a layer from <filename>bblayers.conf</filename>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>flatten:</filename></emphasis>
+                        Flattens the layer configuration into a separate output
+                        directory.
+                        Flattening your layer configuration builds a "flattened"
+                        directory that contains the contents of all layers,
+                        with any overlayed recipes removed and any
+                        <filename>.bbappend</filename> files appended to the
+                        corresponding recipes.
+                        You might have to perform some manual cleanup of the
+                        flattened layer as follows:
+                        <itemizedlist>
+                            <listitem><para>
+                                Non-recipe files (such as patches)
+                                are overwritten.
+                                The flatten command shows a warning for these
+                                files.
+                                </para></listitem>
+                            <listitem><para>
+                                Anything beyond the normal layer
+                                setup has been added to the
+                                <filename>layer.conf</filename> file.
+                                Only the lowest priority layer's
+                                <filename>layer.conf</filename> is used.
+                                </para></listitem>
+                            <listitem><para>
+                                Overridden and appended items from
+                                <filename>.bbappend</filename> files need to be
+                                cleaned up.
+                                The contents of each
+                                <filename>.bbappend</filename> end up in the
+                                flattened recipe.
+                                However, if there are appended or changed
+                                variable values, you need to tidy these up
+                                yourself.
+                                Consider the following example.
+                                Here, the <filename>bitbake-layers</filename>
+                                command adds the line
+                                <filename>#### bbappended ...</filename> so that
+                                you know where the following lines originate:
+                                <literallayout class='monospaced'>
+     ...
+     DESCRIPTION = "A useful utility"
+     ...
+     EXTRA_OECONF = "--enable-something"
+     ...
+
+     #### bbappended from meta-anotherlayer ####
+
+     DESCRIPTION = "Customized utility"
+     EXTRA_OECONF += "--enable-somethingelse"
+                                </literallayout>
+                                Ideally, you would tidy up these utilities as
+                                follows:
+                                <literallayout class='monospaced'>
+     ...
+     DESCRIPTION = "Customized utility"
+     ...
+     EXTRA_OECONF = "--enable-something --enable-somethingelse"
+     ...
+                                </literallayout>
+                                </para></listitem>
+                        </itemizedlist>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>layerindex-fetch</filename>:</emphasis>
+                        Fetches a layer from a layer index, along with its
+                        dependent layers, and adds the layers to the
+                        <filename>conf/bblayers.conf</filename> file.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>layerindex-show-depends</filename>:</emphasis>
+                        Finds layer dependencies from the layer index.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>create-layer</filename>:</emphasis>
+                        Creates a basic layer.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='creating-a-general-layer-using-the-bitbake-layers-script'>
+            <title>Creating a General Layer Using the <filename>bitbake-layers</filename> Script</title>
+
+            <para>
+                The <filename>bitbake-layers</filename> script with the
+                <filename>create-layer</filename> subcommand simplifies
+                creating a new general layer.
+                <note><title>Notes</title>
+                    <itemizedlist>
+                        <listitem><para>
+                            For information on BSP layers, see the
+                            "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-layers'>BSP Layers</ulink>"
+                            section in the Yocto Project Board Specific (BSP)
+                            Developer's Guide.
+                            </para></listitem>
+                        <listitem><para>
+                            In order to use a layer with the OpenEmbedded
+                            build system, you need to add the layer to your
+                            <filename>bblayers.conf</filename> configuration
+                            file.
+                            See the
+                            "<link linkend='adding-a-layer-using-the-bitbake-layers-script'>Adding a Layer Using the <filename>bitbake-layers</filename> Script</link>"
+                            section for more information.
+                            </para></listitem>
+                    </itemizedlist>
+                </note>
+                The default mode of the script's operation with this
+                subcommand is to create a layer with the following:
+                <itemizedlist>
+                    <listitem><para>A layer priority of 6.
+                        </para></listitem>
+                    <listitem><para>A <filename>conf</filename>
+                        subdirectory that contains a
+                        <filename>layer.conf</filename> file.
+                        </para></listitem>
+                    <listitem><para>
+                        A <filename>recipes-example</filename> subdirectory
+                        that contains a further subdirectory named
+                        <filename>example</filename>, which contains
+                        an <filename>example.bb</filename> recipe file.
+                        </para></listitem>
+                    <listitem><para>A <filename >COPYING.MIT</filename>,
+                        which is the license statement for the layer.
+                        The script assumes you want to use the MIT license,
+                        which is typical for most layers, for the contents of
+                        the layer itself.
+                        </para></listitem>
+                    <listitem><para>
+                        A <filename>README</filename> file, which is a file
+                        describing the contents of your new layer.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                In its simplest form, you can use the following command form
+                to create a layer.
+                The command creates a layer whose name corresponds to
+                <replaceable>your_layer_name</replaceable> in the current
+                directory:
+                <literallayout class='monospaced'>
+     $ bitbake-layers create-layer <replaceable>your_layer_name</replaceable>
+                </literallayout>
+                As an example, the following command creates a layer named
+                <filename>meta-scottrif</filename> in your home directory:
+                <literallayout class='monospaced'>
+     $ cd /usr/home
+     $ bitbake-layers create-layer meta-scottrif
+     NOTE: Starting bitbake server...
+     Add your new layer with 'bitbake-layers add-layer meta-scottrif'
+                </literallayout>
+            </para>
+
+            <para>
+                If you want to set the priority of the layer to other than the
+                default value of "6", you can either use the
+                <filename>&dash;&dash;priority</filename> option or you can
+                edit the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILE_PRIORITY'><filename>BBFILE_PRIORITY</filename></ulink>
+                value in the <filename>conf/layer.conf</filename> after the
+                script creates it.
+                Furthermore, if you want to give the example recipe file
+                some name other than the default, you can
+                use the
+                <filename>&dash;&dash;example-recipe-name</filename> option.
+            </para>
+
+            <para>
+                The easiest way to see how the
+                <filename>bitbake-layers create-layer</filename> command
+                works is to experiment with the script.
+                You can also read the usage information by entering the
+                following:
+                <literallayout class='monospaced'>
+     $ bitbake-layers create-layer --help
+     NOTE: Starting bitbake server...
+     usage: bitbake-layers create-layer [-h] [--priority PRIORITY]
+                                        [--example-recipe-name EXAMPLERECIPE]
+                                        layerdir
+
+     Create a basic layer
+
+     positional arguments:
+       layerdir              Layer directory to create
+
+     optional arguments:
+       -h, --help            show this help message and exit
+       --priority PRIORITY, -p PRIORITY
+                             Layer directory to create
+       --example-recipe-name EXAMPLERECIPE, -e EXAMPLERECIPE
+                             Filename of the example recipe
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='adding-a-layer-using-the-bitbake-layers-script'>
+            <title>Adding a Layer Using the <filename>bitbake-layers</filename> Script</title>
+
+            <para>
+                Once you create your general layer, you must add it to your
+                <filename>bblayers.conf</filename> file.
+                Adding the layer to this configuration file makes the
+                OpenEmbedded build system aware of your layer so that it can
+                search it for metadata.
+            </para>
+
+            <para>
+                Add your layer by using the
+                <filename>bitbake-layers add-layer</filename> command:
+                <literallayout class='monospaced'>
+     $ bitbake-layers add-layer <replaceable>your_layer_name</replaceable>
+                </literallayout>
+                Here is an example that adds a layer named
+                <filename>meta-scottrif</filename> to the configuration file.
+                Following the command that adds the layer is another
+                <filename>bitbake-layers</filename> command that shows the
+                layers that are in your <filename>bblayers.conf</filename>
+                file:
+                <literallayout class='monospaced'>
+     $ bitbake-layers add-layer meta-scottrif
+     NOTE: Starting bitbake server...
+     Parsing recipes: 100% |##########################################################| Time: 0:00:49
+     Parsing of 1441 .bb files complete (0 cached, 1441 parsed). 2055 targets, 56 skipped, 0 masked, 0 errors.
+     $ bitbake-layers show-layers
+     NOTE: Starting bitbake server...
+     layer                 path                                      priority
+     ==========================================================================
+     meta                  /home/scottrif/poky/meta                  5
+     meta-poky             /home/scottrif/poky/meta-poky             5
+     meta-yocto-bsp        /home/scottrif/poky/meta-yocto-bsp        5
+     workspace             /home/scottrif/poky/build/workspace       99
+     meta-scottrif         /home/scottrif/poky/build/meta-scottrif   6
+                </literallayout>
+                Adding the layer to this file enables the build system to
+                locate the layer during the build.
+                <note>
+                    During a build, the OpenEmbedded build system looks in
+                    the layers from the top of the list down to the bottom
+                    in that order.
+                </note>
+                </para>
+        </section>
+    </section>
+
+    <section id='usingpoky-extend-customimage'>
+        <title>Customizing Images</title>
+
+        <para>
+            You can customize images to satisfy particular requirements.
+            This section describes several methods and provides guidelines for each.
+        </para>
+
+        <section id='usingpoky-extend-customimage-localconf'>
+            <title>Customizing Images Using <filename>local.conf</filename></title>
+
+            <para>
+                Probably the easiest way to customize an image is to add a
+                package by way of the <filename>local.conf</filename>
+                configuration file.
+                Because it is limited to local use, this method generally only
+                allows you to add packages and is not as flexible as creating
+                your own customized image.
+                When you add packages using local variables this way, you need
+                to realize that these variable changes are in effect for every
+                build and consequently affect all images, which might not
+                be what you require.
+            </para>
+
+            <para>
+                To add a package to your image using the local configuration
+                file, use the
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'>IMAGE_INSTALL</ulink></filename>
+                variable with the <filename>_append</filename> operator:
+                <literallayout class='monospaced'>
+     IMAGE_INSTALL_append = " strace"
+                </literallayout>
+                Use of the syntax is important - specifically, the space between
+                the quote and the package name, which is
+                <filename>strace</filename> in this example.
+                This space is required since the <filename>_append</filename>
+                operator does not add the space.
+            </para>
+
+            <para>
+                Furthermore, you must use <filename>_append</filename> instead
+                of the <filename>+=</filename> operator if you want to avoid
+                ordering issues.
+                The reason for this is because doing so unconditionally appends
+                to the variable and avoids ordering problems due to the
+                variable being set in image recipes and
+                <filename>.bbclass</filename> files with operators like
+                <filename>?=</filename>.
+                Using <filename>_append</filename> ensures the operation takes
+                affect.
+            </para>
+
+            <para>
+                As shown in its simplest use,
+                <filename>IMAGE_INSTALL_append</filename> affects all images.
+                It is possible to extend the syntax so that the variable
+                applies to a specific image only.
+                Here is an example:
+                <literallayout class='monospaced'>
+     IMAGE_INSTALL_append_pn-core-image-minimal = " strace"
+                </literallayout>
+                This example adds <filename>strace</filename> to the
+                <filename>core-image-minimal</filename> image only.
+            </para>
+
+            <para>
+                You can add packages using a similar approach through the
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-CORE_IMAGE_EXTRA_INSTALL'>CORE_IMAGE_EXTRA_INSTALL</ulink></filename>
+                variable.
+                If you use this variable, only
+                <filename>core-image-*</filename> images are affected.
+            </para>
+        </section>
+
+        <section id='usingpoky-extend-customimage-imagefeatures'>
+            <title>Customizing Images Using Custom <filename>IMAGE_FEATURES</filename> and
+                <filename>EXTRA_IMAGE_FEATURES</filename></title>
+
+            <para>
+                Another method for customizing your image is to enable or
+                disable high-level image features by using the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></ulink>
+                and <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_IMAGE_FEATURES'><filename>EXTRA_IMAGE_FEATURES</filename></ulink>
+                variables.
+                Although the functions for both variables are nearly equivalent,
+                best practices dictate using <filename>IMAGE_FEATURES</filename>
+                from within a recipe and using
+                <filename>EXTRA_IMAGE_FEATURES</filename> from within
+                your <filename>local.conf</filename> file, which is found in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+            </para>
+
+            <para>
+                To understand how these features work, the best reference is
+                <filename>meta/classes/core-image.bbclass</filename>.
+                This class lists out the available
+                <filename>IMAGE_FEATURES</filename> of which most map to
+                package groups while some, such as
+                <filename>debug-tweaks</filename> and
+                <filename>read-only-rootfs</filename>, resolve as general
+                configuration settings.
+            </para>
+
+            <para>
+                In summary, the file looks at the contents of the
+                <filename>IMAGE_FEATURES</filename> variable and then maps
+                or configures the feature accordingly.
+                Based on this information, the build system automatically
+                adds the appropriate packages or configurations to the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'><filename>IMAGE_INSTALL</filename></ulink>
+                variable.
+                Effectively, you are enabling extra features by extending the
+                class or creating a custom class for use with specialized image
+                <filename>.bb</filename> files.
+            </para>
+
+            <para>
+                Use the <filename>EXTRA_IMAGE_FEATURES</filename> variable
+                from within your local configuration file.
+                Using a separate area from which to enable features with
+                this variable helps you avoid overwriting the features in the
+                image recipe that are enabled with
+                <filename>IMAGE_FEATURES</filename>.
+                The value of <filename>EXTRA_IMAGE_FEATURES</filename> is added
+                to <filename>IMAGE_FEATURES</filename> within
+                <filename>meta/conf/bitbake.conf</filename>.
+            </para>
+
+            <para>
+                To illustrate how you can use these variables to modify your
+                image, consider an example that selects the SSH server.
+                The Yocto Project ships with two SSH servers you can use
+                with your images: Dropbear and OpenSSH.
+                Dropbear is a minimal SSH server appropriate for
+                resource-constrained environments, while OpenSSH is a
+                well-known standard SSH server implementation.
+                By default, the <filename>core-image-sato</filename> image
+                is configured to use Dropbear.
+                The <filename>core-image-full-cmdline</filename> and
+                <filename>core-image-lsb</filename> images both
+                include OpenSSH.
+                The <filename>core-image-minimal</filename> image does not
+                contain an SSH server.
+            </para>
+
+            <para>
+                You can customize your image and change these defaults.
+                Edit the <filename>IMAGE_FEATURES</filename> variable
+                in your recipe or use the
+                <filename>EXTRA_IMAGE_FEATURES</filename> in your
+                <filename>local.conf</filename> file so that it configures the
+                image you are working with to include
+                <filename>ssh-server-dropbear</filename> or
+                <filename>ssh-server-openssh</filename>.
+            </para>
+
+            <note>
+                See the
+                "<ulink url='&YOCTO_DOCS_REF_URL;#ref-images'>Images</ulink>"
+                section in the Yocto Project Reference Manual for a complete
+                list of image features that ship with the Yocto Project.
+            </note>
+        </section>
+
+        <section id='usingpoky-extend-customimage-custombb'>
+            <title>Customizing Images Using Custom .bb Files</title>
+
+            <para>
+                You can also customize an image by creating a custom recipe
+                that defines additional software as part of the image.
+                The following example shows the form for the two lines you need:
+                <literallayout class='monospaced'>
+     IMAGE_INSTALL = "packagegroup-core-x11-base package1 package2"
+
+     inherit core-image
+                </literallayout>
+            </para>
+
+            <para>
+                Defining the software using a custom recipe gives you total
+                control over the contents of the image.
+                It is important to use the correct names of packages in the
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'>IMAGE_INSTALL</ulink></filename>
+                variable.
+                You must use the OpenEmbedded notation and not the Debian notation for the names
+                (e.g. <filename>glibc-dev</filename> instead of <filename>libc6-dev</filename>).
+            </para>
+
+            <para>
+                The other method for creating a custom image is to base it on an existing image.
+                For example, if you want to create an image based on <filename>core-image-sato</filename>
+                but add the additional package <filename>strace</filename> to the image,
+                copy the <filename>meta/recipes-sato/images/core-image-sato.bb</filename> to a
+                new <filename>.bb</filename> and add the following line to the end of the copy:
+                <literallayout class='monospaced'>
+     IMAGE_INSTALL += "strace"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='usingpoky-extend-customimage-customtasks'>
+            <title>Customizing Images Using Custom Package Groups</title>
+
+            <para>
+                For complex custom images, the best approach for customizing
+                an image is to create a custom package group recipe that is
+                used to build the image or images.
+                A good example of a package group recipe is
+                <filename>meta/recipes-core/packagegroups/packagegroup-base.bb</filename>.
+            </para>
+
+            <para>
+                If you examine that recipe, you see that the
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'>PACKAGES</ulink></filename>
+                variable lists the package group packages to produce.
+                The <filename>inherit packagegroup</filename> statement
+                sets appropriate default values and automatically adds
+                <filename>-dev</filename>, <filename>-dbg</filename>, and
+                <filename>-ptest</filename> complementary packages for each
+                package specified in the <filename>PACKAGES</filename>
+                statement.
+                <note>
+                    The <filename>inherit packagegroup</filename> line should be
+                    located near the top of the recipe, certainly before
+                    the <filename>PACKAGES</filename> statement.
+                </note>
+            </para>
+
+            <para>
+                For each package you specify in <filename>PACKAGES</filename>,
+                you can use
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'>RDEPENDS</ulink></filename>
+                and
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'>RRECOMMENDS</ulink></filename>
+                entries to provide a list of packages the parent task package
+                should contain.
+                You can see examples of these further down in the
+                <filename>packagegroup-base.bb</filename> recipe.
+            </para>
+
+            <para>
+                Here is a short, fabricated example showing the same basic
+                pieces for a hypothetical packagegroup defined in
+                <filename>packagegroup-custom.bb</filename>, where the
+                variable <filename>PN</filename> is the standard way to
+                abbreviate the reference to the full packagegroup name
+                <filename>packagegroup-custom</filename>:
+                <literallayout class='monospaced'>
+     DESCRIPTION = "My Custom Package Groups"
+
+     inherit packagegroup
+
+     PACKAGES = "\
+         ${PN}-apps \
+         ${PN}-tools \
+         "
+
+     RDEPENDS_${PN}-apps = "\
+         dropbear \
+         portmap \
+         psplash"
+
+     RDEPENDS_${PN}-tools = "\
+         oprofile \
+         oprofileui-server \
+         lttng-tools"
+
+     RRECOMMENDS_${PN}-tools = "\
+         kernel-module-oprofile"
+                </literallayout>
+            </para>
+
+            <para>
+                In the previous example, two package group packages are created with their dependencies and their
+                recommended package dependencies listed: <filename>packagegroup-custom-apps</filename>, and
+                <filename>packagegroup-custom-tools</filename>.
+                To build an image using these package group packages, you need to add
+                <filename>packagegroup-custom-apps</filename> and/or
+                <filename>packagegroup-custom-tools</filename> to
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'>IMAGE_INSTALL</ulink></filename>.
+                For other forms of image dependencies see the other areas of this section.
+            </para>
+        </section>
+
+        <section id='usingpoky-extend-customimage-image-name'>
+            <title>Customizing an Image Hostname</title>
+
+            <para>
+                By default, the configured hostname (i.e.
+                <filename>/etc/hostname</filename>) in an image is the
+                same as the machine name.
+                For example, if
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                equals "qemux86", the configured hostname written to
+                <filename>/etc/hostname</filename> is "qemux86".
+            </para>
+
+            <para>
+                You can customize this name by altering the value of the
+                "hostname" variable in the
+                <filename>base-files</filename> recipe using either
+                an append file or a configuration file.
+                Use the following in an append file:
+                <literallayout class='monospaced'>
+     hostname="myhostname"
+                </literallayout>
+                Use the following in a configuration file:
+                <literallayout class='monospaced'>
+     hostname_pn-base-files = "myhostname"
+                </literallayout>
+            </para>
+
+            <para>
+                Changing the default value of the variable "hostname" can be
+                useful in certain situations.
+                For example, suppose you need to do extensive testing on an
+                image and you would like to easily identify the image
+                under test from existing images with typical default
+                hostnames.
+                In this situation, you could change the default hostname to
+                "testme", which results in all the images using the name
+                "testme".
+                Once testing is complete and you do not need to rebuild the
+                image for test any longer, you can easily reset the default
+                hostname.
+            </para>
+
+            <para>
+                Another point of interest is that if you unset the variable,
+                the image will have no default hostname in the filesystem.
+                Here is an example that unsets the variable in a
+                configuration file:
+                <literallayout class='monospaced'>
+     hostname_pn-base-files = ""
+                </literallayout>
+                Having no default hostname in the filesystem is suitable for
+                environments that use dynamic hostnames such as virtual
+                machines.
+            </para>
+        </section>
+    </section>
+
+    <section id='new-recipe-writing-a-new-recipe'>
+        <title>Writing a New Recipe</title>
+
+        <para>
+            Recipes (<filename>.bb</filename> files) are fundamental components
+            in the Yocto Project environment.
+            Each software component built by the OpenEmbedded build system
+            requires a recipe to define the component.
+            This section describes how to create, write, and test a new
+            recipe.
+            <note>
+                For information on variables that are useful for recipes and
+                for information about recipe naming issues, see the
+                "<ulink url='&YOCTO_DOCS_REF_URL;#ref-varlocality-recipe-required'>Required</ulink>"
+                section of the Yocto Project Reference Manual.
+            </note>
+        </para>
+
+        <section id='new-recipe-overview'>
+            <title>Overview</title>
+
+            <para>
+                The following figure shows the basic process for creating a
+                new recipe.
+                The remainder of the section provides details for the steps.
+                <imagedata fileref="figures/recipe-workflow.png" width="6in" depth="7in" align="center" scalefit="1" />
+            </para>
+        </section>
+
+        <section id='new-recipe-locate-or-automatically-create-a-base-recipe'>
+            <title>Locate or Automatically Create a Base Recipe</title>
+
+            <para>
+                You can always write a recipe from scratch.
+                However, three choices exist that can help you quickly get a
+                start on a new recipe:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis><filename>devtool add</filename>:</emphasis>
+                        A command that assists in creating a recipe and
+                        an environment conducive to development.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>recipetool create</filename>:</emphasis>
+                        A command provided by the Yocto Project that automates
+                        creation of a base recipe based on the source
+                        files.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Existing Recipes:</emphasis>
+                        Location and modification of an existing recipe that is
+                        similar in function to the recipe you need.
+                        </para></listitem>
+                </itemizedlist>
+                <note>
+                    For information on recipe syntax, see the
+                    "<link linkend='recipe-syntax'>Recipe Syntax</link>"
+                    section.
+                </note>
+            </para>
+
+            <section id='new-recipe-creating-the-base-recipe-using-devtool'>
+                <title>Creating the Base Recipe Using <filename>devtool add</filename></title>
+
+                <para>
+                    The <filename>devtool add</filename> command uses the same
+                    logic for auto-creating the recipe as
+                    <filename>recipetool create</filename>, which is listed
+                    below.
+                    Additionally, however, <filename>devtool add</filename>
+                    sets up an environment that makes it easy for you to
+                    patch the source and to make changes to the recipe as
+                    is often necessary when adding a recipe to build a new
+                    piece of software to be included in a build.
+                </para>
+
+                <para>
+                    You can find a complete description of the
+                    <filename>devtool add</filename> command in the
+                    "<ulink url='&YOCTO_DOCS_SDK_URL;#sdk-a-closer-look-at-devtool-add'>A Closer Look at <filename>devtool</filename> add</ulink>"
+                    section in the Yocto Project Application Development
+                    and the Extensible Software Development Kit (eSDK) manual.
+                </para>
+            </section>
+
+            <section id='new-recipe-creating-the-base-recipe-using-recipetool'>
+                <title>Creating the Base Recipe Using <filename>recipetool create</filename></title>
+
+                <para>
+                    <filename>recipetool create</filename> automates creation
+                    of a base recipe given a set of source code files.
+                    As long as you can extract or point to the source files,
+                    the tool will construct a recipe and automatically
+                    configure all pre-build information into the recipe.
+                    For example, suppose you have an application that builds
+                    using Autotools.
+                    Creating the base recipe using
+                    <filename>recipetool</filename> results in a recipe
+                    that has the pre-build dependencies, license requirements,
+                    and checksums configured.
+                </para>
+
+                <para>
+                    To run the tool, you just need to be in your
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                    and have sourced the build environment setup script
+                    (i.e.
+                    <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>oe-init-build-env</filename></ulink>).
+                    To get help on the tool, use the following command:
+                    <literallayout class='monospaced'>
+     $ recipetool -h
+     NOTE: Starting bitbake server...
+     usage: recipetool [-d] [-q] [--color COLOR] [-h] &lt;subcommand&gt; ...
+
+     OpenEmbedded recipe tool
+
+     options:
+       -d, --debug     Enable debug output
+       -q, --quiet     Print only errors
+       --color COLOR   Colorize output (where COLOR is auto, always, never)
+       -h, --help      show this help message and exit
+
+     subcommands:
+       create          Create a new recipe
+       newappend       Create a bbappend for the specified target in the specified
+                       layer
+       setvar          Set a variable within a recipe
+       appendfile      Create/update a bbappend to replace a target file
+       appendsrcfiles  Create/update a bbappend to add or replace source files
+       appendsrcfile   Create/update a bbappend to add or replace a source file
+     Use recipetool &lt;subcommand&gt; --help to get help on a specific command
+                    </literallayout>
+                </para>
+
+                <para>
+                    Running
+                    <filename>recipetool create -o</filename>&nbsp;<replaceable>OUTFILE</replaceable>
+                    creates the base recipe and locates it properly in the
+                    layer that contains your source files.
+                    Following are some syntax examples:
+                </para>
+
+                <para>
+                    Use this syntax to generate a recipe based on
+                    <replaceable>source</replaceable>.
+                    Once generated, the recipe resides in the existing source
+                    code layer:
+                    <literallayout class='monospaced'>
+     recipetool create -o <replaceable>OUTFILE</replaceable>&nbsp;<replaceable>source</replaceable>
+                    </literallayout>
+                    Use this syntax to generate a recipe using code that you
+                    extract from <replaceable>source</replaceable>.
+                    The extracted code is placed in its own layer defined
+                    by <replaceable>EXTERNALSRC</replaceable>.
+                    <literallayout class='monospaced'>
+     recipetool create -o <replaceable>OUTFILE</replaceable> -x <replaceable>EXTERNALSRC</replaceable> <replaceable>source</replaceable>
+                    </literallayout>
+                    Use this syntax to generate a recipe based on
+                    <replaceable>source</replaceable>.
+                    The options direct <filename>recipetool</filename> to
+                    generate debugging information.
+                    Once generated, the recipe resides in the existing source
+                    code layer:
+                    <literallayout class='monospaced'>
+     recipetool create -d -o <replaceable>OUTFILE</replaceable> <replaceable>source</replaceable>
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='new-recipe-locating-and-using-a-similar-recipe'>
+                <title>Locating and Using a Similar Recipe</title>
+
+                <para>
+                    Before writing a recipe from scratch, it is often useful to
+                    discover whether someone else has already written one that
+                    meets (or comes close to meeting) your needs.
+                    The Yocto Project and OpenEmbedded communities maintain many
+                    recipes that might be candidates for what you are doing.
+                    You can find a good central index of these recipes in the
+                    <ulink url='http://layers.openembedded.org'>OpenEmbedded Layer Index</ulink>.
+                </para>
+
+                <para>
+                    Working from an existing recipe or a skeleton recipe is the
+                    best way to get started.
+                    Here are some points on both methods:
+                    <itemizedlist>
+                        <listitem><para><emphasis>Locate and modify a recipe that
+                            is close to what you want to do:</emphasis>
+                            This method works when you are familiar with the
+                            current recipe space.
+                            The method does not work so well for those new to
+                            the Yocto Project or writing recipes.</para>
+                            <para>Some risks associated with this method are
+                            using a recipe that has areas totally unrelated to
+                            what you are trying to accomplish with your recipe,
+                            not recognizing areas of the recipe that you might
+                            have to add from scratch, and so forth.
+                            All these risks stem from unfamiliarity with the
+                            existing recipe space.</para></listitem>
+                        <listitem><para><emphasis>Use and modify the following
+                            skeleton recipe:</emphasis>
+                            If for some reason you do not want to use
+                            <filename>recipetool</filename> and you cannot
+                            find an existing recipe that is close to meeting
+                            your needs, you can use the following structure to
+                            provide the fundamental areas of a new recipe.
+                            <literallayout class='monospaced'>
+     DESCRIPTION = ""
+     HOMEPAGE = ""
+     LICENSE = ""
+     SECTION = ""
+     DEPENDS = ""
+     LIC_FILES_CHKSUM = ""
+
+     SRC_URI = ""
+                            </literallayout>
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+        </section>
+
+        <section id='new-recipe-storing-and-naming-the-recipe'>
+            <title>Storing and Naming the Recipe</title>
+
+            <para>
+                Once you have your base recipe, you should put it in your
+                own layer and name it appropriately.
+                Locating it correctly ensures that the OpenEmbedded build
+                system can find it when you use BitBake to process the
+                recipe.
+            </para>
+
+            <itemizedlist>
+                <listitem><para><emphasis>Storing Your Recipe:</emphasis>
+                    The OpenEmbedded build system locates your recipe
+                    through the layer's <filename>conf/layer.conf</filename>
+                    file and the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-BBFILES'><filename>BBFILES</filename></ulink>
+                    variable.
+                    This variable sets up a path from which the build system can
+                    locate recipes.
+                    Here is the typical use:
+                    <literallayout class='monospaced'>
+     BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
+                 ${LAYERDIR}/recipes-*/*/*.bbappend"
+                    </literallayout>
+                    Consequently, you need to be sure you locate your new recipe
+                    inside your layer such that it can be found.</para>
+                    <para>You can find more information on how layers are
+                    structured in the
+                    "<link linkend='understanding-and-creating-layers'>Understanding and Creating Layers</link>"
+                    section.</para></listitem>
+                <listitem><para><emphasis>Naming Your Recipe:</emphasis>
+                    When you name your recipe, you need to follow this naming
+                    convention:
+                    <literallayout class='monospaced'>
+     <replaceable>basename</replaceable>_<replaceable>version</replaceable>.bb
+                    </literallayout>
+                    Use lower-cased characters and do not include the reserved
+                    suffixes <filename>-native</filename>,
+                    <filename>-cross</filename>, <filename>-initial</filename>,
+                    or <filename>-dev</filename> casually (i.e. do not use them
+                    as part of your recipe name unless the string applies).
+                    Here are some examples:
+                    <literallayout class='monospaced'>
+     cups_1.7.0.bb
+     gawk_4.0.2.bb
+     irssi_0.8.16-rc1.bb
+                    </literallayout></para></listitem>
+            </itemizedlist>
+        </section>
+
+        <section id='new-recipe-running-a-build-on-the-recipe'>
+            <title>Running a Build on the Recipe</title>
+
+            <para>
+                Creating a new recipe is usually an iterative process that
+                requires using BitBake to process the recipe multiple times in
+                order to progressively discover and add information to the
+                recipe file.
+            </para>
+
+            <para>
+                Assuming you have sourced the build environment setup script (i.e.
+                <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>&OE_INIT_FILE;</filename></ulink>)
+                and you are in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>,
+                use BitBake to process your recipe.
+                All you need to provide is the
+                <filename><replaceable>basename</replaceable></filename> of the recipe as described
+                in the previous section:
+                <literallayout class='monospaced'>
+     $ bitbake <replaceable>basename</replaceable>
+                </literallayout>
+
+            </para>
+
+            <para>
+                During the build, the OpenEmbedded build system creates a
+                temporary work directory for each recipe
+                (<filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink><filename>}</filename>)
+                where it keeps extracted source files, log files, intermediate
+                compilation and packaging files, and so forth.
+            </para>
+
+            <para>
+                The path to the per-recipe temporary work directory depends
+                on the context in which it is being built.
+                The quickest way to find this path is to have BitBake return it
+                by running the following:
+                <literallayout class='monospaced'>
+     $ bitbake -e <replaceable>basename</replaceable> | grep ^WORKDIR=
+                </literallayout>
+                As an example, assume a Source Directory top-level folder named
+                <filename>poky</filename>, a default Build Directory at
+                <filename>poky/build</filename>, and a
+                <filename>qemux86-poky-linux</filename> machine target system.
+                Furthermore, suppose your recipe is named
+                <filename>foo_1.3.0.bb</filename>.
+                In this case, the work directory the build system uses to
+                build the package would be as follows:
+                <literallayout class='monospaced'>
+     poky/build/tmp/work/qemux86-poky-linux/foo/1.3.0-r0
+                </literallayout>
+                Inside this directory you can find sub-directories such as
+                <filename>image</filename>, <filename>packages-split</filename>,
+                and <filename>temp</filename>.
+                After the build, you can examine these to determine how well
+                the build went.
+                <note>
+                    You can find log files for each task in the recipe's
+                    <filename>temp</filename> directory (e.g.
+                    <filename>poky/build/tmp/work/qemux86-poky-linux/foo/1.3.0-r0/temp</filename>).
+                    Log files are named <filename>log.<replaceable>taskname</replaceable></filename>
+                    (e.g. <filename>log.do_configure</filename>,
+                    <filename>log.do_fetch</filename>, and
+                    <filename>log.do_compile</filename>).
+                </note>
+            </para>
+
+            <para>
+                You can find more information about the build process in
+                "<ulink url='&YOCTO_DOCS_OM_URL;#overview-development-environment'>The Yocto Project Development Environment</ulink>"
+                chapter of the Yocto Project Overview and Concepts Manual.
+            </para>
+        </section>
+
+        <section id='new-recipe-fetching-code'>
+            <title>Fetching Code</title>
+
+            <para>
+                The first thing your recipe must do is specify how to fetch
+                the source files.
+                Fetching is controlled mainly through the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                variable.
+                Your recipe must have a <filename>SRC_URI</filename> variable
+                that points to where the source is located.
+                For a graphical representation of source locations, see the
+                "<ulink url='&YOCTO_DOCS_OM_URL;#sources-dev-environment'>Sources</ulink>"
+                section in the Yocto Project Overview and Concepts Manual.
+            </para>
+
+            <para>
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-fetch'><filename>do_fetch</filename></ulink>
+                task uses the prefix of each entry in the
+                <filename>SRC_URI</filename> variable value to determine which
+                <ulink url='&YOCTO_DOCS_BB_URL;#bb-fetchers'>fetcher</ulink>
+                to use to get your source files.
+                It is the <filename>SRC_URI</filename> variable that triggers
+                the fetcher.
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-patch'><filename>do_patch</filename></ulink>
+                task uses the variable after source is fetched to apply
+                patches.
+                The OpenEmbedded build system uses
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESOVERRIDES'><filename>FILESOVERRIDES</filename></ulink>
+                for scanning directory locations for local files in
+                <filename>SRC_URI</filename>.
+            </para>
+
+            <para>
+                The <filename>SRC_URI</filename> variable in your recipe must
+                define each unique location for your source files.
+                It is good practice to not hard-code version numbers in a URL used
+                in <filename>SRC_URI</filename>.
+                Rather than hard-code these values, use
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink><filename>}</filename>,
+                which causes the fetch process to use the version specified in
+                the recipe filename.
+                Specifying the version in this manner means that upgrading the
+                recipe to a future version is as simple as renaming the recipe
+                to match the new version.
+            </para>
+
+            <para>
+                Here is a simple example from the
+                <filename>meta/recipes-devtools/strace/strace_5.5.bb</filename>
+                recipe where the source comes from a single tarball.
+                Notice the use of the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+                variable:
+                <literallayout class='monospaced'>
+     SRC_URI = "https://strace.io/files/${PV}/strace-${PV}.tar.xz \
+                </literallayout>
+            </para>
+
+            <para>
+                Files mentioned in <filename>SRC_URI</filename> whose names end
+                in a typical archive extension (e.g. <filename>.tar</filename>,
+                <filename>.tar.gz</filename>, <filename>.tar.bz2</filename>,
+                <filename>.zip</filename>, and so forth), are automatically
+                extracted during the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-unpack'><filename>do_unpack</filename></ulink>
+                task.
+                For another example that specifies these types of files, see
+                the
+                "<link linkend='new-recipe-autotooled-package'>Autotooled Package</link>"
+                section.
+            </para>
+
+            <para>
+                Another way of specifying source is from an SCM.
+                For Git repositories, you must specify
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCREV'><filename>SRCREV</filename></ulink>
+                and you should specify
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+                to include the revision with
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCPV'><filename>SRCPV</filename></ulink>.
+                Here is an example from the recipe
+                <filename>meta/recipes-kernel/blktrace/blktrace_git.bb</filename>:
+                <literallayout class='monospaced'>
+     SRCREV = "d6918c8832793b4205ed3bfede78c2f915c23385"
+
+     PR = "r6"
+     PV = "1.0.5+git${SRCPV}"
+
+     SRC_URI = "git://git.kernel.dk/blktrace.git \
+                file://ldflags.patch"
+                </literallayout>
+            </para>
+
+            <para>
+                If your <filename>SRC_URI</filename> statement includes
+                URLs pointing to individual files fetched from a remote server
+                other than a version control system, BitBake attempts to
+                verify the files against checksums defined in your recipe to
+                ensure they have not been tampered with or otherwise modified
+                since the recipe was written.
+                Two checksums are used:
+                <filename>SRC_URI[md5sum]</filename> and
+                <filename>SRC_URI[sha256sum]</filename>.
+            </para>
+
+            <para>
+                If your <filename>SRC_URI</filename> variable points to
+                more than a single URL (excluding SCM URLs), you need to
+                provide the <filename>md5</filename> and
+                <filename>sha256</filename> checksums for each URL.
+                For these cases, you provide a name for each URL as part of
+                the <filename>SRC_URI</filename> and then reference that name
+                in the subsequent checksum statements.
+                Here is an example combining lines from the files
+                <filename>git.inc</filename> and
+                <filename>git_2.24.1.bb</filename>:
+                <literallayout class='monospaced'>
+     SRC_URI = "${KERNELORG_MIRROR}/software/scm/git/git-${PV}.tar.gz;name=tarball \
+                ${KERNELORG_MIRROR}/software/scm/git/git-manpages-${PV}.tar.gz;name=manpages"
+
+     SRC_URI[tarball.md5sum] = "166bde96adbbc11c8843d4f8f4f9811b"
+     SRC_URI[tarball.sha256sum] = "ad5334956301c86841eb1e5b1bb20884a6bad89a10a6762c958220c7cf64da02"
+     SRC_URI[manpages.md5sum] = "31c2272a8979022497ba3d4202df145d"
+     SRC_URI[manpages.sha256sum] = "9a7ae3a093bea39770eb96ca3e5b40bff7af0b9f6123f089d7821d0e5b8e1230"
+                </literallayout>
+            </para>
+
+            <para>
+                Proper values for <filename>md5</filename> and
+                <filename>sha256</filename> checksums might be available
+                with other signatures on the download page for the upstream
+                source (e.g. <filename>md5</filename>,
+                <filename>sha1</filename>, <filename>sha256</filename>,
+                <filename>GPG</filename>, and so forth).
+                Because the OpenEmbedded build system only deals with
+                <filename>sha256sum</filename> and <filename>md5sum</filename>,
+                you should verify all the signatures you find by hand.
+            </para>
+
+            <para>
+                If no <filename>SRC_URI</filename> checksums are specified
+                when you attempt to build the recipe, or you provide an
+                incorrect checksum, the build will produce an error for each
+                missing or incorrect checksum.
+                As part of the error message, the build system provides
+                the checksum string corresponding to the fetched file.
+                Once you have the correct checksums, you can copy and paste
+                them into your recipe and then run the build again to continue.
+                <note>
+                    As mentioned, if the upstream source provides signatures
+                    for verifying the downloaded source code, you should
+                    verify those manually before setting the checksum values
+                    in the recipe and continuing with the build.
+                </note>
+            </para>
+
+            <para>
+                This final example is a bit more complicated and is from the
+                <filename>meta/recipes-sato/rxvt-unicode/rxvt-unicode_9.20.bb</filename>
+                recipe.
+                The example's <filename>SRC_URI</filename> statement identifies
+                multiple files as the source files for the recipe: a tarball, a
+                patch file, a desktop file, and an icon.
+                <literallayout class='monospaced'>
+     SRC_URI = "http://dist.schmorp.de/rxvt-unicode/Attic/rxvt-unicode-${PV}.tar.bz2 \
+                file://xwc.patch \
+                file://rxvt.desktop \
+                file://rxvt.png"
+                </literallayout>
+            </para>
+
+            <para>
+                When you specify local files using the
+                <filename>file://</filename> URI protocol, the build system
+                fetches files from the local machine.
+                The path is relative to the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESPATH'><filename>FILESPATH</filename></ulink>
+                variable and searches specific directories in a certain order:
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BP'><filename>BP</filename></ulink><filename>}</filename>,
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BPN'><filename>BPN</filename></ulink><filename>}</filename>,
+                and <filename>files</filename>.
+                The directories are assumed to be subdirectories of the
+                directory in which the recipe or append file resides.
+                For another example that specifies these types of files, see the
+                "<link linkend='new-recipe-single-c-file-package-hello-world'>Single .c File Package (Hello World!)</link>"
+                section.
+            </para>
+
+            <para>
+                The previous example also specifies a patch file.
+                Patch files are files whose names usually end in
+                <filename>.patch</filename> or <filename>.diff</filename> but
+                can end with compressed suffixes such as
+                <filename>diff.gz</filename> and
+                <filename>patch.bz2</filename>, for example.
+                The build system automatically applies patches as described
+                in the
+                "<link linkend='new-recipe-patching-code'>Patching Code</link>" section.
+            </para>
+        </section>
+
+        <section id='new-recipe-unpacking-code'>
+            <title>Unpacking Code</title>
+
+            <para>
+                During the build, the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-unpack'><filename>do_unpack</filename></ulink>
+                task unpacks the source with
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink><filename>}</filename>
+                pointing to where it is unpacked.
+            </para>
+
+            <para>
+                If you are fetching your source files from an upstream source
+                archived tarball and the tarball's internal structure matches
+                the common convention of a top-level subdirectory named
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-BPN'><filename>BPN</filename></ulink><filename>}-${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink><filename>}</filename>,
+                then you do not need to set <filename>S</filename>.
+                However, if <filename>SRC_URI</filename> specifies to fetch
+                source from an archive that does not use this convention,
+                or from an SCM like Git or Subversion, your recipe needs to
+                define <filename>S</filename>.
+            </para>
+
+            <para>
+                If processing your recipe using BitBake successfully unpacks
+                the source files, you need to be sure that the directory
+                pointed to by <filename>${S}</filename> matches the structure
+                of the source.
+            </para>
+        </section>
+
+        <section id='new-recipe-patching-code'>
+            <title>Patching Code</title>
+
+            <para>
+                Sometimes it is necessary to patch code after it has been
+                fetched.
+                Any files mentioned in <filename>SRC_URI</filename> whose
+                names end in <filename>.patch</filename> or
+                <filename>.diff</filename> or compressed versions of these
+                suffixes (e.g. <filename>diff.gz</filename> are treated as
+                patches.
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-patch'><filename>do_patch</filename></ulink>
+                task automatically applies these patches.
+            </para>
+
+            <para>
+                The build system should be able to apply patches with the "-p1"
+                option (i.e. one directory level in the path will be stripped
+                off).
+                If your patch needs to have more directory levels stripped off,
+                specify the number of levels using the "striplevel" option in
+                the <filename>SRC_URI</filename> entry for the patch.
+                Alternatively, if your patch needs to be applied in a specific
+                subdirectory that is not specified in the patch file, use the
+                "patchdir" option in the entry.
+            </para>
+
+            <para>
+                As with all local files referenced in
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                using <filename>file://</filename>, you should place
+                patch files in a directory next to the recipe either
+                named the same as the base name of the recipe
+                (<ulink url='&YOCTO_DOCS_REF_URL;#var-BP'><filename>BP</filename></ulink>
+                and
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BPN'><filename>BPN</filename></ulink>)
+                or "files".
+            </para>
+        </section>
+
+        <section id='new-recipe-licensing'>
+            <title>Licensing</title>
+
+            <para>
+                Your recipe needs to have both the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE</filename></ulink>
+                and
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></ulink>
+                variables:
+                <itemizedlist>
+                    <listitem><para><emphasis><filename>LICENSE</filename>:</emphasis>
+                        This variable specifies the license for the software.
+                        If you do not know the license under which the software
+                        you are building is distributed, you should go to the
+                        source code and look for that information.
+                        Typical files containing this information include
+                        <filename>COPYING</filename>,
+                        <filename>LICENSE</filename>, and
+                        <filename>README</filename> files.
+                        You could also find the information near the top of
+                        a source file.
+                        For example, given a piece of software licensed under
+                        the GNU General Public License version 2, you would
+                        set <filename>LICENSE</filename> as follows:
+                        <literallayout class='monospaced'>
+     LICENSE = "GPLv2"
+                        </literallayout></para>
+                        <para>The licenses you specify within
+                        <filename>LICENSE</filename> can have any name as long
+                        as you do not use spaces, since spaces are used as
+                        separators between license names.
+                        For standard licenses, use the names of the files in
+                        <filename>meta/files/common-licenses/</filename>
+                        or the <filename>SPDXLICENSEMAP</filename> flag names
+                        defined in <filename>meta/conf/licenses.conf</filename>.
+                        </para></listitem>
+                    <listitem><para><emphasis><filename>LIC_FILES_CHKSUM</filename>:</emphasis>
+                        The OpenEmbedded build system uses this variable to
+                        make sure the license text has not changed.
+                        If it has, the build produces an error and it affords
+                        you the chance to figure it out and correct the problem.
+                        </para>
+                        <para>You need to specify all applicable licensing
+                        files for the software.
+                        At the end of the configuration step, the build process
+                        will compare the checksums of the files to be sure
+                        the text has not changed.
+                        Any differences result in an error with the message
+                        containing the current checksum.
+                        For more explanation and examples of how to set the
+                        <filename>LIC_FILES_CHKSUM</filename> variable, see the
+                        "<link link='usingpoky-configuring-LIC_FILES_CHKSUM'>Tracking License Changes</link>"
+                        section.</para>
+
+                        <para>To determine the correct checksum string, you
+                        can list the appropriate files in the
+                        <filename>LIC_FILES_CHKSUM</filename> variable with
+                        incorrect md5 strings, attempt to build the software,
+                        and then note the resulting error messages that will
+                        report the correct md5 strings.
+                        See the
+                        "<link linkend='new-recipe-fetching-code'>Fetching Code</link>"
+                        section for additional information.
+                    </para>
+
+                    <para>
+                        Here is an example that assumes the software has a
+                        <filename>COPYING</filename> file:
+                        <literallayout class='monospaced'>
+     LIC_FILES_CHKSUM = "file://COPYING;md5=xxx"
+                        </literallayout>
+                        When you try to build the software, the build system
+                        will produce an error and give you the correct string
+                        that you can substitute into the recipe file for a
+                        subsequent build.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+<!--
+
+            <para>
+                For trying this out I created a new recipe named
+                <filename>htop_1.0.2.bb</filename> and put it in
+                <filename>poky/meta/recipes-extended/htop</filename>.
+                There are two license type statements in my very simple
+                recipe:
+                <literallayout class='monospaced'>
+     LICENSE = ""
+
+     LIC_FILES_CHKSUM = ""
+
+     SRC_URI[md5sum] = ""
+     SRC_URI[sha256sum] = ""
+                </literallayout>
+                Evidently, you need to run a <filename>bitbake -c cleanall htop</filename>.
+                Next, you delete or comment out the two <filename>SRC_URI</filename>
+                lines at the end and then attempt to build the software with
+                <filename>bitbake htop</filename>.
+                Doing so causes BitBake to report some errors and and give
+                you the actual strings you need for the last two
+                <filename>SRC_URI</filename> lines.
+                Prior to this, you have to dig around in the home page of the
+                source for <filename>htop</filename> and determine that the
+                software is released under GPLv2.
+                You can provide that in the <filename>LICENSE</filename>
+                statement.
+                Now you edit your recipe to have those two strings for
+                the <filename>SRC_URI</filename> statements:
+                <literallayout class='monospaced'>
+     LICENSE = "GPLv2"
+
+     LIC_FILES_CHKSUM = ""
+
+     SRC_URI = "${SOURCEFORGE_MIRROR}/htop/htop-${PV}.tar.gz"
+     SRC_URI[md5sum] = "0d01cca8df3349c74569cefebbd9919e"
+     SRC_URI[sha256sum] = "ee60657b044ece0df096c053060df7abf3cce3a568ab34d260049e6a37ccd8a1"
+                </literallayout>
+                At this point, you can build the software again using the
+                <filename>bitbake htop</filename> command.
+                There is just a set of errors now associated with the
+                empty <filename>LIC_FILES_CHKSUM</filename> variable now.
+            </para>
+-->
+
+        </section>
+
+        <section id='new-dependencies'>
+            <title>Dependencies</title>
+
+            <para>
+                Most software packages have a short list of other packages
+                that they require, which are called dependencies.
+                These dependencies fall into two main categories: build-time
+                dependencies, which are required when the software is built;
+                and runtime dependencies, which are required to be installed
+                on the target in order for the software to run.
+            </para>
+
+            <para>
+                Within a recipe, you specify build-time dependencies using the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                variable.
+                Although nuances exist, items specified in
+                <filename>DEPENDS</filename> should be names of other recipes.
+                It is important that you specify all build-time dependencies
+                explicitly.
+                If you do not, due to the parallel nature of BitBake's
+                execution, you can end up with a race condition where the
+                dependency is present for one task of a recipe (e.g.
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-configure'><filename>do_configure</filename></ulink>)
+                and then gone when the next task runs (e.g.
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-compile'><filename>do_compile</filename></ulink>).
+            </para>
+
+            <para>
+                Another consideration is that configure scripts might
+                automatically check for optional dependencies and enable
+                corresponding functionality if those dependencies are found.
+                This behavior means that to ensure deterministic results and
+                thus avoid more race conditions, you need to either explicitly
+                specify these dependencies as well, or tell the configure
+                script explicitly to disable the functionality.
+                If you wish to make a recipe that is more generally useful
+                (e.g. publish the recipe in a layer for others to use),
+                instead of hard-disabling the functionality, you can use the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGECONFIG'><filename>PACKAGECONFIG</filename></ulink>
+                variable to allow functionality and the corresponding
+                dependencies to be enabled and disabled easily by other
+                users of the recipe.
+            </para>
+
+            <para>
+                Similar to build-time dependencies, you specify runtime
+                dependencies through a variable -
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>,
+                which is package-specific.
+                All variables that are package-specific need to have the name
+                of the package added to the end as an override.
+                Since the main package for a recipe has the same name as the
+                recipe, and the recipe's name can be found through the
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>
+                variable, then you specify the dependencies for the main
+                package by setting <filename>RDEPENDS_${PN}</filename>.
+                If the package were named <filename>${PN}-tools</filename>,
+                then you would set <filename>RDEPENDS_${PN}-tools</filename>,
+                and so forth.
+            </para>
+
+            <para>
+                Some runtime dependencies will be set automatically at
+                packaging time.
+                These dependencies include any shared library dependencies
+                (i.e. if a package "example" contains "libexample" and
+                another package "mypackage" contains a binary that links to
+                "libexample" then the OpenEmbedded build system will
+                automatically add a runtime dependency to "mypackage" on
+                "example").
+                See the
+                "<ulink url='&YOCTO_DOCS_OM_URL;#automatically-added-runtime-dependencies'>Automatically Added Runtime Dependencies</ulink>"
+                section in the Yocto Project Overview and Concepts Manual for
+                further details.
+            </para>
+        </section>
+
+        <section id='new-recipe-configuring-the-recipe'>
+            <title>Configuring the Recipe</title>
+
+            <para>
+                Most software provides some means of setting build-time
+                configuration options before compilation.
+                Typically, setting these options is accomplished by running a
+                configure script with options, or by modifying a build
+                configuration file.
+                <note>
+                    As of Yocto Project Release 1.7, some of the core recipes
+                    that package binary configuration scripts now disable the
+                    scripts due to the scripts previously requiring error-prone
+                    path substitution.
+                    The OpenEmbedded build system uses
+                    <filename>pkg-config</filename> now, which is much more
+                    robust.
+                    You can find a list of the <filename>*-config</filename>
+                    scripts that are disabled list in the
+                    "<ulink url='&YOCTO_DOCS_REF_URL;#migration-1.7-binary-configuration-scripts-disabled'>Binary Configuration Scripts Disabled</ulink>"
+                    section in the Yocto Project Reference Manual.
+                </note>
+            </para>
+
+            <para>
+                A major part of build-time configuration is about checking for
+                build-time dependencies and possibly enabling optional
+                functionality as a result.
+                You need to specify any build-time dependencies for the
+                software you are building in your recipe's
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                value, in terms of other recipes that satisfy those
+                dependencies.
+                You can often find build-time or runtime
+                dependencies described in the software's documentation.
+            </para>
+
+            <para>
+                The following list provides configuration items of note based
+                on how your software is built:
+                <itemizedlist>
+                    <listitem><para><emphasis>Autotools:</emphasis>
+                        If your source files have a
+                        <filename>configure.ac</filename> file, then your
+                        software is built using Autotools.
+                        If this is the case, you just need to worry about
+                        modifying the configuration.</para>
+
+                        <para>When using Autotools, your recipe needs to inherit
+                        the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-autotools'><filename>autotools</filename></ulink>
+                        class and your recipe does not have to contain a
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-configure'><filename>do_configure</filename></ulink>
+                        task.
+                        However, you might still want to make some adjustments.
+                        For example, you can set
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OECONF'><filename>EXTRA_OECONF</filename></ulink>
+                        or
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGECONFIG_CONFARGS'><filename>PACKAGECONFIG_CONFARGS</filename></ulink>
+                        to pass any needed configure options that are specific
+                        to the recipe.
+                        </para></listitem>
+                    <listitem><para><emphasis>CMake:</emphasis>
+                        If your source files have a
+                        <filename>CMakeLists.txt</filename> file, then your
+                        software is built using CMake.
+                        If this is the case, you just need to worry about
+                        modifying the configuration.</para>
+
+                        <para>When you use CMake, your recipe needs to inherit
+                        the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-cmake'><filename>cmake</filename></ulink>
+                        class and your recipe does not have to contain a
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-configure'><filename>do_configure</filename></ulink>
+                        task.
+                        You can make some adjustments by setting
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OECMAKE'><filename>EXTRA_OECMAKE</filename></ulink>
+                        to pass any needed configure options that are specific
+                        to the recipe.
+                        <note>
+                            If you need to install one or more custom CMake
+                            toolchain files that are supplied by the
+                            application you are building, install the files to
+                            <filename>${D}${datadir}/cmake/</filename> Modules
+                            during
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>.
+                        </note>
+                        </para></listitem>
+                    <listitem><para><emphasis>Other:</emphasis>
+                        If your source files do not have a
+                        <filename>configure.ac</filename> or
+                        <filename>CMakeLists.txt</filename> file, then your
+                        software is built using some method other than Autotools
+                        or CMake.
+                        If this is the case, you normally need to provide a
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-configure'><filename>do_configure</filename></ulink>
+                        task in your recipe
+                        unless, of course, there is nothing to configure.
+                        </para>
+                        <para>Even if your software is not being built by
+                        Autotools or CMake, you still might not need to deal
+                        with any configuration issues.
+                        You need to determine if configuration is even a required step.
+                        You might need to modify a Makefile or some configuration file
+                        used for the build to specify necessary build options.
+                        Or, perhaps you might need to run a provided, custom
+                        configure script with the appropriate options.</para>
+                        <para>For the case involving a custom configure
+                        script, you would run
+                        <filename>./configure --help</filename> and look for
+                        the options you need to set.</para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Once configuration succeeds, it is always good practice to
+                look at the <filename>log.do_configure</filename> file to
+                ensure that the appropriate options have been enabled and no
+                additional build-time dependencies need to be added to
+                <filename>DEPENDS</filename>.
+                For example, if the configure script reports that it found
+                something not mentioned in <filename>DEPENDS</filename>, or
+                that it did not find something that it needed for some
+                desired optional functionality, then you would need to add
+                those to <filename>DEPENDS</filename>.
+                Looking at the log might also reveal items being checked for,
+                enabled, or both that you do not want, or items not being found
+                that are in <filename>DEPENDS</filename>, in which case
+                you would need to look at passing extra options to the
+                configure script as needed.
+                For reference information on configure options specific to the
+                software you are building, you can consult the output of the
+                <filename>./configure --help</filename> command within
+                <filename>${S}</filename> or consult the software's upstream
+                documentation.
+            </para>
+        </section>
+
+        <section id='new-recipe-using-headers-to-interface-with-devices'>
+            <title>Using Headers to Interface with Devices</title>
+
+            <para>
+                If your recipe builds an application that needs to
+                communicate with some device or needs an API into a custom
+                kernel, you will need to provide appropriate header files.
+                Under no circumstances should you ever modify the existing
+                <filename>meta/recipes-kernel/linux-libc-headers/linux-libc-headers.inc</filename>
+                file.
+                These headers are used to build <filename>libc</filename> and
+                must not be compromised with custom or machine-specific
+                header information.
+                If you customize <filename>libc</filename> through modified
+                headers all other applications that use
+                <filename>libc</filename> thus become affected.
+                <note><title>Warning</title>
+                    Never copy and customize the <filename>libc</filename>
+                    header file (i.e.
+                    <filename>meta/recipes-kernel/linux-libc-headers/linux-libc-headers.inc</filename>).
+                </note>
+                The correct way to interface to a device or custom kernel is
+                to use a separate package that provides the additional headers
+                for the driver or other unique interfaces.
+                When doing so, your application also becomes responsible for
+                creating a dependency on that specific provider.
+            </para>
+
+            <para>
+                Consider the following:
+                <itemizedlist>
+                    <listitem><para>
+                        Never modify
+                        <filename>linux-libc-headers.inc</filename>.
+                        Consider that file to be part of the
+                        <filename>libc</filename> system, and not something
+                        you use to access the kernel directly.
+                        You should access <filename>libc</filename> through
+                        specific <filename>libc</filename> calls.
+                        </para></listitem>
+                    <listitem><para>
+                        Applications that must talk directly to devices
+                        should either provide necessary headers themselves,
+                        or establish a dependency on a special headers package
+                        that is specific to that driver.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                For example, suppose you want to modify an existing header
+                that adds I/O control or network support.
+                If the modifications are used by a small number programs,
+                providing a unique version of a header is easy and has little
+                impact.
+                When doing so, bear in mind the guidelines in the previous
+                list.
+                <note>
+                    If for some reason your changes need to modify the behavior
+                    of the <filename>libc</filename>, and subsequently all
+                    other applications on the system, use a
+                    <filename>.bbappend</filename> to modify the
+                    <filename>linux-kernel-headers.inc</filename> file.
+                    However, take care to not make the changes
+                    machine specific.
+                </note>
+            </para>
+
+            <para>
+                Consider a case where your kernel is older and you need
+                an older <filename>libc</filename> ABI.
+                The headers installed by your recipe should still be a
+                standard mainline kernel, not your own custom one.
+            </para>
+
+            <para>
+                When you use custom kernel headers you need to get them from
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-STAGING_KERNEL_DIR'><filename>STAGING_KERNEL_DIR</filename></ulink>,
+                which is the directory with kernel headers that are
+                required to build out-of-tree modules.
+                Your recipe will also need the following:
+                <literallayout class='monospaced'>
+     do_configure[depends] += "virtual/kernel:do_shared_workdir"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='new-recipe-compilation'>
+            <title>Compilation</title>
+
+            <para>
+                During a build, the <filename>do_compile</filename> task
+                happens after source is fetched, unpacked, and configured.
+                If the recipe passes through <filename>do_compile</filename>
+                successfully, nothing needs to be done.
+            </para>
+
+            <para>
+                However, if the compile step fails, you need to diagnose the
+                failure.
+                Here are some common issues that cause failures.
+                <note>
+                    For cases where improper paths are detected for
+                    configuration files or for when libraries/headers cannot
+                    be found, be sure you are using the more robust
+                    <filename>pkg-config</filename>.
+                    See the note in section
+                    "<link linkend='new-recipe-configuring-the-recipe'>Configuring the Recipe</link>"
+                    for additional information.
+                </note>
+                <itemizedlist>
+                    <listitem><para><emphasis>Parallel build failures:</emphasis>
+                        These failures manifest themselves as intermittent
+                        errors, or errors reporting that a file or directory
+                        that should be created by some other part of the build
+                        process could not be found.
+                        This type of failure can occur even if, upon inspection,
+                        the file or directory does exist after the build has
+                        failed, because that part of the build process happened
+                        in the wrong order.</para>
+                        <para>To fix the problem, you need to either satisfy
+                        the missing dependency in the Makefile or whatever
+                        script produced the Makefile, or (as a workaround)
+                        set
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKE'><filename>PARALLEL_MAKE</filename></ulink>
+                        to an empty string:
+                        <literallayout class='monospaced'>
+     PARALLEL_MAKE = ""
+                        </literallayout></para>
+                        <para>
+                            For information on parallel Makefile issues, see the
+                            "<link linkend='debugging-parallel-make-races'>Debugging Parallel Make Races</link>"
+                            section.
+                            </para></listitem>
+                    <listitem><para><emphasis>Improper host path usage:</emphasis>
+                        This failure applies to recipes building for the target
+                        or <filename>nativesdk</filename> only.
+                        The failure occurs when the compilation process uses
+                        improper headers, libraries, or other files from the
+                        host system when cross-compiling for the target.
+                        </para>
+                        <para>To fix the problem, examine the
+                        <filename>log.do_compile</filename> file to identify
+                        the host paths being used (e.g.
+                        <filename>/usr/include</filename>,
+                        <filename>/usr/lib</filename>, and so forth) and then
+                        either add configure options, apply a patch, or do both.
+                        </para></listitem>
+                    <listitem><para><emphasis>Failure to find required
+                        libraries/headers:</emphasis>
+                        If a build-time dependency is missing because it has
+                        not been declared in
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>,
+                        or because the dependency exists but the path used by
+                        the build process to find the file is incorrect and the
+                        configure step did not detect it, the compilation
+                        process could fail.
+                        For either of these failures, the compilation process
+                        notes that files could not be found.
+                        In these cases, you need to go back and add additional
+                        options to the configure script as well as possibly
+                        add additional build-time dependencies to
+                        <filename>DEPENDS</filename>.</para>
+                        <para>Occasionally, it is necessary to apply a patch
+                        to the source to ensure the correct paths are used.
+                        If you need to specify paths to find files staged
+                        into the sysroot from other recipes, use the variables
+                        that the OpenEmbedded build system provides
+                        (e.g.
+                        <filename>STAGING_BINDIR</filename>,
+                        <filename>STAGING_INCDIR</filename>,
+                        <filename>STAGING_DATADIR</filename>, and so forth).
+<!--
+                        (e.g.
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-STAGING_BINDIR'><filename>STAGING_BINDIR</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-STAGING_INCDIR'><filename>STAGING_INCDIR</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-STAGING_DATADIR'><filename>STAGING_DATADIR</filename></ulink>,
+                        and so forth).
+-->
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='new-recipe-installing'>
+            <title>Installing</title>
+
+            <para>
+                During <filename>do_install</filename>, the task copies the
+                built files along with their hierarchy to locations that
+                would mirror their locations on the target device.
+                The installation process copies files from the
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink><filename>}</filename>,
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-B'><filename>B</filename></ulink><filename>}</filename>,
+                and
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink><filename>}</filename>
+                directories to the
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink><filename>}</filename>
+                directory to create the structure as it should appear on the
+                target system.
+            </para>
+
+            <para>
+                How your software is built affects what you must do to be
+                sure your software is installed correctly.
+                The following list describes what you must do for installation
+                depending on the type of build system used by the software
+                being built:
+                <itemizedlist>
+                    <listitem><para><emphasis>Autotools and CMake:</emphasis>
+                        If the software your recipe is building uses Autotools
+                        or CMake, the OpenEmbedded build
+                        system understands how to install the software.
+                        Consequently, you do not have to have a
+                        <filename>do_install</filename> task as part of your
+                        recipe.
+                        You just need to make sure the install portion of the
+                        build completes with no issues.
+                        However, if you wish to install additional files not
+                        already being installed by
+                        <filename>make install</filename>, you should do this
+                        using a <filename>do_install_append</filename> function
+                        using the install command as described in
+                        the "Manual" bulleted item later in this list.
+                        </para></listitem>
+                    <listitem><para><emphasis>Other (using
+                        <filename>make install</filename>):</emphasis>
+                        You need to define a
+                        <filename>do_install</filename> function in your
+                        recipe.
+                        The function should call
+                        <filename>oe_runmake install</filename> and will likely
+                        need to pass in the destination directory as well.
+                        How you pass that path is dependent on how the
+                        <filename>Makefile</filename> being run is written
+                        (e.g. <filename>DESTDIR=${D}</filename>,
+                        <filename>PREFIX=${D}</filename>,
+                        <filename>INSTALLROOT=${D}</filename>, and so forth).
+                        </para>
+                        <para>For an example recipe using
+                        <filename>make install</filename>, see the
+                        "<link linkend='new-recipe-makefile-based-package'>Makefile-Based Package</link>"
+                        section.</para></listitem>
+                    <listitem><para><emphasis>Manual:</emphasis>
+                        You need to define a
+                        <filename>do_install</filename> function in your
+                        recipe.
+                        The function must first use
+                        <filename>install -d</filename> to create the
+                        directories under
+                        <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink><filename>}</filename>.
+                        Once the directories exist, your function can use
+                        <filename>install</filename> to manually install the
+                        built software into the directories.</para>
+                        <para>You can find more information on
+                        <filename>install</filename> at
+                        <ulink url='http://www.gnu.org/software/coreutils/manual/html_node/install-invocation.html'></ulink>.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                For the scenarios that do not use Autotools or
+                CMake, you need to track the installation
+                and diagnose and fix any issues until everything installs
+                correctly.
+                You need to look in the default location of
+                <filename>${D}</filename>, which is
+                <filename>${WORKDIR}/image</filename>, to be sure your
+                files have been installed correctly.
+            </para>
+
+            <note><title>Notes</title>
+                <itemizedlist>
+                    <listitem><para>
+                        During the installation process, you might need to
+                        modify some of the installed files to suit the target
+                        layout.
+                        For example, you might need to replace hard-coded paths
+                        in an initscript with values of variables provided by
+                        the build system, such as replacing
+                        <filename>/usr/bin/</filename> with
+                        <filename>${bindir}</filename>.
+                        If you do perform such modifications during
+                        <filename>do_install</filename>, be sure to modify the
+                        destination file after copying rather than before
+                        copying.
+                        Modifying after copying ensures that the build system
+                        can re-execute <filename>do_install</filename> if
+                        needed.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>oe_runmake install</filename>, which can be
+                        run directly or can be run indirectly by the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-autotools'><filename>autotools</filename></ulink>
+                        and
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-cmake'><filename>cmake</filename></ulink>
+                        classes, runs <filename>make install</filename> in
+                        parallel.
+                        Sometimes, a Makefile can have missing dependencies
+                        between targets that can result in race conditions.
+                        If you experience intermittent failures during
+                        <filename>do_install</filename>, you might be able to
+                        work around them by disabling parallel Makefile
+                        installs by adding the following to the recipe:
+                        <literallayout class='monospaced'>
+     PARALLEL_MAKEINST = ""
+                        </literallayout>
+                        See
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKEINST'><filename>PARALLEL_MAKEINST</filename></ulink>
+                        for additional information.
+                        </para></listitem>
+                    <listitem><para>
+                        If you need to install one or more custom CMake
+                        toolchain files that are supplied by the
+                        application you are building, install the files to
+                        <filename>${D}${datadir}/cmake/</filename> Modules
+                        during
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>.
+                        </para></listitem>
+                </itemizedlist>
+            </note>
+        </section>
+
+        <section id='new-recipe-enabling-system-services'>
+            <title>Enabling System Services</title>
+
+            <para>
+                If you want to install a service, which is a process that
+                usually starts on boot and runs in the background, then
+                you must include some additional definitions in your recipe.
+            </para>
+
+            <para>
+                If you are adding services and the service initialization
+                script or the service file itself is not installed, you must
+                provide for that installation in your recipe using a
+                <filename>do_install_append</filename> function.
+                If your recipe already has a <filename>do_install</filename>
+                function, update the function near its end rather than
+                adding an additional <filename>do_install_append</filename>
+                function.
+            </para>
+
+            <para>
+                When you create the installation for your services, you need
+                to accomplish what is normally done by
+                <filename>make install</filename>.
+                In other words, make sure your installation arranges the output
+                similar to how it is arranged on the target system.
+            </para>
+
+            <para>
+                The OpenEmbedded build system provides support for starting
+                services two different ways:
+                <itemizedlist>
+                    <listitem><para><emphasis>SysVinit:</emphasis>
+                        SysVinit is a system and service manager that
+                        manages the init system used to control the very basic
+                        functions of your system.
+                        The init program is the first program
+                        started by the Linux kernel when the system boots.
+                        Init then controls the startup, running and shutdown
+                        of all other programs.</para>
+                        <para>To enable a service using SysVinit, your recipe
+                        needs to inherit the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-update-rc.d'><filename>update-rc.d</filename></ulink>
+                        class.
+                        The class helps facilitate safely installing the
+                        package on the target.</para>
+                        <para>You will need to set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-INITSCRIPT_PACKAGES'><filename>INITSCRIPT_PACKAGES</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-INITSCRIPT_NAME'><filename>INITSCRIPT_NAME</filename></ulink>,
+                        and
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-INITSCRIPT_PARAMS'><filename>INITSCRIPT_PARAMS</filename></ulink>
+                        variables within your recipe.</para></listitem>
+                    <listitem><para><emphasis>systemd:</emphasis>
+                        System Management Daemon (systemd) was designed to
+                        replace SysVinit and to provide
+                        enhanced management of services.
+                        For more information on systemd, see the systemd
+                        homepage at
+                        <ulink url='http://freedesktop.org/wiki/Software/systemd/'></ulink>.
+                        </para>
+                        <para>To enable a service using systemd, your recipe
+                        needs to inherit the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-systemd'><filename>systemd</filename></ulink>
+                        class.
+                        See the <filename>systemd.bbclass</filename> file
+                        located in your
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
+                        section for more information.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='new-recipe-packaging'>
+            <title>Packaging</title>
+
+            <para>
+                Successful packaging is a combination of automated processes
+                performed by the OpenEmbedded build system and some
+                specific steps you need to take.
+                The following list describes the process:
+                <itemizedlist>
+                    <listitem><para><emphasis>Splitting Files</emphasis>:
+                        The <filename>do_package</filename> task splits the
+                        files produced by the recipe into logical components.
+                        Even software that produces a single binary might
+                        still have debug symbols, documentation, and other
+                        logical components that should be split out.
+                        The <filename>do_package</filename> task ensures
+                        that files are split up and packaged correctly.
+                        </para></listitem>
+                    <listitem><para><emphasis>Running QA Checks</emphasis>:
+                        The
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-insane'><filename>insane</filename></ulink>
+                        class adds a step to
+                        the package generation process so that output quality
+                        assurance checks are generated by the OpenEmbedded
+                        build system.
+                        This step performs a range of checks to be sure the
+                        build's output is free of common problems that show
+                        up during runtime.
+                        For information on these checks, see the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-insane'><filename>insane</filename></ulink>
+                        class and the
+                        "<ulink url='&YOCTO_DOCS_REF_URL;#ref-qa-checks'>QA Error and Warning Messages</ulink>"
+                        chapter in the Yocto Project Reference Manual.
+                        </para></listitem>
+                    <listitem><para><emphasis>Hand-Checking Your Packages</emphasis>:
+                        After you build your software, you need to be sure
+                        your packages are correct.
+                        Examine the
+                        <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink><filename>}/packages-split</filename>
+                        directory and make sure files are where you expect
+                        them to be.
+                        If you discover problems, you can set
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'><filename>PACKAGES</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'><filename>FILES</filename></ulink>,
+                        <filename>do_install(_append)</filename>, and so forth as
+                        needed.
+                        </para></listitem>
+                    <listitem><para><emphasis>Splitting an Application into Multiple Packages</emphasis>:
+                        If you need to split an application into several
+                        packages, see the
+                        "<link linkend='splitting-an-application-into-multiple-packages'>Splitting an Application into Multiple Packages</link>"
+                        section for an example.
+                        </para></listitem>
+                    <listitem><para><emphasis>Installing a Post-Installation Script</emphasis>:
+                        For an example showing how to install a
+                        post-installation script, see the
+                        "<link linkend='new-recipe-post-installation-scripts'>Post-Installation Scripts</link>"
+                        section.
+                        </para></listitem>
+                    <listitem><para><emphasis>Marking Package Architecture</emphasis>:
+                        Depending on what your recipe is building and how it
+                        is configured, it might be important to mark the
+                        packages produced as being specific to a particular
+                        machine, or to mark them as not being specific to
+                        a particular machine or architecture at all.</para>
+                        <para>By default, packages apply to any machine with the
+                        same architecture as the target machine.
+                        When a recipe produces packages that are
+                        machine-specific (e.g. the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                        value is passed into the configure script or a patch
+                        is applied only for a particular machine), you should
+                        mark them as such by adding the following to the
+                        recipe:
+                        <literallayout class='monospaced'>
+     PACKAGE_ARCH = "${MACHINE_ARCH}"
+                        </literallayout></para>
+                        <para>On the other hand, if the recipe produces packages
+                        that do not contain anything specific to the target
+                        machine or architecture at all (e.g. recipes
+                        that simply package script files or configuration
+                        files), you should use the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-allarch'><filename>allarch</filename></ulink>
+                        class to do this for you by adding this to your
+                        recipe:
+                        <literallayout class='monospaced'>
+     inherit allarch
+                        </literallayout>
+                        Ensuring that the package architecture is correct is
+                        not critical while you are doing the first few builds
+                        of your recipe.
+                        However, it is important in order
+                        to ensure that your recipe rebuilds (or does not
+                        rebuild) appropriately in response to changes in
+                        configuration, and to ensure that you get the
+                        appropriate packages installed on the target machine,
+                        particularly if you run separate builds for more
+                        than one target machine.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='new-sharing-files-between-recipes'>
+            <title>Sharing Files Between Recipes</title>
+
+            <para>
+                Recipes often need to use files provided by other recipes on
+                the build host.
+                For example, an application linking to a common library needs
+                access to the library itself and its associated headers.
+                The way this access is accomplished is by populating a sysroot
+                with files.
+                Each recipe has two sysroots in its work directory, one for
+                target files
+                (<filename>recipe-sysroot</filename>) and one for files that
+                are native to the build host
+                (<filename>recipe-sysroot-native</filename>).
+                <note>
+                    You could find the term "staging" used within the Yocto
+                    project regarding files populating sysroots (e.g. the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-STAGING_DIR'><filename>STAGING_DIR</filename></ulink>
+                    variable).
+                </note>
+            </para>
+
+            <para>
+                Recipes should never populate the sysroot directly (i.e. write
+                files into sysroot).
+                Instead, files should be installed into standard locations
+                during the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+                task within the
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink><filename>}</filename>
+                directory.
+                The reason for this limitation is that almost all files that
+                populate the sysroot are cataloged in manifests in order to
+                ensure the files can be removed later when a recipe is either
+                modified or removed.
+                Thus, the sysroot is able to remain free from stale files.
+            </para>
+
+            <para>
+                A subset of the files installed by the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+                task are used by the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-populate_sysroot'><filename>do_populate_sysroot</filename></ulink>
+                task as defined by the the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SYSROOT_DIRS'><filename>SYSROOT_DIRS</filename></ulink>
+                variable to automatically populate the sysroot.
+                It is possible to modify the list of directories that populate
+                the sysroot.
+                The following example shows how you could add the
+                <filename>/opt</filename> directory to the list of
+                directories within a recipe:
+                <literallayout class='monospaced'>
+     SYSROOT_DIRS += "/opt"
+                </literallayout>
+            </para>
+
+            <para>
+                For a more complete description of the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-populate_sysroot'><filename>do_populate_sysroot</filename></ulink>
+                task and its associated functions, see the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-staging'><filename>staging</filename></ulink>
+                class.
+            </para>
+        </section>
+
+        <section id='metadata-virtual-providers'>
+            <title>Using Virtual Providers</title>
+
+            <para>
+                Prior to a build, if you know that several different recipes
+                provide the same functionality, you can use a virtual provider
+                (i.e. <filename>virtual/*</filename>) as a placeholder for the
+                actual provider.
+                The actual provider is determined at build-time.
+            </para>
+
+            <para>
+                A common scenario where a virtual provider is used would be
+                for the kernel recipe.
+                Suppose you have three kernel recipes whose
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>
+                values map to <filename>kernel-big</filename>,
+                <filename>kernel-mid</filename>, and
+                <filename>kernel-small</filename>.
+                Furthermore, each of these recipes in some way uses a
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PROVIDES'><filename>PROVIDES</filename></ulink>
+                statement that essentially identifies itself as being able
+                to provide <filename>virtual/kernel</filename>.
+                Here is one way through the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-kernel'><filename>kernel</filename></ulink>
+                class:
+                <literallayout class='monospaced'>
+     PROVIDES += "${@ "virtual/kernel" if (d.getVar("KERNEL_PACKAGE_NAME") == "kernel") else "" }"
+                </literallayout>
+                Any recipe that inherits the <filename>kernel</filename> class
+                is going to utilize a <filename>PROVIDES</filename> statement
+                that identifies that recipe as being able to provide the
+                <filename>virtual/kernel</filename> item.
+            </para>
+
+            <para>
+                Now comes the time to actually build an image and you need a
+                kernel recipe, but which one?
+                You can configure your build to call out the kernel recipe
+                you want by using the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PREFERRED_PROVIDER'><filename>PREFERRED_PROVIDER</filename></ulink>
+                variable.
+                As an example, consider the
+                <ulink url='https://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/conf/machine/include/x86-base.inc'><filename>x86-base.inc</filename></ulink>
+                include file, which is a machine
+                (i.e. <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>)
+                configuration file.
+                This include file is the reason all x86-based machines use the
+                <filename>linux-yocto</filename> kernel.
+                Here are the relevant lines from the include file:
+                <literallayout class='monospaced'>
+     PREFERRED_PROVIDER_virtual/kernel ??= "linux-yocto"
+     PREFERRED_VERSION_linux-yocto ??= "4.15%"
+                </literallayout>
+            </para>
+
+            <para>
+                When you use a virtual provider, you do not have to
+                "hard code" a recipe name as a build dependency.
+                You can use the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                variable to state the build is dependent on
+                <filename>virtual/kernel</filename> for example:
+                <literallayout class='monospaced'>
+     DEPENDS = "virtual/kernel"
+                </literallayout>
+                During the build, the OpenEmbedded build system picks
+                the correct recipe needed for the
+                <filename>virtual/kernel</filename> dependency based on the
+                <filename>PREFERRED_PROVIDER</filename> variable.
+                If you want to use the small kernel mentioned at the beginning
+                of this section, configure your build as follows:
+                <literallayout class='monospaced'>
+     PREFERRED_PROVIDER_virtual/kernel ??= "kernel-small"
+                </literallayout>
+                <note>
+                    Any recipe that
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PROVIDES'><filename>PROVIDES</filename></ulink>
+                    a <filename>virtual/*</filename> item that is ultimately
+                    not selected through
+                    <filename>PREFERRED_PROVIDER</filename> does not get built.
+                    Preventing these recipes from building is usually the
+                    desired behavior since this mechanism's purpose is to
+                    select between mutually exclusive alternative providers.
+                </note>
+            </para>
+
+            <para>
+                The following lists specific examples of virtual providers:
+                <itemizedlist>
+                    <listitem><para>
+                        <filename>virtual/kernel</filename>:
+                        Provides the name of the kernel recipe to use when
+                        building a kernel image.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>virtual/bootloader</filename>:
+                        Provides the name of the bootloader to use when
+                        building an image.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>virtual/libgbm</filename>:
+                        Provides <filename>gbm.pc</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>virtual/egl</filename>:
+                        Provides <filename>egl.pc</filename> and possibly
+                        <filename>wayland-egl.pc</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>virtual/libgl</filename>:
+                        Provides <filename>gl.pc</filename> (i.e. libGL).
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>virtual/libgles1</filename>:
+                        Provides <filename>glesv1_cm.pc</filename>
+                        (i.e. libGLESv1_CM).
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>virtual/libgles2</filename>:
+                        Provides <filename>glesv2.pc</filename>
+                        (i.e. libGLESv2).
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='properly-versioning-pre-release-recipes'>
+            <title>Properly Versioning Pre-Release Recipes</title>
+
+            <para>
+                Sometimes the name of a recipe can lead to versioning
+                problems when the recipe is upgraded to a final release.
+                For example, consider the
+                <filename>irssi_0.8.16-rc1.bb</filename> recipe file in
+                the list of example recipes in the
+                "<link linkend='new-recipe-storing-and-naming-the-recipe'>Storing and Naming the Recipe</link>"
+                section.
+                This recipe is at a release candidate stage (i.e.
+                "rc1").
+                When the recipe is released, the recipe filename becomes
+                <filename>irssi_0.8.16.bb</filename>.
+                The version change from <filename>0.8.16-rc1</filename>
+                to <filename>0.8.16</filename> is seen as a decrease by the
+                build system and package managers, so the resulting packages
+                will not correctly trigger an upgrade.
+            </para>
+
+            <para>
+                In order to ensure the versions compare properly, the
+                recommended convention is to set
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+                within the recipe to
+                "<replaceable>previous_version</replaceable>+<replaceable>current_version</replaceable>".
+                You can use an additional variable so that you can use the
+                current version elsewhere.
+                Here is an example:
+                <literallayout class='monospaced'>
+     REALPV = "0.8.16-rc1"
+     PV = "0.8.15+${REALPV}"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='new-recipe-post-installation-scripts'>
+            <title>Post-Installation Scripts</title>
+
+            <para>
+                Post-installation scripts run immediately after installing
+                a package on the target or during image creation when a
+                package is included in an image.
+                To add a post-installation script to a package, add a
+                <filename>pkg_postinst_</filename><replaceable>PACKAGENAME</replaceable><filename>()</filename> function to
+                the recipe file (<filename>.bb</filename>) and replace
+                <replaceable>PACKAGENAME</replaceable> with the name of the package
+                you want to attach to the <filename>postinst</filename>
+                script.
+                To apply the post-installation script to the main package
+                for the recipe, which is usually what is required, specify
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>
+                in place of <replaceable>PACKAGENAME</replaceable>.
+            </para>
+
+            <para>
+                A post-installation function has the following structure:
+                <literallayout class='monospaced'>
+     pkg_postinst_<replaceable>PACKAGENAME</replaceable>() {
+     # Commands to carry out
+     }
+                </literallayout>
+            </para>
+
+            <para>
+                The script defined in the post-installation function is
+                called when the root filesystem is created.
+                If the script succeeds, the package is marked as installed.
+                <note>
+                    Any RPM post-installation script that runs on the target
+                    should return a 0 exit code.
+                    RPM does not allow non-zero exit codes for these scripts,
+                    and the RPM package manager will cause the package to fail
+                    installation on the target.
+                </note>
+            </para>
+
+            <para>
+                Sometimes it is necessary for the execution of a
+                post-installation script to be delayed until the first boot.
+                For example, the script might need to be executed on the
+                device itself.
+                To delay script execution until boot time, you must explicitly
+                mark post installs to defer to the target.
+                You can use <filename>pkg_postinst_ontarget()</filename> or
+                call
+                <filename>postinst_intercept delay_to_first_boot</filename>
+                from <filename>pkg_postinst()</filename>.
+                Any failure of a <filename>pkg_postinst()</filename> script
+                (including exit 1) triggers an error during the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-rootfs'><filename>do_rootfs</filename></ulink>
+                task.
+            </para>
+
+            <para>
+                If you have recipes that use
+                <filename>pkg_postinst</filename> function
+                and they require the use of non-standard native
+                tools that have dependencies during rootfs construction, you
+                need to use the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_WRITE_DEPS'><filename>PACKAGE_WRITE_DEPS</filename></ulink>
+                variable in your recipe to list these tools.
+                If you do not use this variable, the tools might be missing and
+                execution of the post-installation script is deferred until
+                first boot.
+                Deferring the script to first boot is undesirable and for
+                read-only rootfs impossible.
+            </para>
+
+            <note>
+                Equivalent support for pre-install, pre-uninstall, and
+                post-uninstall scripts exist by way of
+                <filename>pkg_preinst</filename>,
+                <filename>pkg_prerm</filename>, and
+                <filename>pkg_postrm</filename>, respectively.
+                These scrips work in exactly the same way as does
+                <filename>pkg_postinst</filename> with the exception
+                that they run at different times.
+                Also, because of when they run, they are not applicable to
+                being run at image creation time like
+                <filename>pkg_postinst</filename>.
+            </note>
+        </section>
+
+        <section id='new-recipe-testing'>
+            <title>Testing</title>
+
+            <para>
+                The final step for completing your recipe is to be sure that
+                the software you built runs correctly.
+                To accomplish runtime testing, add the build's output
+                packages to your image and test them on the target.
+            </para>
+
+            <para>
+                For information on how to customize your image by adding
+                specific packages, see the
+                "<link linkend='usingpoky-extend-customimage'>Customizing Images</link>"
+                section.
+            </para>
+        </section>
+
+        <section id='new-recipe-testing-examples'>
+            <title>Examples</title>
+
+            <para>
+                To help summarize how to write a recipe, this section provides
+                some examples given various scenarios:
+                <itemizedlist>
+                    <listitem><para>Recipes that use local files</para></listitem>
+                    <listitem><para>Using an Autotooled package</para></listitem>
+                    <listitem><para>Using a Makefile-based package</para></listitem>
+                    <listitem><para>Splitting an application into multiple packages</para></listitem>
+                    <listitem><para>Adding binaries to an image</para></listitem>
+                </itemizedlist>
+            </para>
+
+            <section id='new-recipe-single-c-file-package-hello-world'>
+                <title>Single .c File Package (Hello World!)</title>
+
+                <para>
+                    Building an application from a single file that is stored
+                    locally (e.g. under <filename>files</filename>) requires
+                    a recipe that has the file listed in the
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>
+                    variable.
+                    Additionally, you need to manually write the
+                    <filename>do_compile</filename> and
+                    <filename>do_install</filename> tasks.
+                    The <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink></filename>
+                    variable defines the directory containing the source code,
+                    which is set to
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>
+                    in this case - the directory BitBake uses for the build.
+                    <literallayout class='monospaced'>
+     SUMMARY = "Simple helloworld application"
+     SECTION = "examples"
+     LICENSE = "MIT"
+     LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
+
+     SRC_URI = "file://helloworld.c"
+
+     S = "${WORKDIR}"
+
+     do_compile() {
+     	${CC} helloworld.c -o helloworld
+     }
+
+     do_install() {
+     	install -d ${D}${bindir}
+     	install -m 0755 helloworld ${D}${bindir}
+     }
+                    </literallayout>
+                </para>
+
+                <para>
+                    By default, the <filename>helloworld</filename>,
+                    <filename>helloworld-dbg</filename>, and
+                    <filename>helloworld-dev</filename> packages are built.
+                    For information on how to customize the packaging process,
+                    see the
+                    "<link linkend='splitting-an-application-into-multiple-packages'>Splitting an Application into Multiple Packages</link>"
+                    section.
+                </para>
+            </section>
+
+            <section id='new-recipe-autotooled-package'>
+                <title>Autotooled Package</title>
+                <para>
+                    Applications that use Autotools such as <filename>autoconf</filename> and
+                    <filename>automake</filename> require a recipe that has a source archive listed in
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename> and
+                    also inherit the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-autotools'><filename>autotools</filename></ulink>
+                    class, which contains the definitions of all the steps
+                    needed to build an Autotool-based application.
+                    The result of the build is automatically packaged.
+                    And, if the application uses NLS for localization, packages with local information are
+                    generated (one package per language).
+                    Following is one example: (<filename>hello_2.3.bb</filename>)
+                    <literallayout class='monospaced'>
+     SUMMARY = "GNU Helloworld application"
+     SECTION = "examples"
+     LICENSE = "GPLv2+"
+     LIC_FILES_CHKSUM = "file://COPYING;md5=751419260aa954499f7abaabaa882bbe"
+
+     SRC_URI = "${GNU_MIRROR}/hello/hello-${PV}.tar.gz"
+
+     inherit autotools gettext
+                     </literallayout>
+                </para>
+
+                <para>
+                    The variable
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'>LIC_FILES_CHKSUM</ulink></filename>
+                    is used to track source license changes as described in the
+                    "<link linkend='usingpoky-configuring-LIC_FILES_CHKSUM'>Tracking License Changes</link>"
+                    section in the Yocto Project Overview and Concepts Manual.
+                    You can quickly create Autotool-based recipes in a manner
+                    similar to the previous example.
+                </para>
+            </section>
+
+            <section id='new-recipe-makefile-based-package'>
+                <title>Makefile-Based Package</title>
+
+                <para>
+                    Applications that use GNU <filename>make</filename> also require a recipe that has
+                    the source archive listed in
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>.
+                    You do not need to add a <filename>do_compile</filename> step since by default BitBake
+                    starts the <filename>make</filename> command to compile the application.
+                    If you need additional <filename>make</filename> options, you should store them in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OEMAKE'><filename>EXTRA_OEMAKE</filename></ulink>
+                    or
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGECONFIG_CONFARGS'><filename>PACKAGECONFIG_CONFARGS</filename></ulink>
+                    variables.
+                    BitBake passes these options into the GNU <filename>make</filename> invocation.
+                    Note that a <filename>do_install</filename> task is still required.
+                    Otherwise, BitBake runs an empty <filename>do_install</filename> task by default.
+                </para>
+
+               <para>
+                    Some applications might require extra parameters to be passed to the compiler.
+                    For example, the application might need an additional header path.
+                    You can accomplish this by adding to the
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-CFLAGS'>CFLAGS</ulink></filename> variable.
+                    The following example shows this:
+                    <literallayout class='monospaced'>
+     CFLAGS_prepend = "-I ${S}/include "
+                    </literallayout>
+                </para>
+
+                <para>
+                In the following example, <filename>mtd-utils</filename> is a makefile-based package:
+                    <literallayout class='monospaced'>
+     SUMMARY = "Tools for managing memory technology devices"
+     SECTION = "base"
+     DEPENDS = "zlib lzo e2fsprogs util-linux"
+     HOMEPAGE = "http://www.linux-mtd.infradead.org/"
+     LICENSE = "GPLv2+"
+     LIC_FILES_CHKSUM = "file://COPYING;md5=0636e73ff0215e8d672dc4c32c317bb3 \
+                         file://include/common.h;beginline=1;endline=17;md5=ba05b07912a44ea2bf81ce409380049c"
+
+     # Use the latest version at 26 Oct, 2013
+     SRCREV = "9f107132a6a073cce37434ca9cda6917dd8d866b"
+     SRC_URI = "git://git.infradead.org/mtd-utils.git \
+                     file://add-exclusion-to-mkfs-jffs2-git-2.patch \
+     "
+
+     PV = "1.5.1+git${SRCPV}"
+
+     S = "${WORKDIR}/git"
+
+     EXTRA_OEMAKE = "'CC=${CC}' 'RANLIB=${RANLIB}' 'AR=${AR}' 'CFLAGS=${CFLAGS} -I${S}/include -DWITHOUT_XATTR' 'BUILDDIR=${S}'"
+
+     do_install () {
+             oe_runmake install DESTDIR=${D} SBINDIR=${sbindir} MANDIR=${mandir} INCLUDEDIR=${includedir}
+     }
+
+     PACKAGES =+ "mtd-utils-jffs2 mtd-utils-ubifs mtd-utils-misc"
+
+     FILES_mtd-utils-jffs2 = "${sbindir}/mkfs.jffs2 ${sbindir}/jffs2dump ${sbindir}/jffs2reader ${sbindir}/sumtool"
+     FILES_mtd-utils-ubifs = "${sbindir}/mkfs.ubifs ${sbindir}/ubi*"
+     FILES_mtd-utils-misc = "${sbindir}/nftl* ${sbindir}/ftl* ${sbindir}/rfd* ${sbindir}/doc* ${sbindir}/serve_image ${sbindir}/recv_image"
+
+     PARALLEL_MAKE = ""
+
+     BBCLASSEXTEND = "native"
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='splitting-an-application-into-multiple-packages'>
+                <title>Splitting an Application into Multiple Packages</title>
+
+                <para>
+                    You can use the variables
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'>PACKAGES</ulink></filename> and
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'>FILES</ulink></filename>
+                    to split an application into multiple packages.
+                </para>
+
+                <para>
+                    Following is an example that uses the <filename>libxpm</filename> recipe.
+                    By default, this recipe generates a single package that contains the library along
+                    with a few binaries.
+                    You can modify the recipe to split the binaries into separate packages:
+                    <literallayout class='monospaced'>
+     require xorg-lib-common.inc
+
+     SUMMARY = "Xpm: X Pixmap extension library"
+     LICENSE = "BSD"
+     LIC_FILES_CHKSUM = "file://COPYING;md5=51f4270b012ecd4ab1a164f5f4ed6cf7"
+     DEPENDS += "libxext libsm libxt"
+     PE = "1"
+
+     XORG_PN = "libXpm"
+
+     PACKAGES =+ "sxpm cxpm"
+     FILES_cxpm = "${bindir}/cxpm"
+     FILES_sxpm = "${bindir}/sxpm"
+                    </literallayout>
+                </para>
+
+                <para>
+                    In the previous example, we want to ship the <filename>sxpm</filename>
+                    and <filename>cxpm</filename> binaries in separate packages.
+                    Since <filename>bindir</filename> would be packaged into the main
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'>PN</ulink></filename>
+                    package by default, we prepend the <filename>PACKAGES</filename>
+                    variable so additional package names are added to the start of list.
+                    This results in the extra <filename>FILES_*</filename>
+                    variables then containing information that define which files and
+                    directories go into which packages.
+                    Files included by earlier packages are skipped by latter packages.
+                    Thus, the main <filename>PN</filename> package
+                    does not include the above listed files.
+                </para>
+            </section>
+
+            <section id='packaging-externally-produced-binaries'>
+                <title>Packaging Externally Produced Binaries</title>
+
+                <para>
+                    Sometimes, you need to add pre-compiled binaries to an
+                    image.
+                    For example, suppose that binaries for proprietary code
+                    exist, which are created by a particular division of a
+                    company.
+                    Your part of the company needs to use those binaries as
+                    part of an image that you are building using the
+                    OpenEmbedded build system.
+                    Since you only have the binaries and not the source code,
+                    you cannot use a typical recipe that expects to fetch the
+                    source specified in
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                    and then compile it.
+                </para>
+
+                <para>
+                    One method is to package the binaries and then install them
+                    as part of the image.
+                    Generally, it is not a good idea to package binaries
+                    since, among other things, it can hinder the ability to
+                    reproduce builds and could lead to compatibility problems
+                    with ABI in the future.
+                    However, sometimes you have no choice.
+                </para>
+
+                <para>
+                    The easiest solution is to create a recipe that uses
+                    the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-bin-package'><filename>bin_package</filename></ulink>
+                    class and to be sure that you are using default locations
+                    for build artifacts.
+                    In most cases, the <filename>bin_package</filename> class
+                    handles "skipping" the configure and compile steps as well
+                    as sets things up to grab packages from the appropriate
+                    area.
+                    In particular, this class sets <filename>noexec</filename>
+                    on both the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-configure'><filename>do_configure</filename></ulink>
+                    and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-compile'><filename>do_compile</filename></ulink>
+                    tasks, sets
+                    <filename>FILES_${PN}</filename> to "/" so that it picks
+                    up all files, and sets up a
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+                    task, which effectively copies all files from
+                    <filename>${S}</filename> to <filename>${D}</filename>.
+                    The <filename>bin_package</filename> class works well when
+                    the files extracted into <filename>${S}</filename> are
+                    already laid out in the way they should be laid out
+                    on the target.
+                    For more information on these variables, see the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'><filename>FILES</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>,
+                    and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink>
+                    variables in the Yocto Project Reference Manual's variable
+                    glossary.
+                    <note><title>Notes</title>
+                        <itemizedlist>
+                            <listitem><para>
+                                Using
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                                is a good idea even for components distributed
+                                in binary form, and is often necessary for
+                                shared libraries.
+                                For a shared library, listing the library
+                                dependencies in
+                                <filename>DEPENDS</filename> makes sure that
+                                the libraries are available in the staging
+                                sysroot when other recipes link against the
+                                library, which might be necessary for
+                                successful linking.
+                                </para></listitem>
+                            <listitem><para>
+                                Using <filename>DEPENDS</filename> also
+                                allows runtime dependencies between packages
+                                to be added automatically.
+                                See the
+                                "<ulink url='&YOCTO_DOCS_OM_URL;#automatically-added-runtime-dependencies'>Automatically Added Runtime Dependencies</ulink>"
+                                section in the Yocto Project Overview and
+                                Concepts Manual for more information.
+                                </para></listitem>
+                        </itemizedlist>
+                    </note>
+                </para>
+
+                <para>
+                    If you cannot use the <filename>bin_package</filename>
+                    class, you need to be sure you are doing the following:
+                    <itemizedlist>
+                        <listitem><para>
+                            Create a recipe where the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-configure'><filename>do_configure</filename></ulink>
+                            and
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-compile'><filename>do_compile</filename></ulink>
+                            tasks do nothing:
+                            It is usually sufficient to just not define these
+                            tasks in the recipe, because the default
+                            implementations do nothing unless a Makefile is
+                            found in
+                            <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink><filename>}</filename>.
+                            </para>
+
+                            <para>If
+                            <filename>${S}</filename> might contain a Makefile,
+                            or if you inherit some class that replaces
+                            <filename>do_configure</filename> and
+                            <filename>do_compile</filename> with custom
+                            versions, then you can use the
+                            <filename>[</filename><ulink url='&YOCTO_DOCS_BB_URL;#variable-flags'><filename>noexec</filename></ulink><filename>]</filename>
+                            flag to turn the tasks into no-ops, as follows:
+                            <literallayout class='monospaced'>
+     do_configure[noexec] = "1"
+     do_compile[noexec] = "1"
+                            </literallayout>
+                            Unlike
+                            <ulink url='&YOCTO_DOCS_BB_URL;#deleting-a-task'><filename>deleting the tasks</filename></ulink>,
+                            using the flag preserves the dependency chain from
+                            the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-fetch'><filename>do_fetch</filename></ulink>,                     <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-unpack'><filename>do_unpack</filename></ulink>,
+                            and
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-patch'><filename>do_patch</filename></ulink>
+                            tasks to the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+                            task.
+                            </para></listitem>
+                        <listitem><para>Make sure your
+                            <filename>do_install</filename> task installs the
+                            binaries appropriately.
+                            </para></listitem>
+                        <listitem><para>Ensure that you set up
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'><filename>FILES</filename></ulink>
+                            (usually
+                            <filename>FILES_${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>)
+                            to point to the files you have installed, which of
+                            course depends on where you have installed them
+                            and whether those files are in different locations
+                            than the defaults.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+        </section>
+
+        <section id="following-recipe-style-guidelines">
+            <title>Following Recipe Style Guidelines</title>
+
+            <para>
+                When writing recipes, it is good to conform to existing
+                style guidelines.
+                The
+                <ulink url='http://www.openembedded.org/wiki/Styleguide'>OpenEmbedded Styleguide</ulink>
+                wiki page provides rough guidelines for preferred recipe style.
+            </para>
+
+            <para>
+                It is common for existing recipes to deviate a bit from this
+                style.
+                However, aiming for at least a consistent style is a good idea.
+                Some practices, such as omitting spaces around
+                <filename>=</filename> operators in assignments or ordering
+                recipe components in an erratic way, are widely seen as poor
+                style.
+            </para>
+        </section>
+
+        <section id='recipe-syntax'>
+            <title>Recipe Syntax</title>
+
+            <para>
+                Understanding recipe file syntax is important for writing
+                recipes.
+                The following list overviews the basic items that make up a
+                BitBake recipe file.
+                For more complete BitBake syntax descriptions, see the
+                "<ulink url='&YOCTO_DOCS_BB_URL;#bitbake-user-manual-metadata'>Syntax and Operators</ulink>"
+                chapter of the BitBake User Manual.
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Variable Assignments and Manipulations:</emphasis>
+                        Variable assignments allow a value to be assigned to a
+                        variable.
+                        The assignment can be static text or might include
+                        the contents of other variables.
+                        In addition to the assignment, appending and prepending
+                        operations are also supported.</para>
+
+                        <para>The following example shows some of the ways
+                        you can use variables in recipes:
+                        <literallayout class='monospaced'>
+     S = "${WORKDIR}/postfix-${PV}"
+     CFLAGS += "-DNO_ASM"
+     SRC_URI_append = " file://fixup.patch"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Functions:</emphasis>
+                        Functions provide a series of actions to be performed.
+                        You usually use functions to override the default
+                        implementation of a task function or to complement
+                        a default function (i.e. append or prepend to an
+                        existing function).
+                        Standard functions use <filename>sh</filename> shell
+                        syntax, although access to OpenEmbedded variables and
+                        internal methods are also available.</para>
+
+                        <para>The following is an example function from the
+                        <filename>sed</filename> recipe:
+                        <literallayout class='monospaced'>
+     do_install () {
+         autotools_do_install
+         install -d ${D}${base_bindir}
+         mv ${D}${bindir}/sed ${D}${base_bindir}/sed
+         rmdir ${D}${bindir}/
+     }
+                        </literallayout>
+                        It is also possible to implement new functions that
+                        are called between existing tasks as long as the
+                        new functions are not replacing or complementing the
+                        default functions.
+                        You can implement functions in Python
+                        instead of shell.
+                        Both of these options are not seen in the majority of
+                        recipes.
+                        </para></listitem>
+                    <listitem><para><emphasis>Keywords:</emphasis>
+                        BitBake recipes use only a few keywords.
+                        You use keywords to include common
+                        functions (<filename>inherit</filename>), load parts
+                        of a recipe from other files
+                        (<filename>include</filename> and
+                        <filename>require</filename>) and export variables
+                        to the environment (<filename>export</filename>).
+                        </para>
+
+                        <para>The following example shows the use of some of
+                        these keywords:
+                        <literallayout class='monospaced'>
+     export POSTCONF = "${STAGING_BINDIR}/postconf"
+     inherit autoconf
+     require otherfile.inc
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Comments (#):</emphasis>
+                        Any lines that begin with the hash character
+                        (<filename>#</filename>) are treated as comment lines
+                        and are ignored:
+                        <literallayout class='monospaced'>
+     # This is a comment
+                        </literallayout>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                This next list summarizes the most important and most commonly
+                used parts of the recipe syntax.
+                For more information on these parts of the syntax, you can
+                reference the
+                <ulink url='&YOCTO_DOCS_BB_URL;#bitbake-user-manual-metadata'>Syntax and Operators</ulink>
+                chapter in the BitBake User Manual.
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Line Continuation (\):</emphasis>
+                        Use the backward slash (<filename>\</filename>)
+                        character to split a statement over multiple lines.
+                        Place the slash character at the end of the line that
+                        is to be continued on the next line:
+                        <literallayout class='monospaced'>
+     VAR = "A really long \
+            line"
+                        </literallayout>
+                        <note>
+                            You cannot have any characters including spaces
+                            or tabs after the slash character.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Using Variables (${<replaceable>VARNAME</replaceable>}):</emphasis>
+                        Use the <filename>${<replaceable>VARNAME</replaceable>}</filename>
+                        syntax to access the contents of a variable:
+                        <literallayout class='monospaced'>
+     SRC_URI = "${SOURCEFORGE_MIRROR}/libpng/zlib-${PV}.tar.gz"
+                        </literallayout>
+                        <note>
+                            It is important to understand that the value of a
+                            variable expressed in this form does not get
+                            substituted automatically.
+                            The expansion of these expressions happens
+                            on-demand later (e.g. usually when a function that
+                            makes reference to the variable executes).
+                            This behavior ensures that the values are most
+                            appropriate for the context in which they are
+                            finally used.
+                            On the rare occasion that you do need the variable
+                            expression to be expanded immediately, you can use
+                            the <filename>:=</filename> operator instead of
+                            <filename>=</filename> when you make the
+                            assignment, but this is not generally needed.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Quote All Assignments ("<replaceable>value</replaceable>"):</emphasis>
+                        Use double quotes around values in all variable
+                        assignments (e.g.
+                        <filename>"<replaceable>value</replaceable>"</filename>).
+                        Following is an example:
+                        <literallayout class='monospaced'>
+     VAR1 = "${OTHERVAR}"
+     VAR2 = "The version is ${PV}"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Conditional Assignment (?=):</emphasis>
+                        Conditional assignment is used to assign a
+                        value to a variable, but only when the variable is
+                        currently unset.
+                        Use the question mark followed by the equal sign
+                        (<filename>?=</filename>) to make a "soft" assignment
+                        used for conditional assignment.
+                        Typically, "soft" assignments are used in the
+                        <filename>local.conf</filename> file for variables
+                        that are allowed to come through from the external
+                        environment.
+                        </para>
+
+                        <para>Here is an example where
+                        <filename>VAR1</filename> is set to "New value" if
+                        it is currently empty.
+                        However, if <filename>VAR1</filename> has already been
+                        set, it remains unchanged:
+                        <literallayout class='monospaced'>
+     VAR1 ?= "New value"
+                        </literallayout>
+                        In this next example, <filename>VAR1</filename>
+                        is left with the value "Original value":
+                        <literallayout class='monospaced'>
+     VAR1 = "Original value"
+     VAR1 ?= "New value"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Appending (+=):</emphasis>
+                        Use the plus character followed by the equals sign
+                        (<filename>+=</filename>) to append values to existing
+                        variables.
+                        <note>
+                            This operator adds a space between the existing
+                            content of the variable and the new content.
+                        </note></para>
+
+                        <para>Here is an example:
+                        <literallayout class='monospaced'>
+     SRC_URI += "file://fix-makefile.patch"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Prepending (=+):</emphasis>
+                        Use the equals sign followed by the plus character
+                        (<filename>=+</filename>) to prepend values to existing
+                        variables.
+                        <note>
+                            This operator adds a space between the new content
+                            and the existing content of the variable.
+                        </note></para>
+
+                        <para>Here is an example:
+                        <literallayout class='monospaced'>
+     VAR =+ "Starts"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Appending (_append):</emphasis>
+                        Use the <filename>_append</filename> operator to
+                        append values to existing variables.
+                        This operator does not add any additional space.
+                        Also, the operator is applied after all the
+                        <filename>+=</filename>, and
+                        <filename>=+</filename> operators have been applied and
+                        after all <filename>=</filename> assignments have
+                        occurred.
+                        </para>
+
+                        <para>The following example shows the space being
+                        explicitly added to the start to ensure the appended
+                        value is not merged with the existing value:
+                        <literallayout class='monospaced'>
+     SRC_URI_append = " file://fix-makefile.patch"
+                        </literallayout>
+                        You can also use the <filename>_append</filename>
+                        operator with overrides, which results in the actions
+                        only being performed for the specified target or
+                        machine:
+                        <literallayout class='monospaced'>
+     SRC_URI_append_sh4 = " file://fix-makefile.patch"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Prepending (_prepend):</emphasis>
+                        Use the <filename>_prepend</filename> operator to
+                        prepend values to existing variables.
+                        This operator does not add any additional space.
+                        Also, the operator is applied after all the
+                        <filename>+=</filename>, and
+                        <filename>=+</filename> operators have been applied and
+                        after all <filename>=</filename> assignments have
+                        occurred.
+                        </para>
+
+                        <para>The following example shows the space being
+                        explicitly added to the end to ensure the prepended
+                        value is not merged with the existing value:
+                        <literallayout class='monospaced'>
+     CFLAGS_prepend = "-I${S}/myincludes "
+                        </literallayout>
+                        You can also use the <filename>_prepend</filename>
+                        operator with overrides, which results in the actions
+                        only being performed for the specified target or
+                        machine:
+                        <literallayout class='monospaced'>
+     CFLAGS_prepend_sh4 = "-I${S}/myincludes "
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Overrides:</emphasis>
+                        You can use overrides to set a value conditionally,
+                        typically based on how the recipe is being built.
+                        For example, to set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-KBRANCH'><filename>KBRANCH</filename></ulink>
+                        variable's value to "standard/base" for any target
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>,
+                        except for qemuarm where it should be set to
+                        "standard/arm-versatile-926ejs", you would do the
+                        following:
+                        <literallayout class='monospaced'>
+     KBRANCH = "standard/base"
+     KBRANCH_qemuarm  = "standard/arm-versatile-926ejs"
+                        </literallayout>
+                        Overrides are also used to separate alternate values
+                        of a variable in other situations.
+                        For example, when setting variables such as
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'><filename>FILES</filename></ulink>
+                        and
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>
+                        that are specific to individual packages produced by
+                        a recipe, you should always use an override that
+                        specifies the name of the package.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Indentation:</emphasis>
+                        Use spaces for indentation rather than than tabs.
+                        For shell functions, both currently work.
+                        However, it is a policy decision of the Yocto Project
+                        to use tabs in shell functions.
+                        Realize that some layers have a policy to use spaces
+                        for all indentation.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Using Python for Complex Operations:</emphasis>
+                        For more advanced processing, it is possible to use
+                        Python code during variable assignments (e.g.
+                        search and replacement on a variable).</para>
+
+                        <para>You indicate Python code using the
+                        <filename>${@<replaceable>python_code</replaceable>}</filename>
+                        syntax for the variable assignment:
+                        <literallayout class='monospaced'>
+     SRC_URI = "ftp://ftp.info-zip.org/pub/infozip/src/zip${@d.getVar('PV',1).replace('.', '')}.tgz
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Shell Function Syntax:</emphasis>
+                        Write shell functions as if you were writing a shell
+                        script when you describe a list of actions to take.
+                        You should ensure that your script works with a generic
+                        <filename>sh</filename> and that it does not require
+                        any <filename>bash</filename> or other shell-specific
+                        functionality.
+                        The same considerations apply to various system
+                        utilities (e.g. <filename>sed</filename>,
+                        <filename>grep</filename>, <filename>awk</filename>,
+                        and so forth) that you might wish to use.
+                        If in doubt, you should check with multiple
+                        implementations - including those from BusyBox.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+    </section>
+
+    <section id="platdev-newmachine">
+        <title>Adding a New Machine</title>
+
+        <para>
+            Adding a new machine to the Yocto Project is a straightforward
+            process.
+            This section describes how to add machines that are similar
+            to those that the Yocto Project already supports.
+            <note>
+                Although well within the capabilities of the Yocto Project,
+                adding a totally new architecture might require
+                changes to <filename>gcc/glibc</filename> and to the site
+                information, which is beyond the scope of this manual.
+            </note>
+        </para>
+
+        <para>
+            For a complete example that shows how to add a new machine,
+            see the
+            "<ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-bitbake-layers-script'>Creating a New BSP Layer Using the <filename>bitbake-layers</filename> Script</ulink>"
+            section in the Yocto Project Board Support Package (BSP)
+            Developer's Guide.
+        </para>
+
+        <section id="platdev-newmachine-conffile">
+            <title>Adding the Machine Configuration File</title>
+
+            <para>
+                To add a new machine, you need to add a new machine
+                configuration file to the layer's
+                <filename>conf/machine</filename> directory.
+                This configuration file provides details about the device
+                you are adding.
+            </para>
+
+            <para>
+                The OpenEmbedded build system uses the root name of the
+                machine configuration file to reference the new machine.
+                For example, given a machine configuration file named
+                <filename>crownbay.conf</filename>, the build system
+                recognizes the machine as "crownbay".
+            </para>
+
+            <para>
+                The most important variables you must set in your machine
+                configuration file or include from a lower-level configuration
+                file are as follows:
+                <itemizedlist>
+                    <listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-TARGET_ARCH'>TARGET_ARCH</ulink></filename>
+                        (e.g. "arm")</para></listitem>
+                    <listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PREFERRED_PROVIDER'>PREFERRED_PROVIDER</ulink>_virtual/kernel</filename>
+                        </para></listitem>
+                    <listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_FEATURES'>MACHINE_FEATURES</ulink></filename>
+                        (e.g. "apm screen wifi")</para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                You might also need these variables:
+                <itemizedlist>
+                    <listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SERIAL_CONSOLES'>SERIAL_CONSOLES</ulink></filename>
+                        (e.g. "115200;ttyS0 115200;ttyS1")</para></listitem>
+                    <listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_IMAGETYPE'>KERNEL_IMAGETYPE</ulink></filename>
+                        (e.g. "zImage")</para></listitem>
+                    <listitem><para><filename><ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FSTYPES'>IMAGE_FSTYPES</ulink></filename>
+                        (e.g. "tar.gz jffs2")</para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                You can find full details on these variables in the reference
+                section.
+                You can leverage existing machine <filename>.conf</filename>
+                files from <filename>meta-yocto-bsp/conf/machine/</filename>.
+            </para>
+        </section>
+
+        <section id="platdev-newmachine-kernel">
+            <title>Adding a Kernel for the Machine</title>
+
+            <para>
+                The OpenEmbedded build system needs to be able to build a kernel
+                for the machine.
+                You need to either create a new kernel recipe for this machine,
+                or extend an existing kernel recipe.
+                You can find several kernel recipe examples in the
+                Source Directory at
+                <filename>meta/recipes-kernel/linux</filename>
+                that you can use as references.
+            </para>
+
+            <para>
+                If you are creating a new kernel recipe, normal recipe-writing
+                rules apply for setting up a
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>.
+                Thus, you need to specify any necessary patches and set
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'>S</ulink></filename>
+                to point at the source code.
+                You need to create a <filename>do_configure</filename> task that
+                configures the unpacked kernel with a
+                <filename>defconfig</filename> file.
+                You can do this by using a <filename>make defconfig</filename>
+                command or, more commonly, by copying in a suitable
+                <filename>defconfig</filename> file and then running
+                <filename>make oldconfig</filename>.
+                By making use of <filename>inherit kernel</filename> and
+                potentially some of the <filename>linux-*.inc</filename> files,
+                most other functionality is centralized and the defaults of the
+                class normally work well.
+            </para>
+
+            <para>
+                If you are extending an existing kernel recipe, it is usually
+                a matter of adding a suitable <filename>defconfig</filename>
+                file.
+                The file needs to be added into a location similar to
+                <filename>defconfig</filename> files used for other machines
+                in a given kernel recipe.
+                A possible way to do this is by listing the file in the
+                <filename>SRC_URI</filename> and adding the machine to the
+                expression in
+                <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-COMPATIBLE_MACHINE'>COMPATIBLE_MACHINE</ulink></filename>:
+                <literallayout class='monospaced'>
+     COMPATIBLE_MACHINE = '(qemux86|qemumips)'
+                </literallayout>
+                For more information on <filename>defconfig</filename> files,
+                see the
+                "<ulink url='&YOCTO_DOCS_KERNEL_DEV_URL;#changing-the-configuration'>Changing the Configuration</ulink>"
+                section in the Yocto Project Linux Kernel Development Manual.
+            </para>
+        </section>
+
+        <section id="platdev-newmachine-formfactor">
+            <title>Adding a Formfactor Configuration File</title>
+
+            <para>
+                A formfactor configuration file provides information about the
+                target hardware for which the image is being built and information that
+                the build system cannot obtain from other sources such as the kernel.
+                Some examples of information contained in a formfactor configuration file include
+                framebuffer orientation, whether or not the system has a keyboard,
+                the positioning of the keyboard in relation to the screen, and
+                the screen resolution.
+            </para>
+
+            <para>
+                The build system uses reasonable defaults in most cases.
+                However, if customization is
+                necessary, you need to create a <filename>machconfig</filename> file
+                in the <filename>meta/recipes-bsp/formfactor/files</filename>
+                directory.
+                This directory contains directories for specific machines such as
+                <filename>qemuarm</filename> and <filename>qemux86</filename>.
+                For information about the settings available and the defaults, see the
+                <filename>meta/recipes-bsp/formfactor/files/config</filename> file found in the
+                same area.
+            </para>
+
+            <para>
+                Following is an example for "qemuarm" machine:
+                <literallayout class='monospaced'>
+     HAVE_TOUCHSCREEN=1
+     HAVE_KEYBOARD=1
+
+     DISPLAY_CAN_ROTATE=0
+     DISPLAY_ORIENTATION=0
+     #DISPLAY_WIDTH_PIXELS=640
+     #DISPLAY_HEIGHT_PIXELS=480
+     #DISPLAY_BPP=16
+     DISPLAY_DPI=150
+     DISPLAY_SUBPIXEL_ORDER=vrgb
+                </literallayout>
+            </para>
+        </section>
+    </section>
+
+    <section id='gs-upgrading-recipes'>
+        <title>Upgrading Recipes</title>
+
+        <para>
+            Over time, upstream developers publish new versions for software
+            built by layer recipes.
+            It is recommended to keep recipes up-to-date with upstream
+            version releases.
+        </para>
+
+        <para>
+            While several methods exist that allow you upgrade a recipe,
+            you might consider checking on the upgrade status of a recipe
+            first.
+            You can do so using the
+            <filename>devtool check-upgrade-status</filename> command.
+            See the
+            "<ulink url='&YOCTO_DOCS_REF_URL;#devtool-checking-on-the-upgrade-status-of-a-recipe'>Checking on the Upgrade Status of a Recipe</ulink>"
+            section in the Yocto Project Reference Manual for more information.
+        </para>
+
+        <para>
+            The remainder of this section describes three ways you can
+            upgrade a recipe.
+            You can use the Automated Upgrade Helper (AUH) to set up
+            automatic version upgrades.
+            Alternatively, you can use <filename>devtool upgrade</filename>
+            to set up semi-automatic version upgrades.
+            Finally, you can manually upgrade a recipe by editing the
+            recipe itself.
+        </para>
+
+        <section id='gs-using-the-auto-upgrade-helper'>
+            <title>Using the Auto Upgrade Helper (AUH)</title>
+
+            <para>
+                The AUH utility works in conjunction with the
+                OpenEmbedded build system in order to automatically generate
+                upgrades for recipes based on new versions being
+                published upstream.
+                Use AUH when you want to create a service that performs the
+                upgrades automatically and optionally sends you an email with
+                the results.
+            </para>
+
+            <para>
+                AUH allows you to update several recipes with a single use.
+                You can also optionally perform build and integration tests
+                using images with the results saved to your hard drive and
+                emails of results optionally sent to recipe maintainers.
+                Finally, AUH creates Git commits with appropriate commit
+                messages in the layer's tree for the changes made to recipes.
+                <note>
+                    Conditions do exist when you should not use AUH to upgrade
+                    recipes and you should instead use either
+                    <filename>devtool upgrade</filename> or upgrade your
+                    recipes manually:
+                    <itemizedlist>
+                        <listitem><para>
+                            When AUH cannot complete the upgrade sequence.
+                            This situation usually results because custom
+                            patches carried by the recipe cannot be
+                            automatically rebased to the new version.
+                            In this case, <filename>devtool upgrade</filename>
+                            allows you to manually resolve conflicts.
+                            </para></listitem>
+                        <listitem><para>
+                            When for any reason you want fuller control over
+                            the upgrade process.
+                            For example, when you want special arrangements
+                            for testing.
+                            </para></listitem>
+                    </itemizedlist>
+                </note>
+            </para>
+
+            <para>
+                The following steps describe how to set up the AUH utility:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Be Sure the Development Host is Set Up:</emphasis>
+                        You need to be sure that your development host is
+                        set up to use the Yocto Project.
+                        For information on how to set up your host, see the
+                        "<link linkend='dev-preparing-the-build-host'>Preparing the Build Host</link>"
+                        section.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Make Sure Git is Configured:</emphasis>
+                        The AUH utility requires Git to be configured because
+                        AUH uses Git to save upgrades.
+                        Thus, you must have Git user and email configured.
+                        The following command shows your configurations:
+                        <literallayout class='monospaced'>
+     $ git config --list
+                        </literallayout>
+                        If you do not have the user and email configured, you
+                        can use the following commands to do so:
+                        <literallayout class='monospaced'>
+     $ git config --global user.name <replaceable>some_name</replaceable>
+     $ git config --global user.email <replaceable>username</replaceable>@<replaceable>domain</replaceable>.com
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Clone the AUH Repository:</emphasis>
+                        To use AUH, you must clone the repository onto your
+                        development host.
+                        The following command uses Git to create a local
+                        copy of the repository on your system:
+                        <literallayout class='monospaced'>
+     $ git clone git://git.yoctoproject.org/auto-upgrade-helper
+     Cloning into 'auto-upgrade-helper'...
+     remote: Counting objects: 768, done.
+     remote: Compressing objects: 100% (300/300), done.
+     remote: Total 768 (delta 499), reused 703 (delta 434)
+     Receiving objects: 100% (768/768), 191.47 KiB | 98.00 KiB/s, done.
+     Resolving deltas: 100% (499/499), done.
+     Checking connectivity... done.
+                        </literallayout>
+                        AUH is not part of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#oe-core'>OpenEmbedded-Core (OE-Core)</ulink>
+                        or
+                        <ulink url='&YOCTO_DOCS_REF_URL;#poky'>Poky</ulink>
+                        repositories.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create a Dedicated Build Directory:</emphasis>
+                        Run the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>oe-init-build-env</filename></ulink>
+                        script to create a fresh build directory that you
+                        use exclusively for running the AUH utility:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky
+     $ source oe-init-build-env <replaceable>your_AUH_build_directory</replaceable>
+                        </literallayout>
+                        Re-using an existing build directory and its
+                        configurations is not recommended as existing settings
+                        could cause AUH to fail or behave undesirably.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Make Configurations in Your Local Configuration File:</emphasis>
+                        Several settings need to exist in the
+                        <filename>local.conf</filename> file in the build
+                        directory you just created for AUH.
+                        Make these following configurations:
+                        <itemizedlist>
+                            <listitem><para>
+                                If you want to enable
+                                <ulink url='&YOCTO_DOCS_DEV_URL;#maintaining-build-output-quality'>Build History</ulink>,
+                                which is optional, you need the following
+                                lines in the
+                                <filename>conf/local.conf</filename> file:
+                                <literallayout class='monospaced'>
+     INHERIT =+ "buildhistory"
+     BUILDHISTORY_COMMIT = "1"
+                                </literallayout>
+                                With this configuration and a successful
+                                upgrade, a build history "diff" file appears in
+                                the
+                                <filename>upgrade-helper/work/recipe/buildhistory-diff.txt</filename>
+                                file found in your build directory.
+                                </para></listitem>
+                            <listitem><para>
+                                If you want to enable testing through the
+                                <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-testimage*'><filename>testimage</filename></ulink>
+                                class, which is optional, you need to have the
+                                following set in your
+                                <filename>conf/local.conf</filename> file:
+                                <literallayout class='monospaced'>
+     INHERIT += "testimage"
+                                </literallayout>
+                                <note>
+                                    If your distro does not enable by default
+                                    ptest, which Poky does, you need the
+                                    following in your
+                                    <filename>local.conf</filename> file:
+                                    <literallayout class='monospaced'>
+     DISTRO_FEATURES_append = " ptest"
+                                    </literallayout>
+                                </note>
+                                </para></listitem>
+                        </itemizedlist>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Optionally Start a vncserver:</emphasis>
+                        If you are running in a server without an X11 session,
+                        you need to start a vncserver:
+                        <literallayout class='monospaced'>
+     $ vncserver :1
+     $ export DISPLAY=:1
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create and Edit an AUH Configuration File:</emphasis>
+                        You need to have the
+                        <filename>upgrade-helper/upgrade-helper.conf</filename>
+                        configuration file in your build directory.
+                        You can find a sample configuration file in the
+                        <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/auto-upgrade-helper/tree/'>AUH source repository</ulink>.
+                        </para>
+
+                        <para>Read through the sample file and make
+                        configurations as needed.
+                        For example, if you enabled build history in your
+                        <filename>local.conf</filename> as described earlier,
+                        you must enable it in
+                        <filename>upgrade-helper.conf</filename>.</para>
+
+                        <para>Also, if you are using the default
+                        <filename>maintainers.inc</filename> file supplied
+                        with Poky and located in
+                        <filename>meta-yocto</filename> and you do not set a
+                        "maintainers_whitelist" or "global_maintainer_override"
+                        in the <filename>upgrade-helper.conf</filename>
+                        configuration, and you specify "-e all" on the
+                        AUH command-line, the utility automatically sends out
+                        emails to all the default maintainers.
+                        Please avoid this.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                This next set of examples describes how to use the AUH:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Upgrading a Specific Recipe:</emphasis>
+                        To upgrade a specific recipe, use the following
+                        form:
+                        <literallayout class='monospaced'>
+     $ upgrade-helper.py <replaceable>recipe_name</replaceable>
+                        </literallayout>
+                        For example, this command upgrades the
+                        <filename>xmodmap</filename> recipe:
+                        <literallayout class='monospaced'>
+     $ upgrade-helper.py xmodmap
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Upgrading a Specific Recipe to a Particular Version:</emphasis>
+                        To upgrade a specific recipe to a particular version,
+                        use the following form:
+                        <literallayout class='monospaced'>
+     $ upgrade-helper.py <replaceable>recipe_name</replaceable> -t <replaceable>version</replaceable>
+                        </literallayout>
+                        For example, this command upgrades the
+                        <filename>xmodmap</filename> recipe to version
+                        1.2.3:
+                        <literallayout class='monospaced'>
+     $ upgrade-helper.py xmodmap -t 1.2.3
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Upgrading all Recipes to the Latest Versions and Suppressing Email Notifications:</emphasis>
+                        To upgrade all recipes to their most recent versions
+                        and suppress the email notifications, use the following
+                        command:
+                        <literallayout class='monospaced'>
+     $ upgrade-helper.py all
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Upgrading all Recipes to the Latest Versions and Send Email Notifications:</emphasis>
+                        To upgrade all recipes to their most recent versions
+                        and send email messages to maintainers for each
+                        attempted recipe as well as a status email, use the
+                        following command:
+                        <literallayout class='monospaced'>
+     $ upgrade-helper.py -e all
+                        </literallayout>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Once you have run the AUH utility, you can find the results
+                in the AUH build directory:
+                <literallayout class='monospaced'>
+     ${BUILDDIR}/upgrade-helper/<replaceable>timestamp</replaceable>
+                </literallayout>
+                The AUH utility also creates recipe update commits from
+                successful upgrade attempts in the layer tree.
+            </para>
+
+            <para>
+                You can easily set up to run the AUH utility on a regular
+                basis by using a cron job.
+                See the
+                <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/auto-upgrade-helper/tree/weeklyjob.sh'><filename>weeklyjob.sh</filename></ulink>
+                file distributed with the utility for an example.
+            </para>
+        </section>
+
+        <section id='gs-using-devtool-upgrade'>
+            <title>Using <filename>devtool upgrade</filename></title>
+
+            <para>
+                As mentioned earlier, an alternative method for upgrading
+                recipes to newer versions is to use
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-devtool-reference'><filename>devtool upgrade</filename></ulink>.
+                You can read about <filename>devtool upgrade</filename> in
+                general in the
+                "<ulink url='&YOCTO_DOCS_SDK_URL;#sdk-devtool-use-devtool-upgrade-to-create-a-version-of-the-recipe-that-supports-a-newer-version-of-the-software'>Use <filename>devtool upgrade</filename> to Create a Version of the Recipe that Supports a Newer Version of the Software</ulink>"
+                section in the Yocto Project Application Development and the
+                Extensible Software Development Kit (eSDK) Manual.
+            </para>
+
+            <para>
+                To see all the command-line options available with
+                <filename>devtool upgrade</filename>, use the following help
+                command:
+                <literallayout class='monospaced'>
+     $ devtool upgrade -h
+                </literallayout>
+            </para>
+
+            <para>
+                If you want to find out what version a recipe is currently at
+                upstream without any attempt to upgrade your local version of
+                the recipe, you can use the following command:
+                <literallayout class='monospaced'>
+     $ devtool latest-version <replaceable>recipe_name</replaceable>
+                </literallayout>
+            </para>
+
+            <para>
+                As mentioned in the previous section describing AUH,
+                <filename>devtool upgrade</filename> works in a
+                less-automated manner than AUH.
+                Specifically, <filename>devtool upgrade</filename> only
+                works on a single recipe that you name on the command line,
+                cannot perform build and integration testing using images,
+                and does not automatically generate commits for changes in
+                the source tree.
+                Despite all these "limitations",
+                <filename>devtool upgrade</filename> updates the recipe file
+                to the new upstream version and attempts to rebase custom
+                patches contained by the recipe as needed.
+                <note>
+                    AUH uses much of <filename>devtool upgrade</filename>
+                    behind the scenes making AUH somewhat of a "wrapper"
+                    application for <filename>devtool upgrade</filename>.
+                </note>
+            </para>
+
+            <para>
+                A typical scenario involves having used Git to clone an
+                upstream repository that you use during build operations.
+                Because you are (or have) built the recipe in the past, the
+                layer is likely added to your configuration already.
+                If for some reason, the layer is not added, you could add
+                it easily using the
+                <ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-bitbake-layers-script'><filename>bitbake-layers</filename></ulink>
+                script.
+                For example, suppose you use the <filename>nano.bb</filename>
+                recipe from the <filename>meta-oe</filename> layer in the
+                <filename>meta-openembedded</filename> repository.
+                For this example, assume that the layer has been cloned into
+                following area:
+                <literallayout class='monospaced'>
+     /home/scottrif/meta-openembedded
+                </literallayout>
+                The following command from your
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                adds the layer to your build configuration (i.e.
+                <filename>${BUILDDIR}/conf/bblayers.conf</filename>):
+                <literallayout class='monospaced'>
+     $ bitbake-layers add-layer /home/scottrif/meta-openembedded/meta-oe
+     NOTE: Starting bitbake server...
+     Parsing recipes: 100% |##########################################| Time: 0:00:55
+     Parsing of 1431 .bb files complete (0 cached, 1431 parsed). 2040 targets, 56 skipped, 0 masked, 0 errors.
+     Removing 12 recipes from the x86_64 sysroot: 100% |##############| Time: 0:00:00
+     Removing 1 recipes from the x86_64_i586 sysroot: 100% |##########| Time: 0:00:00
+     Removing 5 recipes from the i586 sysroot: 100% |#################| Time: 0:00:00
+     Removing 5 recipes from the qemux86 sysroot: 100% |##############| Time: 0:00:00
+                </literallayout>
+                For this example, assume that the <filename>nano.bb</filename>
+                recipe that is upstream has a 2.9.3 version number.
+                However, the version in the local repository is 2.7.4.
+                The following command from your build directory automatically
+                upgrades the recipe for you:
+                <note>
+                    Using the <filename>-V</filename> option is not necessary.
+                    Omitting the version number causes
+                    <filename>devtool upgrade</filename> to upgrade the recipe
+                    to the most recent version.
+                </note>
+                <literallayout class='monospaced'>
+     $ devtool upgrade nano -V 2.9.3
+     NOTE: Starting bitbake server...
+     NOTE: Creating workspace layer in /home/scottrif/poky/build/workspace
+     Parsing recipes: 100% |##########################################| Time: 0:00:46
+     Parsing of 1431 .bb files complete (0 cached, 1431 parsed). 2040 targets, 56 skipped, 0 masked, 0 errors.
+     NOTE: Extracting current version source...
+     NOTE: Resolving any missing task queue dependencies
+            .
+            .
+            .
+     NOTE: Executing SetScene Tasks
+     NOTE: Executing RunQueue Tasks
+     NOTE: Tasks Summary: Attempted 74 tasks of which 72 didn't need to be rerun and all succeeded.
+     Adding changed files: 100% |#####################################| Time: 0:00:00
+     NOTE: Upgraded source extracted to /home/scottrif/poky/build/workspace/sources/nano
+     NOTE: New recipe is /home/scottrif/poky/build/workspace/recipes/nano/nano_2.9.3.bb
+                </literallayout>
+                Continuing with this example, you can use
+                <filename>devtool build</filename> to build the newly upgraded
+                recipe:
+                <literallayout class='monospaced'>
+     $ devtool build nano
+     NOTE: Starting bitbake server...
+     Loading cache: 100% |################################################################################################| Time: 0:00:01
+     Loaded 2040 entries from dependency cache.
+     Parsing recipes: 100% |##############################################################################################| Time: 0:00:00
+     Parsing of 1432 .bb files complete (1431 cached, 1 parsed). 2041 targets, 56 skipped, 0 masked, 0 errors.
+     NOTE: Resolving any missing task queue dependencies
+            .
+            .
+            .
+     NOTE: Executing SetScene Tasks
+     NOTE: Executing RunQueue Tasks
+     NOTE: nano: compiling from external source tree /home/scottrif/poky/build/workspace/sources/nano
+     NOTE: Tasks Summary: Attempted 520 tasks of which 304 didn't need to be rerun and all succeeded.
+                </literallayout>
+                Within the <filename>devtool upgrade</filename> workflow,
+                opportunity exists to deploy and test your rebuilt software.
+                For this example, however, running
+                <filename>devtool finish</filename> cleans up the workspace
+                once the source in your workspace is clean.
+                This usually means using Git to stage and submit commits
+                for the changes generated by the upgrade process.
+            </para>
+
+            <para>
+                Once the tree is clean, you can clean things up in this
+                example with the following command from the
+                <filename>${BUILDDIR}/workspace/sources/nano</filename>
+                directory:
+                <literallayout class='monospaced'>
+     $ devtool finish nano meta-oe
+     NOTE: Starting bitbake server...
+     Loading cache: 100% |################################################################################################| Time: 0:00:00
+     Loaded 2040 entries from dependency cache.
+     Parsing recipes: 100% |##############################################################################################| Time: 0:00:01
+     Parsing of 1432 .bb files complete (1431 cached, 1 parsed). 2041 targets, 56 skipped, 0 masked, 0 errors.
+     NOTE: Adding new patch 0001-nano.bb-Stuff-I-changed-when-upgrading-nano.bb.patch
+     NOTE: Updating recipe nano_2.9.3.bb
+     NOTE: Removing file /home/scottrif/meta-openembedded/meta-oe/recipes-support/nano/nano_2.7.4.bb
+     NOTE: Moving recipe file to /home/scottrif/meta-openembedded/meta-oe/recipes-support/nano
+     NOTE: Leaving source tree /home/scottrif/poky/build/workspace/sources/nano as-is; if you no longer need it then please delete it manually
+                </literallayout>
+                Using the <filename>devtool finish</filename> command cleans
+                up the workspace and creates a patch file based on your
+                commits.
+                The tool puts all patch files back into the source directory
+                in a sub-directory named <filename>nano</filename> in this
+                case.
+            </para>
+        </section>
+
+        <section id='dev-manually-upgrading-a-recipe'>
+            <title>Manually Upgrading a Recipe</title>
+
+            <para>
+                If for some reason you choose not to upgrade recipes using the
+                <link linkend='gs-using-the-auto-upgrade-helper'>Auto Upgrade Helper (AUH)</link>
+                or by using
+                <link linkend='gs-using-devtool-upgrade'><filename>devtool upgrade</filename></link>,
+                you can manually edit the recipe files to upgrade the versions.
+                <note><title>Caution</title>
+                    Manually updating multiple recipes scales poorly and
+                    involves many steps.
+                    The recommendation to upgrade recipe versions is through
+                    AUH or <filename>devtool upgrade</filename>, both of which
+                    automate some steps and provide guidance for others needed
+                    for the manual process.
+                </note>
+            </para>
+
+            <para>
+                To manually upgrade recipe versions, follow these general steps:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Change the Version:</emphasis>
+                        Rename the recipe such that the version (i.e. the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+                        part of the recipe name) changes appropriately.
+                        If the version is not part of the recipe name, change
+                        the value as it is set for <filename>PV</filename>
+                        within the recipe itself.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Update <filename>SRCREV</filename> if Needed:</emphasis>
+                        If the source code your recipe builds is fetched from
+                        Git or some other version control system, update
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCREV'><filename>SRCREV</filename></ulink>
+                        to point to the commit hash that matches the new
+                        version.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Build the Software:</emphasis>
+                        Try to build the recipe using BitBake.
+                        Typical build failures include the following:
+                        <itemizedlist>
+                            <listitem><para>
+                                License statements were updated for the new
+                                version.
+                                For this case, you need to review any changes
+                                to the license and update the values of
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE</filename></ulink>
+                                and
+                                <ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></ulink>
+                                as needed.
+                                <note>
+                                    License changes are often inconsequential.
+                                    For example, the license text's copyright
+                                    year might have changed.
+                                </note>
+                                </para></listitem>
+                            <listitem><para>
+                                Custom patches carried by the older version of
+                                the recipe might fail to apply to the new
+                                version.
+                                For these cases, you need to review the
+                                failures.
+                                Patches might not be necessary for the new
+                                version of the software if the upgraded version
+                                has fixed those issues.
+                                If a patch is necessary and failing, you need
+                                to rebase it into the new version.
+                                </para></listitem>
+                        </itemizedlist>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Optionally Attempt to Build for Several Architectures:</emphasis>
+                        Once you successfully build the new software for a
+                        given architecture, you could test the build for
+                        other architectures by changing the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                        variable and rebuilding the software.
+                        This optional step is especially important if the
+                        recipe is to be released publicly.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Check the Upstream Change Log or Release Notes:</emphasis>
+                        Checking both these reveals if new features exist that
+                        could break backwards-compatibility.
+                        If so, you need to take steps to mitigate or eliminate
+                        that situation.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Optionally Create a Bootable Image and Test:</emphasis>
+                        If you want, you can test the new software by booting
+                        it onto actual hardware.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create a Commit with the Change in the Layer Repository:</emphasis>
+                        After all builds work and any testing is successful,
+                        you can create commits for any changes in the layer
+                        holding your upgraded recipe.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+    </section>
+
+    <section id='finding-the-temporary-source-code'>
+        <title>Finding Temporary Source Code</title>
+
+        <para>
+            You might find it helpful during development to modify the
+            temporary source code used by recipes to build packages.
+            For example, suppose you are developing a patch and you need to
+            experiment a bit to figure out your solution.
+            After you have initially built the package, you can iteratively
+            tweak the source code, which is located in the
+            <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>,
+            and then you can force a re-compile and quickly test your altered
+            code.
+            Once you settle on a solution, you can then preserve your changes
+            in the form of patches.
+        </para>
+
+        <para>
+            During a build, the unpacked temporary source code used by recipes
+            to build packages is available in the Build Directory as
+            defined by the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>
+            variable.
+            Below is the default value for the <filename>S</filename> variable
+            as defined in the
+            <filename>meta/conf/bitbake.conf</filename> configuration file
+            in the
+            <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>:
+            <literallayout class='monospaced'>
+     S = "${WORKDIR}/${BP}"
+            </literallayout>
+            You should be aware that many recipes override the
+            <filename>S</filename> variable.
+            For example, recipes that fetch their source from Git usually set
+            <filename>S</filename> to <filename>${WORKDIR}/git</filename>.
+            <note>
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BP'><filename>BP</filename></ulink>
+                represents the base recipe name, which consists of the name
+                and version:
+                <literallayout class='monospaced'>
+     BP = "${BPN}-${PV}"
+                </literallayout>
+            </note>
+        </para>
+
+        <para>
+            The path to the work directory for the recipe
+            (<ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>)
+            is defined as follows:
+            <literallayout class='monospaced'>
+     ${TMPDIR}/work/${MULTIMACH_TARGET_SYS}/${PN}/${EXTENDPE}${PV}-${PR}
+            </literallayout>
+            The actual directory depends on several things:
+            <itemizedlist>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>:
+                    The top-level build output directory.
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-MULTIMACH_TARGET_SYS'><filename>MULTIMACH_TARGET_SYS</filename></ulink>:
+                    The target system identifier.
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>:
+                    The recipe name.
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTENDPE'><filename>EXTENDPE</filename></ulink>:
+                    The epoch - (if
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PE'><filename>PE</filename></ulink>
+                    is not specified, which is usually the case for most
+                    recipes, then <filename>EXTENDPE</filename> is blank).
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>:
+                    The recipe version.
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>:
+                    The recipe revision.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <para>
+            As an example, assume a Source Directory top-level folder
+            named <filename>poky</filename>, a default Build Directory at
+            <filename>poky/build</filename>, and a
+            <filename>qemux86-poky-linux</filename> machine target
+            system.
+            Furthermore, suppose your recipe is named
+            <filename>foo_1.3.0.bb</filename>.
+            In this case, the work directory the build system uses to
+            build the package would be as follows:
+            <literallayout class='monospaced'>
+     poky/build/tmp/work/qemux86-poky-linux/foo/1.3.0-r0
+            </literallayout>
+        </para>
+    </section>
+
+    <section id="using-a-quilt-workflow">
+        <title>Using Quilt in Your Workflow</title>
+
+        <para>
+            <ulink url='http://savannah.nongnu.org/projects/quilt'>Quilt</ulink>
+            is a powerful tool that allows you to capture source code changes
+            without having a clean source tree.
+            This section outlines the typical workflow you can use to modify
+            source code, test changes, and then preserve the changes in the
+            form of a patch all using Quilt.
+            <note><title>Tip</title>
+                With regard to preserving changes to source files, if you
+                clean a recipe or have <filename>rm_work</filename> enabled,
+                the
+                <ulink url='&YOCTO_DOCS_SDK_URL;#using-devtool-in-your-sdk-workflow'><filename>devtool</filename> workflow</ulink>
+                as described in the Yocto Project Application Development
+                and the Extensible Software Development Kit (eSDK) manual
+                is a safer development flow than the flow that uses Quilt.
+            </note>
+        </para>
+
+        <para>
+            Follow these general steps:
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Find the Source Code:</emphasis>
+                    Temporary source code used by the OpenEmbedded build system
+                    is kept in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                    See the
+                    "<link linkend='finding-the-temporary-source-code'>Finding Temporary Source Code</link>"
+                    section to learn how to locate the directory that has the
+                    temporary source code for a particular package.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Change Your Working Directory:</emphasis>
+                    You need to be in the directory that has the temporary
+                    source code.
+                    That directory is defined by the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>
+                    variable.</para></listitem>
+                <listitem><para>
+                    <emphasis>Create a New Patch:</emphasis>
+                    Before modifying source code, you need to create a new
+                    patch.
+                    To create a new patch file, use
+                    <filename>quilt new</filename> as below:
+                    <literallayout class='monospaced'>
+     $ quilt new my_changes.patch
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Notify Quilt and Add Files:</emphasis>
+                    After creating the patch, you need to notify Quilt about
+                    the files you plan to edit.
+                    You notify Quilt by adding the files to the patch you
+                    just created:
+                    <literallayout class='monospaced'>
+     $ quilt add file1.c file2.c file3.c
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Edit the Files:</emphasis>
+                    Make your changes in the source code to the files you added
+                    to the patch.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Test Your Changes:</emphasis>
+                    Once you have modified the source code, the easiest way to
+                    test your changes is by calling the
+                    <filename>do_compile</filename> task as shown in the
+                    following example:
+                    <literallayout class='monospaced'>
+     $ bitbake -c compile -f <replaceable>package</replaceable>
+                    </literallayout>
+                    The <filename>-f</filename> or <filename>--force</filename>
+                    option forces the specified task to execute.
+                    If you find problems with your code, you can just keep
+                    editing and re-testing iteratively until things work
+                    as expected.
+                    <note>
+                        All the modifications you make to the temporary
+                        source code disappear once you run the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-clean'><filename>do_clean</filename></ulink>
+                        or
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-cleanall'><filename>do_cleanall</filename></ulink>
+                        tasks using BitBake (i.e.
+                        <filename>bitbake -c clean <replaceable>package</replaceable></filename>
+                        and
+                        <filename>bitbake -c cleanall <replaceable>package</replaceable></filename>).
+                        Modifications will also disappear if you use the
+                        <filename>rm_work</filename> feature as described
+                        in the
+                        "<ulink url='&YOCTO_DOCS_DEV_URL;#dev-saving-memory-during-a-build'>Conserving Disk Space During Builds</ulink>"
+                        section.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Generate the Patch:</emphasis>
+                    Once your changes work as expected, you need to use Quilt
+                    to generate the final patch that contains all your
+                    modifications.
+                    <literallayout class='monospaced'>
+     $ quilt refresh
+                    </literallayout>
+                    At this point, the <filename>my_changes.patch</filename>
+                    file has all your edits made to the
+                    <filename>file1.c</filename>, <filename>file2.c</filename>,
+                    and <filename>file3.c</filename> files.</para>
+
+                    <para>You can find the resulting patch file in the
+                    <filename>patches/</filename> subdirectory of the source
+                    (<filename>S</filename>) directory.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Copy the Patch File:</emphasis>
+                    For simplicity, copy the patch file into a directory
+                    named <filename>files</filename>, which you can create
+                    in the same directory that holds the recipe
+                    (<filename>.bb</filename>) file or the append
+                    (<filename>.bbappend</filename>) file.
+                    Placing the patch here guarantees that the OpenEmbedded
+                    build system will find the patch.
+                    Next, add the patch into the
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'>SRC_URI</ulink></filename>
+                    of the recipe.
+                    Here is an example:
+                    <literallayout class='monospaced'>
+     SRC_URI += "file://my_changes.patch"
+                    </literallayout>
+                    </para></listitem>
+            </orderedlist>
+        </para>
+    </section>
+
+    <section id="platdev-appdev-devshell">
+        <title>Using a Development Shell</title>
+
+        <para>
+            When debugging certain commands or even when just editing packages,
+            <filename>devshell</filename> can be a useful tool.
+            When you invoke <filename>devshell</filename>, all tasks up to and
+            including
+            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-patch'><filename>do_patch</filename></ulink>
+            are run for the specified target.
+            Then, a new terminal is opened and you are placed in
+            <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink><filename>}</filename>,
+            the source directory.
+            In the new terminal, all the OpenEmbedded build-related environment variables are
+            still defined so you can use commands such as <filename>configure</filename> and
+            <filename>make</filename>.
+            The commands execute just as if the OpenEmbedded build system were executing them.
+            Consequently, working this way can be helpful when debugging a build or preparing
+            software to be used with the OpenEmbedded build system.
+        </para>
+
+        <para>
+            Following is an example that uses <filename>devshell</filename> on a target named
+            <filename>matchbox-desktop</filename>:
+            <literallayout class='monospaced'>
+     $ bitbake matchbox-desktop -c devshell
+            </literallayout>
+        </para>
+
+        <para>
+            This command spawns a terminal with a shell prompt within the OpenEmbedded build environment.
+            The <ulink url='&YOCTO_DOCS_REF_URL;#var-OE_TERMINAL'><filename>OE_TERMINAL</filename></ulink>
+            variable controls what type of shell is opened.
+        </para>
+
+        <para>
+            For spawned terminals, the following occurs:
+            <itemizedlist>
+                <listitem><para>The <filename>PATH</filename> variable includes the
+                    cross-toolchain.</para></listitem>
+                <listitem><para>The <filename>pkgconfig</filename> variables find the correct
+                    <filename>.pc</filename> files.</para></listitem>
+                <listitem><para>The <filename>configure</filename> command finds the
+                    Yocto Project site files as well as any other necessary files.</para></listitem>
+            </itemizedlist>
+        </para>
+
+        <para>
+            Within this environment, you can run configure or compile
+            commands as if they were being run by
+            the OpenEmbedded build system itself.
+            As noted earlier, the working directory also automatically changes to the
+            Source Directory (<ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>).
+        </para>
+
+        <para>
+            To manually run a specific task using <filename>devshell</filename>,
+            run the corresponding <filename>run.*</filename> script in
+            the
+            <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink><filename>}/temp</filename>
+            directory (e.g.,
+            <filename>run.do_configure.</filename><replaceable>pid</replaceable>).
+            If a task's script does not exist, which would be the case if the task was
+            skipped by way of the sstate cache, you can create the task by first running
+            it outside of the <filename>devshell</filename>:
+            <literallayout class='monospaced'>
+     $ bitbake -c <replaceable>task</replaceable>
+            </literallayout>
+            <note><title>Notes</title>
+                <itemizedlist>
+                    <listitem><para>Execution of a task's <filename>run.*</filename>
+                        script and BitBake's execution of a task are identical.
+                        In other words, running the script re-runs the task
+                        just as it would be run using the
+                        <filename>bitbake -c</filename> command.
+                        </para></listitem>
+                    <listitem><para>Any <filename>run.*</filename> file that does not
+                        have a <filename>.pid</filename> extension is a
+                        symbolic link (symlink) to the most recent version of that
+                        file.
+                        </para></listitem>
+                </itemizedlist>
+            </note>
+        </para>
+
+        <para>
+            Remember, that the <filename>devshell</filename> is a mechanism that allows
+            you to get into the BitBake task execution environment.
+            And as such, all commands must be called just as BitBake would call them.
+            That means you need to provide the appropriate options for
+            cross-compilation and so forth as applicable.
+        </para>
+
+        <para>
+            When you are finished using <filename>devshell</filename>, exit the shell
+            or close the terminal window.
+        </para>
+
+        <note><title>Notes</title>
+            <itemizedlist>
+                <listitem><para>
+                    It is worth remembering that when using <filename>devshell</filename>
+                    you need to use the full compiler name such as <filename>arm-poky-linux-gnueabi-gcc</filename>
+                    instead of just using <filename>gcc</filename>.
+                    The same applies to other applications such as <filename>binutils</filename>,
+                    <filename>libtool</filename> and so forth.
+                    BitBake sets up environment variables such as <filename>CC</filename>
+                    to assist applications, such as <filename>make</filename> to find the correct tools.
+                    </para></listitem>
+                <listitem><para>
+                    It is also worth noting that <filename>devshell</filename> still works over
+                    X11 forwarding and similar situations.
+                    </para></listitem>
+            </itemizedlist>
+        </note>
+    </section>
+
+    <section id="platdev-appdev-devpyshell">
+        <title>Using a Development Python Shell</title>
+
+        <para>
+            Similar to working within a development shell as described in
+            the previous section, you can also spawn and work within an
+            interactive Python development shell.
+            When debugging certain commands or even when just editing packages,
+            <filename>devpyshell</filename> can be a useful tool.
+            When you invoke <filename>devpyshell</filename>, all tasks up to and
+            including
+            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-patch'><filename>do_patch</filename></ulink>
+            are run for the specified target.
+            Then a new terminal is opened.
+            Additionally, key Python objects and code are available in the same
+            way they are to BitBake tasks, in particular, the data store 'd'.
+            So, commands such as the following are useful when exploring the data
+            store and running functions:
+            <literallayout class='monospaced'>
+     pydevshell> d.getVar("STAGING_DIR")
+     '/media/build1/poky/build/tmp/sysroots'
+     pydevshell> d.getVar("STAGING_DIR")
+     '${TMPDIR}/sysroots'
+     pydevshell> d.setVar("FOO", "bar")
+     pydevshell> d.getVar("FOO")
+     'bar'
+     pydevshell> d.delVar("FOO")
+     pydevshell> d.getVar("FOO")
+     pydevshell> bb.build.exec_func("do_unpack", d)
+     pydevshell>
+            </literallayout>
+            The commands execute just as if the OpenEmbedded build system were executing them.
+            Consequently, working this way can be helpful when debugging a build or preparing
+            software to be used with the OpenEmbedded build system.
+        </para>
+
+        <para>
+            Following is an example that uses <filename>devpyshell</filename> on a target named
+            <filename>matchbox-desktop</filename>:
+            <literallayout class='monospaced'>
+     $ bitbake matchbox-desktop -c devpyshell
+            </literallayout>
+        </para>
+
+        <para>
+            This command spawns a terminal and places you in an interactive
+            Python interpreter within the OpenEmbedded build environment.
+            The <ulink url='&YOCTO_DOCS_REF_URL;#var-OE_TERMINAL'><filename>OE_TERMINAL</filename></ulink>
+            variable controls what type of shell is opened.
+        </para>
+
+        <para>
+            When you are finished using <filename>devpyshell</filename>, you
+            can exit the shell either by using Ctrl+d or closing the terminal
+            window.
+        </para>
+    </section>
+
+    <section id='dev-building'>
+        <title>Building</title>
+
+        <para>
+            This section describes various build procedures.
+            For example, the steps needed for a simple build, a target that
+            uses multiple configurations, building an image for more than
+            one machine, and so forth.
+        </para>
+
+        <section id='dev-building-a-simple-image'>
+            <title>Building a Simple Image</title>
+
+            <para>
+                In the development environment, you need to build an image
+                whenever you change hardware support, add or change system
+                libraries, or add or change services that have dependencies.
+                Several methods exist that allow you to build an image within
+                the Yocto Project.
+                This section presents the basic steps you need to build a
+                simple image using BitBake from a build host running Linux.
+                <note><title>Notes</title>
+                    <itemizedlist>
+                        <listitem><para>
+                            For information on how to build an image using
+                            <ulink url='&YOCTO_DOCS_REF_URL;#toaster-term'>Toaster</ulink>,
+                            see the
+                            <ulink url='&YOCTO_DOCS_TOAST_URL;'>Toaster User Manual</ulink>.
+                            </para></listitem>
+                        <listitem><para>
+                            For information on how to use
+                            <filename>devtool</filename> to build images, see
+                            the
+                            "<ulink url='&YOCTO_DOCS_SDK_URL;#using-devtool-in-your-sdk-workflow'>Using <filename>devtool</filename> in Your SDK Workflow</ulink>"
+                            section in the Yocto Project Application
+                            Development and the Extensible Software Development
+                            Kit (eSDK) manual.
+                            </para></listitem>
+                        <listitem><para>
+                            For a quick example on how to build an image using
+                            the OpenEmbedded build system, see the
+                            <ulink url='&YOCTO_DOCS_BRIEF_URL;'>Yocto Project Quick Build</ulink>
+                            document.
+                            </para></listitem>
+                    </itemizedlist>
+                </note>
+            </para>
+
+            <para>
+                The build process creates an entire Linux distribution from
+                source and places it in your
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                under <filename>tmp/deploy/images</filename>.
+                For detailed information on the build process using BitBake,
+                see the
+                "<ulink url='&YOCTO_DOCS_OM_URL;#images-dev-environment'>Images</ulink>"
+                section in the Yocto Project Overview and Concepts Manual.
+            </para>
+
+            <para>
+                The following figure and list overviews the build process:
+                <imagedata fileref="figures/bitbake-build-flow.png" width="7in" depth="4in" align="center" scalefit="1" />
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Set up Your Host Development System to Support
+                        Development Using the Yocto Project</emphasis>:
+                        See the
+                        "<link linkend='dev-manual-start'>Setting Up to Use the Yocto Project</link>"
+                        section for options on how to get a build host ready to
+                        use the Yocto Project.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Initialize the Build Environment:</emphasis>
+                        Initialize the build environment by sourcing the build
+                        environment script (i.e.
+                        <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>&OE_INIT_FILE;</filename></ulink>):
+                        <literallayout class='monospaced'>
+     $ source &OE_INIT_FILE; [<replaceable>build_dir</replaceable>]
+                        </literallayout></para>
+
+                        <para>When you use the initialization script, the
+                        OpenEmbedded build system uses
+                        <filename>build</filename> as the default Build
+                        Directory in your current work directory.
+                        You can use a <replaceable>build_dir</replaceable>
+                        argument with the script to specify a different build
+                        directory.
+                        <note><title>Tip</title>
+                            A common practice is to use a different Build
+                            Directory for different targets.
+                            For example, <filename>~/build/x86</filename> for a
+                            <filename>qemux86</filename> target, and
+                            <filename>~/build/arm</filename> for a
+                            <filename>qemuarm</filename> target.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Make Sure Your <filename>local.conf</filename>
+                        File is Correct:</emphasis>
+                        Ensure the <filename>conf/local.conf</filename>
+                        configuration file, which is found in the Build
+                        Directory, is set up how you want it.
+                        This file defines many aspects of the build environment
+                        including the target machine architecture through the
+                        <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'>MACHINE</ulink></filename> variable,
+                        the packaging format used during the build
+                        (<ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_CLASSES'><filename>PACKAGE_CLASSES</filename></ulink>),
+                        and a centralized tarball download directory through the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-DL_DIR'><filename>DL_DIR</filename></ulink> variable.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Build the Image:</emphasis>
+                        Build the image using the <filename>bitbake</filename>
+                        command:
+                        <literallayout class='monospaced'>
+     $ bitbake <replaceable>target</replaceable>
+                        </literallayout>
+                        <note>
+                            For information on BitBake, see the
+                            <ulink url='&YOCTO_DOCS_BB_URL;'>BitBake User Manual</ulink>.
+                        </note>
+                        The <replaceable>target</replaceable> is the name of the
+                        recipe you want to build.
+                        Common targets are the images in
+                        <filename>meta/recipes-core/images</filename>,
+                        <filename>meta/recipes-sato/images</filename>, and so
+                        forth all found in the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
+                        Or, the target can be the name of a recipe for a
+                        specific piece of software such as BusyBox.
+                        For more details about the images the OpenEmbedded build
+                        system supports, see the
+                        "<ulink url='&YOCTO_DOCS_REF_URL;#ref-images'>Images</ulink>"
+                        chapter in the Yocto Project Reference Manual.</para>
+
+                        <para>As an example, the following command builds the
+                        <filename>core-image-minimal</filename> image:
+                        <literallayout class='monospaced'>
+     $ bitbake core-image-minimal
+                        </literallayout>
+                        Once an image has been built, it often needs to be
+                        installed.
+                        The images and kernels built by the OpenEmbedded
+                        build system are placed in the Build Directory in
+                        <filename class="directory">tmp/deploy/images</filename>.
+                        For information on how to run pre-built images such as
+                        <filename>qemux86</filename> and <filename>qemuarm</filename>,
+                        see the
+                        <ulink url='&YOCTO_DOCS_SDK_URL;'>Yocto Project Application Development and the Extensible Software Development Kit (eSDK)</ulink>
+                        manual.
+                        For information about how to install these images,
+                        see the documentation for your particular board or
+                        machine.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+
+        <section id='dev-building-images-for-multiple-targets-using-multiple-configurations'>
+            <title>Building Images for Multiple Targets Using Multiple Configurations</title>
+
+            <para>
+                You can use a single <filename>bitbake</filename> command
+                to build multiple images or packages for different targets
+                where each image or package requires a different configuration
+                (multiple configuration builds).
+                The builds, in this scenario, are sometimes referred to as
+                "multiconfigs", and this section uses that term throughout.
+            </para>
+
+            <para>
+                This section describes how to set up for multiple
+                configuration builds and how to account for cross-build
+                dependencies between the multiconfigs.
+            </para>
+
+            <section id='dev-setting-up-and-running-a-multiple-configuration-build'>
+                <title>Setting Up and Running a Multiple Configuration Build</title>
+
+                <para>
+                    To accomplish a multiple configuration build, you must
+                    define each target's configuration separately using
+                    a parallel configuration file in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>,
+                    and you must follow a required file hierarchy.
+                    Additionally, you must enable the multiple configuration
+                    builds in your <filename>local.conf</filename> file.
+                </para>
+
+                <para>
+                    Follow these steps to set up and execute multiple
+                    configuration builds:
+                    <itemizedlist>
+                        <listitem><para>
+                            <emphasis>Create Separate Configuration Files</emphasis>:
+                            You need to create a single configuration file for
+                            each build target (each multiconfig).
+                            Minimally, each configuration file must define the
+                            machine and the temporary directory BitBake uses
+                            for the build.
+                            Suggested practice dictates that you do not
+                            overlap the temporary directories
+                            used during the builds.
+                            However, it is possible that you can share the
+                            temporary directory
+                            (<ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>).
+                            For example, consider a scenario with two
+                            different multiconfigs for the same
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>: "qemux86" built for
+                            two distributions such as "poky" and "poky-lsb".
+                            In this case, you might want to use the same
+                            <filename>TMPDIR</filename>.</para>
+
+                            <para>Here is an example showing the minimal
+                            statements needed in a configuration file for
+                            a "qemux86" target whose temporary build directory
+                            is <filename>tmpmultix86</filename>:
+                            <literallayout class='monospaced'>
+     MACHINE="qemux86"
+     TMPDIR="${TOPDIR}/tmpmultix86"
+                            </literallayout></para>
+
+                            <para>The location for these multiconfig
+                            configuration files is specific.
+                            They must reside in the current build directory in
+                            a sub-directory of <filename>conf</filename> named
+                            <filename>multiconfig</filename>.
+                            Following is an example that defines two
+                            configuration files for the "x86" and "arm"
+                            multiconfigs:
+                            <imagedata fileref="figures/multiconfig_files.png" align="center" width="4in" depth="3in" />
+                            </para>
+
+                            <para>The reason for this required file hierarchy
+                            is because the <filename>BBPATH</filename> variable
+                            is not constructed until the layers are parsed.
+                            Consequently, using the configuration file as a
+                            pre-configuration file is not possible unless it is
+                            located in the current working directory.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Add the BitBake Multi-configuration Variable to the Local Configuration File</emphasis>:
+                            Use the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-BBMULTICONFIG'><filename>BBMULTICONFIG</filename></ulink>
+                            variable in your
+                            <filename>conf/local.conf</filename> configuration
+                            file to specify each multiconfig.
+                            Continuing with the example from the previous
+                            figure, the <filename>BBMULTICONFIG</filename>
+                            variable needs to enable two multiconfigs: "x86"
+                            and "arm" by specifying each configuration file:
+                            <literallayout class='monospaced'>
+     BBMULTICONFIG = "x86 arm"
+                            </literallayout>
+                            <note>
+                                A "default" configuration already exists by
+                                definition.
+                                This configuration is named: "" (i.e. empty
+                                string) and is defined by the variables coming
+                                from your <filename>local.conf</filename> file.
+                                Consequently, the previous example actually
+                                adds two additional configurations to your
+                                build: "arm" and "x86" along with "".
+                            </note>
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Launch BitBake</emphasis>:
+                            Use the following BitBake command form to launch the
+                            multiple configuration build:
+                            <literallayout class='monospaced'>
+     $ bitbake [mc:<replaceable>multiconfigname</replaceable>:]<replaceable>target</replaceable> [[[mc:<replaceable>multiconfigname</replaceable>:]<replaceable>target</replaceable>] ... ]
+                            </literallayout>
+                            For the example in this section, the following
+                            command applies:
+                            <literallayout class='monospaced'>
+     $ bitbake mc:x86:core-image-minimal mc:arm:core-image-sato mc::core-image-base
+                            </literallayout>
+                            The previous BitBake command builds a
+                            <filename>core-image-minimal</filename> image that
+                            is configured through the
+                            <filename>x86.conf</filename> configuration file,
+                            a <filename>core-image-sato</filename>
+                            image that is configured through the
+                            <filename>arm.conf</filename> configuration file
+                            and a <filename>core-image-base</filename> that is
+                            configured through your
+                            <filename>local.conf</filename> configuration file.
+                            </para></listitem>
+                    </itemizedlist>
+                    <note>
+                        Support for multiple configuration builds in the
+                        Yocto Project &DISTRO; (&DISTRO_NAME;) Release does
+                        not include Shared State (sstate) optimizations.
+                        Consequently, if a build uses the same object twice
+                        in, for example, two different
+                        <filename>TMPDIR</filename> directories, the build
+                        either loads from an existing sstate cache for that
+                        build at the start or builds the object fresh.
+                    </note>
+                </para>
+            </section>
+
+            <section id='dev-enabling-multiple-configuration-build-dependencies'>
+                <title>Enabling Multiple Configuration Build Dependencies</title>
+
+                <para>
+                    Sometimes dependencies can exist between targets
+                    (multiconfigs) in a multiple configuration build.
+                    For example, suppose that in order to build a
+                    <filename>core-image-sato</filename> image for an "x86"
+                    multiconfig, the root filesystem of an "arm"
+                    multiconfig must exist.
+                    This dependency is essentially that the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-image'><filename>do_image</filename></ulink>
+                    task in the <filename>core-image-sato</filename> recipe
+                    depends on the completion of the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-rootfs'><filename>do_rootfs</filename></ulink>
+                    task of the <filename>core-image-minimal</filename>
+                    recipe.
+                </para>
+
+                <para>
+                    To enable dependencies in a multiple configuration
+                    build, you must declare the dependencies in the recipe
+                    using the following statement form:
+                    <literallayout class='monospaced'>
+     <replaceable>task_or_package</replaceable>[mcdepends] = "mc:<replaceable>from_multiconfig</replaceable>:<replaceable>to_multiconfig</replaceable>:<replaceable>recipe_name</replaceable>:<replaceable>task_on_which_to_depend</replaceable>"
+                    </literallayout>
+                    To better show how to use this statement, consider the
+                    example scenario from the first paragraph of this section.
+                    The following statement needs to be added to the recipe
+                    that builds the <filename>core-image-sato</filename>
+                    image:
+                    <literallayout class='monospaced'>
+     do_image[mcdepends] = "mc:x86:arm:core-image-minimal:do_rootfs"
+                    </literallayout>
+                    In this example, the
+                    <replaceable>from_multiconfig</replaceable> is "x86".
+                    The <replaceable>to_multiconfig</replaceable> is "arm".
+                    The task on which the <filename>do_image</filename> task
+                    in the recipe depends is the <filename>do_rootfs</filename>
+                    task from the <filename>core-image-minimal</filename>
+                    recipe associated with the "arm" multiconfig.
+               </para>
+
+               <para>
+                   Once you set up this dependency, you can build the
+                   "x86" multiconfig using a BitBake command as follows:
+                   <literallayout class='monospaced'>
+     $ bitbake mc:x86:core-image-sato
+                   </literallayout>
+                   This command executes all the tasks needed to create
+                   the <filename>core-image-sato</filename> image for the
+                   "x86" multiconfig.
+                   Because of the dependency, BitBake also executes through
+                   the <filename>do_rootfs</filename> task for the "arm"
+                   multiconfig build.
+               </para>
+
+               <para>
+                   Having a recipe depend on the root filesystem of another
+                   build might not seem that useful.
+                   Consider this change to the statement in the
+                   <filename>core-image-sato</filename> recipe:
+                   <literallayout class='monospaced'>
+     do_image[mcdepends] = "mc:x86:arm:core-image-minimal:do_image"
+                   </literallayout>
+                   In this case, BitBake must create the
+                   <filename>core-image-minimal</filename> image for the
+                   "arm" build since the "x86" build depends on it.
+               </para>
+
+               <para>
+                   Because "x86" and "arm" are enabled for multiple
+                   configuration builds and have separate configuration
+                   files, BitBake places the artifacts for each build in the
+                   respective temporary build directories (i.e.
+                   <ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>).
+               </para>
+            </section>
+        </section>
+
+        <section id='building-an-initramfs-image'>
+            <title>Building an Initial RAM Filesystem (initramfs) Image</title>
+
+            <para>
+                An initial RAM filesystem (initramfs) image provides a temporary
+                root filesystem used for early system initialization (e.g.
+                loading of modules needed to locate and mount the "real" root
+                filesystem).
+                <note>
+                    The initramfs image is the successor of initial RAM disk
+                    (initrd).
+                    It is a "copy in and out" (cpio) archive of the initial
+                    filesystem that gets loaded into memory during the Linux
+                    startup process.
+                    Because Linux uses the contents of the archive during
+                    initialization, the initramfs image needs to contain all of the
+                    device drivers and tools needed to mount the final root
+                    filesystem.
+                </note>
+            </para>
+
+            <para>
+                Follow these steps to create an initramfs image:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Create the initramfs Image Recipe:</emphasis>
+                        You can reference the
+                        <filename>core-image-minimal-initramfs.bb</filename>
+                        recipe found in the <filename>meta/recipes-core</filename>
+                        directory of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                        as an example from which to work.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Decide if You Need to Bundle the initramfs Image
+                        Into the Kernel Image:</emphasis>
+                        If you want the initramfs image that is built to be
+                        bundled in with the kernel image, set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-INITRAMFS_IMAGE_BUNDLE'><filename>INITRAMFS_IMAGE_BUNDLE</filename></ulink>
+                        variable to "1" in your <filename>local.conf</filename>
+                        configuration file and set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-INITRAMFS_IMAGE'><filename>INITRAMFS_IMAGE</filename></ulink>
+                        variable in the recipe that builds the kernel image.
+                        <note><title>Tip</title>
+                            It is recommended that you do bundle the initramfs
+                            image with the kernel image to avoid circular
+                            dependencies between the kernel recipe and the
+                            initramfs recipe should the initramfs image
+                            include kernel modules.
+                        </note>
+                        Setting the <filename>INITRAMFS_IMAGE_BUNDLE</filename>
+                        flag causes the initramfs image to be unpacked
+                        into the <filename>${B}/usr/</filename> directory.
+                        The unpacked initramfs image is then passed to the kernel's
+                        <filename>Makefile</filename> using the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-CONFIG_INITRAMFS_SOURCE'><filename>CONFIG_INITRAMFS_SOURCE</filename></ulink>
+                        variable, allowing the initramfs image to be built into
+                        the kernel normally.
+                        <note>
+                            If you choose to not bundle the initramfs image with
+                            the kernel image, you are essentially using an
+                            <ulink url='https://en.wikipedia.org/wiki/Initrd'>Initial RAM Disk (initrd)</ulink>.
+                            Creating an initrd is handled primarily through the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-INITRD_IMAGE'><filename>INITRD_IMAGE</filename></ulink>,
+                            <filename>INITRD_LIVE</filename>, and
+                            <filename>INITRD_IMAGE_LIVE</filename> variables.
+                            For more information, see the
+                            <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/poky/tree/meta/classes/image-live.bbclass'><filename>image-live.bbclass</filename></ulink>
+                            file.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Optionally Add Items to the initramfs Image
+                        Through the initramfs Image Recipe:</emphasis>
+                        If you add items to the initramfs image by way of its
+                        recipe, you should use
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_INSTALL'><filename>PACKAGE_INSTALL</filename></ulink>
+                        rather than
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'><filename>IMAGE_INSTALL</filename></ulink>.
+                        <filename>PACKAGE_INSTALL</filename> gives more direct
+                        control of what is added to the image as compared to
+                        the defaults you might not necessarily want that are
+                        set by the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-image'><filename>image</filename></ulink>
+                        or
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-core-image'><filename>core-image</filename></ulink>
+                        classes.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Build the Kernel Image and the initramfs
+                        Image:</emphasis>
+                        Build your kernel image using BitBake.
+                        Because the initramfs image recipe is a dependency of the
+                        kernel image, the initramfs image is built as well and
+                        bundled with the kernel image if you used the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-INITRAMFS_IMAGE_BUNDLE'><filename>INITRAMFS_IMAGE_BUNDLE</filename></ulink>
+                        variable described earlier.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+
+        <section id='building-a-tiny-system'>
+            <title>Building a Tiny System</title>
+
+            <para>
+                Very small distributions have some significant advantages such
+                as requiring less on-die or in-package memory (cheaper), better
+                performance through efficient cache usage, lower power requirements
+                due to less memory, faster boot times, and reduced development
+                overhead.
+                Some real-world examples where a very small distribution gives
+                you distinct advantages are digital cameras, medical devices,
+                and small headless systems.
+            </para>
+
+            <para>
+                This section presents information that shows you how you can
+                trim your distribution to even smaller sizes than the
+                <filename>poky-tiny</filename> distribution, which is around
+                5 Mbytes, that can be built out-of-the-box using the Yocto Project.
+            </para>
+
+            <section id='tiny-system-overview'>
+                <title>Overview</title>
+
+                <para>
+                    The following list presents the overall steps you need to
+                    consider and perform to create distributions with smaller
+                    root filesystems, achieve faster boot times, maintain your critical
+                    functionality, and avoid initial RAM disks:
+                    <itemizedlist>
+                        <listitem><para>
+                            <link linkend='goals-and-guiding-principles'>Determine your goals and guiding principles.</link>
+                            </para></listitem>
+                        <listitem><para>
+                            <link linkend='understand-what-gives-your-image-size'>Understand what contributes to your image size.</link>
+                            </para></listitem>
+                        <listitem><para>
+                            <link linkend='trim-the-root-filesystem'>Reduce the size of the root filesystem.</link>
+                            </para></listitem>
+                        <listitem><para>
+                            <link linkend='trim-the-kernel'>Reduce the size of the kernel.</link>
+                            </para></listitem>
+                        <listitem><para>
+                            <link linkend='remove-package-management-requirements'>Eliminate packaging requirements.</link>
+                            </para></listitem>
+                        <listitem><para>
+                            <link linkend='look-for-other-ways-to-minimize-size'>Look for other ways to minimize size.</link>
+                            </para></listitem>
+                        <listitem><para>
+                            <link linkend='iterate-on-the-process'>Iterate on the process.</link>
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='goals-and-guiding-principles'>
+                <title>Goals and Guiding Principles</title>
+
+                <para>
+                    Before you can reach your destination, you need to know
+                    where you are going.
+                    Here is an example list that you can use as a guide when
+                    creating very small distributions:
+                    <itemizedlist>
+                        <listitem><para>Determine how much space you need
+                            (e.g. a kernel that is 1 Mbyte or less and
+                            a root filesystem that is 3 Mbytes or less).
+                            </para></listitem>
+                        <listitem><para>Find the areas that are currently
+                            taking 90% of the space and concentrate on reducing
+                            those areas.
+                            </para></listitem>
+                        <listitem><para>Do not create any difficult "hacks"
+                            to achieve your goals.</para></listitem>
+                        <listitem><para>Leverage the device-specific
+                            options.</para></listitem>
+                        <listitem><para>Work in a separate layer so that you
+                            keep changes isolated.
+                            For information on how to create layers, see
+                            the "<link linkend='understanding-and-creating-layers'>Understanding and Creating Layers</link>" section.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='understand-what-gives-your-image-size'>
+                <title>Understand What Contributes to Your Image Size</title>
+
+                <para>
+                    It is easiest to have something to start with when creating
+                    your own distribution.
+                    You can use the Yocto Project out-of-the-box to create the
+                    <filename>poky-tiny</filename> distribution.
+                    Ultimately, you will want to make changes in your own
+                    distribution that are likely modeled after
+                    <filename>poky-tiny</filename>.
+                    <note>
+                        To use <filename>poky-tiny</filename> in your build,
+                        set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO'><filename>DISTRO</filename></ulink>
+                        variable in your
+                        <filename>local.conf</filename> file to "poky-tiny"
+                        as described in the
+                        "<link linkend='creating-your-own-distribution'>Creating Your Own Distribution</link>"
+                        section.
+                    </note>
+                </para>
+
+                <para>
+                    Understanding some memory concepts will help you reduce the
+                    system size.
+                    Memory consists of static, dynamic, and temporary memory.
+                    Static memory is the TEXT (code), DATA (initialized data
+                    in the code), and BSS (uninitialized data) sections.
+                    Dynamic memory represents memory that is allocated at runtime:
+                    stacks, hash tables, and so forth.
+                    Temporary memory is recovered after the boot process.
+                    This memory consists of memory used for decompressing
+                    the kernel and for the <filename>__init__</filename>
+                    functions.
+                </para>
+
+                <para>
+                    To help you see where you currently are with kernel and root
+                    filesystem sizes, you can use two tools found in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink> in
+                    the <filename>scripts/tiny/</filename> directory:
+                    <itemizedlist>
+                        <listitem><para><filename>ksize.py</filename>: Reports
+                            component sizes for the kernel build objects.
+                            </para></listitem>
+                        <listitem><para><filename>dirsize.py</filename>: Reports
+                            component sizes for the root filesystem.</para></listitem>
+                    </itemizedlist>
+                    This next tool and command help you organize configuration
+                    fragments and view file dependencies in a human-readable form:
+                    <itemizedlist>
+                        <listitem><para><filename>merge_config.sh</filename>:
+                            Helps you manage configuration files and fragments
+                            within the kernel.
+                            With this tool, you can merge individual configuration
+                            fragments together.
+                            The tool allows you to make overrides and warns you
+                            of any missing configuration options.
+                            The tool is ideal for allowing you to iterate on
+                            configurations, create minimal configurations, and
+                            create configuration files for different machines
+                            without having to duplicate your process.</para>
+                            <para>The <filename>merge_config.sh</filename> script is
+                            part of the Linux Yocto kernel Git repositories
+                            (i.e. <filename>linux-yocto-3.14</filename>,
+                            <filename>linux-yocto-3.10</filename>,
+                            <filename>linux-yocto-3.8</filename>, and so forth)
+                            in the
+                            <filename>scripts/kconfig</filename> directory.</para>
+                            <para>For more information on configuration fragments,
+                            see the
+                            "<ulink url='&YOCTO_DOCS_KERNEL_DEV_URL;#creating-config-fragments'>Creating Configuration Fragments</ulink>"
+                            section in the Yocto Project Linux Kernel Development
+                            Manual.
+                            </para></listitem>
+                        <listitem><para><filename>bitbake -u taskexp -g <replaceable>bitbake_target</replaceable></filename>:
+                            Using the BitBake command with these options brings up
+                            a Dependency Explorer from which you can view file
+                            dependencies.
+                            Understanding these dependencies allows you to make
+                            informed decisions when cutting out various pieces of the
+                            kernel and root filesystem.</para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='trim-the-root-filesystem'>
+                <title>Trim the Root Filesystem</title>
+
+                <para>
+                    The root filesystem is made up of packages for booting,
+                    libraries, and applications.
+                    To change things, you can configure how the packaging happens,
+                    which changes the way you build them.
+                    You can also modify the filesystem itself or select a different
+                    filesystem.
+                </para>
+
+                <para>
+                    First, find out what is hogging your root filesystem by running the
+                    <filename>dirsize.py</filename> script from your root directory:
+                    <literallayout class='monospaced'>
+     $ cd <replaceable>root-directory-of-image</replaceable>
+     $ dirsize.py 100000 > dirsize-100k.log
+     $ cat dirsize-100k.log
+                    </literallayout>
+                    You can apply a filter to the script to ignore files under
+                    a certain size.
+                    The previous example filters out any files below 100 Kbytes.
+                    The sizes reported by the tool are uncompressed, and thus
+                    will be smaller by a relatively constant factor in a
+                    compressed root filesystem.
+                    When you examine your log file, you can focus on areas of the
+                    root filesystem that take up large amounts of memory.
+                </para>
+
+                <para>
+                    You need to be sure that what you eliminate does not cripple
+                    the functionality you need.
+                    One way to see how packages relate to each other is by using
+                    the Dependency Explorer UI with the BitBake command:
+                    <literallayout class='monospaced'>
+     $ cd <replaceable>image-directory</replaceable>
+     $ bitbake -u taskexp -g <replaceable>image</replaceable>
+                    </literallayout>
+                    Use the interface to select potential packages you wish to
+                    eliminate and see their dependency relationships.
+                </para>
+
+                <para>
+                    When deciding how to reduce the size, get rid of packages that
+                    result in minimal impact on the feature set.
+                    For example, you might not need a VGA display.
+                    Or, you might be able to get by with <filename>devtmpfs</filename>
+                    and <filename>mdev</filename> instead of
+                    <filename>udev</filename>.
+                </para>
+
+                <para>
+                    Use your <filename>local.conf</filename> file to make changes.
+                    For example, to eliminate <filename>udev</filename> and
+                    <filename>glib</filename>, set the following in the
+                    local configuration file:
+                    <literallayout class='monospaced'>
+     VIRTUAL-RUNTIME_dev_manager = ""
+                    </literallayout>
+                </para>
+
+                <para>
+                    Finally, you should consider exactly the type of root
+                    filesystem you need to meet your needs while also reducing
+                    its size.
+                    For example, consider <filename>cramfs</filename>,
+                    <filename>squashfs</filename>, <filename>ubifs</filename>,
+                    <filename>ext2</filename>, or an <filename>initramfs</filename>
+                    using <filename>initramfs</filename>.
+                    Be aware that <filename>ext3</filename> requires a 1 Mbyte
+                    journal.
+                    If you are okay with running read-only, you do not need this
+                    journal.
+                </para>
+
+                <note>
+                    After each round of elimination, you need to rebuild your
+                    system and then use the tools to see the effects of your
+                    reductions.
+                </note>
+            </section>
+
+            <section id='trim-the-kernel'>
+                <title>Trim the Kernel</title>
+
+                <para>
+                    The kernel is built by including policies for hardware-independent
+                    aspects.
+                    What subsystems do you enable?
+                    For what architecture are you building?
+                    Which drivers do you build by default?
+                    <note>You can modify the kernel source if you want to help
+                        with boot time.
+                    </note>
+                </para>
+
+                <para>
+                    Run the <filename>ksize.py</filename> script from the top-level
+                    Linux build directory to get an idea of what is making up
+                    the kernel:
+                    <literallayout class='monospaced'>
+     $ cd <replaceable>top-level-linux-build-directory</replaceable>
+     $ ksize.py > ksize.log
+     $ cat ksize.log
+                    </literallayout>
+                    When you examine the log, you will see how much space is
+                    taken up with the built-in <filename>.o</filename> files for
+                    drivers, networking, core kernel files, filesystem, sound,
+                    and so forth.
+                    The sizes reported by the tool are uncompressed, and thus
+                    will be smaller by a relatively constant factor in a compressed
+                    kernel image.
+                    Look to reduce the areas that are large and taking up around
+                    the "90% rule."
+                </para>
+
+                <para>
+                    To examine, or drill down, into any particular area, use the
+                    <filename>-d</filename> option with the script:
+                    <literallayout class='monospaced'>
+     $ ksize.py -d > ksize.log
+                    </literallayout>
+                    Using this option breaks out the individual file information
+                    for each area of the kernel (e.g. drivers, networking, and
+                    so forth).
+                </para>
+
+                <para>
+                    Use your log file to see what you can eliminate from the kernel
+                    based on features you can let go.
+                    For example, if you are not going to need sound, you do not
+                    need any drivers that support sound.
+                </para>
+
+                <para>
+                    After figuring out what to eliminate, you need to reconfigure
+                    the kernel to reflect those changes during the next build.
+                    You could run <filename>menuconfig</filename> and make all your
+                    changes at once.
+                    However, that makes it difficult to see the effects of your
+                    individual eliminations and also makes it difficult to replicate
+                    the changes for perhaps another target device.
+                    A better method is to start with no configurations using
+                    <filename>allnoconfig</filename>, create configuration
+                    fragments for individual changes, and then manage the
+                    fragments into a single configuration file using
+                    <filename>merge_config.sh</filename>.
+                    The tool makes it easy for you to iterate using the
+                    configuration change and build cycle.
+                </para>
+
+                <para>
+                    Each time you make configuration changes, you need to rebuild
+                    the kernel and check to see what impact your changes had on
+                    the overall size.
+                </para>
+            </section>
+
+            <section id='remove-package-management-requirements'>
+                <title>Remove Package Management Requirements</title>
+
+                <para>
+                    Packaging requirements add size to the image.
+                    One way to reduce the size of the image is to remove all the
+                    packaging requirements from the image.
+                    This reduction includes both removing the package manager
+                    and its unique dependencies as well as removing the package
+                    management data itself.
+                </para>
+
+                <para>
+                    To eliminate all the packaging requirements for an image,
+                    be sure that "package-management" is not part of your
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></ulink>
+                    statement for the image.
+                    When you remove this feature, you are removing the package
+                    manager as well as its dependencies from the root filesystem.
+                </para>
+            </section>
+
+            <section id='look-for-other-ways-to-minimize-size'>
+                <title>Look for Other Ways to Minimize Size</title>
+
+                <para>
+                    Depending on your particular circumstances, other areas that you
+                    can trim likely exist.
+                    The key to finding these areas is through tools and methods
+                    described here combined with experimentation and iteration.
+                    Here are a couple of areas to experiment with:
+                    <itemizedlist>
+                        <listitem><para><filename>glibc</filename>:
+                            In general, follow this process:
+                            <orderedlist>
+                                <listitem><para>Remove <filename>glibc</filename>
+                                    features from
+                                    <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></ulink>
+                                    that you think you do not need.</para></listitem>
+                                <listitem><para>Build your distribution.
+                                    </para></listitem>
+                                <listitem><para>If the build fails due to missing
+                                    symbols in a package, determine if you can
+                                    reconfigure the package to not need those
+                                    features.
+                                    For example, change the configuration to not
+                                    support wide character support as is done for
+                                    <filename>ncurses</filename>.
+                                    Or, if support for those characters is needed,
+                                    determine what <filename>glibc</filename>
+                                    features provide the support and restore the
+                                    configuration.
+                                    </para></listitem>
+                                <listitem><para>Rebuild and repeat the process.
+                                    </para></listitem>
+                            </orderedlist></para></listitem>
+                        <listitem><para><filename>busybox</filename>:
+                            For BusyBox, use a process similar as described for
+                            <filename>glibc</filename>.
+                            A difference is you will need to boot the resulting
+                            system to see if you are able to do everything you
+                            expect from the running system.
+                            You need to be sure to integrate configuration fragments
+                            into Busybox because BusyBox handles its own core
+                            features and then allows you to add configuration
+                            fragments on top.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='iterate-on-the-process'>
+                <title>Iterate on the Process</title>
+
+                <para>
+                    If you have not reached your goals on system size, you need
+                    to iterate on the process.
+                    The process is the same.
+                    Use the tools and see just what is taking up 90% of the root
+                    filesystem and the kernel.
+                    Decide what you can eliminate without limiting your device
+                    beyond what you need.
+                </para>
+
+                <para>
+                    Depending on your system, a good place to look might be
+                    Busybox, which provides a stripped down
+                    version of Unix tools in a single, executable file.
+                    You might be able to drop virtual terminal services or perhaps
+                    ipv6.
+                </para>
+            </section>
+        </section>
+
+        <section id='building-images-for-more-than-one-machine'>
+            <title>Building Images for More than One Machine</title>
+
+            <para>
+                A common scenario developers face is creating images for several
+                different machines that use the same software environment.
+                In this situation, it is tempting to set the
+                tunings and optimization flags for each build specifically for
+                the targeted hardware (i.e. "maxing out" the tunings).
+                Doing so can considerably add to build times and package feed
+                maintenance collectively for the machines.
+                For example, selecting tunes that are extremely specific to a
+                CPU core used in a system might enable some micro optimizations
+                in GCC for that particular system but would otherwise not gain
+                you much of a performance difference across the other systems
+                as compared to using a more general tuning across all the builds
+                (e.g. setting
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DEFAULTTUNE'><filename>DEFAULTTUNE</filename></ulink>
+                specifically for each machine's build).
+                Rather than "max out" each build's tunings, you can take steps that
+                cause the OpenEmbedded build system to reuse software across the
+                various machines where it makes sense.
+            </para>
+
+            <para>
+                If build speed and package feed maintenance are considerations,
+                you should consider the points in this section that can help you
+                optimize your tunings to best consider build times and package
+                feed maintenance.
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Share the Build Directory:</emphasis>
+                        If at all possible, share the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>
+                        across builds.
+                        The Yocto Project supports switching between different
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                        values in the same <filename>TMPDIR</filename>.
+                        This practice is well supported and regularly used by
+                        developers when building for multiple machines.
+                        When you use the same <filename>TMPDIR</filename> for
+                        multiple machine builds, the OpenEmbedded build system can
+                        reuse the existing native and often cross-recipes for
+                        multiple machines.
+                        Thus, build time decreases.
+                        <note>
+                            If
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO'><filename>DISTRO</filename></ulink>
+                            settings change or fundamental configuration settings
+                            such as the filesystem layout, you need to work with
+                            a clean <filename>TMPDIR</filename>.
+                            Sharing <filename>TMPDIR</filename> under these
+                            circumstances might work but since it is not
+                            guaranteed, you should use a clean
+                            <filename>TMPDIR</filename>.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Enable the Appropriate Package Architecture:</emphasis>
+                        By default, the OpenEmbedded build system enables three
+                        levels of package architectures: "all", "tune" or "package",
+                        and "machine".
+                        Any given recipe usually selects one of these package
+                        architectures (types) for its output.
+                        Depending for what a given recipe creates packages, making
+                        sure you enable the appropriate package architecture can
+                        directly impact the build time.</para>
+
+                        <para>A recipe that just generates scripts can enable
+                        "all" architecture because there are no binaries to build.
+                        To specifically enable "all" architecture, be sure your
+                        recipe inherits the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-allarch'><filename>allarch</filename></ulink>
+                        class.
+                        This class is useful for "all" architectures because it
+                        configures many variables so packages can be used across
+                        multiple architectures.</para>
+
+                        <para>If your recipe needs to generate packages that are
+                        machine-specific or when one of the build or runtime
+                        dependencies is already machine-architecture dependent,
+                        which makes your recipe also machine-architecture dependent,
+                        make sure your recipe enables the "machine" package
+                        architecture through the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ARCH'><filename>MACHINE_ARCH</filename></ulink>
+                        variable:
+                        <literallayout class='monospaced'>
+     PACKAGE_ARCH = "${MACHINE_ARCH}"
+                        </literallayout>
+                        When you do not specifically enable a package
+                        architecture through the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_ARCH'><filename>PACKAGE_ARCH</filename></ulink>,
+                        The OpenEmbedded build system defaults to the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-TUNE_PKGARCH'><filename>TUNE_PKGARCH</filename></ulink>
+                        setting:
+                        <literallayout class='monospaced'>
+     PACKAGE_ARCH = "${TUNE_PKGARCH}"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Choose a Generic Tuning File if Possible:</emphasis>
+                        Some tunes are more generic and can run on multiple targets
+                        (e.g. an <filename>armv5</filename> set of packages could
+                        run on <filename>armv6</filename> and
+                        <filename>armv7</filename> processors in most cases).
+                        Similarly, <filename>i486</filename> binaries could work
+                        on <filename>i586</filename> and higher processors.
+                        You should realize, however, that advances on newer
+                        processor versions would not be used.</para>
+
+                        <para>If you select the same tune for several different
+                        machines, the OpenEmbedded build system reuses software
+                        previously built, thus speeding up the overall build time.
+                        Realize that even though a new sysroot for each machine is
+                        generated, the software is not recompiled and only one
+                        package feed exists.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Manage Granular Level Packaging:</emphasis>
+                        Sometimes cases exist where injecting another level of
+                        package architecture beyond the three higher levels noted
+                        earlier can be useful.
+                        For example, consider how NXP (formerly Freescale) allows
+                        for the easy reuse of binary packages in their layer
+                        <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/meta-freescale/'><filename>meta-freescale</filename></ulink>.
+                        In this example, the
+                        <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/meta-freescale/tree/classes/fsl-dynamic-packagearch.bbclass'><filename>fsl-dynamic-packagearch</filename></ulink>
+                        class shares GPU packages for i.MX53 boards because
+                        all boards share the AMD GPU.
+                        The i.MX6-based boards can do the same because all boards
+                        share the Vivante GPU.
+                        This class inspects the BitBake datastore to identify if
+                        the package provides or depends on one of the
+                        sub-architecture values.
+                        If so, the class sets the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_ARCH'><filename>PACKAGE_ARCH</filename></ulink>
+                        value based on the <filename>MACHINE_SUBARCH</filename>
+                        value.
+                        If the package does not provide or depend on one of the
+                        sub-architecture values but it matches a value in the
+                        machine-specific filter, it sets
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ARCH'><filename>MACHINE_ARCH</filename></ulink>.
+                        This behavior reduces the number of packages built and
+                        saves build time by reusing binaries.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Use Tools to Debug Issues:</emphasis>
+                        Sometimes you can run into situations where software is
+                        being rebuilt when you think it should not be.
+                        For example, the OpenEmbedded build system might not be
+                        using shared state between machines when you think it
+                        should be.
+                        These types of situations are usually due to references
+                        to machine-specific variables such as
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-SERIAL_CONSOLES'><filename>SERIAL_CONSOLES</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-XSERVER'><filename>XSERVER</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_FEATURES'><filename>MACHINE_FEATURES</filename></ulink>,
+                        and so forth in code that is supposed to only be
+                        tune-specific or when the recipe depends
+                        (<ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'><filename>RRECOMMENDS</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-RSUGGESTS'><filename>RSUGGESTS</filename></ulink>,
+                        and so forth) on some other recipe that already has
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_ARCH'><filename>PACKAGE_ARCH</filename></ulink>
+                        defined as "${MACHINE_ARCH}".
+                        <note>
+                            Patches to fix any issues identified are most welcome
+                            as these issues occasionally do occur.
+                        </note></para>
+
+                        <para>For such cases, you can use some tools to help you
+                        sort out the situation:
+                        <itemizedlist>
+                            <listitem><para>
+                                <emphasis><filename>sstate-diff-machines.sh</filename>:</emphasis>
+                                You can find this tool in the
+                                <filename>scripts</filename> directory of the
+                                Source Repositories.
+                                See the comments in the script for information on
+                                how to use the tool.
+                                </para></listitem>
+                            <listitem><para>
+                                <emphasis>BitBake's "-S printdiff" Option:</emphasis>
+                                Using this option causes BitBake to try to
+                                establish the closest signature match it can
+                                (e.g. in the shared state cache) and then run
+                                <filename>bitbake-diffsigs</filename> over the
+                                matches to determine the stamps and delta where
+                                these two stamp trees diverge.
+                                </para></listitem>
+                        </itemizedlist>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id="building-software-from-an-external-source">
+            <title>Building Software from an External Source</title>
+
+            <para>
+                By default, the OpenEmbedded build system uses the
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                when building source code.
+                The build process involves fetching the source files, unpacking
+                them, and then patching them if necessary before the build takes
+                place.
+            </para>
+
+            <para>
+                Situations exist where you might want to build software from source
+                files that are external to and thus outside of the
+                OpenEmbedded build system.
+                For example, suppose you have a project that includes a new BSP with
+                a heavily customized kernel.
+                And, you want to minimize exposing the build system to the
+                development team so that they can focus on their project and
+                maintain everyone's workflow as much as possible.
+                In this case, you want a kernel source directory on the development
+                machine where the development occurs.
+                You want the recipe's
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                variable to point to the external directory and use it as is, not
+                copy it.
+            </para>
+
+            <para>
+                To build from software that comes from an external source, all you
+                need to do is inherit the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-externalsrc'><filename>externalsrc</filename></ulink>
+                class and then set the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTERNALSRC'><filename>EXTERNALSRC</filename></ulink>
+                variable to point to your external source code.
+                Here are the statements to put in your
+                <filename>local.conf</filename> file:
+                <literallayout class='monospaced'>
+     INHERIT += "externalsrc"
+     EXTERNALSRC_pn-<replaceable>myrecipe</replaceable> = "<replaceable>path-to-your-source-tree</replaceable>"
+                </literallayout>
+            </para>
+
+            <para>
+                This next example shows how to accomplish the same thing by setting
+                <filename>EXTERNALSRC</filename> in the recipe itself or in the
+                recipe's append file:
+                <literallayout class='monospaced'>
+     EXTERNALSRC = "<replaceable>path</replaceable>"
+     EXTERNALSRC_BUILD = "<replaceable>path</replaceable>"
+                </literallayout>
+                <note>
+                    In order for these settings to take effect, you must globally
+                    or locally inherit the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-externalsrc'><filename>externalsrc</filename></ulink>
+                    class.
+                </note>
+            </para>
+
+            <para>
+                By default, <filename>externalsrc.bbclass</filename> builds
+                the source code in a directory separate from the external source
+                directory as specified by
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTERNALSRC'><filename>EXTERNALSRC</filename></ulink>.
+                If you need to have the source built in the same directory in
+                which it resides, or some other nominated directory, you can set
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTERNALSRC_BUILD'><filename>EXTERNALSRC_BUILD</filename></ulink>
+                to point to that directory:
+                <literallayout class='monospaced'>
+     EXTERNALSRC_BUILD_pn-<replaceable>myrecipe</replaceable> = "<replaceable>path-to-your-source-tree</replaceable>"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id="replicating-a-build-offline">
+            <title>Replicating a Build Offline</title>
+
+            <para>
+                It can be useful to take a "snapshot" of upstream sources
+                used in a build and then use that "snapshot" later to
+                replicate the build offline.
+                To do so, you need to first prepare and populate your downloads
+                directory your "snapshot" of files.
+                Once your downloads directory is ready, you can use it at
+                any time and from any machine to replicate your build.
+            </para>
+
+            <para>
+                Follow these steps to populate your Downloads directory:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Create a Clean Downloads Directory:</emphasis>
+                        Start with an empty downloads directory
+                        (<ulink url='&YOCTO_DOCS_REF_URL;#var-DL_DIR'><filename>DL_DIR</filename></ulink>).
+                        You start with an empty downloads directory by either
+                        removing the files in the existing directory or by
+                        setting
+                        <filename>DL_DIR</filename> to point to either an
+                        empty location or one that does not yet exist.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Generate Tarballs of the Source Git Repositories:</emphasis>
+                        Edit your <filename>local.conf</filename> configuration
+                        file as follows:
+                        <literallayout class='monospaced'>
+     DL_DIR = "/home/<replaceable>your-download-dir</replaceable>/"
+     BB_GENERATE_MIRROR_TARBALLS = "1"
+                        </literallayout>
+                        During the fetch process in the next step, BitBake
+                        gathers the source files and creates tarballs in
+                        the directory pointed to by <filename>DL_DIR</filename>.
+                        See the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-BB_GENERATE_MIRROR_TARBALLS'><filename>BB_GENERATE_MIRROR_TARBALLS</filename></ulink>
+                        variable for more information.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Populate Your Downloads Directory Without Building:</emphasis>
+                        Use BitBake to fetch your sources but inhibit the
+                        build:
+                        <literallayout class='monospaced'>
+     $ bitbake <replaceable>target</replaceable> --runonly=fetch
+                        </literallayout>
+                        The downloads directory (i.e.
+                        <filename>${DL_DIR}</filename>) now has a "snapshot" of
+                        the source files in the form of tarballs, which can
+                        be used for the build.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Optionally Remove Any Git or other SCM Subdirectories From the Downloads Directory:</emphasis>
+                        If you want, you can clean up your downloads directory
+                        by removing any Git or other Source Control Management
+                        (SCM) subdirectories such as
+                        <filename>${DL_DIR}/git2/*</filename>.
+                        The tarballs already contain these subdirectories.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                Once your downloads directory has everything it needs regarding
+                source files, you can create your "own-mirror" and build
+                your target.
+                Understand that you can use the files to build the target
+                offline from any machine and at any time.
+            </para>
+
+            <para>
+                Follow these steps to build your target using the files in the
+                downloads directory:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Using Local Files Only:</emphasis>
+                        Inside your <filename>local.conf</filename> file, add
+                        the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-SOURCE_MIRROR_URL'><filename>SOURCE_MIRROR_URL</filename></ulink>
+                        variable,
+                        inherit the <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-own-mirrors'><filename>own-mirrors</filename></ulink>
+                        class, and use the
+                        <ulink url='&YOCTO_DOCS_BB_URL;#var-bb-BB_NO_NETWORK'><filename>BB_NO_NETWORK</filename></ulink>
+                        variable to your <filename>local.conf</filename>.
+                        <literallayout class='monospaced'>
+     SOURCE_MIRROR_URL ?= "file:///home/<replaceable>your-download-dir</replaceable>/"
+     INHERIT += "own-mirrors"
+     BB_NO_NETWORK = "1"
+                        </literallayout>
+                        The <filename>SOURCE_MIRROR_URL</filename> and
+                        <filename>own-mirror</filename> class set up the system
+                        to use the downloads directory as your "own mirror".
+                        Using the <filename>BB_NO_NETWORK</filename>
+                        variable makes sure that BitBake's fetching process
+                        in step 3 stays local, which means files from
+                        your "own-mirror" are used.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Start With a Clean Build:</emphasis>
+                        You can start with a clean build by removing the
+                        <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink><filename>}</filename>
+                        directory or using a new
+                        <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Build Your Target:</emphasis>
+                        Use BitBake to build your target:
+                        <literallayout class='monospaced'>
+     $ bitbake <replaceable>target</replaceable>
+                        </literallayout>
+                        The build completes using the known local "snapshot" of
+                        source files from your mirror.
+                        The resulting tarballs for your "snapshot" of source
+                        files are in the downloads directory.
+                        <note>
+                            <para>The offline build does not work if recipes
+                            attempt to find the latest version of software
+                            by setting
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCREV'><filename>SRCREV</filename></ulink>
+                            to
+                            <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-AUTOREV'><filename>AUTOREV</filename></ulink><filename>}</filename>:
+                            <literallayout class='monospaced'>
+     SRCREV = "${AUTOREV}"
+                            </literallayout>
+                            When a recipe sets
+                            <filename>SRCREV</filename> to
+                            <filename>${AUTOREV}</filename>, the build system
+                            accesses the network in an attempt to determine the
+                            latest version of software from the SCM.
+                            Typically, recipes that use
+                            <filename>AUTOREV</filename> are custom or
+                            modified recipes.
+                            Recipes that reside in public repositories
+                            usually do not use <filename>AUTOREV</filename>.
+                            </para>
+
+                            <para>If you do have recipes that use
+                            <filename>AUTOREV</filename>, you can take steps to
+                            still use the recipes in an offline build.
+                            Do the following:
+                                <orderedlist>
+                                    <listitem><para>
+                                        Use a configuration generated by
+                                        enabling
+                                        <link linkend='maintaining-build-output-quality'>build history</link>.
+                                        </para></listitem>
+                                    <listitem><para>
+                                        Use the
+                                        <filename>buildhistory-collect-srcrevs</filename>
+                                        command to collect the stored
+                                        <filename>SRCREV</filename> values from
+                                        the build's history.
+                                        For more information on collecting these
+                                        values, see the
+                                        "<link linkend='build-history-package-information'>Build History Package Information</link>"
+                                        section.
+                                        </para></listitem>
+                                    <listitem><para>
+                                        Once you have the correct source
+                                        revisions, you can modify those recipes
+                                        to to set <filename>SRCREV</filename>
+                                        to specific versions of the software.
+                                        </para></listitem>
+                                </orderedlist>
+                            </para>
+                        </note>
+                        </para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+    </section>
+
+    <section id='speeding-up-a-build'>
+        <title>Speeding Up a Build</title>
+
+        <para>
+            Build time can be an issue.
+            By default, the build system uses simple controls to try and maximize
+            build efficiency.
+            In general, the default settings for all the following variables
+            result in the most efficient build times when dealing with single
+            socket systems (i.e. a single CPU).
+            If you have multiple CPUs, you might try increasing the default
+            values to gain more speed.
+            See the descriptions in the glossary for each variable for more
+            information:
+            <itemizedlist>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-BB_NUMBER_THREADS'><filename>BB_NUMBER_THREADS</filename>:</ulink>
+                    The maximum number of threads BitBake simultaneously executes.
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_BB_URL;#var-BB_NUMBER_PARSE_THREADS'><filename>BB_NUMBER_PARSE_THREADS</filename>:</ulink>
+                    The number of threads BitBake uses during parsing.
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKE'><filename>PARALLEL_MAKE</filename>:</ulink>
+                    Extra options passed to the <filename>make</filename> command
+                    during the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-compile'><filename>do_compile</filename></ulink>
+                    task in order to specify parallel compilation on the
+                    local build host.
+                    </para></listitem>
+                <listitem><para>
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKEINST'><filename>PARALLEL_MAKEINST</filename>:</ulink>
+                    Extra options passed to the <filename>make</filename> command
+                    during the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+                    task in order to specify parallel installation on the
+                    local build host.
+                    </para></listitem>
+            </itemizedlist>
+            As mentioned, these variables all scale to the number of processor
+            cores available on the build system.
+            For single socket systems, this auto-scaling ensures that the build
+            system fundamentally takes advantage of potential parallel operations
+            during the build based on the build machine's capabilities.
+        </para>
+
+        <para>
+            Following are additional factors that can affect build speed:
+            <itemizedlist>
+                <listitem><para>
+                    File system type:
+                    The file system type that the build is being performed on can
+                    also influence performance.
+                    Using <filename>ext4</filename> is recommended as compared
+                    to <filename>ext2</filename> and <filename>ext3</filename>
+                    due to <filename>ext4</filename> improved features
+                    such as extents.
+                    </para></listitem>
+                <listitem><para>
+                    Disabling the updating of access time using
+                    <filename>noatime</filename>:
+                    The <filename>noatime</filename> mount option prevents the
+                    build system from updating file and directory access times.
+                    </para></listitem>
+                <listitem><para>
+                    Setting a longer commit:
+                    Using the "commit=" mount option increases the interval
+                    in seconds between disk cache writes.
+                    Changing this interval from the five second default to
+                    something longer increases the risk of data loss but decreases
+                    the need to write to the disk, thus increasing the build
+                    performance.
+                    </para></listitem>
+                <listitem><para>
+                    Choosing the packaging backend:
+                    Of the available packaging backends, IPK is the fastest.
+                    Additionally, selecting a singular packaging backend also
+                    helps.
+                    </para></listitem>
+                <listitem><para>
+                    Using <filename>tmpfs</filename> for
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>
+                    as a temporary file system:
+                    While this can help speed up the build, the benefits are
+                    limited due to the compiler using
+                    <filename>-pipe</filename>.
+                    The build system goes to some lengths to avoid
+                    <filename>sync()</filename> calls into the
+                    file system on the principle that if there was a significant
+                    failure, the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                    contents could easily be rebuilt.
+                    </para></listitem>
+                <listitem><para>
+                    Inheriting the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-rm-work'><filename>rm_work</filename></ulink>
+                    class:
+                    Inheriting this class has shown to speed up builds due to
+                    significantly lower amounts of data stored in the data
+                    cache as well as on disk.
+                    Inheriting this class also makes cleanup of
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>
+                    faster, at the expense of being easily able to dive into the
+                    source code.
+                    File system maintainers have recommended that the fastest way
+                    to clean up large numbers of files is to reformat partitions
+                    rather than delete files due to the linear nature of
+                    partitions.
+                    This, of course, assumes you structure the disk partitions and
+                    file systems in a way that this is practical.
+                    </para></listitem>
+            </itemizedlist>
+            Aside from the previous list, you should keep some trade offs in
+            mind that can help you speed up the build:
+            <itemizedlist>
+                <listitem><para>
+                    Remove items from
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></ulink>
+                    that you might not need.
+                    </para></listitem>
+                <listitem><para>
+                    Exclude debug symbols and other debug information:
+                    If you do not need these symbols and other debug information,
+                    disabling the <filename>*-dbg</filename> package generation
+                    can speed up the build.
+                    You can disable this generation by setting the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-INHIBIT_PACKAGE_DEBUG_SPLIT'><filename>INHIBIT_PACKAGE_DEBUG_SPLIT</filename></ulink>
+                    variable to "1".
+                    </para></listitem>
+                <listitem><para>
+                    Disable static library generation for recipes derived from
+                    <filename>autoconf</filename> or <filename>libtool</filename>:
+                    Following is an example showing how to disable static
+                    libraries and still provide an override to handle exceptions:
+                    <literallayout class='monospaced'>
+     STATICLIBCONF = "--disable-static"
+     STATICLIBCONF_sqlite3-native = ""
+     EXTRA_OECONF += "${STATICLIBCONF}"
+                    </literallayout>
+                    <note><title>Notes</title>
+                        <itemizedlist>
+                            <listitem><para>
+                                Some recipes need static libraries in order to work
+                                correctly (e.g. <filename>pseudo-native</filename>
+                                needs <filename>sqlite3-native</filename>).
+                                Overrides, as in the previous example, account for
+                                these kinds of exceptions.
+                                </para></listitem>
+                            <listitem><para>
+                                Some packages have packaging code that assumes the
+                                presence of the static libraries.
+                                If so, you might need to exclude them as well.
+                                </para></listitem>
+                        </itemizedlist>
+                    </note>
+                </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id="platdev-working-with-libraries">
+        <title>Working With Libraries</title>
+
+        <para>
+            Libraries are an integral part of your system.
+            This section describes some common practices you might find
+            helpful when working with libraries to build your system:
+            <itemizedlist>
+                <listitem><para><link linkend='including-static-library-files'>How to include static library files</link>
+                    </para></listitem>
+                <listitem><para><link linkend='combining-multiple-versions-library-files-into-one-image'>How to use the Multilib feature to combine multiple versions of library files into a single image</link>
+                    </para></listitem>
+                <listitem><para><link linkend='installing-multiple-versions-of-the-same-library'>How to install multiple versions of the same library in parallel on the same system</link>
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <section id='including-static-library-files'>
+            <title>Including Static Library Files</title>
+
+            <para>
+                If you are building a library and the library offers static linking, you can control
+                which static library files (<filename>*.a</filename> files) get included in the
+                built library.
+            </para>
+
+            <para>
+                The <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'><filename>PACKAGES</filename></ulink>
+                and <ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'><filename>FILES_*</filename></ulink>
+                variables in the
+                <filename>meta/conf/bitbake.conf</filename> configuration file define how files installed
+                by the <filename>do_install</filename> task are packaged.
+                By default, the <filename>PACKAGES</filename> variable includes
+                <filename>${PN}-staticdev</filename>, which represents all static library files.
+                <note>
+                    Some previously released versions of the Yocto Project
+                    defined the static library files through
+                    <filename>${PN}-dev</filename>.
+                </note>
+                Following is part of the BitBake configuration file, where
+                you can see how the static library files are defined:
+                <literallayout class='monospaced'>
+     PACKAGE_BEFORE_PN ?= ""
+     PACKAGES = "${PN}-dbg ${PN}-staticdev ${PN}-dev ${PN}-doc ${PN}-locale ${PACKAGE_BEFORE_PN} ${PN}"
+     PACKAGES_DYNAMIC = "^${PN}-locale-.*"
+     FILES = ""
+
+     FILES_${PN} = "${bindir}/* ${sbindir}/* ${libexecdir}/* ${libdir}/lib*${SOLIBS} \
+                 ${sysconfdir} ${sharedstatedir} ${localstatedir} \
+                 ${base_bindir}/* ${base_sbindir}/* \
+                 ${base_libdir}/*${SOLIBS} \
+                 ${base_prefix}/lib/udev/rules.d ${prefix}/lib/udev/rules.d \
+                 ${datadir}/${BPN} ${libdir}/${BPN}/* \
+                 ${datadir}/pixmaps ${datadir}/applications \
+                 ${datadir}/idl ${datadir}/omf ${datadir}/sounds \
+                 ${libdir}/bonobo/servers"
+
+     FILES_${PN}-bin = "${bindir}/* ${sbindir}/*"
+
+     FILES_${PN}-doc = "${docdir} ${mandir} ${infodir} ${datadir}/gtk-doc \
+                 ${datadir}/gnome/help"
+     SECTION_${PN}-doc = "doc"
+
+     FILES_SOLIBSDEV ?= "${base_libdir}/lib*${SOLIBSDEV} ${libdir}/lib*${SOLIBSDEV}"
+     FILES_${PN}-dev = "${includedir} ${FILES_SOLIBSDEV} ${libdir}/*.la \
+                     ${libdir}/*.o ${libdir}/pkgconfig ${datadir}/pkgconfig \
+                     ${datadir}/aclocal ${base_libdir}/*.o \
+                     ${libdir}/${BPN}/*.la ${base_libdir}/*.la"
+     SECTION_${PN}-dev = "devel"
+     ALLOW_EMPTY_${PN}-dev = "1"
+     RDEPENDS_${PN}-dev = "${PN} (= ${EXTENDPKGV})"
+
+     FILES_${PN}-staticdev = "${libdir}/*.a ${base_libdir}/*.a ${libdir}/${BPN}/*.a"
+     SECTION_${PN}-staticdev = "devel"
+     RDEPENDS_${PN}-staticdev = "${PN}-dev (= ${EXTENDPKGV})"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id="combining-multiple-versions-library-files-into-one-image">
+            <title>Combining Multiple Versions of Library Files into One Image</title>
+
+            <para>
+                The build system offers the ability to build libraries with different
+                target optimizations or architecture formats and combine these together
+                into one system image.
+                You can link different binaries in the image
+                against the different libraries as needed for specific use cases.
+                This feature is called "Multilib."
+            </para>
+
+            <para>
+                An example would be where you have most of a system compiled in 32-bit
+                mode using 32-bit libraries, but you have something large, like a database
+                engine, that needs to be a 64-bit application and uses 64-bit libraries.
+                Multilib allows you to get the best of both 32-bit and 64-bit libraries.
+            </para>
+
+            <para>
+                While the Multilib feature is most commonly used for 32 and 64-bit differences,
+                the approach the build system uses facilitates different target optimizations.
+                You could compile some binaries to use one set of libraries and other binaries
+                to use a different set of libraries.
+                The libraries could differ in architecture, compiler options, or other
+                optimizations.
+            </para>
+
+            <para>
+                Several examples exist in the
+                <filename>meta-skeleton</filename> layer found in the
+               <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>:
+                <itemizedlist>
+                    <listitem><para><filename>conf/multilib-example.conf</filename>
+                        configuration file</para></listitem>
+                    <listitem><para><filename>conf/multilib-example2.conf</filename>
+                        configuration file</para></listitem>
+                    <listitem><para><filename>recipes-multilib/images/core-image-multilib-example.bb</filename>
+                        recipe</para></listitem>
+                </itemizedlist>
+            </para>
+
+            <section id='preparing-to-use-multilib'>
+                <title>Preparing to Use Multilib</title>
+
+                <para>
+                    User-specific requirements drive the Multilib feature.
+                    Consequently, there is no one "out-of-the-box" configuration that likely
+                    exists to meet your needs.
+                </para>
+
+                <para>
+                    In order to enable Multilib, you first need to ensure your recipe is
+                    extended to support multiple libraries.
+                    Many standard recipes are already extended and support multiple libraries.
+                    You can check in the <filename>meta/conf/multilib.conf</filename>
+                    configuration file in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink> to see how this is
+                    done using the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-BBCLASSEXTEND'><filename>BBCLASSEXTEND</filename></ulink>
+                    variable.
+                    Eventually, all recipes will be covered and this list will
+                    not be needed.
+                </para>
+
+                <para>
+                    For the most part, the Multilib class extension works automatically to
+                    extend the package name from <filename>${PN}</filename> to
+                    <filename>${MLPREFIX}${PN}</filename>, where <filename>MLPREFIX</filename>
+                    is the particular multilib (e.g. "lib32-" or "lib64-").
+                    Standard variables such as
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-RPROVIDES'><filename>RPROVIDES</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'><filename>RRECOMMENDS</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'><filename>PACKAGES</filename></ulink>, and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES_DYNAMIC'><filename>PACKAGES_DYNAMIC</filename></ulink>
+                    are automatically extended by the system.
+                    If you are extending any manual code in the recipe, you can use the
+                    <filename>${MLPREFIX}</filename> variable to ensure those names are extended
+                    correctly.
+                    This automatic extension code resides in <filename>multilib.bbclass</filename>.
+                </para>
+            </section>
+
+            <section id='using-multilib'>
+                <title>Using Multilib</title>
+
+                <para>
+                    After you have set up the recipes, you need to define the actual
+                    combination of multiple libraries you want to build.
+                    You accomplish this through your <filename>local.conf</filename>
+                    configuration file in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                    An example configuration would be as follows:
+                    <literallayout class='monospaced'>
+     MACHINE = "qemux86-64"
+     require conf/multilib.conf
+     MULTILIBS = "multilib:lib32"
+     DEFAULTTUNE_virtclass-multilib-lib32 = "x86"
+     IMAGE_INSTALL_append = " lib32-glib-2.0"
+                    </literallayout>
+                    This example enables an
+                    additional library named <filename>lib32</filename> alongside the
+                    normal target packages.
+                    When combining these "lib32" alternatives, the example uses "x86" for tuning.
+                    For information on this particular tuning, see
+                    <filename>meta/conf/machine/include/ia32/arch-ia32.inc</filename>.
+                </para>
+
+                <para>
+                    The example then includes <filename>lib32-glib-2.0</filename>
+                    in all the images, which illustrates one method of including a
+                    multiple library dependency.
+                    You can use a normal image build to include this dependency,
+                    for example:
+                    <literallayout class='monospaced'>
+     $ bitbake core-image-sato
+                    </literallayout>
+                    You can also build Multilib packages specifically with a command like this:
+                    <literallayout class='monospaced'>
+     $ bitbake lib32-glib-2.0
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='additional-implementation-details'>
+                <title>Additional Implementation Details</title>
+
+                <para>
+                    Generic implementation details as well as details that are
+                    specific to package management systems exist.
+                    Following are implementation details that exist regardless
+                    of the package management system:
+                    <itemizedlist>
+                        <listitem><para>The typical convention used for the
+                            class extension code as used by
+                            Multilib assumes that all package names specified
+                            in
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'><filename>PACKAGES</filename></ulink>
+                            that contain <filename>${PN}</filename> have
+                            <filename>${PN}</filename> at the start of the name.
+                            When that convention is not followed and
+                            <filename>${PN}</filename> appears at
+                            the middle or the end of a name, problems occur.
+                            </para></listitem>
+                        <listitem><para>The
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-TARGET_VENDOR'><filename>TARGET_VENDOR</filename></ulink>
+                            value under Multilib will be extended to
+                            "-<replaceable>vendor</replaceable>ml<replaceable>multilib</replaceable>"
+                            (e.g. "-pokymllib32" for a "lib32" Multilib with
+                            Poky).
+                            The reason for this slightly unwieldy contraction
+                            is that any "-" characters in the vendor
+                            string presently break Autoconf's
+                            <filename>config.sub</filename>, and
+                            other separators are problematic for different
+                            reasons.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+
+                <para>
+                    For the RPM Package Management System, the following implementation details
+                    exist:
+                    <itemizedlist>
+                        <listitem><para>A unique architecture is defined for the Multilib packages,
+                            along with creating a unique deploy folder under
+                            <filename>tmp/deploy/rpm</filename> in the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                            For example, consider <filename>lib32</filename> in a
+                            <filename>qemux86-64</filename> image.
+                            The possible architectures in the system are "all", "qemux86_64",
+                            "lib32_qemux86_64", and "lib32_x86".</para></listitem>
+                        <listitem><para>The <filename>${MLPREFIX}</filename> variable is stripped from
+                            <filename>${PN}</filename> during RPM packaging.
+                            The naming for a normal RPM package and a Multilib RPM package in a
+                            <filename>qemux86-64</filename> system resolves to something similar to
+                            <filename>bash-4.1-r2.x86_64.rpm</filename> and
+                            <filename>bash-4.1.r2.lib32_x86.rpm</filename>, respectively.
+                            </para></listitem>
+                        <listitem><para>When installing a Multilib image, the RPM backend first
+                            installs the base image and then installs the Multilib libraries.
+                            </para></listitem>
+                        <listitem><para>The build system relies on RPM to resolve the identical files in the
+                            two (or more) Multilib packages.</para></listitem>
+                    </itemizedlist>
+                </para>
+
+                <para>
+                    For the IPK Package Management System, the following implementation details exist:
+                    <itemizedlist>
+                        <listitem><para>The <filename>${MLPREFIX}</filename> is not stripped from
+                            <filename>${PN}</filename> during IPK packaging.
+                            The naming for a normal RPM package and a Multilib IPK package in a
+                            <filename>qemux86-64</filename> system resolves to something like
+                            <filename>bash_4.1-r2.x86_64.ipk</filename> and
+                            <filename>lib32-bash_4.1-rw_x86.ipk</filename>, respectively.
+                            </para></listitem>
+                        <listitem><para>The IPK deploy folder is not modified with
+                            <filename>${MLPREFIX}</filename> because packages with and without
+                            the Multilib feature can exist in the same folder due to the
+                            <filename>${PN}</filename> differences.</para></listitem>
+                        <listitem><para>IPK defines a sanity check for Multilib installation
+                            using certain rules for file comparison, overridden, etc.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+        </section>
+
+        <section id='installing-multiple-versions-of-the-same-library'>
+            <title>Installing Multiple Versions of the Same Library</title>
+
+            <para>
+                Situations can exist where you need to install and use
+                multiple versions of the same library on the same system
+                at the same time.
+                These situations almost always exist when a library API
+                changes and you have multiple pieces of software that
+                depend on the separate versions of the library.
+                To accommodate these situations, you can install multiple
+                versions of the same library in parallel on the same system.
+            </para>
+
+            <para>
+                The process is straightforward as long as the libraries use
+                proper versioning.
+                With properly versioned libraries, all you need to do to
+                individually specify the libraries is create separate,
+                appropriately named recipes where the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink> part of the
+                name includes a portion that differentiates each library version
+                (e.g.the major part of the version number).
+                Thus, instead of having a single recipe that loads one version
+                of a library (e.g. <filename>clutter</filename>), you provide
+                multiple recipes that result in different versions
+                of the libraries you want.
+                As an example, the following two recipes would allow the
+                two separate versions of the <filename>clutter</filename>
+                library to co-exist on the same system:
+                <literallayout class='monospaced'>
+     clutter-1.6_1.6.20.bb
+     clutter-1.8_1.8.4.bb
+                </literallayout>
+                Additionally, if you have other recipes that depend on a given
+                library, you need to use the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                variable to create the dependency.
+                Continuing with the same example, if you want to have a recipe
+                depend on the 1.8 version of the <filename>clutter</filename>
+                library, use the following in your recipe:
+                <literallayout class='monospaced'>
+     DEPENDS = "clutter-1.8"
+                </literallayout>
+            </para>
+        </section>
+    </section>
+
+    <section id='using-x32-psabi'>
+        <title>Using x32 psABI</title>
+
+        <para>
+            x32 processor-specific Application Binary Interface
+            (<ulink url='https://software.intel.com/en-us/node/628948'>x32 psABI</ulink>)
+            is a native 32-bit processor-specific ABI for
+            <trademark class='registered'>Intel</trademark> 64 (x86-64)
+            architectures.
+            An ABI defines the calling conventions between functions in a
+            processing environment.
+            The interface determines what registers are used and what the
+            sizes are for various C data types.
+        </para>
+
+        <para>
+            Some processing environments prefer using 32-bit applications even
+            when running on Intel 64-bit platforms.
+            Consider the i386 psABI, which is a very old 32-bit ABI for Intel
+            64-bit platforms.
+            The i386 psABI does not provide efficient use and access of the
+            Intel 64-bit processor resources, leaving the system underutilized.
+            Now consider the x86_64 psABI.
+            This ABI is newer and uses 64-bits for data sizes and program
+            pointers.
+            The extra bits increase the footprint size of the programs,
+            libraries, and also increases the memory and file system size
+            requirements.
+            Executing under the x32 psABI enables user programs to utilize CPU
+            and system resources more efficiently while keeping the memory
+            footprint of the applications low.
+            Extra bits are used for registers but not for addressing mechanisms.
+        </para>
+
+        <para>
+            The Yocto Project supports the final specifications of x32 psABI
+            as follows:
+            <itemizedlist>
+                <listitem><para>
+                    You can create packages and images in x32 psABI format on
+                    x86_64 architecture targets.
+                    </para></listitem>
+                <listitem><para>
+                    You can successfully build recipes with the x32 toolchain.
+                    </para></listitem>
+                <listitem><para>
+                    You can create and boot
+                    <filename>core-image-minimal</filename> and
+                    <filename>core-image-sato</filename> images.
+                    </para></listitem>
+                <listitem><para>
+                    RPM Package Manager (RPM) support exists for x32 binaries.
+                    </para></listitem>
+                <listitem><para>
+                    Support for large images exists.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <para>
+            To use the x32 psABI, you need to edit your
+            <filename>conf/local.conf</filename> configuration file as
+            follows:
+            <literallayout class='monospaced'>
+     MACHINE = "qemux86-64"
+     DEFAULTTUNE = "x86-64-x32"
+     baselib = "${@d.getVar('BASE_LIB_tune-' + (d.getVar('DEFAULTTUNE') \
+        or 'INVALID')) or 'lib'}"
+            </literallayout>
+            Once you have set up your configuration file, use BitBake to
+            build an image that supports the x32 psABI.
+            Here is an example:
+            <literallayout class='monospaced'>
+     $ bitbake core-image-sato
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='enabling-gobject-introspection-support'>
+        <title>Enabling GObject Introspection Support</title>
+
+        <para>
+            <ulink url='https://wiki.gnome.org/Projects/GObjectIntrospection'>GObject introspection</ulink>
+            is the standard mechanism for accessing GObject-based software
+            from runtime environments.
+            GObject is a feature of the GLib library that provides an object
+            framework for the GNOME desktop and related software.
+            GObject Introspection adds information to GObject that allows
+            objects created within it to be represented across different
+            programming languages.
+            If you want to construct GStreamer pipelines using Python, or
+            control UPnP infrastructure using Javascript and GUPnP,
+            GObject introspection is the only way to do it.
+        </para>
+
+        <para>
+            This section describes the Yocto Project support for generating
+            and packaging GObject introspection data.
+            GObject introspection data is a description of the
+            API provided by libraries built on top of GLib framework,
+            and, in particular, that framework's GObject mechanism.
+            GObject Introspection Repository (GIR) files go to
+            <filename>-dev</filename> packages,
+            <filename>typelib</filename> files go to main packages as they
+            are packaged together with libraries that are introspected.
+        </para>
+
+        <para>
+            The data is generated when building such a library, by linking
+            the library with a small executable binary that asks the library
+            to describe itself, and then executing the binary and
+            processing its output.
+        </para>
+
+        <para>
+            Generating this data in a cross-compilation environment
+            is difficult because the library is produced for the target
+            architecture, but its code needs to be executed on the build host.
+            This problem is solved with the OpenEmbedded build system by
+            running the code through QEMU, which allows precisely that.
+            Unfortunately, QEMU does not always work perfectly as mentioned
+            in the
+            "<link linkend='known-issues'>Known Issues</link>" section.
+        </para>
+
+        <section id='enabling-the-generation-of-introspection-data'>
+            <title>Enabling the Generation of Introspection Data</title>
+
+            <para>
+                Enabling the generation of introspection data (GIR files)
+                in your library package involves the following:
+                <orderedlist>
+                    <listitem><para>
+                        Inherit the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-gobject-introspection'><filename>gobject-introspection</filename></ulink>
+                        class.
+                        </para></listitem>
+                    <listitem><para>
+                        Make sure introspection is not disabled anywhere in
+                        the recipe or from anything the recipe includes.
+                        Also, make sure that "gobject-introspection-data" is
+                        not in
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES_BACKFILL_CONSIDERED'><filename>DISTRO_FEATURES_BACKFILL_CONSIDERED</filename></ulink>
+                        and that "qemu-usermode" is not in
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_FEATURES_BACKFILL_CONSIDERED'><filename>MACHINE_FEATURES_BACKFILL_CONSIDERED</filename></ulink>.
+                        If either of these conditions exist, nothing will
+                        happen.
+                        </para></listitem>
+                    <listitem><para>
+                        Try to build the recipe.
+                        If you encounter build errors that look like
+                        something is unable to find
+                        <filename>.so</filename> libraries, check where these
+                        libraries are located in the source tree and add
+                        the following to the recipe:
+                        <literallayout class='monospaced'>
+     GIR_EXTRA_LIBS_PATH = "${B}/<replaceable>something</replaceable>/.libs"
+                        </literallayout>
+                        <note>
+                            See recipes in the <filename>oe-core</filename>
+                            repository that use that
+                            <filename>GIR_EXTRA_LIBS_PATH</filename> variable
+                            as an example.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        Look for any other errors, which probably mean that
+                        introspection support in a package is not entirely
+                        standard, and thus breaks down in a cross-compilation
+                        environment.
+                        For such cases, custom-made fixes are needed.
+                        A good place to ask and receive help in these cases
+                        is the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#resources-mailinglist'>Yocto Project mailing lists</ulink>.
+                        </para></listitem>
+                </orderedlist>
+                <note>
+                    Using a library that no longer builds against the latest
+                    Yocto Project release and prints introspection related
+                    errors is a good candidate for the previous procedure.
+                </note>
+            </para>
+        </section>
+
+        <section id='disabling-the-generation-of-introspection-data'>
+            <title>Disabling the Generation of Introspection Data</title>
+
+            <para>
+                You might find that you do not want to generate
+                introspection data.
+                Or, perhaps QEMU does not work on your build host and
+                target architecture combination.
+                If so, you can use either of the following methods to
+                disable GIR file generations:
+                <itemizedlist>
+                    <listitem><para>
+                        Add the following to your distro configuration:
+                        <literallayout class='monospaced'>
+     DISTRO_FEATURES_BACKFILL_CONSIDERED = "gobject-introspection-data"
+                        </literallayout>
+                        Adding this statement disables generating
+                        introspection data using QEMU but will still enable
+                        building introspection tools and libraries
+                        (i.e. building them does not require the use of QEMU).
+                        </para></listitem>
+                    <listitem><para>
+                        Add the following to your machine configuration:
+                        <literallayout class='monospaced'>
+     MACHINE_FEATURES_BACKFILL_CONSIDERED = "qemu-usermode"
+                        </literallayout>
+                        Adding this statement disables the use of QEMU
+                        when building packages for your machine.
+                        Currently, this feature is used only by introspection
+                        recipes and has the same effect as the previously
+                        described option.
+                        <note>
+                            Future releases of the Yocto Project might have
+                            other features affected by this option.
+                        </note>
+                        </para></listitem>
+                </itemizedlist>
+                If you disable introspection data, you can still
+                obtain it through other means such as copying the data
+                from a suitable sysroot, or by generating it on the
+                target hardware.
+                The OpenEmbedded build system does not currently
+                provide specific support for these techniques.
+            </para>
+        </section>
+
+        <section id='testing-that-introspection-works-in-an-image'>
+            <title>Testing that Introspection Works in an Image</title>
+
+            <para>
+                Use the following procedure to test if generating
+                introspection data is working in an image:
+                <orderedlist>
+                    <listitem><para>
+                        Make sure that "gobject-introspection-data" is not in
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES_BACKFILL_CONSIDERED'><filename>DISTRO_FEATURES_BACKFILL_CONSIDERED</filename></ulink>
+                        and that "qemu-usermode" is not in
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_FEATURES_BACKFILL_CONSIDERED'><filename>MACHINE_FEATURES_BACKFILL_CONSIDERED</filename></ulink>.
+                        </para></listitem>
+                    <listitem><para>
+                        Build <filename>core-image-sato</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        Launch a Terminal and then start Python in the
+                        terminal.
+                        </para></listitem>
+                    <listitem><para>
+                        Enter the following in the terminal:
+                        <literallayout class='monospaced'>
+     >>> from gi.repository import GLib
+     >>> GLib.get_host_name()
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        For something a little more advanced, enter the
+                        following:
+                        <literallayout class='monospaced'>
+     http://python-gtk-3-tutorial.readthedocs.org/en/latest/introduction.html
+                        </literallayout>
+                        </para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+
+        <section id='known-issues'>
+            <title>Known Issues</title>
+
+            <para>
+                The following know issues exist for
+                GObject Introspection Support:
+                <itemizedlist>
+                    <listitem><para>
+                        <filename>qemu-ppc64</filename> immediately crashes.
+                        Consequently, you cannot build introspection data on
+                        that architecture.
+                        </para></listitem>
+                    <listitem><para>
+                        x32 is not supported by QEMU.
+                        Consequently, introspection data is disabled.
+                        </para></listitem>
+                    <listitem><para>
+                        musl causes transient GLib binaries to crash on
+                        assertion failures.
+                        Consequently, generating introspection data is
+                        disabled.
+                        </para></listitem>
+                    <listitem><para>
+                        Because QEMU is not able to run the binaries correctly,
+                        introspection is disabled for some specific packages
+                        under specific architectures (e.g.
+                        <filename>gcr</filename>,
+                        <filename>libsecret</filename>, and
+                        <filename>webkit</filename>).
+                        </para></listitem>
+                    <listitem><para>
+                        QEMU usermode might not work properly when running
+                        64-bit binaries under 32-bit host machines.
+                        In particular, "qemumips64" is known to not work under
+                        i686.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+    </section>
+
+    <section id='dev-optionally-using-an-external-toolchain'>
+        <title>Optionally Using an External Toolchain</title>
+
+        <para>
+            You might want to use an external toolchain as part of your
+            development.
+            If this is the case, the fundamental steps you need to accomplish
+            are as follows:
+            <itemizedlist>
+                <listitem><para>
+                    Understand where the installed toolchain resides.
+                    For cases where you need to build the external toolchain,
+                    you would need to take separate steps to build and install
+                    the toolchain.
+                    </para></listitem>
+                <listitem><para>
+                    Make sure you add the layer that contains the toolchain to
+                    your <filename>bblayers.conf</filename> file through the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-BBLAYERS'><filename>BBLAYERS</filename></ulink>
+                    variable.
+                    </para></listitem>
+                <listitem><para>
+                    Set the <filename>EXTERNAL_TOOLCHAIN</filename>
+                    variable in your <filename>local.conf</filename> file
+                    to the location in which you installed the toolchain.
+                    </para></listitem>
+            </itemizedlist>
+            A good example of an external toolchain used with the Yocto Project
+            is <trademark class='registered'>Mentor Graphics</trademark>
+            Sourcery G++ Toolchain.
+            You can see information on how to use that particular layer in the
+            <filename>README</filename> file at
+            <ulink url='http://github.com/MentorEmbedded/meta-sourcery/'></ulink>.
+            You can find further information by reading about the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-TCMODE'><filename>TCMODE</filename></ulink>
+            variable in the Yocto Project Reference Manual's variable glossary.
+        </para>
+    </section>
+
+    <section id='creating-partitioned-images-using-wic'>
+        <title>Creating Partitioned Images Using Wic</title>
+
+        <para>
+            Creating an image for a particular hardware target using the
+            OpenEmbedded build system does not necessarily mean you can boot
+            that image as is on your device.
+            Physical devices accept and boot images in various ways depending
+            on the specifics of the device.
+            Usually, information about the hardware can tell you what image
+            format the device requires.
+            Should your device require multiple partitions on an SD card, flash,
+            or an HDD, you can use the OpenEmbedded Image Creator,
+	        Wic, to create the properly partitioned image.
+        </para>
+
+        <para>
+            The <filename>wic</filename> command generates partitioned
+            images from existing OpenEmbedded build artifacts.
+            Image generation is driven by partitioning commands
+            contained in an Openembedded kickstart file
+            (<filename>.wks</filename>) specified either directly on
+            the command line or as one of a selection of canned
+            kickstart files as shown with the
+            <filename>wic list images</filename> command in the
+            "<link linkend='using-a-provided-kickstart-file'>Using an Existing Kickstart File</link>"
+            section.
+            When you apply the command to a given set of build
+            artifacts, the result is an image or set of images that
+            can be directly written onto media and used on a particular
+            system.
+            <note>
+                For a kickstart file reference, see the
+                "<ulink url='&YOCTO_DOCS_REF_URL;#ref-kickstart'>OpenEmbedded Kickstart (<filename>.wks</filename>) Reference</ulink>"
+                Chapter in the Yocto Project Reference Manual.
+            </note>
+        </para>
+
+        <para>
+            The <filename>wic</filename> command and the infrastructure
+            it is based on is by definition incomplete.
+            The purpose of the command is to allow the generation of
+            customized images, and as such, was designed to be
+            completely extensible through a plugin interface.
+            See the
+            "<link linkend='wic-using-the-wic-plugin-interface'>Using the Wic PlugIn Interface</link>"
+            section for information on these plugins.
+        </para>
+
+        <para>
+            This section provides some background information on Wic,
+            describes what you need to have in
+            place to run the tool, provides instruction on how to use
+            the Wic utility, provides information on using the Wic plugins
+            interface, and provides several examples that show how to use
+            Wic.
+        </para>
+
+        <section id='wic-background'>
+            <title>Background</title>
+
+            <para>
+                This section provides some background on the Wic utility.
+                While none of this information is required to use
+                Wic, you might find it interesting.
+                <itemizedlist>
+                    <listitem><para>
+                        The name "Wic" is derived from OpenEmbedded
+                        Image Creator (oeic).
+                        The "oe" diphthong in "oeic" was promoted to the
+                        letter "w", because "oeic" is both difficult to
+                        remember and to pronounce.
+                        </para></listitem>
+                    <listitem><para>
+                        Wic is loosely based on the
+                        Meego Image Creator (<filename>mic</filename>)
+                        framework.
+                        The Wic implementation has been
+                        heavily modified to make direct use of OpenEmbedded
+                        build artifacts instead of package installation and
+                        configuration, which are already incorporated within
+                        the OpenEmbedded artifacts.
+                        </para></listitem>
+                    <listitem><para>
+                        Wic is a completely independent
+                        standalone utility that initially provides
+                        easier-to-use and more flexible replacements for an
+                        existing functionality in OE-Core's
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-image-live'><filename>image-live</filename></ulink>
+                        class.
+                        The difference between Wic and those examples is
+                        that with Wic the functionality of those scripts is
+                        implemented by a general-purpose partitioning language,
+                        which is based on Redhat kickstart syntax.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='wic-requirements'>
+            <title>Requirements</title>
+
+            <para>
+                In order to use the Wic utility with the OpenEmbedded Build
+                system, your system needs to meet the following
+                requirements:
+                <itemizedlist>
+                    <listitem><para>
+                        The Linux distribution on your development host must
+                        support the Yocto Project.
+                        See the
+                        "<ulink url='&YOCTO_DOCS_REF_URL;#detailed-supported-distros'>Supported Linux Distributions</ulink>"
+                        section in the Yocto Project Reference Manual for
+                        the list of distributions that support the
+                        Yocto Project.
+                        </para></listitem>
+                    <listitem><para>
+                        The standard system utilities, such as
+                        <filename>cp</filename>, must be installed on your
+                        development host system.
+                        </para></listitem>
+                    <listitem><para>
+                        You must have sourced the build environment
+                        setup script (i.e.
+                        <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>&OE_INIT_FILE;</filename></ulink>)
+                        found in the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                        </para></listitem>
+                    <listitem><para>
+                        You need to have the build artifacts already
+                        available, which typically means that you must
+                        have already created an image using the
+                        Openembedded build system (e.g.
+                        <filename>core-image-minimal</filename>).
+                        While it might seem redundant to generate an image
+                        in order to create an image using
+                        Wic, the current version of
+                        Wic requires the artifacts
+                        in the form generated by the OpenEmbedded build
+                        system.
+                        </para></listitem>
+                    <listitem><para>
+                        You must build several native tools, which are
+                        built to run on the build system:
+                        <literallayout class='monospaced'>
+     $ bitbake parted-native dosfstools-native mtools-native
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        Include "wic" as part of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></ulink>
+                        variable.
+                        </para></listitem>
+                    <listitem><para>
+                        Include the name of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#openembedded-kickstart-wks-reference'>wic kickstart file</ulink>
+                        as part of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-WKS_FILE'><filename>WKS_FILE</filename></ulink>
+                        variable
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='wic-getting-help'>
+            <title>Getting Help</title>
+
+            <para>
+                You can get general help for the <filename>wic</filename>
+                command by entering the <filename>wic</filename> command
+                by itself or by entering the command with a help argument
+                as follows:
+                <literallayout class='monospaced'>
+     $ wic -h
+     $ wic --help
+     $ wic help
+                </literallayout>
+            </para>
+
+            <para>
+                Currently, Wic supports seven commands:
+                <filename>cp</filename>, <filename>create</filename>,
+                <filename>help</filename>, <filename>list</filename>,
+                <filename>ls</filename>, <filename>rm</filename>, and
+                <filename>write</filename>.
+                You can get help for all these commands except "help" by
+                using the following form:
+                <literallayout class='monospaced'>
+     $ wic help <replaceable>command</replaceable>
+                </literallayout>
+                For example, the following command returns help for the
+                <filename>write</filename> command:
+                <literallayout class='monospaced'>
+     $ wic help write
+                </literallayout>
+            </para>
+
+            <para>
+                Wic supports help for three topics:
+                <filename>overview</filename>,
+                <filename>plugins</filename>, and
+                <filename>kickstart</filename>.
+                You can get help for any topic using the following form:
+                <literallayout class='monospaced'>
+     $ wic help <replaceable>topic</replaceable>
+                </literallayout>
+                For example, the following returns overview help for Wic:
+                <literallayout class='monospaced'>
+     $ wic help overview
+                </literallayout>
+            </para>
+
+            <para>
+                One additional level of help exists for Wic.
+                You can get help on individual images through the
+                <filename>list</filename> command.
+                You can use the <filename>list</filename> command to return the
+                available Wic images as follows:
+                <literallayout class='monospaced'>
+     $ wic list images
+       genericx86                    		Create an EFI disk image for genericx86*
+       beaglebone-yocto              		Create SD card image for Beaglebone
+       edgerouter                    		Create SD card image for Edgerouter
+       qemux86-directdisk            		Create a qemu machine 'pcbios' direct disk image
+       directdisk-gpt                		Create a 'pcbios' direct disk image
+       mkefidisk                     		Create an EFI disk image
+       directdisk                    		Create a 'pcbios' direct disk image
+       systemd-bootdisk              		Create an EFI disk image with systemd-boot
+       mkhybridiso                   		Create a hybrid ISO image
+       sdimage-bootpart              		Create SD card image with a boot partition
+       directdisk-multi-rootfs       		Create multi rootfs image using rootfs plugin
+       directdisk-bootloader-config  		Create a 'pcbios' direct disk image with custom bootloader config
+                </literallayout>
+                Once you know the list of available Wic images, you can use
+                <filename>help</filename> with the command to get help on a
+                particular image.
+                For example, the following command returns help on the
+                "beaglebone-yocto" image:
+                <literallayout class='monospaced'>
+     $ wic list beaglebone-yocto help
+
+
+     Creates a partitioned SD card image for Beaglebone.
+     Boot files are located in the first vfat partition.
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='operational-modes'>
+            <title>Operational Modes</title>
+
+            <para>
+                You can use Wic in two different
+                modes, depending on how much control you need for
+                specifying the Openembedded build artifacts that are
+                used for creating the image: Raw and Cooked:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Raw Mode:</emphasis>
+                        You explicitly specify build artifacts through
+                        Wic command-line arguments.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Cooked Mode:</emphasis>
+                        The current
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                        setting and image name are used to automatically
+                        locate and provide the build artifacts.
+                        You just supply a kickstart file and the name
+                        of the image from which to use artifacts.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Regardless of the mode you use, you need to have the build
+                artifacts ready and available.
+            </para>
+
+            <section id='raw-mode'>
+                <title>Raw Mode</title>
+
+                <para>
+                    Running Wic in raw mode allows you to specify all the
+                    partitions through the <filename>wic</filename>
+                    command line.
+                    The primary use for raw mode is if you have built
+                    your kernel outside of the Yocto Project
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                    In other words, you can point to arbitrary kernel,
+                    root filesystem locations, and so forth.
+                    Contrast this behavior with cooked mode where Wic
+                    looks in the Build Directory (e.g.
+                    <filename>tmp/deploy/images/</filename><replaceable>machine</replaceable>).
+                </para>
+
+                <para>
+                    The general form of the
+                    <filename>wic</filename> command in raw mode is:
+                    <literallayout class='monospaced'>
+     $ wic create <replaceable>wks_file</replaceable> <replaceable>options</replaceable> ...
+
+       Where:
+
+          <replaceable>wks_file</replaceable>:
+             An OpenEmbedded kickstart file.  You can provide
+             your own custom file or use a file from a set of
+             existing files as described by further options.
+
+          optional arguments:
+            -h, --help            show this help message and exit
+            -o <replaceable>OUTDIR</replaceable>, --outdir <replaceable>OUTDIR</replaceable>
+                                  name of directory to create image in
+            -e <replaceable>IMAGE_NAME</replaceable>, --image-name <replaceable>IMAGE_NAME</replaceable>
+                                  name of the image to use the artifacts from e.g. core-
+                                  image-sato
+            -r <replaceable>ROOTFS_DIR</replaceable>, --rootfs-dir <replaceable>ROOTFS_DIR</replaceable>
+                                  path to the /rootfs dir to use as the .wks rootfs
+                                  source
+            -b <replaceable>BOOTIMG_DIR</replaceable>, --bootimg-dir <replaceable>BOOTIMG_DIR</replaceable>
+                                  path to the dir containing the boot artifacts (e.g.
+                                  /EFI or /syslinux dirs) to use as the .wks bootimg
+                                  source
+            -k <replaceable>KERNEL_DIR</replaceable>, --kernel-dir <replaceable>KERNEL_DIR</replaceable>
+                                  path to the dir containing the kernel to use in the
+                                  .wks bootimg
+            -n <replaceable>NATIVE_SYSROOT</replaceable>, --native-sysroot <replaceable>NATIVE_SYSROOT</replaceable>
+                                  path to the native sysroot containing the tools to use
+                                  to build the image
+            -s, --skip-build-check
+                                  skip the build check
+            -f, --build-rootfs    build rootfs
+            -c {gzip,bzip2,xz}, --compress-with {gzip,bzip2,xz}
+                                  compress image with specified compressor
+            -m, --bmap            generate .bmap
+            --no-fstab-update     Do not change fstab file.
+            -v <replaceable>VARS_DIR</replaceable>, --vars <replaceable>VARS_DIR</replaceable>
+                                  directory with &lt;image&gt;.env files that store bitbake
+                                  variables
+            -D, --debug           output debug information
+                    </literallayout>
+                    <note>
+                        You do not need root privileges to run
+                        Wic.
+                        In fact, you should not run as root when using the
+                        utility.
+                    </note>
+                </para>
+            </section>
+
+            <section id='cooked-mode'>
+                <title>Cooked Mode</title>
+
+                <para>
+                    Running Wic in cooked mode leverages off artifacts in
+                    the Build Directory.
+                    In other words, you do not have to specify kernel or
+                    root filesystem locations as part of the command.
+                    All you need to provide is a kickstart file and the
+                    name of the image from which to use artifacts by using
+                    the "-e" option.
+                    Wic looks in the Build Directory (e.g.
+                    <filename>tmp/deploy/images/</filename><replaceable>machine</replaceable>)
+                    for artifacts.
+                </para>
+
+                <para>
+                    The general form of the <filename>wic</filename>
+                    command using Cooked Mode is as follows:
+                    <literallayout class='monospaced'>
+     $ wic create <replaceable>wks_file</replaceable> -e <replaceable>IMAGE_NAME</replaceable>
+
+       Where:
+
+          <replaceable>wks_file</replaceable>:
+             An OpenEmbedded kickstart file.  You can provide
+             your own custom file or use a file from a set of
+             existing files provided with the Yocto Project
+             release.
+
+          required argument:
+             -e <replaceable>IMAGE_NAME</replaceable>, --image-name <replaceable>IMAGE_NAME</replaceable>
+                                  name of the image to use the artifacts from e.g. core-
+                                  image-sato
+                    </literallayout>
+                </para>
+            </section>
+        </section>
+
+        <section id='using-a-provided-kickstart-file'>
+            <title>Using an Existing Kickstart File</title>
+
+            <para>
+                If you do not want to create your own kickstart file, you
+                can use an existing file provided by the Wic installation.
+                As shipped, kickstart files can be found in the
+                Yocto Project
+                <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>
+                in the following two locations:
+                <literallayout class='monospaced'>
+     poky/meta-yocto-bsp/wic
+     poky/scripts/lib/wic/canned-wks
+                </literallayout>
+                Use the following command to list the available kickstart
+                files:
+                <literallayout class='monospaced'>
+     $ wic list images
+       genericx86                    		Create an EFI disk image for genericx86*
+       beaglebone-yocto              		Create SD card image for Beaglebone
+       edgerouter                    		Create SD card image for Edgerouter
+       qemux86-directdisk            		Create a qemu machine 'pcbios' direct disk image
+       directdisk-gpt                		Create a 'pcbios' direct disk image
+       mkefidisk                     		Create an EFI disk image
+       directdisk                    		Create a 'pcbios' direct disk image
+       systemd-bootdisk              		Create an EFI disk image with systemd-boot
+       mkhybridiso                   		Create a hybrid ISO image
+       sdimage-bootpart              		Create SD card image with a boot partition
+       directdisk-multi-rootfs       		Create multi rootfs image using rootfs plugin
+       directdisk-bootloader-config  		Create a 'pcbios' direct disk image with custom bootloader config
+                </literallayout>
+                When you use an existing file, you do not have to use the
+                <filename>.wks</filename> extension.
+                Here is an example in Raw Mode that uses the
+                <filename>directdisk</filename> file:
+                <literallayout class='monospaced'>
+     $ wic create directdisk -r <replaceable>rootfs_dir</replaceable> -b <replaceable>bootimg_dir</replaceable> \
+           -k <replaceable>kernel_dir</replaceable> -n <replaceable>native_sysroot</replaceable>
+                </literallayout>
+            </para>
+
+            <para>
+                Here are the actual partition language commands
+                used in the <filename>genericx86.wks</filename> file to
+                generate an image:
+                <literallayout class='monospaced'>
+     # short-description: Create an EFI disk image for genericx86*
+     # long-description: Creates a partitioned EFI disk image for genericx86* machines
+     part /boot --source bootimg-efi --sourceparams="loader=grub-efi" --ondisk sda --label msdos --active --align 1024
+     part / --source rootfs --ondisk sda --fstype=ext4 --label platform --align 1024 --use-uuid
+     part swap --ondisk sda --size 44 --label swap1 --fstype=swap
+
+     bootloader --ptable gpt --timeout=5 --append="rootfstype=ext4 console=ttyS0,115200 console=tty0"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='wic-using-the-wic-plugin-interface'>
+            <title>Using the Wic Plugin Interface</title>
+
+            <para>
+                You can extend and specialize Wic functionality by using
+                Wic plugins.
+                This section explains the Wic plugin interface.
+                <note>
+                    Wic plugins consist of "source" and "imager" plugins.
+                    Imager plugins are beyond the scope of this section.
+                </note>
+            </para>
+
+            <para>
+                Source plugins provide a mechanism to customize partition
+                content during the Wic image generation process.
+                You can use source plugins to map values that you specify
+                using <filename>--source</filename> commands in kickstart
+                files (i.e. <filename>*.wks</filename>) to a plugin
+                implementation used to populate a given partition.
+                <note>
+                    If you use plugins that have build-time dependencies
+                    (e.g. native tools, bootloaders, and so forth)
+                    when building a Wic image, you need to specify those
+                    dependencies using the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-WKS_FILE_DEPENDS'><filename>WKS_FILE_DEPENDS</filename></ulink>
+                    variable.
+                </note>
+            </para>
+
+            <para>
+                Source plugins are subclasses defined in plugin files.
+                As shipped, the Yocto Project provides several plugin
+                files.
+                You can see the source plugin files that ship with the
+                Yocto Project
+                <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/poky/tree/scripts/lib/wic/plugins/source'>here</ulink>.
+                Each of these plugin files contains source plugins that
+                are designed to populate a specific Wic image partition.
+            </para>
+
+            <para>
+                Source plugins are subclasses of the
+                <filename>SourcePlugin</filename> class, which is
+                defined in the
+                <filename>poky/scripts/lib/wic/pluginbase.py</filename>
+                file.
+                For example, the <filename>BootimgEFIPlugin</filename>
+                source plugin found in the
+                <filename>bootimg-efi.py</filename> file is a subclass of
+                the <filename>SourcePlugin</filename> class, which is found
+                in the <filename>pluginbase.py</filename> file.
+            </para>
+
+            <para>
+                You can also implement source plugins in a layer outside
+                of the Source Repositories (external layer).
+                To do so, be sure that your plugin files are located in
+                a directory whose path is
+                <filename>scripts/lib/wic/plugins/source/</filename>
+                within your external layer.
+                When the plugin files are located there, the source
+                plugins they contain are made available to Wic.
+            </para>
+
+            <para>
+                When the Wic implementation needs to invoke a
+                partition-specific implementation, it looks for the plugin
+                with the same name as the <filename>--source</filename>
+                parameter used in the kickstart file given to that
+                partition.
+                For example, if the partition is set up using the following
+                command in a kickstart file:
+                <literallayout class='monospaced'>
+     part /boot --source bootimg-pcbios --ondisk sda --label boot --active --align 1024
+                </literallayout>
+                The methods defined as class members of the matching
+                source plugin (i.e. <filename>bootimg-pcbios</filename>)
+                in the <filename>bootimg-pcbios.py</filename> plugin file
+                are used.
+            </para>
+
+            <para>
+                To be more concrete, here is the corresponding plugin
+                definition from the <filename>bootimg-pcbios.py</filename>
+                file for the previous command along with an example
+                method called by the Wic implementation when it needs to
+                prepare a partition using an implementation-specific
+                function:
+                <literallayout class='monospaced'>
+                  .
+                  .
+                  .
+     class BootimgPcbiosPlugin(SourcePlugin):
+         """
+         Create MBR boot partition and install syslinux on it.
+         """
+
+         name = 'bootimg-pcbios'
+                  .
+                  .
+                  .
+         @classmethod
+         def do_prepare_partition(cls, part, source_params, creator, cr_workdir,
+                                  oe_builddir, bootimg_dir, kernel_dir,
+                                  rootfs_dir, native_sysroot):
+             """
+             Called to do the actual content population for a partition i.e. it
+             'prepares' the partition to be incorporated into the image.
+             In this case, prepare content for legacy bios boot partition.
+             """
+                  .
+                  .
+                  .
+                </literallayout>
+                If a subclass (plugin) itself does not implement a
+                particular function, Wic locates and uses the default
+                version in the superclass.
+                It is for this reason that all source plugins are derived
+                from the <filename>SourcePlugin</filename> class.
+            </para>
+
+            <para>
+                The <filename>SourcePlugin</filename> class defined in
+                the <filename>pluginbase.py</filename> file defines
+                a set of methods that source plugins can implement or
+                override.
+                Any plugins (subclass of
+                <filename>SourcePlugin</filename>) that do not implement
+                a particular method inherit the implementation of the
+                method from the <filename>SourcePlugin</filename> class.
+                For more information, see the
+                <filename>SourcePlugin</filename> class in the
+                <filename>pluginbase.py</filename> file for details:
+            </para>
+
+            <para>
+                The following list describes the methods implemented in the
+                <filename>SourcePlugin</filename> class:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis><filename>do_prepare_partition()</filename>:</emphasis>
+                        Called to populate a partition with actual content.
+                        In other words, the method prepares the final
+                        partition image that is incorporated into the
+                        disk image.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>do_configure_partition()</filename>:</emphasis>
+                        Called before
+                        <filename>do_prepare_partition()</filename> to
+                        create custom configuration files for a partition
+                        (e.g. syslinux or grub configuration files).
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>do_install_disk()</filename>:</emphasis>
+                        Called after all partitions have been prepared and
+                        assembled into a disk image.
+                        This method provides a hook to allow finalization
+                        of a disk image (e.g. writing an MBR).
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis><filename>do_stage_partition()</filename>:</emphasis>
+                        Special content-staging hook called before
+                        <filename>do_prepare_partition()</filename>.
+                        This method is normally empty.</para>
+
+                        <para>Typically, a partition just uses the passed-in
+                        parameters (e.g. the unmodified value of
+                        <filename>bootimg_dir</filename>).
+                        However, in some cases, things might need to be
+                        more tailored.
+                        As an example, certain files might additionally
+                        need to be taken from
+                        <filename>bootimg_dir + /boot</filename>.
+                        This hook allows those files to be staged in a
+                        customized fashion.
+                        <note>
+                            <filename>get_bitbake_var()</filename>
+                            allows you to access non-standard variables
+                            that you might want to use for this
+                            behavior.
+                        </note>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                You can extend the source plugin mechanism.
+                To add more hooks, create more source plugin methods
+                within <filename>SourcePlugin</filename> and the
+                corresponding derived subclasses.
+                The code that calls the plugin methods uses the
+                <filename>plugin.get_source_plugin_methods()</filename>
+                function to find the method or methods needed by the call.
+                Retrieval of those methods is accomplished by filling up
+                a dict with keys that contain the method names of interest.
+                On success, these will be filled in with the actual
+                methods.
+                See the Wic implementation for examples and details.
+            </para>
+        </section>
+
+        <section id='wic-usage-examples'>
+            <title>Examples</title>
+
+            <para>
+                This section provides several examples that show how to use
+                the Wic utility.
+                All the examples assume the list of requirements in the
+                "<link linkend='wic-requirements'>Requirements</link>"
+                section have been met.
+                The examples assume the previously generated image is
+                <filename>core-image-minimal</filename>.
+            </para>
+
+            <section id='generate-an-image-using-a-provided-kickstart-file'>
+                <title>Generate an Image using an Existing Kickstart File</title>
+
+                <para>
+                    This example runs in Cooked Mode and uses the
+                    <filename>mkefidisk</filename> kickstart file:
+                    <literallayout class='monospaced'>
+     $ wic create mkefidisk -e core-image-minimal
+     INFO: Building wic-tools...
+               .
+               .
+               .
+     INFO: The new image(s) can be found here:
+       ./mkefidisk-201804191017-sda.direct
+
+     The following build artifacts were used to create the image(s):
+       ROOTFS_DIR:                   /home/stephano/build/master/build/tmp-glibc/work/qemux86-oe-linux/core-image-minimal/1.0-r0/rootfs
+       BOOTIMG_DIR:                  /home/stephano/build/master/build/tmp-glibc/work/qemux86-oe-linux/core-image-minimal/1.0-r0/recipe-sysroot/usr/share
+       KERNEL_DIR:                   /home/stephano/build/master/build/tmp-glibc/deploy/images/qemux86
+       NATIVE_SYSROOT:               /home/stephano/build/master/build/tmp-glibc/work/i586-oe-linux/wic-tools/1.0-r0/recipe-sysroot-native
+
+     INFO: The image(s) were created using OE kickstart file:
+       /home/stephano/build/master/openembedded-core/scripts/lib/wic/canned-wks/mkefidisk.wks
+                    </literallayout>
+                    The previous example shows the easiest way to create
+                    an image by running in cooked mode and supplying
+                    a kickstart file and the "-e" option to point to the
+                    existing build artifacts.
+                    Your <filename>local.conf</filename> file needs to have
+                    the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                    variable set to the machine you are using, which is
+                    "qemux86" in this example.
+                </para>
+
+                <para>
+                    Once the image builds, the output provides image
+                    location, artifact use, and kickstart file information.
+                    <note>
+                        You should always verify the details provided in the
+                        output to make sure that the image was indeed
+                        created exactly as expected.
+                    </note>
+                </para>
+
+                <para>
+                    Continuing with the example, you can now write the
+                    image from the Build Directory onto a USB stick, or
+                    whatever media for which you built your image, and boot
+                    from the media.
+                    You can write the image by using
+                    <filename>bmaptool</filename> or
+                    <filename>dd</filename>:
+                    <literallayout class='monospaced'>
+     $ oe-run-native bmaptool copy mkefidisk-201804191017-sda.direct /dev/sd<replaceable>X</replaceable>
+                    </literallayout>
+                    or
+                    <literallayout class='monospaced'>
+     $ sudo dd if=mkefidisk-201804191017-sda.direct of=/dev/sd<replaceable>X</replaceable>
+                    </literallayout>
+                    <note>
+                        For more information on how to use the
+                        <filename>bmaptool</filename> to flash a device
+                        with an image, see the
+                        "<link linkend='flashing-images-using-bmaptool'>Flashing Images Using <filename>bmaptool</filename></link>"
+                        section.
+                    </note>
+                </para>
+            </section>
+
+            <section id='using-a-modified-kickstart-file'>
+                <title>Using a Modified Kickstart File</title>
+
+                <para>
+                    Because partitioned image creation is driven by the
+                    kickstart file, it is easy to affect image creation by
+                    changing the parameters in the file.
+                    This next example demonstrates that through modification
+                    of the <filename>directdisk-gpt</filename> kickstart
+                    file.
+                </para>
+
+                <para>
+                    As mentioned earlier, you can use the command
+                    <filename>wic list images</filename> to show the list
+                    of existing kickstart files.
+                    The directory in which the
+                    <filename>directdisk-gpt.wks</filename> file resides is
+                    <filename>scripts/lib/image/canned-wks/</filename>,
+                    which is located in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                    (e.g. <filename>poky</filename>).
+                    Because available files reside in this directory,
+                    you can create and add your own custom files to the
+                    directory.
+                    Subsequent use of the
+                    <filename>wic list images</filename> command would then
+                    include your kickstart files.
+                </para>
+
+                <para>
+                    In this example, the existing
+                    <filename>directdisk-gpt</filename> file already does
+                    most of what is needed.
+                    However, for the hardware in this example, the image
+                    will need to boot from <filename>sdb</filename> instead
+                    of <filename>sda</filename>, which is what the
+                    <filename>directdisk-gpt</filename> kickstart file
+                    uses.
+                </para>
+
+                <para>
+                    The example begins by making a copy of the
+                    <filename>directdisk-gpt.wks</filename> file in the
+                    <filename>scripts/lib/image/canned-wks</filename>
+                    directory and then by changing the lines that specify
+                    the target disk from which to boot.
+                    <literallayout class='monospaced'>
+     $ cp /home/stephano/poky/scripts/lib/wic/canned-wks/directdisk-gpt.wks \
+          /home/stephano/poky/scripts/lib/wic/canned-wks/directdisksdb-gpt.wks
+                    </literallayout>
+                    Next, the example modifies the
+                    <filename>directdisksdb-gpt.wks</filename> file and
+                    changes all instances of
+                    "<filename>--ondisk sda</filename>" to
+                    "<filename>--ondisk sdb</filename>".
+                    The example changes the following two lines and leaves
+                    the remaining lines untouched:
+                    <literallayout class='monospaced'>
+     part /boot --source bootimg-pcbios --ondisk sdb --label boot --active --align 1024
+     part / --source rootfs --ondisk sdb --fstype=ext4 --label platform --align 1024 --use-uuid
+                    </literallayout>
+                    Once the lines are changed, the example generates the
+                    <filename>directdisksdb-gpt</filename> image.
+                    The command points the process at the
+                    <filename>core-image-minimal</filename> artifacts for
+                    the Next Unit of Computing (nuc)
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                    the <filename>local.conf</filename>.
+                    <literallayout class='monospaced'>
+     $ wic create directdisksdb-gpt -e core-image-minimal
+     INFO: Building wic-tools...
+                .
+                .
+                .
+     Initialising tasks: 100% |#######################################| Time: 0:00:01
+     NOTE: Executing SetScene Tasks
+     NOTE: Executing RunQueue Tasks
+     NOTE: Tasks Summary: Attempted 1161 tasks of which 1157 didn't need to be rerun and all succeeded.
+     INFO: Creating image(s)...
+
+     INFO: The new image(s) can be found here:
+       ./directdisksdb-gpt-201710090938-sdb.direct
+
+     The following build artifacts were used to create the image(s):
+       ROOTFS_DIR:                   /home/stephano/build/master/build/tmp-glibc/work/qemux86-oe-linux/core-image-minimal/1.0-r0/rootfs
+       BOOTIMG_DIR:                  /home/stephano/build/master/build/tmp-glibc/work/qemux86-oe-linux/core-image-minimal/1.0-r0/recipe-sysroot/usr/share
+       KERNEL_DIR:                   /home/stephano/build/master/build/tmp-glibc/deploy/images/qemux86
+       NATIVE_SYSROOT:               /home/stephano/build/master/build/tmp-glibc/work/i586-oe-linux/wic-tools/1.0-r0/recipe-sysroot-native
+
+     INFO: The image(s) were created using OE kickstart file:
+       /home/stephano/poky/scripts/lib/wic/canned-wks/directdisksdb-gpt.wks
+                    </literallayout>
+                    Continuing with the example, you can now directly
+                    <filename>dd</filename> the image to a USB stick, or
+                    whatever media for which you built your image,
+                    and boot the resulting media:
+                    <literallayout class='monospaced'>
+     $ sudo dd if=directdisksdb-gpt-201710090938-sdb.direct of=/dev/sdb
+     140966+0 records in
+     140966+0 records out
+     72174592 bytes (72 MB, 69 MiB) copied, 78.0282 s, 925 kB/s
+     $ sudo eject /dev/sdb
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='using-a-modified-kickstart-file-and-running-in-raw-mode'>
+                <title>Using a Modified Kickstart File and Running in Raw Mode</title>
+
+                <para>
+                    This next example manually specifies each build artifact
+                    (runs in Raw Mode) and uses a modified kickstart file.
+                    The example also uses the <filename>-o</filename> option
+                    to cause Wic to create the output
+                    somewhere other than the default output directory,
+                    which is the current directory:
+                    <literallayout class='monospaced'>
+     $ wic create /home/stephano/my_yocto/test.wks -o /home/stephano/testwic \
+          --rootfs-dir /home/stephano/build/master/build/tmp/work/qemux86-poky-linux/core-image-minimal/1.0-r0/rootfs \
+          --bootimg-dir /home/stephano/build/master/build/tmp/work/qemux86-poky-linux/core-image-minimal/1.0-r0/recipe-sysroot/usr/share \
+          --kernel-dir /home/stephano/build/master/build/tmp/deploy/images/qemux86 \
+          --native-sysroot /home/stephano/build/master/build/tmp/work/i586-poky-linux/wic-tools/1.0-r0/recipe-sysroot-native
+
+     INFO: Creating image(s)...
+
+     INFO: The new image(s) can be found here:
+       /home/stephano/testwic/test-201710091445-sdb.direct
+
+     The following build artifacts were used to create the image(s):
+       ROOTFS_DIR:                   /home/stephano/build/master/build/tmp-glibc/work/qemux86-oe-linux/core-image-minimal/1.0-r0/rootfs
+       BOOTIMG_DIR:                  /home/stephano/build/master/build/tmp-glibc/work/qemux86-oe-linux/core-image-minimal/1.0-r0/recipe-sysroot/usr/share
+       KERNEL_DIR:                   /home/stephano/build/master/build/tmp-glibc/deploy/images/qemux86
+       NATIVE_SYSROOT:               /home/stephano/build/master/build/tmp-glibc/work/i586-oe-linux/wic-tools/1.0-r0/recipe-sysroot-native
+
+     INFO: The image(s) were created using OE kickstart file:
+       /home/stephano/my_yocto/test.wks
+                    </literallayout>
+                    For this example,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                    did not have to be specified in the
+                    <filename>local.conf</filename> file since the
+                    artifact is manually specified.
+                </para>
+            </section>
+
+            <section id='using-wic-to-manipulate-an-image'>
+                <title>Using Wic to Manipulate an Image</title>
+
+                <para>
+                    Wic image manipulation allows you to shorten turnaround
+                    time during image development.
+                    For example, you can use Wic to delete the kernel partition
+                    of a Wic image and then insert a newly built kernel.
+                    This saves you time from having to rebuild the entire image
+                    each time you modify the kernel.
+                    <note>
+                        In order to use Wic to manipulate a Wic image as in
+                        this example, your development machine must have the
+                        <filename>mtools</filename> package installed.
+                    </note>
+                </para>
+
+                <para>
+                    The following example examines the contents of the Wic
+                    image, deletes the existing kernel, and then inserts a
+                    new kernel:
+                    <orderedlist>
+                        <listitem><para>
+                            <emphasis>List the Partitions:</emphasis>
+                            Use the <filename>wic ls</filename> command to list
+                            all the partitions in the Wic image:
+                            <literallayout class='monospaced'>
+     $ wic ls tmp/deploy/images/qemux86/core-image-minimal-qemux86.wic
+     Num     Start        End          Size      Fstype
+      1       1048576     25041919     23993344  fat16
+      2      25165824     72157183     46991360  ext4
+                            </literallayout>
+                            The previous output shows two partitions in the
+                            <filename>core-image-minimal-qemux86.wic</filename>
+                            image.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Examine a Particular Partition:</emphasis>
+                            Use the <filename>wic ls</filename> command again
+                            but in a different form to examine a particular
+                            partition.
+                            <note>
+                                You can get command usage on any Wic command
+                                using the following form:
+                                <literallayout class='monospaced'>
+     $ wic help <replaceable>command</replaceable>
+                                </literallayout>
+                                For example, the following command shows you
+                                the various ways to use the
+                                <filename>wic ls</filename> command:
+                                <literallayout class='monospaced'>
+     $ wic help ls
+                                </literallayout>
+                            </note>
+                            The following command shows what is in Partition
+                            one:
+                            <literallayout class='monospaced'>
+     $ wic ls tmp/deploy/images/qemux86/core-image-minimal-qemux86.wic:1
+     Volume in drive : is boot
+      Volume Serial Number is E894-1809
+     Directory for ::/
+
+     libcom32 c32    186500 2017-10-09  16:06
+     libutil  c32     24148 2017-10-09  16:06
+     syslinux cfg       220 2017-10-09  16:06
+     vesamenu c32     27104 2017-10-09  16:06
+     vmlinuz        6904608 2017-10-09  16:06
+             5 files           7 142 580 bytes
+                              16 582 656 bytes free
+                            </literallayout>
+                            The previous output shows five files, with the
+                            <filename>vmlinuz</filename> being the kernel.
+                            <note>
+                                If you see the following error, you need to
+                                update or create a
+                                <filename>~/.mtoolsrc</filename> file and
+                                be sure to have the line "mtools_skip_check=1"
+                                in the file.
+                                Then, run the Wic command again:
+                                <literallayout class='monospaced'>
+     ERROR: _exec_cmd: /usr/bin/mdir -i /tmp/wic-parttfokuwra ::/ returned '1' instead of 0
+      output: Total number of sectors (47824) not a multiple of sectors per track (32)!
+      Add mtools_skip_check=1 to your .mtoolsrc file to skip this test
+                                </literallayout>
+                             </note>
+                             </para></listitem>
+                         <listitem><para>
+                             <emphasis>Remove the Old Kernel:</emphasis>
+                             Use the <filename>wic rm</filename> command to
+                             remove the <filename>vmlinuz</filename> file
+                             (kernel):
+                             <literallayout class='monospaced'>
+     $ wic rm tmp/deploy/images/qemux86/core-image-minimal-qemux86.wic:1/vmlinuz
+                             </literallayout>
+                             </para></listitem>
+                         <listitem><para>
+                             <emphasis>Add In the New Kernel:</emphasis>
+                             Use the <filename>wic cp</filename> command to
+                             add the updated kernel to the Wic image.
+                             Depending on how you built your kernel, it could
+                             be in different places.
+                             If you used <filename>devtool</filename> and
+                             an SDK to build your kernel, it resides in the
+                             <filename>tmp/work</filename> directory of the
+                             extensible SDK.
+                             If you used <filename>make</filename> to build the
+                             kernel, the kernel will be in the
+                             <filename>workspace/sources</filename> area.
+                             </para>
+
+                             <para>The following example assumes
+                             <filename>devtool</filename> was used to build
+                             the kernel:
+                             <literallayout class='monospaced'>
+     cp ~/poky_sdk/tmp/work/qemux86-poky-linux/linux-yocto/4.12.12+git999-r0/linux-yocto-4.12.12+git999/arch/x86/boot/bzImage \
+        ~/poky/build/tmp/deploy/images/qemux86/core-image-minimal-qemux86.wic:1/vmlinuz
+                             </literallayout>
+                             Once the new kernel is added back into the image,
+                             you can use the <filename>dd</filename>
+                             command or
+                             <link linkend='flashing-images-using-bmaptool'><filename>bmaptool</filename></link>
+                             to flash your wic image onto an SD card
+                             or USB stick and test your target.
+                             <note>
+                                 Using <filename>bmaptool</filename> is
+                                 generally 10 to 20 times faster than using
+                                 <filename>dd</filename>.
+                             </note>
+                             </para></listitem>
+                     </orderedlist>
+                 </para>
+             </section>
+        </section>
+    </section>
+
+    <section id='flashing-images-using-bmaptool'>
+        <title>Flashing Images Using <filename>bmaptool</filename></title>
+
+        <para>
+            A fast and easy way to flash an image to a bootable device
+            is to use Bmaptool, which is integrated into the OpenEmbedded
+            build system.
+            Bmaptool is a generic tool that creates a file's block map (bmap)
+            and then uses that map to copy the file.
+            As compared to traditional tools such as dd or cp, Bmaptool
+            can copy (or flash) large files like raw system image files
+            much faster.
+            <note><title>Notes</title>
+                <itemizedlist>
+                    <listitem><para>
+                        If you are using Ubuntu or Debian distributions, you
+                        can install the <filename>bmap-tools</filename> package
+                        using the following command and then use the tool
+                        without specifying <filename>PATH</filename> even from
+                        the root account:
+                        <literallayout class='monospaced'>
+     $ sudo apt-get install bmap-tools
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        If you are unable to install the
+                        <filename>bmap-tools</filename> package, you will
+                        need to build Bmaptool before using it.
+                        Use the following command:
+                        <literallayout class='monospaced'>
+     $ bitbake bmap-tools-native
+                        </literallayout>
+                        </para></listitem>
+                </itemizedlist>
+            </note>
+        </para>
+
+        <para>
+            Following, is an example that shows how to flash a Wic image.
+            Realize that while this example uses a Wic image, you can use
+            Bmaptool to flash any type of image.
+            Use these steps to flash an image using Bmaptool:
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Update your <filename>local.conf</filename> File:</emphasis>
+                    You need to have the following set in your
+                    <filename>local.conf</filename> file before building
+                    your image:
+                    <literallayout class='monospaced'>
+     IMAGE_FSTYPES += "wic wic.bmap"
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Get Your Image:</emphasis>
+                    Either have your image ready (pre-built with the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></ulink>
+                    setting previously mentioned) or take the step to build
+                    the image:
+                    <literallayout class='monospaced'>
+     $ bitbake <replaceable>image</replaceable>
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Flash the Device:</emphasis>
+                    Flash the device with the image by using Bmaptool
+                    depending on your particular setup.
+                    The following commands assume the image resides in the
+                    Build Directory's <filename>deploy/images/</filename>
+                    area:
+                    <itemizedlist>
+                        <listitem><para>
+                            If you have write access to the media, use this
+                            command form:
+                            <literallayout class='monospaced'>
+     $ oe-run-native bmap-tools-native bmaptool copy <replaceable>build-directory</replaceable>/tmp/deploy/images/<replaceable>machine</replaceable>/<replaceable>image</replaceable>.wic /dev/sd<replaceable>X</replaceable>
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para>
+                            If you do not have write access to the media, set
+                            your permissions first and then use the same
+                            command form:
+                            <literallayout class='monospaced'>
+     $ sudo chmod 666 /dev/sd<replaceable>X</replaceable>
+     $ oe-run-native bmap-tools-native bmaptool copy <replaceable>build-directory</replaceable>/tmp/deploy/images/<replaceable>machine</replaceable>/<replaceable>image</replaceable>.wic /dev/sd<replaceable>X</replaceable>
+                            </literallayout>
+                            </para></listitem>
+                    </itemizedlist>
+                    </para></listitem>
+            </orderedlist>
+        </para>
+
+        <para>
+            For help on the <filename>bmaptool</filename> command, use the
+            following command:
+            <literallayout class='monospaced'>
+     $ bmaptool --help
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='making-images-more-secure'>
+        <title>Making Images More Secure</title>
+
+        <para>
+            Security is of increasing concern for embedded devices.
+            Consider the issues and problems discussed in just this
+            sampling of work found across the Internet:
+            <itemizedlist>
+                <listitem><para><emphasis>
+                    "<ulink url='https://www.schneier.com/blog/archives/2014/01/security_risks_9.html'>Security Risks of Embedded Systems</ulink>"</emphasis>
+                    by Bruce Schneier
+                    </para></listitem>
+                <listitem><para><emphasis>
+                    "<ulink url='http://census2012.sourceforge.net/paper.html'>Internet Census 2012</ulink>"</emphasis>
+                    by Carna Botnet</para></listitem>
+                <listitem><para><emphasis>
+                    "<ulink url='http://elinux.org/images/6/6f/Security-issues.pdf'>Security Issues for Embedded Devices</ulink>"</emphasis>
+                    by Jake Edge
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <para>
+            When securing your image is of concern, there are steps, tools,
+            and variables that you can consider to help you reach the
+            security goals you need for your particular device.
+            Not all situations are identical when it comes to making an
+            image secure.
+            Consequently, this section provides some guidance and suggestions
+            for consideration when you want to make your image more secure.
+            <note>
+                Because the security requirements and risks are
+                different for every type of device, this section cannot
+                provide a complete reference on securing your custom OS.
+                It is strongly recommended that you also consult other sources
+                of information on embedded Linux system hardening and on
+                security.
+            </note>
+        </para>
+
+        <section id='general-considerations'>
+            <title>General Considerations</title>
+
+            <para>
+                General considerations exist that help you create more
+                secure images.
+                You should consider the following suggestions to help
+                make your device more secure:
+                <itemizedlist>
+                    <listitem><para>
+                        Scan additional code you are adding to the system
+                        (e.g. application code) by using static analysis
+                        tools.
+                        Look for buffer overflows and other potential
+                        security problems.
+                    </para></listitem>
+                    <listitem><para>
+                        Pay particular attention to the security for
+                        any web-based administration interface.
+                        </para>
+                        <para>Web interfaces typically need to perform
+                        administrative functions and tend to need to run with
+                        elevated privileges.
+                        Thus, the consequences resulting from the interface's
+                        security becoming compromised can be serious.
+                        Look for common web vulnerabilities such as
+                        cross-site-scripting (XSS), unvalidated inputs,
+                        and so forth.</para>
+                        <para>As with system passwords, the default credentials
+                        for accessing a web-based interface should not be the
+                        same across all devices.
+                        This is particularly true if the interface is enabled
+                        by default as it can be assumed that many end-users
+                        will not change the credentials.
+                    </para></listitem>
+                    <listitem><para>
+                        Ensure you can update the software on the device to
+                        mitigate vulnerabilities discovered in the future.
+                        This consideration especially applies when your
+                        device is network-enabled.
+                    </para></listitem>
+                    <listitem><para>
+                        Ensure you remove or disable debugging functionality
+                        before producing the final image.
+                        For information on how to do this, see the
+                        "<link linkend='considerations-specific-to-the-openembedded-build-system'>Considerations Specific to the OpenEmbedded Build System</link>"
+                        section.
+                        </para></listitem>
+                    <listitem><para>
+                        Ensure you have no network services listening that
+                        are not needed.
+                    </para></listitem>
+                    <listitem><para>
+                        Remove any software from the image that is not needed.
+                    </para></listitem>
+                    <listitem><para>
+                        Enable hardware support for secure boot functionality
+                        when your device supports this functionality.
+                    </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='security-flags'>
+            <title>Security Flags</title>
+
+            <para>
+                The Yocto Project has security flags that you can enable that
+                help make your build output more secure.
+                The security flags are in the
+                <filename>meta/conf/distro/include/security_flags.inc</filename>
+                file in your
+                <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                (e.g. <filename>poky</filename>).
+                <note>
+                    Depending on the recipe, certain security flags are enabled
+                    and disabled by default.
+                </note>
+            </para>
+
+            <para>
+<!--
+                The GCC/LD flags in <filename>security_flags.inc</filename>
+                enable more secure code generation.
+                By including the <filename>security_flags.inc</filename>
+                file, you enable flags to the compiler and linker that cause
+                them to generate more secure code.
+                <note>
+                    The GCC/LD flags are enabled by default in the
+                    <filename>poky-lsb</filename> distribution.
+                </note>
+-->
+                Use the following line in your
+                <filename>local.conf</filename> file or in your custom
+                distribution configuration file to enable the security
+                compiler and linker flags for your build:
+                <literallayout class='monospaced'>
+     require conf/distro/include/security_flags.inc
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='considerations-specific-to-the-openembedded-build-system'>
+            <title>Considerations Specific to the OpenEmbedded Build System</title>
+
+            <para>
+                You can take some steps that are specific to the
+                OpenEmbedded build system to make your images more secure:
+                <itemizedlist>
+                    <listitem><para>
+                        Ensure "debug-tweaks" is not one of your selected
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></ulink>.
+                        When creating a new project, the default is to provide you
+                        with an initial <filename>local.conf</filename> file that
+                        enables this feature using the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_IMAGE_FEATURES'><filename>EXTRA_IMAGE_FEATURES</filename></ulink> variable with the line:
+                <literallayout class='monospaced'>
+     EXTRA_IMAGE_FEATURES = "debug-tweaks"
+                </literallayout>
+                        To disable that feature, simply comment out that line in your
+                        <filename>local.conf</filename> file, or
+                        make sure <filename>IMAGE_FEATURES</filename> does not contain
+                        "debug-tweaks" before producing your final image.
+                        Among other things, leaving this in place sets the
+                        root password as blank, which makes logging in for
+                        debugging or inspection easy during
+                        development but also means anyone can easily log in
+                        during production.
+                        </para></listitem>
+                    <listitem><para>
+                        It is possible to set a root password for the image
+                        and also to set passwords for any extra users you might
+                        add (e.g. administrative or service type users).
+                        When you set up passwords for multiple images or
+                        users, you should not duplicate passwords.
+                        </para>
+                        <para>
+                        To set up passwords, use the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-extrausers'><filename>extrausers</filename></ulink>
+                        class, which is the preferred method.
+                        For an example on how to set up both root and user
+                        passwords, see the
+                        "<ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-extrausers'><filename>extrausers.bbclass</filename></ulink>"
+                        section.
+                        <note>
+                            When adding extra user accounts or setting a
+                            root password, be cautious about setting the
+                            same password on every device.
+                            If you do this, and the password you have set
+                            is exposed, then every device is now potentially
+                            compromised.
+                            If you need this access but want to ensure
+                            security, consider setting a different,
+                            random password for each device.
+                            Typically, you do this as a separate step after
+                            you deploy the image onto the device.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        Consider enabling a Mandatory Access Control (MAC)
+                        framework such as SMACK or SELinux and tuning it
+                        appropriately for your device's usage.
+                        You can find more information in the
+                        <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/meta-selinux/'><filename>meta-selinux</filename></ulink>
+                        layer.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+            </para>
+        </section>
+
+        <section id='tools-for-hardening-your-image'>
+            <title>Tools for Hardening Your Image</title>
+
+            <para>
+                The Yocto Project provides tools for making your image
+                more secure.
+                You can find these tools in the
+                <filename>meta-security</filename> layer of the
+                <ulink url='&YOCTO_GIT_URL;'>Yocto Project Source Repositories</ulink>.
+            </para>
+        </section>
+    </section>
+
+    <section id='creating-your-own-distribution'>
+        <title>Creating Your Own Distribution</title>
+
+        <para>
+            When you build an image using the Yocto Project and
+            do not alter any distribution
+            <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink>,
+            you are creating a Poky distribution.
+            If you wish to gain more control over package alternative
+            selections, compile-time options, and other low-level
+            configurations, you can create your own distribution.
+        </para>
+
+        <para>
+            To create your own distribution, the basic steps consist of
+            creating your own distribution layer, creating your own
+            distribution configuration file, and then adding any needed
+            code and Metadata to the layer.
+            The following steps provide some more detail:
+            <itemizedlist>
+                <listitem><para><emphasis>Create a layer for your new distro:</emphasis>
+                    Create your distribution layer so that you can keep your
+                    Metadata and code for the distribution separate.
+                    It is strongly recommended that you create and use your own
+                    layer for configuration and code.
+                    Using your own layer as compared to just placing
+                    configurations in a <filename>local.conf</filename>
+                    configuration file makes it easier to reproduce the same
+                    build configuration when using multiple build machines.
+                    See the
+                    "<link linkend='creating-a-general-layer-using-the-bitbake-layers-script'>Creating a General Layer Using the <filename>bitbake-layers</filename> Script</link>"
+                    section for information on how to quickly set up a layer.
+                    </para></listitem>
+                <listitem><para><emphasis>Create the distribution configuration file:</emphasis>
+                    The distribution configuration file needs to be created in
+                    the <filename>conf/distro</filename> directory of your
+                    layer.
+                    You need to name it using your distribution name
+                    (e.g. <filename>mydistro.conf</filename>).
+                    <note>
+                        The
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO'><filename>DISTRO</filename></ulink>
+                        variable in your
+                        <filename>local.conf</filename> file determines the
+                        name of your distribution.
+                    </note></para>
+                    <para>You can split out parts of your configuration file
+                    into include files and then "require" them from within
+                    your distribution configuration file.
+                    Be sure to place the include files in the
+                    <filename>conf/distro/include</filename> directory of
+                    your layer.
+                    A common example usage of include files would be to
+                    separate out the selection of desired version and revisions
+                    for individual recipes.
+</para>
+                    <para>Your configuration file needs to set the following
+                    required variables:
+                    <literallayout class='monospaced'>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_NAME'><filename>DISTRO_NAME</filename></ulink>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_VERSION'><filename>DISTRO_VERSION</filename></ulink>
+                    </literallayout>
+                    These following variables are optional and you typically
+                    set them from the distribution configuration file:
+                    <literallayout class='monospaced'>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></ulink>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_EXTRA_RDEPENDS'><filename>DISTRO_EXTRA_RDEPENDS</filename></ulink>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_EXTRA_RRECOMMENDS'><filename>DISTRO_EXTRA_RRECOMMENDS</filename></ulink>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-TCLIBC'><filename>TCLIBC</filename></ulink>
+                    </literallayout>
+                    <tip>
+                        If you want to base your distribution configuration file
+                        on the very basic configuration from OE-Core, you
+                        can use
+                        <filename>conf/distro/defaultsetup.conf</filename> as
+                        a reference and just include variables that differ
+                        as compared to <filename>defaultsetup.conf</filename>.
+                        Alternatively, you can create a distribution
+                        configuration file from scratch using the
+                        <filename>defaultsetup.conf</filename> file
+                        or configuration files from other distributions
+                        such as Poky or Angstrom as references.
+                    </tip></para></listitem>
+                <listitem><para><emphasis>Provide miscellaneous variables:</emphasis>
+                    Be sure to define any other variables for which you want to
+                    create a default or enforce as part of the distribution
+                    configuration.
+                    You can include nearly any variable from the
+                    <filename>local.conf</filename> file.
+                    The variables you use are not limited to the list in the
+                    previous bulleted item.</para></listitem>
+                <listitem><para><emphasis>Point to Your distribution configuration file:</emphasis>
+                    In your <filename>local.conf</filename> file in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>,
+                    set your
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO'><filename>DISTRO</filename></ulink>
+                    variable to point to your distribution's configuration file.
+                    For example, if your distribution's configuration file is
+                    named <filename>mydistro.conf</filename>, then you point
+                    to it as follows:
+                    <literallayout class='monospaced'>
+     DISTRO = "mydistro"
+                    </literallayout></para></listitem>
+                <listitem><para><emphasis>Add more to the layer if necessary:</emphasis>
+                    Use your layer to hold other information needed for the
+                    distribution:
+                    <itemizedlist>
+                        <listitem><para>Add recipes for installing
+                            distro-specific configuration files that are not
+                            already installed by another recipe.
+                            If you have distro-specific configuration files
+                            that are included by an existing recipe, you should
+                            add an append file (<filename>.bbappend</filename>)
+                            for those.
+                            For general information and recommendations
+                            on how to add recipes to your layer, see the
+                            "<link linkend='creating-your-own-layer'>Creating Your Own Layer</link>"
+                            and
+                            "<link linkend='best-practices-to-follow-when-creating-layers'>Following Best Practices When Creating Layers</link>"
+                            sections.</para></listitem>
+                        <listitem><para>Add any image recipes that are specific
+                            to your distribution.</para></listitem>
+                        <listitem><para>Add a <filename>psplash</filename>
+                            append file for a branded splash screen.
+                            For information on append files, see the
+                            "<link linkend='using-bbappend-files'>Using .bbappend Files in Your Layer</link>"
+                            section.</para></listitem>
+                        <listitem><para>Add any other append files to make
+                            custom changes that are specific to individual
+                            recipes.</para></listitem>
+                    </itemizedlist></para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='creating-a-custom-template-configuration-directory'>
+        <title>Creating a Custom Template Configuration Directory</title>
+
+        <para>
+            If you are producing your own customized version
+            of the build system for use by other users, you might
+            want to customize the message shown by the setup script or
+            you might want to change the template configuration files (i.e.
+            <filename>local.conf</filename> and
+            <filename>bblayers.conf</filename>) that are created in
+            a new build directory.
+        </para>
+
+        <para>
+            The OpenEmbedded build system uses the environment variable
+            <filename>TEMPLATECONF</filename> to locate the directory
+            from which it gathers configuration information that ultimately
+            ends up in the
+            <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+            <filename>conf</filename> directory.
+            By default, <filename>TEMPLATECONF</filename> is set as
+            follows in the <filename>poky</filename> repository:
+            <literallayout class='monospaced'>
+     TEMPLATECONF=${TEMPLATECONF:-meta-poky/conf}
+            </literallayout>
+            This is the directory used by the build system to find templates
+            from which to build some key configuration files.
+            If you look at this directory, you will see the
+            <filename>bblayers.conf.sample</filename>,
+            <filename>local.conf.sample</filename>, and
+            <filename>conf-notes.txt</filename> files.
+            The build system uses these files to form the respective
+            <filename>bblayers.conf</filename> file,
+            <filename>local.conf</filename> file, and display the list of
+            BitBake targets when running the setup script.
+        </para>
+
+        <para>
+            To override these default configuration files with
+            configurations you want used within every new
+            Build Directory, simply set the
+            <filename>TEMPLATECONF</filename> variable to your directory.
+            The <filename>TEMPLATECONF</filename> variable is set in the
+            <filename>.templateconf</filename> file, which is in the
+            top-level
+            <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+            folder (e.g. <filename>poky</filename>).
+            Edit the <filename>.templateconf</filename> so that it can locate
+            your directory.
+        </para>
+
+        <para>
+            Best practices dictate that you should keep your
+            template configuration directory in your custom distribution layer.
+            For example, suppose you have a layer named
+            <filename>meta-mylayer</filename> located in your home directory
+            and you want your template configuration directory named
+            <filename>myconf</filename>.
+            Changing the <filename>.templateconf</filename> as follows
+            causes the OpenEmbedded build system to look in your directory
+            and base its configuration files on the
+            <filename>*.sample</filename> configuration files it finds.
+            The final configuration files (i.e.
+            <filename>local.conf</filename> and
+            <filename>bblayers.conf</filename> ultimately still end up in
+            your Build Directory, but they are based on your
+            <filename>*.sample</filename> files.
+            <literallayout class='monospaced'>
+     TEMPLATECONF=${TEMPLATECONF:-meta-mylayer/myconf}
+            </literallayout>
+        </para>
+
+        <para>
+            Aside from the <filename>*.sample</filename> configuration files,
+            the <filename>conf-notes.txt</filename> also resides in the
+            default <filename>meta-poky/conf</filename> directory.
+            The script that sets up the build environment
+            (i.e.
+            <ulink url="&YOCTO_DOCS_REF_URL;#structure-core-script"><filename>&OE_INIT_FILE;</filename></ulink>)
+            uses this file to display BitBake targets as part of the script
+            output.
+            Customizing this <filename>conf-notes.txt</filename> file is a
+            good way to make sure your list of custom targets appears
+            as part of the script's output.
+        </para>
+
+        <para>
+            Here is the default list of targets displayed as a result of
+            running either of the setup scripts:
+            <literallayout class='monospaced'>
+     You can now run 'bitbake &lt;target&gt;'
+
+     Common targets are:
+         core-image-minimal
+         core-image-sato
+         meta-toolchain
+         meta-ide-support
+            </literallayout>
+        </para>
+
+        <para>
+            Changing the listed common targets is as easy as editing your
+            version of <filename>conf-notes.txt</filename> in your
+            custom template configuration directory and making sure you
+            have <filename>TEMPLATECONF</filename> set to your directory.
+        </para>
+    </section>
+
+    <section id='dev-saving-memory-during-a-build'>
+        <title>Conserving Disk Space During Builds</title>
+
+        <para>
+            To help conserve disk space during builds, you can add the
+            following statement to your project's
+            <filename>local.conf</filename> configuration file found in the
+            <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>:
+            <literallayout class='monospaced'>
+     INHERIT += "rm_work"
+            </literallayout>
+            Adding this statement deletes the work directory used for building
+            a recipe once the recipe is built.
+            For more information on "rm_work", see the
+            <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-rm-work'><filename>rm_work</filename></ulink>
+            class in the Yocto Project Reference Manual.
+        </para>
+    </section>
+
+    <section id='working-with-packages'>
+        <title>Working with Packages</title>
+
+        <para>
+            This section describes a few tasks that involve packages:
+            <itemizedlist>
+                <listitem><para>
+                    <link linkend='excluding-packages-from-an-image'>Excluding packages from an image</link>
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='incrementing-a-binary-package-version'>Incrementing a binary package version</link>
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='handling-optional-module-packaging'>Handling optional module packaging</link>
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='using-runtime-package-management'>Using runtime package management</link>
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='generating-and-using-signed-packages'>Generating and using signed packages</link>
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='testing-packages-with-ptest'>Setting up and running package test (ptest)</link>
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='creating-node-package-manager-npm-packages'>Creating node package manager (NPM) packages</link>
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='adding-custom-metadata-to-packages'>Adding custom metadata to packages</link>
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <section id='excluding-packages-from-an-image'>
+            <title>Excluding Packages from an Image</title>
+
+            <para>
+                You might find it necessary to prevent specific packages
+                from being installed into an image.
+                If so, you can use several variables to direct the build
+                system to essentially ignore installing recommended packages
+                or to not install a package at all.
+            </para>
+
+            <para>
+                The following list introduces variables you can use to
+                prevent packages from being installed into your image.
+                Each of these variables only works with IPK and RPM
+                package types.
+                Support for Debian packages does not exist.
+                Also, you can use these variables from your
+                <filename>local.conf</filename> file or attach them to a
+                specific image recipe by using a recipe name override.
+                For more detail on the variables, see the descriptions in the
+                Yocto Project Reference Manual's glossary chapter.
+                <itemizedlist>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-BAD_RECOMMENDATIONS'><filename>BAD_RECOMMENDATIONS</filename></ulink>:
+                        Use this variable to specify "recommended-only"
+                        packages that you do not want installed.
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-NO_RECOMMENDATIONS'><filename>NO_RECOMMENDATIONS</filename></ulink>:
+                        Use this variable to prevent all "recommended-only"
+                        packages from being installed.
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_EXCLUDE'><filename>PACKAGE_EXCLUDE</filename></ulink>:
+                        Use this variable to prevent specific packages from
+                        being installed regardless of whether they are
+                        "recommended-only" or not.
+                        You need to realize that the build process could
+                        fail with an error when you
+                        prevent the installation of a package whose presence
+                        is required by an installed package.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='incrementing-a-binary-package-version'>
+            <title>Incrementing a Package Version</title>
+
+            <para>
+                This section provides some background on how binary package
+                versioning is accomplished and presents some of the services,
+                variables, and terminology involved.
+            </para>
+
+            <para>
+                In order to understand binary package versioning, you need
+                to consider the following:
+                <itemizedlist>
+                    <listitem><para>
+                        Binary Package:  The binary package that is eventually
+                        built and installed into an image.
+                        </para></listitem>
+                    <listitem><para>
+                        Binary Package Version:  The binary package version
+                        is composed of two components - a version and a
+                        revision.
+                        <note>
+                            Technically, a third component, the "epoch" (i.e.
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PE'><filename>PE</filename></ulink>)
+                            is involved but this discussion for the most part
+                            ignores <filename>PE</filename>.
+                        </note>
+                        The version and revision are taken from the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+                        and
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>
+                        variables, respectively.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>PV</filename>:  The recipe version.
+                        <filename>PV</filename> represents the version of the
+                        software being packaged.
+                        Do not confuse <filename>PV</filename> with the
+                        binary package version.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>PR</filename>:  The recipe revision.
+                        </para></listitem>
+                    <listitem><para>
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCPV'><filename>SRCPV</filename></ulink>:
+                        The OpenEmbedded build system uses this string
+                        to help define the value of <filename>PV</filename>
+                        when the source code revision needs to be included
+                        in it.
+                        </para></listitem>
+                    <listitem><para>
+                        <ulink url='https://wiki.yoctoproject.org/wiki/PR_Service'>PR Service</ulink>:
+                        A network-based service that helps automate keeping
+                        package feeds compatible with existing package
+                        manager applications such as RPM, APT, and OPKG.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Whenever the binary package content changes, the binary package
+                version must change.
+                Changing the binary package version is accomplished by changing
+                or "bumping" the <filename>PR</filename> and/or
+                <filename>PV</filename> values.
+                Increasing these values occurs one of two ways:
+                <itemizedlist>
+                    <listitem><para>Automatically using a Package Revision
+                        Service (PR Service).
+                        </para></listitem>
+                    <listitem><para>Manually incrementing the
+                        <filename>PR</filename> and/or
+                        <filename>PV</filename> variables.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Given a primary challenge of any build system and its users
+                is how to maintain a package feed that is compatible with
+                existing package manager applications such as RPM, APT, and
+                OPKG, using an automated system is much preferred over a
+                manual system.
+                In either system, the main requirement is that binary package
+                version numbering increases in a linear fashion and that a
+                number of version components exist that support that linear
+                progression.
+                For information on how to ensure package revisioning remains
+                linear, see the
+                "<link linkend='automatically-incrementing-a-binary-package-revision-number'>Automatically Incrementing a Binary Package Revision Number</link>"
+                section.
+            </para>
+
+            <para>
+                The following three sections provide related information on the
+                PR Service, the manual method for "bumping"
+                <filename>PR</filename> and/or <filename>PV</filename>, and
+                on how to ensure binary package revisioning remains linear.
+            </para>
+
+            <section id='working-with-a-pr-service'>
+                <title>Working With a PR Service</title>
+
+                <para>
+                    As mentioned, attempting to maintain revision numbers in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink>
+                    is error prone, inaccurate, and causes problems for people
+                    submitting recipes.
+                    Conversely, the PR Service automatically generates
+                    increasing numbers, particularly the revision field,
+                    which removes the human element.
+                    <note>
+                        For additional information on using a PR Service, you
+                        can see the
+                        <ulink url='&YOCTO_WIKI_URL;/wiki/PR_Service'>PR Service</ulink>
+                        wiki page.
+                    </note>
+                </para>
+
+                <para>
+                    The Yocto Project uses variables in order of
+                    decreasing priority to facilitate revision numbering (i.e.
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PE'><filename>PE</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>, and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>
+                    for epoch, version, and revision, respectively).
+                    The values are highly dependent on the policies and
+                    procedures of a given distribution and package feed.
+                </para>
+
+                <para>
+                    Because the OpenEmbedded build system uses
+                    "<ulink url='&YOCTO_DOCS_OM_URL;#overview-checksums'>signatures</ulink>",
+                    which are unique to a given build, the build system
+                    knows when to rebuild packages.
+                    All the inputs into a given task are represented by a
+                    signature, which can trigger a rebuild when different.
+                    Thus, the build system itself does not rely on the
+                    <filename>PR</filename>, <filename>PV</filename>, and
+                    <filename>PE</filename> numbers to trigger a rebuild.
+                    The signatures, however, can be used to generate
+                    these values.
+                </para>
+
+                <para>
+                    The PR Service works with both
+                    <filename>OEBasic</filename> and
+                    <filename>OEBasicHash</filename> generators.
+                    The value of <filename>PR</filename> bumps when the
+                    checksum changes and the different generator mechanisms
+                    change signatures under different circumstances.
+                </para>
+
+                <para>
+                    As implemented, the build system includes values from
+                    the PR Service into the <filename>PR</filename> field as
+                    an addition using the form "<filename>.x</filename>" so
+                    <filename>r0</filename> becomes <filename>r0.1</filename>,
+                    <filename>r0.2</filename> and so forth.
+                    This scheme allows existing <filename>PR</filename> values
+                    to be used for whatever reasons, which include manual
+                    <filename>PR</filename> bumps, should it be necessary.
+                </para>
+
+                <para>
+                    By default, the PR Service is not enabled or running.
+                    Thus, the packages generated are just "self consistent".
+                    The build system adds and removes packages and
+                    there are no guarantees about upgrade paths but images
+                    will be consistent and correct with the latest changes.
+                </para>
+
+                <para>
+                    The simplest form for a PR Service is for it to exist
+                    for a single host development system that builds the
+                    package feed (building system).
+                    For this scenario, you can enable a local PR Service by
+                    setting
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PRSERV_HOST'><filename>PRSERV_HOST</filename></ulink>
+                    in your <filename>local.conf</filename> file in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>:
+                    <literallayout class='monospaced'>
+     PRSERV_HOST = "localhost:0"
+                    </literallayout>
+                    Once the service is started, packages will automatically
+                    get increasing <filename>PR</filename> values and
+                    BitBake takes care of starting and stopping the server.
+                </para>
+
+                <para>
+                    If you have a more complex setup where multiple host
+                    development systems work against a common, shared package
+                    feed, you have a single PR Service running and it is
+                    connected to each building system.
+                    For this scenario, you need to start the PR Service using
+                    the <filename>bitbake-prserv</filename> command:
+                    <literallayout class='monospaced'>
+     bitbake-prserv --host <replaceable>ip</replaceable> --port <replaceable>port</replaceable> --start
+                    </literallayout>
+                    In addition to hand-starting the service, you need to
+                    update the <filename>local.conf</filename> file of each
+                    building system as described earlier so each system
+                    points to the server and port.
+                </para>
+
+                <para>
+                    It is also recommended you use build history, which adds
+                    some sanity checks to binary package versions, in
+                    conjunction with the server that is running the PR Service.
+                    To enable build history, add the following to each building
+                    system's <filename>local.conf</filename> file:
+                    <literallayout class='monospaced'>
+     # It is recommended to activate "buildhistory" for testing the PR service
+     INHERIT += "buildhistory"
+     BUILDHISTORY_COMMIT = "1"
+                    </literallayout>
+                    For information on build history, see the
+                    "<link linkend='maintaining-build-output-quality'>Maintaining Build Output Quality</link>"
+                    section.
+                </para>
+
+                <note>
+                    <para>
+                        The OpenEmbedded build system does not maintain
+                        <filename>PR</filename> information as part of the
+                        shared state (sstate) packages.
+                        If you maintain an sstate feed, its expected that either
+                        all your building systems that contribute to the sstate
+                         feed use a shared PR Service, or you do not run a PR
+                        Service on any of your building systems.
+                        Having some systems use a PR Service while others do
+                        not leads to obvious problems.
+                    </para>
+
+                    <para>
+                        For more information on shared state, see the
+                        "<ulink url='&YOCTO_DOCS_OM_URL;#shared-state-cache'>Shared State Cache</ulink>"
+                        section in the Yocto Project Overview and Concepts
+                        Manual.
+                    </para>
+                </note>
+            </section>
+
+            <section id='manually-bumping-pr'>
+                <title>Manually Bumping PR</title>
+
+                <para>
+                    The alternative to setting up a PR Service is to manually
+                    "bump" the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>
+                    variable.
+                </para>
+
+                <para>
+                    If a committed change results in changing the package
+                    output, then the value of the PR variable needs to be
+                    increased (or "bumped") as part of that commit.
+                    For new recipes you should add the <filename>PR</filename>
+                    variable and set its initial value equal to "r0", which is
+                    the default.
+                    Even though the default value is "r0", the practice of
+                    adding it to a new recipe makes it harder to forget to bump
+                    the variable when you make changes to the recipe in future.
+                </para>
+
+                <para>
+                    If you are sharing a common <filename>.inc</filename> file
+                    with multiple recipes, you can also use the
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-INC_PR'>INC_PR</ulink></filename>
+                    variable to ensure that the recipes sharing the
+                    <filename>.inc</filename> file are rebuilt when the
+                    <filename>.inc</filename> file itself is changed.
+                    The <filename>.inc</filename> file must set
+                    <filename>INC_PR</filename> (initially to "r0"), and all
+                    recipes referring to it should set <filename>PR</filename>
+                    to "${INC_PR}.0" initially, incrementing the last number
+                    when the recipe is changed.
+                    If the <filename>.inc</filename> file is changed then its
+                    <filename>INC_PR</filename> should be incremented.
+                </para>
+
+                <para>
+                    When upgrading the version of a binary package, assuming the
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PV'>PV</ulink></filename>
+                    changes, the <filename>PR</filename> variable should be
+                    reset to "r0" (or "${INC_PR}.0" if you are using
+                    <filename>INC_PR</filename>).
+                </para>
+
+                <para>
+                    Usually, version increases occur only to binary packages.
+                    However, if for some reason <filename>PV</filename> changes
+                    but does not increase, you can increase the
+                    <filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PE'>PE</ulink></filename>
+                    variable (Package Epoch).
+                    The <filename>PE</filename> variable defaults to "0".
+                </para>
+
+                <para>
+                    Binary package version numbering strives to follow the
+                    <ulink url='http://www.debian.org/doc/debian-policy/ch-controlfields.html'>
+                    Debian Version Field Policy Guidelines</ulink>.
+                    These guidelines define how versions are compared and what
+                    "increasing" a version means.
+                </para>
+            </section>
+
+            <section id='automatically-incrementing-a-binary-package-revision-number'>
+                <title>Automatically Incrementing a Package Version Number</title>
+
+                <para>
+                    When fetching a repository, BitBake uses the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCREV'><filename>SRCREV</filename></ulink>
+                    variable to determine the specific source code revision
+                    from which to build.
+                    You set the <filename>SRCREV</filename> variable to
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-AUTOREV'><filename>AUTOREV</filename></ulink>
+                    to cause the OpenEmbedded build system to automatically use the
+                    latest revision of the software:
+                    <literallayout class='monospaced'>
+     SRCREV = "${AUTOREV}"
+                    </literallayout>
+                </para>
+
+                <para>
+                    Furthermore, you need to reference <filename>SRCPV</filename>
+                    in <filename>PV</filename> in order to automatically update
+                    the version whenever the revision of the source code
+                    changes.
+                    Here is an example:
+                    <literallayout class='monospaced'>
+     PV = "1.0+git${SRCPV}"
+                    </literallayout>
+                    The OpenEmbedded build system substitutes
+                    <filename>SRCPV</filename> with the following:
+                    <literallayout class='monospaced'>
+     AUTOINC+<replaceable>source_code_revision</replaceable>
+                    </literallayout>
+                    The build system replaces the <filename>AUTOINC</filename> with
+                    a number.
+                    The number used depends on the state of the PR Service:
+                    <itemizedlist>
+                        <listitem><para>
+                            If PR Service is enabled, the build system increments
+                            the number, which is similar to the behavior of
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>.
+                            This behavior results in linearly increasing package
+                            versions, which is desirable.
+                            Here is an example:
+                            <literallayout class='monospaced'>
+     hello-world-git_0.0+git0+b6558dd387-r0.0_armv7a-neon.ipk
+     hello-world-git_0.0+git1+dd2f5c3565-r0.0_armv7a-neon.ipk
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para>
+                            If PR Service is not enabled, the build system
+                            replaces the <filename>AUTOINC</filename>
+                            placeholder with zero (i.e. "0").
+                            This results in changing the package version since
+                            the source revision is included.
+                            However, package versions are not increased linearly.
+                            Here is an example:
+                            <literallayout class='monospaced'>
+     hello-world-git_0.0+git0+b6558dd387-r0.0_armv7a-neon.ipk
+     hello-world-git_0.0+git0+dd2f5c3565-r0.0_armv7a-neon.ipk
+                            </literallayout>
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+
+                <para>
+                    In summary, the OpenEmbedded build system does not track the
+                    history of binary package versions for this purpose.
+                    <filename>AUTOINC</filename>, in this case, is comparable to
+                    <filename>PR</filename>.
+                    If PR server is not enabled, <filename>AUTOINC</filename>
+                    in the package version is simply replaced by "0".
+                    If PR server is enabled, the build system keeps track of the
+                    package versions and bumps the number when the package
+                    revision changes.
+                </para>
+            </section>
+        </section>
+
+        <section id='handling-optional-module-packaging'>
+            <title>Handling Optional Module Packaging</title>
+
+            <para>
+                Many pieces of software split functionality into optional
+                modules (or plugins) and the plugins that are built
+                might depend on configuration options.
+                To avoid having to duplicate the logic that determines what
+                modules are available in your recipe or to avoid having
+                to package each module by hand, the OpenEmbedded build system
+                provides functionality to handle module packaging dynamically.
+            </para>
+
+            <para>
+                To handle optional module packaging, you need to do two things:
+                <itemizedlist>
+                    <listitem><para>Ensure the module packaging is actually
+                        done.</para></listitem>
+                    <listitem><para>Ensure that any dependencies on optional
+                        modules from other recipes are satisfied by your recipe.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <section id='making-sure-the-packaging-is-done'>
+                <title>Making Sure the Packaging is Done</title>
+
+                <para>
+                    To ensure the module packaging actually gets done, you use
+                    the <filename>do_split_packages</filename> function within
+                    the <filename>populate_packages</filename> Python function
+                    in your recipe.
+                    The <filename>do_split_packages</filename> function
+                    searches for a pattern of files or directories under a
+                    specified path and creates a package for each one it finds
+                    by appending to the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'><filename>PACKAGES</filename></ulink>
+                    variable and setting the appropriate values for
+                    <filename>FILES_packagename</filename>,
+                    <filename>RDEPENDS_packagename</filename>,
+                    <filename>DESCRIPTION_packagename</filename>, and so forth.
+                    Here is an example from the <filename>lighttpd</filename>
+                    recipe:
+                    <literallayout class='monospaced'>
+     python populate_packages_prepend () {
+         lighttpd_libdir = d.expand('${libdir}')
+         do_split_packages(d, lighttpd_libdir, '^mod_(.*)\.so$',
+                          'lighttpd-module-%s', 'Lighttpd module for %s',
+                           extra_depends='')
+     }
+                    </literallayout>
+                    The previous example specifies a number of things in the
+                    call to <filename>do_split_packages</filename>.
+                    <itemizedlist>
+                        <listitem><para>A directory within the files installed
+                            by your recipe through <filename>do_install</filename>
+                            in which to search.</para></listitem>
+                        <listitem><para>A regular expression used to match module
+                            files in that directory.
+                            In the example, note the parentheses () that mark
+                            the part of the expression from which the module
+                            name should be derived.</para></listitem>
+                        <listitem><para>A pattern to use for the package names.
+                            </para></listitem>
+                        <listitem><para>A description for each package.
+                            </para></listitem>
+                        <listitem><para>An empty string for
+                            <filename>extra_depends</filename>, which disables
+                            the default dependency on the main
+                            <filename>lighttpd</filename> package.
+                            Thus, if a file in <filename>${libdir}</filename>
+                            called <filename>mod_alias.so</filename> is found,
+                            a package called <filename>lighttpd-module-alias</filename>
+                            is created for it and the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-DESCRIPTION'><filename>DESCRIPTION</filename></ulink>
+                            is set to "Lighttpd module for alias".</para></listitem>
+                    </itemizedlist>
+                </para>
+
+                <para>
+                    Often, packaging modules is as simple as the previous
+                    example.
+                    However, more advanced options exist that you can use
+                    within <filename>do_split_packages</filename> to modify its
+                    behavior.
+                    And, if you need to, you can add more logic by specifying
+                    a hook function that is called for each package.
+                    It is also perfectly acceptable to call
+                    <filename>do_split_packages</filename> multiple times if
+                    you have more than one set of modules to package.
+                </para>
+
+                <para>
+                    For more examples that show how to use
+                    <filename>do_split_packages</filename>, see the
+                    <filename>connman.inc</filename> file in the
+                    <filename>meta/recipes-connectivity/connman/</filename>
+                    directory of the <filename>poky</filename>
+                    <ulink url='&YOCTO_DOCS_OM_URL;#yocto-project-repositories'>source repository</ulink>.
+                    You can also find examples in
+                    <filename>meta/classes/kernel.bbclass</filename>.
+                 </para>
+
+                 <para>
+                     Following is a reference that shows
+                     <filename>do_split_packages</filename> mandatory and
+                     optional arguments:
+                     <literallayout class='monospaced'>
+     Mandatory arguments
+
+     root
+        The path in which to search
+     file_regex
+        Regular expression to match searched files.
+        Use parentheses () to mark the part of this
+        expression that should be used to derive the
+        module name (to be substituted where %s is
+        used in other function arguments as noted below)
+     output_pattern
+        Pattern to use for the package names. Must
+        include %s.
+     description
+        Description to set for each package. Must
+        include %s.
+
+     Optional arguments
+
+     postinst
+        Postinstall script to use for all packages
+        (as a string)
+     recursive
+        True to perform a recursive search - default
+        False
+     hook
+        A hook function to be called for every match.
+        The function will be called with the following
+        arguments (in the order listed):
+
+        f
+           Full path to the file/directory match
+        pkg
+           The package name
+        file_regex
+           As above
+        output_pattern
+           As above
+        modulename
+           The module name derived using file_regex
+
+     extra_depends
+        Extra runtime dependencies (RDEPENDS) to be
+        set for all packages. The default value of None
+        causes a dependency on the main package
+        (${PN}) - if you do not want this, pass empty
+        string '' for this parameter.
+     aux_files_pattern
+        Extra item(s) to be added to FILES for each
+        package. Can be a single string item or a list
+        of strings for multiple items. Must include %s.
+     postrm
+        postrm script to use for all packages (as a
+        string)
+     allow_dirs
+        True to allow directories to be matched -
+        default False
+     prepend
+        If True, prepend created packages to PACKAGES
+        instead of the default False which appends them
+     match_path
+        match file_regex on the whole relative path to
+        the root rather than just the file name
+     aux_files_pattern_verbatim
+        Extra item(s) to be added to FILES for each
+        package, using the actual derived module name
+        rather than converting it to something legal
+        for a package name. Can be a single string item
+        or a list of strings for multiple items. Must
+        include %s.
+     allow_links
+        True to allow symlinks to be matched - default
+        False
+     summary
+        Summary to set for each package. Must include %s;
+        defaults to description if not set.
+                     </literallayout>
+                 </para>
+            </section>
+
+            <section id='satisfying-dependencies'>
+                <title>Satisfying Dependencies</title>
+
+                <para>
+                    The second part for handling optional module packaging
+                    is to ensure that any dependencies on optional modules
+                    from other recipes are satisfied by your recipe.
+                    You can be sure these dependencies are satisfied by
+                    using the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES_DYNAMIC'><filename>PACKAGES_DYNAMIC</filename></ulink> variable.
+                    Here is an example that continues with the
+                    <filename>lighttpd</filename> recipe shown earlier:
+                    <literallayout class='monospaced'>
+     PACKAGES_DYNAMIC = "lighttpd-module-.*"
+                    </literallayout>
+                    The name specified in the regular expression can of
+                    course be anything.
+                    In this example, it is <filename>lighttpd-module-</filename>
+                    and is specified as the prefix to ensure that any
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>
+                    and <ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'><filename>RRECOMMENDS</filename></ulink>
+                    on a package name starting with the prefix are satisfied
+                    during build time.
+                    If you are using <filename>do_split_packages</filename>
+                    as described in the previous section, the value you put in
+                    <filename>PACKAGES_DYNAMIC</filename> should correspond to
+                    the name pattern specified in the call to
+                    <filename>do_split_packages</filename>.
+                </para>
+            </section>
+        </section>
+
+        <section id='using-runtime-package-management'>
+            <title>Using Runtime Package Management</title>
+
+            <para>
+                During a build, BitBake always transforms a recipe into one or
+                more packages.
+                For example, BitBake takes the <filename>bash</filename> recipe
+                and produces a number of packages (e.g.
+                <filename>bash</filename>, <filename>bash-bashbug</filename>,
+                <filename>bash-completion</filename>,
+                <filename>bash-completion-dbg</filename>,
+                <filename>bash-completion-dev</filename>,
+                <filename>bash-completion-extra</filename>,
+                <filename>bash-dbg</filename>, and so forth).
+                Not all generated packages are included in an image.
+            </para>
+
+            <para>
+                In several situations, you might need to update, add, remove,
+                or query the packages on a target device at runtime
+                (i.e. without having to generate a new image).
+                Examples of such situations include:
+                <itemizedlist>
+                    <listitem><para>
+                        You want to provide in-the-field updates to deployed
+                        devices (e.g. security updates).
+                        </para></listitem>
+                    <listitem><para>
+                        You want to have a fast turn-around development cycle
+                        for one or more applications that run on your device.
+                        </para></listitem>
+                    <listitem><para>
+                        You want to temporarily install the "debug" packages
+                        of various applications on your device so that
+                        debugging can be greatly improved by allowing
+                        access to symbols and source debugging.
+                        </para></listitem>
+                    <listitem><para>
+                        You want to deploy a more minimal package selection of
+                        your device but allow in-the-field updates to add a
+                        larger selection for customization.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                In all these situations, you have something similar to a more
+                traditional Linux distribution in that in-field devices
+                are able to receive pre-compiled packages from a server for
+                installation or update.
+                Being able to install these packages on a running,
+                in-field device is what is termed "runtime package
+                management".
+            </para>
+
+            <para>
+                In order to use runtime package management, you
+                need a host or server machine that serves up the pre-compiled
+                packages plus the required metadata.
+                You also need package manipulation tools on the target.
+                The build machine is a likely candidate to act as the server.
+                However, that machine does not necessarily have to be the
+                package server.
+                The build machine could push its artifacts to another machine
+                that acts as the server (e.g. Internet-facing).
+                In fact, doing so is advantageous for a production
+                environment as getting the packages away from the
+                development system's build directory prevents accidental
+                overwrites.
+            </para>
+
+            <para>
+                A simple build that targets just one device produces
+                more than one package database.
+                In other words, the packages produced by a build are separated
+                out into a couple of different package groupings based on
+                criteria such as the target's CPU architecture, the target
+                board, or the C library used on the target.
+                For example, a build targeting the <filename>qemux86</filename>
+                device produces the following three package databases:
+                <filename>noarch</filename>, <filename>i586</filename>, and
+                <filename>qemux86</filename>.
+                If you wanted your <filename>qemux86</filename> device to be
+                aware of all the packages that were available to it,
+                you would need to point it to each of these databases
+                individually.
+                In a similar way, a traditional Linux distribution usually is
+                configured to be aware of a number of software repositories
+                from which it retrieves packages.
+            </para>
+
+            <para>
+                Using runtime package management is completely optional and
+                not required for a successful build or deployment in any
+                way.
+                But if you want to make use of runtime package management,
+                you need to do a couple things above and beyond the basics.
+                The remainder of this section describes what you need to do.
+            </para>
+
+            <section id='runtime-package-management-build'>
+                <title>Build Considerations</title>
+
+                <para>
+                    This section describes build considerations of which you
+                    need to be aware in order to provide support for runtime
+                    package management.
+                </para>
+
+                <para>
+                    When BitBake generates packages, it needs to know
+                    what format or formats to use.
+                    In your configuration, you use the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_CLASSES'><filename>PACKAGE_CLASSES</filename></ulink>
+                    variable to specify the format:
+                    <orderedlist>
+                        <listitem><para>
+                            Open the <filename>local.conf</filename> file
+                            inside your
+                            <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                            (e.g. <filename>~/poky/build/conf/local.conf</filename>).
+                            </para></listitem>
+                        <listitem><para>
+                            Select the desired package format as follows:
+                            <literallayout class='monospaced'>
+     PACKAGE_CLASSES ?= "package_<replaceable>packageformat</replaceable>"
+                            </literallayout>
+                            where <replaceable>packageformat</replaceable>
+                            can be "ipk", "rpm", "deb", or "tar" which are the
+                            supported package formats.
+                            <note>
+                                Because the Yocto Project supports four
+                                different package formats, you can set the
+                                variable with more than one argument.
+                                However, the OpenEmbedded build system only
+                                uses the first argument when creating an image
+                                or Software Development Kit (SDK).
+                            </note>
+                            </para></listitem>
+                    </orderedlist>
+                </para>
+
+                <para>
+                    If you would like your image to start off with a basic
+                    package database containing the packages in your current
+                    build as well as to have the relevant tools available on the
+                    target for runtime package management, you can include
+                    "package-management" in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></ulink>
+                    variable.
+                    Including "package-management" in this configuration
+                    variable ensures that when the image is assembled for your
+                    target, the image includes the currently-known package
+                    databases as well as the target-specific tools required
+                    for runtime package management to be performed on the
+                    target.
+                    However, this is not strictly necessary.
+                    You could start your image off without any databases
+                    but only include the required on-target package
+                    tool(s).
+                    As an example, you could include "opkg" in your
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'><filename>IMAGE_INSTALL</filename></ulink>
+                    variable if you are using the IPK package format.
+                    You can then initialize your target's package database(s)
+                    later once your image is up and running.
+                </para>
+
+                <para>
+                    Whenever you perform any sort of build step that can
+                    potentially generate a package or modify   existing
+                    package, it is always a good idea to re-generate the
+                    package index after the build by using the following
+                    command:
+                    <literallayout class='monospaced'>
+    $ bitbake package-index
+                    </literallayout>
+                    It might be tempting to build the package and the
+                    package index at the same time with a command such as
+                    the following:
+                    <literallayout class='monospaced'>
+    $ bitbake <replaceable>some-package</replaceable> package-index
+                    </literallayout>
+                    Do not do this as BitBake does not schedule the package
+                    index for after the completion of the package you are
+                    building.
+                    Consequently, you cannot be sure of the package index
+                    including information for the package you just built.
+                    Thus, be sure to run the package update step separately
+                    after building any packages.
+                </para>
+
+                <para>
+                    You can use the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_ARCHS'><filename>PACKAGE_FEED_ARCHS</filename></ulink>,
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_BASE_PATHS'><filename>PACKAGE_FEED_BASE_PATHS</filename></ulink>,
+                    and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_URIS'><filename>PACKAGE_FEED_URIS</filename></ulink>
+                    variables to pre-configure target images to use a package
+                    feed.
+                    If you do not define these variables, then manual steps
+                    as described in the subsequent sections are necessary to
+                    configure the target.
+                    You should set these variables before building the image
+                    in order to produce a correctly configured image.
+                </para>
+
+                <para>
+                    When your build is complete, your packages reside in the
+                    <filename>${TMPDIR}/deploy/<replaceable>packageformat</replaceable></filename>
+                    directory.
+                    For example, if
+                    <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink><filename>}</filename>
+                    is <filename>tmp</filename> and your selected package type
+                    is RPM, then your RPM packages are available in
+                    <filename>tmp/deploy/rpm</filename>.
+                </para>
+            </section>
+
+            <section id='runtime-package-management-server'>
+                <title>Host or Server Machine Setup</title>
+
+                <para>
+                    Although other protocols are possible, a server using HTTP
+                    typically serves packages.
+                    If you want to use HTTP, then set up and configure a
+                    web server such as Apache 2, lighttpd, or
+                    SimpleHTTPServer on the machine serving the packages.
+                </para>
+
+                <para>
+                    To keep things simple, this section describes how to set
+                    up a SimpleHTTPServer web server to share package feeds
+                    from the developer's machine.
+                    Although this server might not be the best for a production
+                    environment, the setup is simple and straight forward.
+                    Should you want to use a different server more suited for
+                    production (e.g. Apache 2, Lighttpd, or Nginx), take the
+                    appropriate steps to do so.
+                </para>
+
+                <para>
+                    From within the build directory where you have built an
+                    image based on your packaging choice (i.e. the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_CLASSES'><filename>PACKAGE_CLASSES</filename></ulink>
+                    setting), simply start the server.
+                    The following example assumes a build directory of
+                    <filename>~/poky/build/tmp/deploy/rpm</filename> and a
+                    <filename>PACKAGE_CLASSES</filename> setting of
+                    "package_rpm":
+                    <literallayout class='monospaced'>
+     $ cd ~/poky/build/tmp/deploy/rpm
+     $ python -m SimpleHTTPServer
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='runtime-package-management-target'>
+                <title>Target Setup</title>
+
+                <para>
+                    Setting up the target differs depending on the
+                    package management system.
+                    This section provides information for RPM, IPK, and DEB.
+                </para>
+
+                <section id='runtime-package-management-target-rpm'>
+                    <title>Using RPM</title>
+
+                    <para>
+                        The
+                        <ulink url='https://en.wikipedia.org/wiki/DNF_(software)'>Dandified Packaging Tool</ulink>
+                        (DNF) performs runtime package management of RPM
+                        packages.
+                        In order to use DNF for runtime package management,
+                        you must perform an initial setup on the target
+                        machine for cases where the
+                        <filename>PACKAGE_FEED_*</filename> variables were not
+                        set as part of the image that is running on the
+                        target.
+                        This means if you built your image and did not not use
+                        these variables as part of the build and your image is
+                        now running on the target, you need to perform the
+                        steps in this section if you want to use runtime
+                        package management.
+                        <note>
+                            For information on the
+                            <filename>PACKAGE_FEED_*</filename> variables, see
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_ARCHS'><filename>PACKAGE_FEED_ARCHS</filename></ulink>,
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_BASE_PATHS'><filename>PACKAGE_FEED_BASE_PATHS</filename></ulink>,
+                            and
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_URIS'><filename>PACKAGE_FEED_URIS</filename></ulink>
+                            in the Yocto Project Reference Manual variables
+                            glossary.
+                        </note>
+                    </para>
+
+                    <para>
+                        On the target, you must inform DNF that package
+                        databases are available.
+                        You do this by creating a file named
+                        <filename>/etc/yum.repos.d/oe-packages.repo</filename>
+                        and defining the <filename>oe-packages</filename>.
+                    </para>
+
+                    <para>
+                        As an example, assume the target is able to use the
+                        following package databases:
+                        <filename>all</filename>, <filename>i586</filename>,
+                        and <filename>qemux86</filename> from a server named
+                        <filename>my.server</filename>.
+                        The specifics for setting up the web server are up to
+                        you.
+                        The critical requirement is that the URIs in the
+                        target repository configuration point to the
+                        correct remote location for the feeds.
+                        <note><title>Tip</title>
+                            For development purposes, you can point the web
+                            server to the build system's
+                            <filename>deploy</filename> directory.
+                            However, for production use, it is better to copy
+                            the package directories to a location outside of
+                            the build area and use that location.
+                            Doing so avoids situations where the build system
+                            overwrites or changes the
+                            <filename>deploy</filename> directory.
+                        </note>
+                    </para>
+
+                    <para>
+                        When telling DNF where to look for the package
+                        databases, you must declare individual locations
+                        per architecture or a single location used for all
+                        architectures.
+                        You cannot do both:
+                        <itemizedlist>
+                            <listitem><para>
+                                <emphasis>Create an Explicit List of Architectures:</emphasis>
+                                Define individual base URLs to identify where
+                                each package database is located:
+                                <literallayout class='monospaced'>
+     [oe-packages]
+     baseurl=http://my.server/rpm/i586 http://my.server/rpm/qemux86 http://my.server/rpm/all
+                                </literallayout>
+                                This example informs DNF about individual
+                                package databases for all three architectures.
+                                </para></listitem>
+                            <listitem><para>
+                                <emphasis>Create a Single (Full) Package Index:</emphasis>
+                                Define a single base URL that identifies where
+                                a full package database is located:
+                                <literallayout class='monospaced'>
+     [oe-packages]
+     baseurl=http://my.server/rpm
+                                </literallayout>
+                                This example informs DNF about a single package
+                                database that contains all the package index
+                                information for all supported architectures.
+                                </para></listitem>
+                        </itemizedlist>
+                    </para>
+
+                    <para>
+                        Once you have informed DNF where to find the package
+                        databases, you need to fetch them:
+                        <literallayout class='monospaced'>
+     # dnf makecache
+                        </literallayout>
+                        DNF is now able to find, install, and upgrade packages
+                        from the specified repository or repositories.
+                        <note>
+                            See the
+                            <ulink url='http://dnf.readthedocs.io/en/latest/'>DNF documentation</ulink>
+                            for additional information.
+                        </note>
+                    </para>
+                </section>
+
+                <section id='runtime-package-management-target-ipk'>
+                    <title>Using IPK</title>
+
+                    <para>
+                        The <filename>opkg</filename> application performs
+                        runtime package management of IPK packages.
+                        You must perform an initial setup for
+                        <filename>opkg</filename> on the target machine
+                        if the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_ARCHS'><filename>PACKAGE_FEED_ARCHS</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_BASE_PATHS'><filename>PACKAGE_FEED_BASE_PATHS</filename></ulink>, and
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_URIS'><filename>PACKAGE_FEED_URIS</filename></ulink>
+                        variables have not been set or the target image was
+                        built before the variables were set.
+                    </para>
+
+                    <para>
+                        The <filename>opkg</filename> application uses
+                        configuration files to find available package
+                        databases.
+                        Thus, you need to create a configuration file inside
+                        the <filename>/etc/opkg/</filename> direction, which
+                        informs <filename>opkg</filename> of any repository
+                        you want to use.
+                    </para>
+
+                    <para>
+                        As an example, suppose you are serving packages from a
+                        <filename>ipk/</filename> directory containing the
+                        <filename>i586</filename>,
+                        <filename>all</filename>, and
+                        <filename>qemux86</filename> databases through an
+                        HTTP server named <filename>my.server</filename>.
+                        On the target, create a configuration file
+                        (e.g. <filename>my_repo.conf</filename>) inside the
+                        <filename>/etc/opkg/</filename> directory containing
+                        the following:
+                        <literallayout class='monospaced'>
+     src/gz all http://my.server/ipk/all
+     src/gz i586 http://my.server/ipk/i586
+     src/gz qemux86 http://my.server/ipk/qemux86
+                        </literallayout>
+                        Next, instruct <filename>opkg</filename> to fetch
+                        the repository information:
+                        <literallayout class='monospaced'>
+     # opkg update
+                        </literallayout>
+                        The <filename>opkg</filename> application is now able
+                        to find, install, and upgrade packages from the
+                        specified repository.
+                    </para>
+                </section>
+
+                <section id='runtime-package-management-target-deb'>
+                    <title>Using DEB</title>
+
+                    <para>
+                        The <filename>apt</filename> application performs
+                        runtime package management of DEB packages.
+                        This application uses a source list file to find
+                        available package databases.
+                        You must perform an initial setup for
+                        <filename>apt</filename> on the target machine
+                        if the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_ARCHS'><filename>PACKAGE_FEED_ARCHS</filename></ulink>,
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_BASE_PATHS'><filename>PACKAGE_FEED_BASE_PATHS</filename></ulink>, and
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_FEED_URIS'><filename>PACKAGE_FEED_URIS</filename></ulink>
+                        variables have not been set or the target image was
+                        built before the variables were set.
+                    </para>
+
+                    <para>
+                        To inform <filename>apt</filename> of the repository
+                        you want to use, you might create a list file (e.g.
+                        <filename>my_repo.list</filename>) inside the
+                        <filename>/etc/apt/sources.list.d/</filename>
+                        directory.
+                        As an example, suppose you are serving packages from a
+                        <filename>deb/</filename> directory containing the
+                        <filename>i586</filename>,
+                        <filename>all</filename>, and
+                        <filename>qemux86</filename> databases through an
+                        HTTP server named <filename>my.server</filename>.
+                        The list file should contain:
+                        <literallayout class='monospaced'>
+     deb http://my.server/deb/all ./
+     deb http://my.server/deb/i586 ./
+     deb http://my.server/deb/qemux86 ./
+                        </literallayout>
+                        Next, instruct the <filename>apt</filename>
+                        application to fetch the repository information:
+                        <literallayout class='monospaced'>
+     # apt-get update
+                        </literallayout>
+                        After this step, <filename>apt</filename> is able
+                        to find, install, and upgrade packages from the
+                        specified repository.
+                    </para>
+                </section>
+            </section>
+        </section>
+
+        <section id='generating-and-using-signed-packages'>
+            <title>Generating and Using Signed Packages</title>
+            <para>
+                In order to add security to RPM packages used during a build,
+                you can take steps to securely sign them.
+                Once a signature is verified, the OpenEmbedded build system
+                can use the package in the build.
+                If security fails for a signed package, the build system
+                aborts the build.
+            </para>
+
+            <para>
+                This section describes how to sign RPM packages during a build
+                and how to use signed package feeds (repositories) when
+                doing a build.
+            </para>
+
+            <section id='signing-rpm-packages'>
+                <title>Signing RPM Packages</title>
+
+                <para>
+                    To enable signing RPM packages, you must set up the
+                    following configurations in either your
+                    <filename>local.config</filename> or
+                    <filename>distro.config</filename> file:
+                    <literallayout class='monospaced'>
+     # Inherit sign_rpm.bbclass to enable signing functionality
+     INHERIT += " sign_rpm"
+     # Define the GPG key that will be used for signing.
+     RPM_GPG_NAME = "<replaceable>key_name</replaceable>"
+     # Provide passphrase for the key
+     RPM_GPG_PASSPHRASE = "<replaceable>passphrase</replaceable>"
+                    </literallayout>
+                    <note>
+                        Be sure to supply appropriate values for both
+                        <replaceable>key_name</replaceable> and
+                        <replaceable>passphrase</replaceable>
+                    </note>
+                    Aside from the
+                    <filename>RPM_GPG_NAME</filename> and
+                    <filename>RPM_GPG_PASSPHRASE</filename> variables in the
+                    previous example, two optional variables related to signing
+                    exist:
+                    <itemizedlist>
+                        <listitem><para>
+                            <emphasis><filename>GPG_BIN</filename>:</emphasis>
+                            Specifies a <filename>gpg</filename> binary/wrapper
+                            that is executed when the package is signed.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis><filename>GPG_PATH</filename>:</emphasis>
+                            Specifies the <filename>gpg</filename> home
+                            directory used when the package is signed.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='processing-package-feeds'>
+                <title>Processing Package Feeds</title>
+
+                <para>
+                    In addition to being able to sign RPM packages, you can
+                    also enable signed package feeds for IPK and RPM packages.
+                </para>
+
+                <para>
+                    The steps you need to take to enable signed package feed
+                    use are similar to the steps used to sign RPM packages.
+                    You must define the following in your
+                    <filename>local.config</filename> or
+                    <filename>distro.config</filename> file:
+                    <literallayout class='monospaced'>
+     INHERIT += "sign_package_feed"
+     PACKAGE_FEED_GPG_NAME = "<replaceable>key_name</replaceable>"
+     PACKAGE_FEED_GPG_PASSPHRASE_FILE = "<replaceable>path_to_file_containing_passphrase</replaceable>"
+                    </literallayout>
+                    For signed package feeds, the passphrase must exist in a
+                    separate file, which is pointed to by the
+                    <filename>PACKAGE_FEED_GPG_PASSPHRASE_FILE</filename>
+                    variable.
+                    Regarding security, keeping a plain text passphrase out of
+                    the configuration is more secure.
+                </para>
+
+                <para>
+                    Aside from the
+                    <filename>PACKAGE_FEED_GPG_NAME</filename> and
+                    <filename>PACKAGE_FEED_GPG_PASSPHRASE_FILE</filename>
+                    variables, three optional variables related to signed
+                    package feeds exist:
+                    <itemizedlist>
+                        <listitem><para>
+                            <emphasis><filename>GPG_BIN</filename>:</emphasis>
+                            Specifies a <filename>gpg</filename> binary/wrapper
+                            that is executed when the package is signed.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis><filename>GPG_PATH</filename>:</emphasis>
+                            Specifies the <filename>gpg</filename> home
+                            directory used when the package is signed.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis><filename>PACKAGE_FEED_GPG_SIGNATURE_TYPE</filename>:</emphasis>
+                            Specifies the type of <filename>gpg</filename>
+                            signature.
+                            This variable applies only to RPM and IPK package
+                            feeds.
+                            Allowable values for the
+                            <filename>PACKAGE_FEED_GPG_SIGNATURE_TYPE</filename>
+                            are "ASC", which is the default and specifies ascii
+                            armored, and "BIN", which specifies binary.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+        </section>
+
+        <section id='testing-packages-with-ptest'>
+            <title>Testing Packages With ptest</title>
+
+            <para>
+                A Package Test (ptest) runs tests against packages built
+                by the OpenEmbedded build system on the target machine.
+                A ptest contains at least two items: the actual test, and
+                a shell script (<filename>run-ptest</filename>) that starts
+                the test.
+                The shell script that starts the test must not contain
+                the actual test - the script only starts the test.
+                On the other hand, the test can be anything from a simple
+                shell script that runs a binary and checks the output to
+                an elaborate system of test binaries and data files.
+            </para>
+
+            <para>
+                The test generates output in the format used by
+                Automake:
+                <literallayout class='monospaced'>
+     <replaceable>result</replaceable>: <replaceable>testname</replaceable>
+                </literallayout>
+                where the result can be <filename>PASS</filename>,
+                <filename>FAIL</filename>, or <filename>SKIP</filename>,
+                and the testname can be any identifying string.
+            </para>
+
+            <para>
+                For a list of Yocto Project recipes that are already
+                enabled with ptest, see the
+                <ulink url='https://wiki.yoctoproject.org/wiki/Ptest'>Ptest</ulink>
+                wiki page.
+                <note>
+                    A recipe is "ptest-enabled" if it inherits the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-ptest'><filename>ptest</filename></ulink>
+                    class.
+                </note>
+            </para>
+
+            <section id='adding-ptest-to-your-build'>
+                <title>Adding ptest to Your Build</title>
+
+                <para>
+                    To add package testing to your build, add the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></ulink>
+                    and <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_IMAGE_FEATURES'><filename>EXTRA_IMAGE_FEATURES</filename></ulink>
+                    variables to your <filename>local.conf</filename> file,
+                    which is found in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>:
+                    <literallayout class='monospaced'>
+     DISTRO_FEATURES_append = " ptest"
+     EXTRA_IMAGE_FEATURES += "ptest-pkgs"
+                    </literallayout>
+                    Once your build is complete, the ptest files are installed
+                    into the
+                    <filename>/usr/lib/<replaceable>package</replaceable>/ptest</filename>
+                    directory within the image, where
+                    <filename><replaceable>package</replaceable></filename>
+                    is the name of the package.
+                </para>
+            </section>
+
+            <section id='running-ptest'>
+                <title>Running ptest</title>
+
+                <para>
+                    The <filename>ptest-runner</filename> package installs a
+                    shell script that loops through all installed ptest test
+                    suites and runs them in sequence.
+                    Consequently, you might want to add this package to
+                    your image.
+                </para>
+            </section>
+
+            <section id='getting-your-package-ready'>
+                <title>Getting Your Package Ready</title>
+
+                <para>
+                    In order to enable a recipe to run installed ptests
+                    on target hardware,
+                    you need to prepare the recipes that build the packages
+                    you want to test.
+                    Here is what you have to do for each recipe:
+                    <itemizedlist>
+                        <listitem><para><emphasis>Be sure the recipe
+                            inherits the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-ptest'><filename>ptest</filename></ulink>
+                            class:</emphasis>
+                            Include the following line in each recipe:
+                            <literallayout class='monospaced'>
+     inherit ptest
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para><emphasis>Create <filename>run-ptest</filename>:</emphasis>
+                            This script starts your test.
+                            Locate the script where you will refer to it
+                            using
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>.
+                            Here is an example that starts a test for
+                            <filename>dbus</filename>:
+                            <literallayout class='monospaced'>
+     #!/bin/sh
+     cd test
+     make -k runtest-TESTS
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para><emphasis>Ensure dependencies are
+                            met:</emphasis>
+                            If the test adds build or runtime dependencies
+                            that normally do not exist for the package
+                            (such as requiring "make" to run the test suite),
+                            use the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                            and
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>
+                            variables in your recipe in order for the package
+                            to meet the dependencies.
+                            Here is an example where the package has a runtime
+                            dependency on "make":
+                            <literallayout class='monospaced'>
+     RDEPENDS_${PN}-ptest += "make"
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para><emphasis>Add a function to build the
+                            test suite:</emphasis>
+                            Not many packages support cross-compilation of
+                            their test suites.
+                            Consequently, you usually need to add a
+                            cross-compilation function to the package.
+                            </para>
+
+                            <para>Many packages based on Automake compile and
+                            run the test suite by using a single command
+                            such as <filename>make check</filename>.
+                            However, the host <filename>make check</filename>
+                            builds and runs on the same computer, while
+                            cross-compiling requires that the package is built
+                            on the host but executed for the target
+                            architecture (though often, as in the case for
+                            ptest, the execution occurs on the host).
+                            The built version of Automake that ships with the
+                            Yocto Project includes a patch that separates
+                            building and execution.
+                            Consequently, packages that use the unaltered,
+                            patched version of <filename>make check</filename>
+                            automatically cross-compiles.</para>
+                            <para>Regardless, you still must add a
+                            <filename>do_compile_ptest</filename> function to
+                            build the test suite.
+                            Add a function similar to the following to your
+                            recipe:
+                            <literallayout class='monospaced'>
+     do_compile_ptest() {
+        oe_runmake buildtest-TESTS
+     }
+                            </literallayout>
+                            </para></listitem>
+                       <listitem><para><emphasis>Ensure special configurations
+                            are set:</emphasis>
+                            If the package requires special configurations
+                            prior to compiling the test code, you must
+                            insert a <filename>do_configure_ptest</filename>
+                            function into the recipe.
+                            </para></listitem>
+                       <listitem><para><emphasis>Install the test
+                            suite:</emphasis>
+                            The <filename>ptest</filename> class
+                            automatically copies the file
+                            <filename>run-ptest</filename> to the target and
+                            then runs make <filename>install-ptest</filename>
+                            to run the tests.
+                            If this is not enough, you need to create a
+                            <filename>do_install_ptest</filename> function and
+                            make sure it gets called after the
+                            "make install-ptest" completes.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+        </section>
+
+        <section id='creating-node-package-manager-npm-packages'>
+            <title>Creating Node Package Manager (NPM) Packages</title>
+
+            <para>
+                <ulink url='https://en.wikipedia.org/wiki/Npm_(software)'>NPM</ulink>
+                is a package manager for the JavaScript programming
+                language.
+                The Yocto Project supports the NPM
+                <ulink url='&YOCTO_DOCS_BB_URL;#bb-fetchers'>fetcher</ulink>.
+                You can use this fetcher in combination with
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-devtool-reference'><filename>devtool</filename></ulink>
+                to create recipes that produce NPM packages.
+            </para>
+
+            <para>
+                Two workflows exist that allow you to create NPM packages
+                using <filename>devtool</filename>: the NPM registry modules
+                method and the NPM project code method.
+                <note>
+                    While it is possible to create NPM recipes manually,
+                    using <filename>devtool</filename> is far simpler.
+                </note>
+                Additionally, some requirements and caveats exist.
+            </para>
+
+            <section id='npm-package-creation-requirements'>
+                <title>Requirements and Caveats</title>
+
+                <para>
+                    You need to be aware of the following before using
+                    <filename>devtool</filename> to create NPM packages:
+                    <itemizedlist>
+                        <listitem><para>
+                            Of the two methods that you can use
+                            <filename>devtool</filename> to create NPM
+                            packages, the registry approach is slightly
+                            simpler.
+                            However, you might consider the project
+                            approach because you do not have to publish
+                            your module in the NPM registry
+                            (<ulink url='https://docs.npmjs.com/misc/registry'><filename>npm-registry</filename></ulink>),
+                            which is NPM's public registry.
+                            </para></listitem>
+                        <listitem><para>
+                            Be familiar with
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-devtool-reference'><filename>devtool</filename></ulink>.
+                            </para></listitem>
+                        <listitem><para>
+                            The NPM host tools need the native
+                            <filename>nodejs-npm</filename> package, which
+                            is part of the OpenEmbedded environment.
+                            You need to get the package by cloning the
+                            <ulink url='https://github.com/openembedded/meta-openembedded'></ulink>
+                            repository out of GitHub.
+                            Be sure to add the path to your local copy to
+                            your <filename>bblayers.conf</filename> file.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>devtool</filename> cannot detect
+                            native libraries in module dependencies.
+                            Consequently, you must manually add packages
+                            to your recipe.
+                            </para></listitem>
+                        <listitem><para>
+                            While deploying NPM packages,
+                            <filename>devtool</filename> cannot determine
+                            which dependent packages are missing on the
+                            target (e.g. the node runtime
+                            <filename>nodejs</filename>).
+                            Consequently, you need to find out what
+                            files are missing and be sure they are on the
+                            target.
+                            </para></listitem>
+                        <listitem><para>
+                            Although you might not need NPM to run your
+                            node package, it is useful to have NPM on your
+                            target.
+                            The NPM package name is
+                            <filename>nodejs-npm</filename>.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='npm-using-the-registry-modules-method'>
+                <title>Using the Registry Modules Method</title>
+
+                <para>
+                    This section presents an example that uses the
+                    <filename>cute-files</filename> module, which is a
+                    file browser web application.
+                    <note>
+                        You must know the <filename>cute-files</filename>
+                        module version.
+                    </note>
+                </para>
+
+                <para>
+                    The first thing you need to do is use
+                    <filename>devtool</filename> and the NPM fetcher to
+                    create the recipe:
+                    <literallayout class='monospaced'>
+     $ devtool add "npm://registry.npmjs.org;package=cute-files;version=1.0.2"
+                    </literallayout>
+                    The <filename>devtool add</filename> command runs
+                    <filename>recipetool create</filename> and uses the
+                    same fetch URI to download each dependency and capture
+                    license details where possible.
+                    The result is a generated recipe.
+                </para>
+
+                <para>
+                    The recipe file is fairly simple and contains every
+                    license that <filename>recipetool</filename> finds
+                    and includes the licenses in the recipe's
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></ulink>
+                    variables.
+                    You need to examine the variables and look for those
+                    with "unknown" in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE</filename></ulink>
+                    field.
+                    You need to track down the license information for
+                    "unknown" modules and manually add the information to the
+                    recipe.
+                </para>
+
+                <para>
+                    <filename>recipetool</filename> creates a "shrinkwrap" file
+                    for your recipe.
+                    Shrinkwrap files capture the version of all dependent
+                    modules.
+                    Many packages do not provide shrinkwrap files.
+                    <filename>recipetool</filename> create a shrinkwrap
+                    file as it runs.
+                    <note>
+                        A package is created for each sub-module.
+                        This policy is the only practical way to have the
+                        licenses for all of the dependencies represented
+                        in the license manifest of the image.
+                    </note>
+                </para>
+
+                <para>
+                    The <filename>devtool edit-recipe</filename> command
+                    lets you take a look at the recipe:
+                    <literallayout class='monospaced'>
+     $ devtool edit-recipe cute-files
+     SUMMARY = "Turn any folder on your computer into a cute file browser, available on the local network."
+     LICENSE = "MIT &amp; ISC &amp; Unknown"
+     LIC_FILES_CHKSUM = "file://LICENSE;md5=71d98c0a1db42956787b1909c74a86ca \
+                         file://node_modules/toidentifier/LICENSE;md5=1a261071a044d02eb6f2bb47f51a3502 \
+                         file://node_modules/debug/LICENSE;md5=ddd815a475e7338b0be7a14d8ee35a99 \
+                         ...
+
+     SRC_URI = " \
+         npm://registry.npmjs.org/;package=cute-files;version=${PV} \
+         npmsw://${THISDIR}/${BPN}/npm-shrinkwrap.json \
+     "
+
+     S = "${WORKDIR}/npm"
+
+     inherit npm
+
+     LICENSE_${PN} = "MIT"
+     LICENSE_${PN}-accepts = "MIT"
+     LICENSE_${PN}-array-flatten = "MIT"
+     ...
+     LICENSE_${PN}-vary = "MIT"
+                    </literallayout>
+                    Three key points exist in the previous example:
+                    <itemizedlist>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                            uses the NPM scheme so that the NPM fetcher
+                            is used.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>recipetool</filename> collects all
+                            the license information.
+                            If a sub-module's license is unavailable,
+                            the sub-module's name appears in the comments.
+                            </para></listitem>
+                        <listitem><para>
+                            The <filename>inherit npm</filename> statement
+                            causes the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-npm'><filename>npm</filename></ulink>
+                            class to package up all the modules.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+
+                <para>
+                    You can run the following command to build the
+                    <filename>cute-files</filename> package:
+                    <literallayout class='monospaced'>
+     $ devtool build cute-files
+                    </literallayout>
+                    Remember that <filename>nodejs</filename> must be
+                    installed on the target before your package.
+                </para>
+
+                <para>
+                    Assuming 192.168.7.2 for the target's IP address, use
+                    the following command to deploy your package:
+                    <literallayout class='monospaced'>
+     $ devtool deploy-target -s cute-files root@192.168.7.2
+                    </literallayout>
+                    Once the package is installed on the target, you can
+                    test the application:
+                    <note>
+                        Because of a know issue, you cannot simply run
+                        <filename>cute-files</filename> as you would if you
+                        had run <filename>npm install</filename>.
+                    </note>
+                    <literallayout class='monospaced'>
+     $ cd /usr/lib/node_modules/cute-files
+     $ node cute-files.js
+                    </literallayout>
+                    On a browser, go to
+                    <filename>http://192.168.7.2:3000</filename> and you
+                    see the following:
+                    <imagedata fileref="figures/cute-files-npm-example.png" align="center" width="6in" depth="4in" />
+                </para>
+
+                <para>
+                    You can find the recipe in
+                    <filename>workspace/recipes/cute-files</filename>.
+                    You can use the recipe in any layer you choose.
+                </para>
+            </section>
+
+            <section id='npm-using-the-npm-projects-method'>
+                <title>Using the NPM Projects Code Method</title>
+
+                <para>
+                    Although it is useful to package modules already in the
+                    NPM registry, adding <filename>node.js</filename> projects
+                    under development is a more common developer use case.
+                </para>
+
+                <para>
+                    This section covers the NPM projects code method, which is
+                    very similar to the "registry" approach described in the
+                    previous section.
+                    In the NPM projects method, you provide
+                    <filename>devtool</filename> with an URL that points to the
+                    source files.
+                </para>
+
+                <para>
+                    Replicating the same example, (i.e.
+                    <filename>cute-files</filename>) use the following command:
+                    <literallayout class='monospaced'>
+     $ devtool add https://github.com/martinaglv/cute-files.git
+                    </literallayout>
+                    The recipe this command generates is very similar to the
+                    recipe created in the previous section.
+                    However, the <filename>SRC_URI</filename> looks like the
+                    following:
+                    <literallayout class='monospaced'>
+     SRC_URI = " \
+         git://github.com/martinaglv/cute-files.git;protocol=https \
+         npmsw://${THISDIR}/${BPN}/npm-shrinkwrap.json \
+         "
+                    </literallayout>
+                    In this example, the main module is taken from the Git
+                    repository and dependents are taken from the NPM registry.
+                    Other than those differences, the recipe is basically the
+                    same between the two methods.
+                    You can build and deploy the package exactly as described
+                    in the previous section that uses the registry modules
+                    method.
+                </para>
+            </section>
+        </section>
+
+        <section id='adding-custom-metadata-to-packages'>
+            <title>Adding custom metadata to packages</title>
+
+            <para>
+                The variable <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGE_ADD_METADATA'><filename>PACKAGE_ADD_METADATA</filename></ulink>
+                can be used to add additional metadata to packages. This is
+                reflected in the package control/spec file. To take the ipk
+                format for example, the CONTROL file stored inside would
+                contain the additional metadata as additional lines.
+            </para>
+
+            <para>
+                The variable can be used in multiple ways, including using
+                suffixes to set it for a specific package type and/or package.
+                Note that the order of precedence is the same as this list:
+                <itemizedlist>
+                    <listitem><para>
+                        <filename>PACKAGE_ADD_METADATA_&lt;PKGTYPE&gt;_&lt;PN&gt;</filename>
+                    </para></listitem>
+                    <listitem><para>
+                        <filename>PACKAGE_ADD_METADATA_&lt;PKGTYPE&gt;</filename>
+                    </para></listitem>
+                    <listitem><para>
+                        <filename>PACKAGE_ADD_METADATA_&lt;PN&gt;</filename>
+                    </para></listitem>
+                    <listitem><para>
+                        <filename>PACKAGE_ADD_METADATA</filename>
+                    </para></listitem>
+                </itemizedlist>
+                &lt;PKGTYPE&gt; is a parameter and expected to be a
+                distinct name of specific package type:
+                <itemizedlist>
+                    <listitem><para>IPK for .ipk packages</para></listitem>
+                    <listitem><para>DEB for .deb packages</para></listitem>
+                    <listitem><para>RPM for .rpm packages</para></listitem>
+                </itemizedlist>
+                &lt;PN&gt; is a parameter and expected to be a package name.
+            </para>
+
+            <para>
+                The variable can contain multiple [one-line] metadata fields
+                separated by the literal sequence '\n'. The separator can be
+                redefined using the variable flag <filename>separator</filename>.
+            </para>
+
+            <para>
+                The following is an example that adds two custom fields for
+                ipk packages:
+                <literallayout class='monospaced'>
+    PACKAGE_ADD_METADATA_IPK = "Vendor: CustomIpk\nGroup: Applications/Spreadsheets"
+                </literallayout>
+            </para>
+        </section>
+
+    </section>
+
+    <section id='efficiently-fetching-source-files-during-a-build'>
+        <title>Efficiently Fetching Source Files During a Build</title>
+
+        <para>
+            The OpenEmbedded build system works with source files located
+            through the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+            variable.
+            When you build something using BitBake, a big part of the operation
+            is locating and downloading all the source tarballs.
+            For images, downloading all the source for various packages can
+            take a significant amount of time.
+        </para>
+
+        <para>
+            This section shows you how you can use mirrors to speed up
+            fetching source files and how you can pre-fetch files all of which
+            leads to more efficient use of resources and time.
+        </para>
+
+        <section id='setting-up-effective-mirrors'>
+            <title>Setting up Effective Mirrors</title>
+
+            <para>
+                A good deal that goes into a Yocto Project
+                build is simply downloading all of the source tarballs.
+                Maybe you have been working with another build system
+                (OpenEmbedded or Angstrom) for which you have built up a
+                sizable directory of source tarballs.
+                Or, perhaps someone else has such a directory for which you
+                have read access.
+                If so, you can save time by adding statements to your
+                configuration file so that the build process checks local
+                directories first for existing tarballs before checking the
+                Internet.
+            </para>
+
+            <para>
+                Here is an efficient way to set it up in your
+                <filename>local.conf</filename> file:
+                <literallayout class='monospaced'>
+     SOURCE_MIRROR_URL ?= "file:///home/you/your-download-dir/"
+     INHERIT += "own-mirrors"
+     BB_GENERATE_MIRROR_TARBALLS = "1"
+     # BB_NO_NETWORK = "1"
+                </literallayout>
+            </para>
+
+            <para>
+                In the previous example, the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BB_GENERATE_MIRROR_TARBALLS'><filename>BB_GENERATE_MIRROR_TARBALLS</filename></ulink>
+                variable causes the OpenEmbedded build system to generate
+                tarballs of the Git repositories and store them in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DL_DIR'><filename>DL_DIR</filename></ulink>
+                directory.
+                Due to performance reasons, generating and storing these
+                tarballs is not the build system's default behavior.
+            </para>
+
+            <para>
+                You can also use the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PREMIRRORS'><filename>PREMIRRORS</filename></ulink>
+                variable.
+                For an example, see the variable's glossary entry in the
+                Yocto Project Reference Manual.
+            </para>
+        </section>
+
+        <section id='getting-source-files-and-suppressing-the-build'>
+            <title>Getting Source Files and Suppressing the Build</title>
+
+            <para>
+                Another technique you can use to ready yourself for a
+                successive string of build operations, is to pre-fetch
+                all the source files without actually starting a build.
+                This technique lets you work through any download issues
+                and ultimately gathers all the source files into your
+                download directory
+                <ulink url='&YOCTO_DOCS_REF_URL;#structure-build-downloads'><filename>build/downloads</filename></ulink>,
+                which is located with
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DL_DIR'><filename>DL_DIR</filename></ulink>.
+            </para>
+
+            <para>
+                Use the following BitBake command form to fetch all the
+                necessary sources without starting the build:
+                <literallayout class='monospaced'>
+     $ bitbake <replaceable>target</replaceable> --runall=fetch
+                </literallayout>
+                This variation of the BitBake command guarantees that you
+                have all the sources for that BitBake target should you
+                disconnect from the Internet and want to do the build
+                later offline.
+            </para>
+        </section>
+    </section>
+
+    <section id="selecting-an-initialization-manager">
+        <title>Selecting an Initialization Manager</title>
+
+        <para>
+            By default, the Yocto Project uses SysVinit as the initialization
+            manager.
+            However, support also exists for systemd,
+            which is a full replacement for init with
+            parallel starting of services, reduced shell overhead and other
+            features that are used by many distributions.
+        </para>
+
+        <para>
+            Within the system, SysVinit treats system components as services.
+            These services are maintained as shell scripts stored in the
+            <filename>/etc/init.d/</filename> directory.
+            Services organize into different run levels.
+            This organization is maintained by putting links to the services
+            in the <filename>/etc/rcN.d/</filename> directories, where
+            <replaceable>N/</replaceable> is one of the following options:
+            "S", "0", "1", "2", "3", "4", "5", or "6".
+            <note>
+                Each runlevel has a dependency on the previous runlevel.
+                This dependency allows the services to work properly.
+            </note>
+        </para>
+
+        <para>
+            In comparison, systemd treats components as units.
+            Using units is a broader concept as compared to using a service.
+            A unit includes several different types of entities.
+            Service is one of the types of entities.
+            The runlevel concept in SysVinit corresponds to the concept of a
+            target in systemd, where target is also a type of supported unit.
+        </para>
+
+        <para>
+            In a SysVinit-based system, services load sequentially (i.e. one
+            by one) during and parallelization is not supported.
+            With systemd, services start in parallel.
+            Needless to say, the method can have an impact on system startup
+            performance.
+        </para>
+
+        <para>
+            If you want to use SysVinit, you do
+            not have to do anything.
+            But, if you want to use systemd, you must
+            take some steps as described in the following sections.
+        </para>
+
+        <section id='using-systemd-exclusively'>
+            <title>Using systemd Exclusively</title>
+
+            <para>
+                Set these variables in your distribution configuration
+                file as follows:
+                <literallayout class='monospaced'>
+     DISTRO_FEATURES_append = " systemd"
+     VIRTUAL-RUNTIME_init_manager = "systemd"
+                </literallayout>
+                You can also prevent the SysVinit
+                distribution feature from
+                being automatically enabled as follows:
+                <literallayout class='monospaced'>
+     DISTRO_FEATURES_BACKFILL_CONSIDERED = "sysvinit"
+                </literallayout>
+                Doing so removes any redundant SysVinit scripts.
+            </para>
+
+            <para>
+                To remove  initscripts from your image altogether,
+                set this variable also:
+                <literallayout class='monospaced'>
+     VIRTUAL-RUNTIME_initscripts = ""
+                </literallayout>
+            </para>
+
+            <para>
+                For information on the backfill variable, see
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES_BACKFILL_CONSIDERED'><filename>DISTRO_FEATURES_BACKFILL_CONSIDERED</filename></ulink>.
+            </para>
+        </section>
+
+        <section id='using-systemd-for-the-main-image-and-using-sysvinit-for-the-rescue-image'>
+            <title>Using systemd for the Main Image and Using SysVinit for the Rescue Image</title>
+
+            <para>
+                Set these variables in your distribution configuration
+                file as follows:
+                <literallayout class='monospaced'>
+     DISTRO_FEATURES_append = " systemd"
+     VIRTUAL-RUNTIME_init_manager = "systemd"
+                </literallayout>
+                Doing so causes your main image to use the
+                <filename>packagegroup-core-boot.bb</filename> recipe and
+                systemd.
+                The rescue/minimal image cannot use this package group.
+                However, it can install SysVinit
+                and the appropriate packages will have support for both
+                systemd and SysVinit.
+            </para>
+        </section>
+    </section>
+
+    <section id="selecting-dev-manager">
+        <title>Selecting a Device Manager</title>
+
+        <para>
+            The Yocto Project provides multiple ways to manage the device
+            manager (<filename>/dev</filename>):
+            <itemizedlist>
+                <listitem><para><emphasis>Persistent and Pre-Populated<filename>/dev</filename>:</emphasis>
+                    For this case, the <filename>/dev</filename> directory
+                    is persistent and the required device nodes are created
+                    during the build.
+                    </para></listitem>
+                <listitem><para><emphasis>Use <filename>devtmpfs</filename> with a Device Manager:</emphasis>
+                    For this case, the <filename>/dev</filename> directory
+                    is provided by the kernel as an in-memory file system and
+                    is automatically populated by the kernel at runtime.
+                    Additional configuration of device nodes is done in user
+                    space by a device manager like
+                    <filename>udev</filename> or
+                    <filename>busybox-mdev</filename>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <section id="static-dev-management">
+            <title>Using Persistent and Pre-Populated<filename>/dev</filename></title>
+
+            <para>
+                To use the static method for device population, you need to
+                set the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-USE_DEVFS'><filename>USE_DEVFS</filename></ulink>
+                variable to "0" as follows:
+                <literallayout class='monospaced'>
+     USE_DEVFS = "0"
+                </literallayout>
+            </para>
+
+            <para>
+                The content of the resulting <filename>/dev</filename>
+                directory is defined in a Device Table file.
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_DEVICE_TABLES'><filename>IMAGE_DEVICE_TABLES</filename></ulink>
+                variable defines the Device Table to use and should be set
+                in the machine or distro configuration file.
+                Alternatively, you can set this variable in your
+                <filename>local.conf</filename> configuration file.
+            </para>
+
+            <para>
+                If you do not define the
+                <filename>IMAGE_DEVICE_TABLES</filename> variable, the default
+                <filename>device_table-minimal.txt</filename> is used:
+                <literallayout class='monospaced'>
+     IMAGE_DEVICE_TABLES = "device_table-mymachine.txt"
+                </literallayout>
+            </para>
+
+            <para>
+                The population is handled by the <filename>makedevs</filename>
+                utility during image creation:
+            </para>
+        </section>
+
+        <section id="devtmpfs-dev-management">
+            <title>Using <filename>devtmpfs</filename> and a Device Manager</title>
+
+            <para>
+                To use the dynamic method for device population, you need to
+                use (or be sure to set) the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-USE_DEVFS'><filename>USE_DEVFS</filename></ulink>
+                variable to "1", which is the default:
+                <literallayout class='monospaced'>
+     USE_DEVFS = "1"
+                </literallayout>
+                With this setting, the resulting <filename>/dev</filename>
+                directory is populated by the kernel using
+                <filename>devtmpfs</filename>.
+                Make sure the corresponding kernel configuration variable
+                <filename>CONFIG_DEVTMPFS</filename> is set when building
+                you build a Linux kernel.
+            </para>
+
+            <para>
+                All devices created by <filename>devtmpfs</filename> will be
+                owned by <filename>root</filename> and have permissions
+                <filename>0600</filename>.
+            </para>
+
+            <para>
+                To have more control over the device nodes, you can use a
+                device manager like <filename>udev</filename> or
+                <filename>busybox-mdev</filename>.
+                You choose the device manager by defining the
+                <filename>VIRTUAL-RUNTIME_dev_manager</filename> variable
+                in your machine or distro configuration file.
+                Alternatively, you can set this variable in your
+                <filename>local.conf</filename> configuration file:
+                <literallayout class='monospaced'>
+     VIRTUAL-RUNTIME_dev_manager = "udev"
+
+     # Some alternative values
+     # VIRTUAL-RUNTIME_dev_manager = "busybox-mdev"
+     # VIRTUAL-RUNTIME_dev_manager = "systemd"
+                </literallayout>
+            </para>
+        </section>
+    </section>
+
+    <section id="platdev-appdev-srcrev">
+        <title>Using an External SCM</title>
+
+        <para>
+            If you're working on a recipe that pulls from an external Source
+            Code Manager (SCM), it is possible to have the OpenEmbedded build
+            system notice new recipe changes added to the SCM and then build
+            the resulting packages that depend on the new recipes by using
+            the latest versions.
+            This only works for SCMs from which it is possible to get a
+            sensible revision number for changes.
+            Currently, you can do this with Apache Subversion (SVN), Git, and
+            Bazaar (BZR) repositories.
+        </para>
+
+        <para>
+            To enable this behavior, the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+            of the recipe needs to reference
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCPV'><filename>SRCPV</filename></ulink>.
+            Here is an example:
+            <literallayout class='monospaced'>
+     PV = "1.2.3+git${SRCPV}"
+            </literallayout>
+            Then, you can add the following to your
+            <filename>local.conf</filename>:
+            <literallayout class='monospaced'>
+     SRCREV_pn-<replaceable>PN</replaceable> = "${AUTOREV}"
+            </literallayout>
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink>
+            is the name of the recipe for which you want to enable automatic source
+            revision updating.
+        </para>
+
+        <para>
+            If you do not want to update your local configuration file, you can
+            add the following directly to the recipe to finish enabling
+            the feature:
+            <literallayout class='monospaced'>
+     SRCREV = "${AUTOREV}"
+            </literallayout>
+        </para>
+
+        <para>
+            The Yocto Project provides a distribution named
+            <filename>poky-bleeding</filename>, whose configuration
+            file contains the line:
+            <literallayout class='monospaced'>
+     require conf/distro/include/poky-floating-revisions.inc
+            </literallayout>
+            This line pulls in the listed include file that contains
+            numerous lines of exactly that form:
+            <literallayout class='monospaced'>
+     #SRCREV_pn-opkg-native ?= "${AUTOREV}"
+     #SRCREV_pn-opkg-sdk ?= "${AUTOREV}"
+     #SRCREV_pn-opkg ?= "${AUTOREV}"
+     #SRCREV_pn-opkg-utils-native ?= "${AUTOREV}"
+     #SRCREV_pn-opkg-utils ?= "${AUTOREV}"
+     SRCREV_pn-gconf-dbus ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-common ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-config-gtk ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-desktop ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-keyboard ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-panel-2 ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-themes-extra ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-terminal ?= "${AUTOREV}"
+     SRCREV_pn-matchbox-wm ?= "${AUTOREV}"
+     SRCREV_pn-settings-daemon ?= "${AUTOREV}"
+     SRCREV_pn-screenshot ?= "${AUTOREV}"
+          .
+          .
+          .
+            </literallayout>
+            These lines allow you to experiment with building a
+            distribution that tracks the latest development source
+            for numerous packages.
+            <note><title>Caution</title>
+                The <filename>poky-bleeding</filename> distribution
+                is not tested on a regular basis.
+                Keep this in mind if you use it.
+            </note>
+        </para>
+    </section>
+
+    <section id='creating-a-read-only-root-filesystem'>
+        <title>Creating a Read-Only Root Filesystem</title>
+
+        <para>
+            Suppose, for security reasons, you need to disable
+            your target device's root filesystem's write permissions
+            (i.e. you need a read-only root filesystem).
+            Or, perhaps you are running the device's operating system
+            from a read-only storage device.
+            For either case, you can customize your image for
+            that behavior.
+        </para>
+
+        <note>
+            Supporting a read-only root filesystem requires that the system and
+            applications do not try to write to the root filesystem.
+            You must configure all parts of the target system to write
+            elsewhere, or to gracefully fail in the event of attempting to
+            write to the root filesystem.
+        </note>
+
+        <section id='creating-the-root-filesystem'>
+            <title>Creating the Root Filesystem</title>
+
+            <para>
+                To create the read-only root filesystem, simply add the
+                "read-only-rootfs" feature to your image, normally in one of two ways.
+                The first way is to add the "read-only-rootfs" image feature
+                in the image's recipe file via the
+                <filename>IMAGE_FEATURES</filename> variable:
+                <literallayout class='monospaced'>
+     IMAGE_FEATURES += "read-only-rootfs"
+                </literallayout>
+                As an alternative, you can add the same feature from within your
+                build directory's <filename>local.conf</filename> file with the
+                associated <filename>EXTRA_IMAGE_FEATURES</filename> variable, as in:
+                <literallayout class='monospaced'>
+     EXTRA_IMAGE_FEATURES = "read-only-rootfs"
+                </literallayout>
+            </para>
+
+            <para>
+                For more information on how to use these variables, see the
+                "<link linkend='usingpoky-extend-customimage-imagefeatures'>Customizing Images Using Custom <filename>IMAGE_FEATURES</filename> and <filename>EXTRA_IMAGE_FEATURES</filename></link>"
+                section.
+                For information on the variables, see
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></ulink>
+                and <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_IMAGE_FEATURES'><filename>EXTRA_IMAGE_FEATURES</filename></ulink>.
+            </para>
+        </section>
+
+        <section id='post-installation-scripts'>
+            <title>Post-Installation Scripts</title>
+
+            <para>
+                It is very important that you make sure all
+                post-Installation (<filename>pkg_postinst</filename>) scripts
+                for packages that are installed into the image can be run
+                at the time when the root filesystem is created during the
+                build on the host system.
+                These scripts cannot attempt to run during first-boot on the
+                target device.
+                With the "read-only-rootfs" feature enabled,
+                the build system checks during root filesystem creation to make
+                sure all post-installation scripts succeed.
+                If any of these scripts still need to be run after the root
+                filesystem is created, the build immediately fails.
+                These build-time checks ensure that the build fails
+                rather than the target device fails later during its
+                initial boot operation.
+            </para>
+
+            <para>
+                Most of the common post-installation scripts generated by the
+                build system for the out-of-the-box Yocto Project are engineered
+                so that they can run during root filesystem creation
+                (e.g. post-installation scripts for caching fonts).
+                However, if you create and add custom scripts, you need
+                to be sure they can be run during this file system creation.
+            </para>
+
+            <para>
+                Here are some common problems that prevent
+                post-installation scripts from running during root filesystem
+                creation:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Not using $D in front of absolute
+                        paths:</emphasis>
+                        The build system defines
+                        <filename>$</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink>
+                        when the root filesystem is created.
+                        Furthermore, <filename>$D</filename> is blank when the
+                        script is run on the target device.
+                        This implies two purposes for <filename>$D</filename>:
+                        ensuring paths are valid in both the host and target
+                        environments, and checking to determine which
+                        environment is being used as a method for taking
+                        appropriate actions.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Attempting to run processes that are
+                        specific to or dependent on the target
+                        architecture:</emphasis>
+                        You can work around these attempts by using native
+                        tools, which run on the host system,
+                        to accomplish the same tasks, or
+                        by alternatively running the processes under QEMU,
+                        which has the <filename>qemu_run_binary</filename>
+                        function.
+                        For more information, see the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-qemu'><filename>qemu</filename></ulink>
+                        class.</para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='areas-with-write-access'>
+            <title>Areas With Write Access</title>
+
+            <para>
+                With the "read-only-rootfs" feature enabled,
+                any attempt by the target to write to the root filesystem at
+                runtime fails.
+                Consequently, you must make sure that you configure processes
+                and applications that attempt these types of writes do so
+                to directories with write access (e.g.
+                <filename>/tmp</filename> or <filename>/var/run</filename>).
+            </para>
+        </section>
+    </section>
+
+
+
+
+    <section id='maintaining-build-output-quality'>
+        <title>Maintaining Build Output Quality</title>
+
+        <para>
+            Many factors can influence the quality of a build.
+            For example, if you upgrade a recipe to use a new version of an
+            upstream software package or you experiment with some new
+            configuration options, subtle changes can occur that you might
+            not detect until later.
+            Consider the case where your recipe is using a newer version of
+            an upstream package.
+            In this case, a new version of a piece of software might
+            introduce an optional dependency on another library, which is
+            auto-detected.
+            If that library has already been built when the software is
+            building, the software will link to the built library and that
+            library will be pulled into your image along with the new
+            software even if you did not want the library.
+        </para>
+
+        <para>
+            The
+            <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-buildhistory'><filename>buildhistory</filename></ulink>
+            class exists to help you maintain the quality of your build
+            output.
+            You can use the class to highlight unexpected and possibly
+            unwanted changes in the build output.
+            When you enable build history, it records information about the
+            contents of each package and image and then commits that
+            information to a local Git repository where you can examine
+            the information.
+        </para>
+
+        <para>
+            The remainder of this section describes the following:
+            <itemizedlist>
+               <listitem><para>
+                   How you can enable and disable build history
+                   </para></listitem>
+               <listitem><para>
+                   How to understand what the build history contains
+                   </para></listitem>
+               <listitem><para>
+                   How to limit the information used for build history
+                   </para></listitem>
+               <listitem><para>
+                   How to examine the build history from both a
+                   command-line and web interface
+                   </para></listitem>
+           </itemizedlist>
+        </para>
+
+        <section id='enabling-and-disabling-build-history'>
+            <title>Enabling and Disabling Build History</title>
+
+            <para>
+                Build history is disabled by default.
+                To enable it, add the following <filename>INHERIT</filename>
+                statement and set the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BUILDHISTORY_COMMIT'><filename>BUILDHISTORY_COMMIT</filename></ulink>
+                variable to "1" at the end of your
+                <filename>conf/local.conf</filename> file found in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>:
+                <literallayout class='monospaced'>
+     INHERIT += "buildhistory"
+     BUILDHISTORY_COMMIT = "1"
+                </literallayout>
+                Enabling build history as previously described causes the
+                OpenEmbedded build system to collect build output information
+                and commit it as a single commit to a local
+                <ulink url='&YOCTO_DOCS_OM_URL;#git'>Git</ulink>
+                repository.
+                <note>
+                    Enabling build history increases your build times slightly,
+                    particularly for images, and increases the amount of disk
+                    space used during the build.
+                </note>
+            </para>
+
+            <para>
+                You can disable build history by removing the previous
+                statements from your <filename>conf/local.conf</filename>
+                file.
+            </para>
+        </section>
+
+        <section id='understanding-what-the-build-history-contains'>
+            <title>Understanding What the Build History Contains</title>
+
+            <para>
+                Build history information is kept in
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-TOPDIR'><filename>TOPDIR</filename></ulink><filename>}/buildhistory</filename>
+                in the Build Directory as defined by the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BUILDHISTORY_DIR'><filename>BUILDHISTORY_DIR</filename></ulink>
+                variable.
+                The following is an example abbreviated listing:
+                <imagedata fileref="figures/buildhistory.png" align="center" width="6in" depth="4in" />
+            </para>
+
+            <para>
+                At the top level, a <filename>metadata-revs</filename>
+                file exists that lists the revisions of the repositories for
+                the enabled layers when the build was produced.
+                The rest of the data splits into separate
+                <filename>packages</filename>, <filename>images</filename>
+                and <filename>sdk</filename> directories, the contents of
+                which are described as follows.
+            </para>
+
+            <section id='build-history-package-information'>
+                <title>Build History Package Information</title>
+
+                <para>
+                    The history for each package contains a text file that has
+                    name-value pairs with information about the package.
+                    For example,
+                    <filename>buildhistory/packages/i586-poky-linux/busybox/busybox/latest</filename>
+                    contains the following:
+                    <literallayout class='monospaced'>
+     PV = 1.22.1
+     PR = r32
+     RPROVIDES =
+     RDEPENDS = glibc (>= 2.20) update-alternatives-opkg
+     RRECOMMENDS = busybox-syslog busybox-udhcpc update-rc.d
+     PKGSIZE = 540168
+     FILES = /usr/bin/* /usr/sbin/* /usr/lib/busybox/* /usr/lib/lib*.so.* \
+        /etc /com /var /bin/* /sbin/* /lib/*.so.* /lib/udev/rules.d \
+        /usr/lib/udev/rules.d /usr/share/busybox /usr/lib/busybox/* \
+        /usr/share/pixmaps /usr/share/applications /usr/share/idl \
+        /usr/share/omf /usr/share/sounds /usr/lib/bonobo/servers
+     FILELIST = /bin/busybox /bin/busybox.nosuid /bin/busybox.suid /bin/sh \
+        /etc/busybox.links.nosuid /etc/busybox.links.suid
+                    </literallayout>
+                    Most of these name-value pairs correspond to variables
+                    used to produce the package.
+                    The exceptions are <filename>FILELIST</filename>, which
+                    is the actual list of files in the package, and
+                    <filename>PKGSIZE</filename>, which is the total size of
+                    files in the package in bytes.
+                </para>
+
+                <para>
+                    A file also exists that corresponds to the recipe from
+                    which the package came (e.g.
+                    <filename>buildhistory/packages/i586-poky-linux/busybox/latest</filename>):
+                    <literallayout class='monospaced'>
+     PV = 1.22.1
+     PR = r32
+     DEPENDS = initscripts kern-tools-native update-rc.d-native \
+        virtual/i586-poky-linux-compilerlibs virtual/i586-poky-linux-gcc \
+        virtual/libc virtual/update-alternatives
+     PACKAGES = busybox-ptest busybox-httpd busybox-udhcpd busybox-udhcpc \
+        busybox-syslog busybox-mdev busybox-hwclock busybox-dbg \
+        busybox-staticdev busybox-dev busybox-doc busybox-locale busybox
+                    </literallayout>
+                </para>
+
+                <para>
+                    Finally, for those recipes fetched from a version control
+                    system (e.g., Git), a file exists that lists source
+                    revisions that are specified in the recipe and lists
+                    the actual revisions used during the build.
+                    Listed and actual revisions might differ when
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCREV'><filename>SRCREV</filename></ulink>
+                    is set to
+                    ${<ulink url='&YOCTO_DOCS_REF_URL;#var-AUTOREV'><filename>AUTOREV</filename></ulink>}.
+                    Here is an example assuming
+                    <filename>buildhistory/packages/qemux86-poky-linux/linux-yocto/latest_srcrev</filename>):
+                    <literallayout class='monospaced'>
+     # SRCREV_machine = "38cd560d5022ed2dbd1ab0dca9642e47c98a0aa1"
+     SRCREV_machine = "38cd560d5022ed2dbd1ab0dca9642e47c98a0aa1"
+     # SRCREV_meta = "a227f20eff056e511d504b2e490f3774ab260d6f"
+     SRCREV_meta = "a227f20eff056e511d504b2e490f3774ab260d6f"
+                    </literallayout>
+                    You can use the
+                    <filename>buildhistory-collect-srcrevs</filename>
+                    command with the <filename>-a</filename> option to
+                    collect the stored <filename>SRCREV</filename> values
+                    from build history and report them in a format suitable for
+                    use in global configuration (e.g.,
+                    <filename>local.conf</filename> or a distro include file)
+                    to override floating <filename>AUTOREV</filename> values
+                    to a fixed set of revisions.
+                    Here is some example output from this command:
+                    <literallayout class='monospaced'>
+     $ buildhistory-collect-srcrevs -a
+     # i586-poky-linux
+     SRCREV_pn-glibc = "b8079dd0d360648e4e8de48656c5c38972621072"
+     SRCREV_pn-glibc-initial = "b8079dd0d360648e4e8de48656c5c38972621072"
+     SRCREV_pn-opkg-utils = "53274f087565fd45d8452c5367997ba6a682a37a"
+     SRCREV_pn-kmod = "fd56638aed3fe147015bfa10ed4a5f7491303cb4"
+     # x86_64-linux
+     SRCREV_pn-gtk-doc-stub-native = "1dea266593edb766d6d898c79451ef193eb17cfa"
+     SRCREV_pn-dtc-native = "65cc4d2748a2c2e6f27f1cf39e07a5dbabd80ebf"
+     SRCREV_pn-update-rc.d-native = "eca680ddf28d024954895f59a241a622dd575c11"
+     SRCREV_glibc_pn-cross-localedef-native = "b8079dd0d360648e4e8de48656c5c38972621072"
+     SRCREV_localedef_pn-cross-localedef-native = "c833367348d39dad7ba018990bfdaffaec8e9ed3"
+     SRCREV_pn-prelink-native = "faa069deec99bf61418d0bab831c83d7c1b797ca"
+     SRCREV_pn-opkg-utils-native = "53274f087565fd45d8452c5367997ba6a682a37a"
+     SRCREV_pn-kern-tools-native = "23345b8846fe4bd167efdf1bd8a1224b2ba9a5ff"
+     SRCREV_pn-kmod-native = "fd56638aed3fe147015bfa10ed4a5f7491303cb4"
+     # qemux86-poky-linux
+     SRCREV_machine_pn-linux-yocto = "38cd560d5022ed2dbd1ab0dca9642e47c98a0aa1"
+     SRCREV_meta_pn-linux-yocto = "a227f20eff056e511d504b2e490f3774ab260d6f"
+     # all-poky-linux
+     SRCREV_pn-update-rc.d = "eca680ddf28d024954895f59a241a622dd575c11"
+                    </literallayout>
+                    <note>
+                        Here are some notes on using the
+                        <filename>buildhistory-collect-srcrevs</filename>
+                        command:
+                        <itemizedlist>
+                            <listitem><para>
+                                By default, only values where the
+                                <filename>SRCREV</filename> was not hardcoded
+                                (usually when <filename>AUTOREV</filename>
+                                is used) are reported.
+                                Use the <filename>-a</filename> option to
+                                see all <filename>SRCREV</filename> values.
+                                </para></listitem>
+                            <listitem><para>
+                                The output statements might not have any effect
+                                if overrides are applied elsewhere in the
+                                build system configuration.
+                                Use the <filename>-f</filename> option to add
+                                the <filename>forcevariable</filename> override
+                                to each output line if you need to work around
+                                this restriction.
+                                </para></listitem>
+                            <listitem><para>
+                                The script does apply special handling when
+                                building for multiple machines.
+                                However, the script does place a comment before
+                                each set of values that specifies which
+                                triplet to which they belong as previously
+                                shown (e.g.,
+                                <filename>i586-poky-linux</filename>).
+                                </para></listitem>
+                        </itemizedlist>
+                    </note>
+                </para>
+            </section>
+
+            <section id='build-history-image-information'>
+                <title>Build History Image Information</title>
+
+                <para>
+                    The files produced for each image are as follows:
+                    <itemizedlist>
+                        <listitem><para>
+                            <filename>image-files:</filename>
+                            A directory containing selected files from the root
+                            filesystem.
+                            The files are defined by
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-BUILDHISTORY_IMAGE_FILES'><filename>BUILDHISTORY_IMAGE_FILES</filename></ulink>.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>build-id.txt:</filename>
+                            Human-readable information about the build
+                            configuration and metadata source revisions.
+                            This file contains the full build header as printed
+                            by BitBake.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>*.dot:</filename>
+                            Dependency graphs for the image that are
+                            compatible with <filename>graphviz</filename>.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>files-in-image.txt:</filename>
+ 	                        A list of files in the image with permissions,
+                            owner, group, size, and symlink information.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>image-info.txt:</filename>
+                            A text file containing name-value pairs with
+                            information about the image.
+                            See the following listing example for more
+                            information.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>installed-package-names.txt:</filename>
+                            A list of installed packages by name only.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>installed-package-sizes.txt:</filename>
+                            A list of installed packages ordered by size.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>installed-packages.txt:</filename>
+                            A list of installed packages with full package
+                            filenames.
+                            </para></listitem>
+                    </itemizedlist>
+                    <note>
+                        Installed package information is able to be gathered
+                        and produced even if package management is disabled
+                        for the final image.
+                    </note>
+                </para>
+
+                <para>
+                    Here is an example of <filename>image-info.txt</filename>:
+                    <literallayout class='monospaced'>
+     DISTRO = poky
+     DISTRO_VERSION = 1.7
+     USER_CLASSES = buildstats image-mklibs image-prelink
+     IMAGE_CLASSES = image_types
+     IMAGE_FEATURES = debug-tweaks
+     IMAGE_LINGUAS =
+     IMAGE_INSTALL = packagegroup-core-boot run-postinsts
+     BAD_RECOMMENDATIONS =
+     NO_RECOMMENDATIONS =
+     PACKAGE_EXCLUDE =
+     ROOTFS_POSTPROCESS_COMMAND = write_package_manifest; license_create_manifest; \
+        write_image_manifest ; buildhistory_list_installed_image ; \
+        buildhistory_get_image_installed ; ssh_allow_empty_password;  \
+        postinst_enable_logging; rootfs_update_timestamp ; ssh_disable_dns_lookup ;
+     IMAGE_POSTPROCESS_COMMAND =   buildhistory_get_imageinfo ;
+     IMAGESIZE = 6900
+                    </literallayout>
+                    Other than <filename>IMAGESIZE</filename>, which is the
+                    total size of the files in the image in Kbytes, the
+                    name-value pairs are variables that may have influenced the
+                    content of the image.
+                    This information is often useful when you are trying to
+                    determine why a change in the package or file
+                    listings has occurred.
+                </para>
+            </section>
+
+            <section id='using-build-history-to-gather-image-information-only'>
+                <title>Using Build History to Gather Image Information Only</title>
+
+                <para>
+                    As you can see, build history produces image information,
+                    including dependency graphs, so you can see why something
+                    was pulled into the image.
+                    If you are just interested in this information and not
+                    interested in collecting specific package or SDK
+                    information, you can enable writing only image information
+                    without any history by adding the following to your
+                    <filename>conf/local.conf</filename> file found in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>:
+                    <literallayout class='monospaced'>
+     INHERIT += "buildhistory"
+     BUILDHISTORY_COMMIT = "0"
+     BUILDHISTORY_FEATURES = "image"
+                    </literallayout>
+                    Here, you set the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-BUILDHISTORY_FEATURES'><filename>BUILDHISTORY_FEATURES</filename></ulink>
+                    variable to use the image feature only.
+                </para>
+            </section>
+
+            <section id='build-history-sdk-information'>
+                <title>Build History SDK Information</title>
+
+                <para>
+                    Build history collects similar information on the contents
+                    of SDKs
+                    (e.g. <filename>bitbake -c populate_sdk imagename</filename>)
+                    as compared to information it collects for images.
+                    Furthermore, this information differs depending on whether
+                    an extensible or standard SDK is being produced.
+                </para>
+
+                <para>
+                    The following list shows the files produced for SDKs:
+                    <itemizedlist>
+                        <listitem><para>
+                            <filename>files-in-sdk.txt:</filename>
+                            A list of files in the SDK with permissions,
+                            owner, group, size, and symlink information.
+                            This list includes both the host and target parts
+                            of the SDK.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>sdk-info.txt:</filename>
+                            A text file containing name-value pairs with
+                            information about the SDK.
+                            See the following listing example for more
+                            information.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>sstate-task-sizes.txt:</filename>
+                            A text file containing name-value pairs with
+                            information about task group sizes
+                            (e.g. <filename>do_populate_sysroot</filename>
+                            tasks have a total size).
+                            The <filename>sstate-task-sizes.txt</filename> file
+                            exists only when an extensible SDK is created.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>sstate-package-sizes.txt:</filename>
+                            A text file containing name-value pairs with
+                            information for the shared-state packages and
+                            sizes in the SDK.
+                            The <filename>sstate-package-sizes.txt</filename>
+                            file exists only when an extensible SDK is created.
+                            </para></listitem>
+                        <listitem><para>
+                            <filename>sdk-files:</filename>
+                            A folder that contains copies of the files
+                            mentioned in
+                            <filename>BUILDHISTORY_SDK_FILES</filename> if the
+                            files are present in the output.
+                            Additionally, the default value of
+                            <filename>BUILDHISTORY_SDK_FILES</filename> is
+                            specific to the extensible SDK although you can
+                            set it differently if you would like to pull in
+                            specific files from the standard SDK.</para>
+
+                            <para>The default files are
+                            <filename>conf/local.conf</filename>,
+                            <filename>conf/bblayers.conf</filename>,
+                            <filename>conf/auto.conf</filename>,
+                            <filename>conf/locked-sigs.inc</filename>, and
+                            <filename>conf/devtool.conf</filename>.
+                            Thus, for an extensible SDK, these files get
+                            copied into the <filename>sdk-files</filename>
+                            directory.
+                            </para></listitem>
+                        <listitem><para>
+                            The following information appears under
+                            each of the <filename>host</filename>
+                            and <filename>target</filename> directories
+                            for the portions of the SDK that run on the host
+                            and on the target, respectively:
+                            <note>
+                                The following files for the most part are empty
+                                when producing an extensible SDK because this
+                                type of SDK is not constructed from packages
+                                as is the standard SDK.
+                            </note>
+                            <itemizedlist>
+                                <listitem><para>
+                                    <filename>depends.dot:</filename>
+                                    Dependency graph for the SDK that is
+                                    compatible with
+                                    <filename>graphviz</filename>.
+                                    </para></listitem>
+                                <listitem><para>
+                                    <filename>installed-package-names.txt:</filename>
+                                    A list of installed packages by name only.
+                                    </para></listitem>
+                                <listitem><para>
+                                    <filename>installed-package-sizes.txt:</filename>
+                                    A list of installed packages ordered by size.
+                                    </para></listitem>
+                                <listitem><para>
+                                    <filename>installed-packages.txt:</filename>
+                                    A list of installed packages with full
+                                    package filenames.
+                                    </para></listitem>
+                                </itemizedlist>
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+
+                <para>
+                    Here is an example of <filename>sdk-info.txt</filename>:
+                    <literallayout class='monospaced'>
+     DISTRO = poky
+     DISTRO_VERSION = 1.3+snapshot-20130327
+     SDK_NAME = poky-glibc-i686-arm
+     SDK_VERSION = 1.3+snapshot
+     SDKMACHINE =
+     SDKIMAGE_FEATURES = dev-pkgs dbg-pkgs
+     BAD_RECOMMENDATIONS =
+     SDKSIZE = 352712
+                    </literallayout>
+                    Other than <filename>SDKSIZE</filename>, which is the
+                    total size of the files in the SDK in Kbytes, the
+                    name-value pairs are variables that might have influenced
+                    the content of the SDK.
+                    This information is often useful when you are trying to
+                    determine why a change in the package or file listings
+                    has occurred.
+                </para>
+            </section>
+
+            <section id='examining-build-history-information'>
+                <title>Examining Build History Information</title>
+
+                <para>
+                    You can examine build history output from the command
+                    line or from a web interface.
+                </para>
+
+                <para>
+                    To see any changes that have occurred (assuming you have
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-BUILDHISTORY_COMMIT'><filename>BUILDHISTORY_COMMIT</filename></ulink><filename>&nbsp;= "1"</filename>),
+                    you can simply use any Git command that allows you to
+                    view the history of a repository.
+                    Here is one method:
+                    <literallayout class='monospaced'>
+      $ git log -p
+                    </literallayout>
+                    You need to realize, however, that this method does show
+                    changes that are not significant (e.g. a package's size
+                    changing by a few bytes).
+                </para>
+
+                <para>
+                    A command-line tool called
+                    <filename>buildhistory-diff</filename> does exist, though,
+                    that queries the Git repository and prints just the
+                    differences that might be significant in human-readable
+                    form.
+                    Here is an example:
+                    <literallayout class='monospaced'>
+     $ ~/poky/poky/scripts/buildhistory-diff . HEAD^
+     Changes to images/qemux86_64/glibc/core-image-minimal (files-in-image.txt):
+        /etc/anotherpkg.conf was added
+        /sbin/anotherpkg was added
+        * (installed-package-names.txt):
+        *   anotherpkg was added
+     Changes to images/qemux86_64/glibc/core-image-minimal (installed-package-names.txt):
+        anotherpkg was added
+     packages/qemux86_64-poky-linux/v86d: PACKAGES: added "v86d-extras"
+        * PR changed from "r0" to "r1"
+        * PV changed from "0.1.10" to "0.1.12"
+     packages/qemux86_64-poky-linux/v86d/v86d: PKGSIZE changed from 110579 to 144381 (+30%)
+        * PR changed from "r0" to "r1"
+        * PV changed from "0.1.10" to "0.1.12"
+                    </literallayout>
+                    <note>
+                        The <filename>buildhistory-diff</filename> tool
+                        requires the <filename>GitPython</filename> package.
+                        Be sure to install it using Pip3 as follows:
+                        <literallayout class='monospaced'>
+   $ pip3 install GitPython --user
+                        </literallayout>
+                        Alternatively, you can install
+                        <filename>python3-git</filename> using the appropriate
+                        distribution package manager (e.g.
+                        <filename>apt-get</filename>, <filename>dnf</filename>,
+                        or <filename>zipper</filename>).
+                    </note>
+                </para>
+
+                <para>
+                    To see changes to the build history using a web interface,
+                    follow the instruction in the <filename>README</filename>
+                    file here.
+                    <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/buildhistory-web/'></ulink>.
+                </para>
+
+                <para>
+                    Here is a sample screenshot of the interface:
+                    <imagedata fileref="figures/buildhistory-web.png" align="center" scalefit="1" width="130%" contentdepth="130%" />
+                </para>
+            </section>
+        </section>
+    </section>
+
+    <section id="performing-automated-runtime-testing">
+        <title>Performing Automated Runtime Testing</title>
+
+        <para>
+            The OpenEmbedded build system makes available a series of automated
+            tests for images to verify runtime functionality.
+            You can run these tests on either QEMU or actual target hardware.
+            Tests are written in Python making use of the
+            <filename>unittest</filename> module, and the majority of them
+            run commands on the target system over SSH.
+            This section describes how you set up the environment to use these
+            tests, run available tests, and write and add your own tests.
+        </para>
+
+        <para>
+            For information on the test and QA infrastructure available
+            within the Yocto Project, see the
+            "<ulink url='&YOCTO_DOCS_REF_URL;#testing-and-quality-assurance'>Testing and Quality Assurance</ulink>"
+            section in the Yocto Project Reference Manual.
+        </para>
+
+        <section id='enabling-tests'>
+            <title>Enabling Tests</title>
+
+            <para>
+                Depending on whether you are planning to run tests using
+                QEMU or on the hardware, you have to take
+                different steps to enable the tests.
+                See the following subsections for information on how to
+                enable both types of tests.
+            </para>
+
+            <section id='qemu-image-enabling-tests'>
+                <title>Enabling Runtime Tests on QEMU</title>
+
+                <para>
+                    In order to run tests, you need to do the following:
+                    <itemizedlist>
+                        <listitem><para><emphasis>Set up to avoid interaction
+                            with <filename>sudo</filename> for networking:</emphasis>
+                            To accomplish this, you must do one of the
+                            following:
+                            <itemizedlist>
+                                <listitem><para>Add
+                                    <filename>NOPASSWD</filename> for your user
+                                    in <filename>/etc/sudoers</filename> either for
+                                    all commands or just for
+                                    <filename>runqemu-ifup</filename>.
+                                    You must provide the full path as that can
+                                    change if you are using multiple clones of the
+                                    source repository.
+                                    <note>
+                                        On some distributions, you also need to
+                                        comment out "Defaults requiretty" in
+                                        <filename>/etc/sudoers</filename>.
+                                    </note></para></listitem>
+                                <listitem><para>Manually configure a tap interface
+                                    for your system.</para></listitem>
+                                <listitem><para>Run as root the script in
+                                    <filename>scripts/runqemu-gen-tapdevs</filename>,
+                                    which should generate a list of tap devices.
+                                    This is the option typically chosen for
+                                    Autobuilder-type environments.
+                                    <note><title>Notes</title>
+                                        <itemizedlist>
+                                            <listitem><para>
+                                                Be sure to use an absolute path
+                                                when calling this script
+                                                with sudo.
+                                                </para></listitem>
+                                            <listitem><para>
+                                                The package recipe
+                                                <filename>qemu-helper-native</filename>
+                                                is required to run this script.
+                                                Build the package using the
+                                                following command:
+                                                <literallayout class='monospaced'>
+     $ bitbake qemu-helper-native
+                                                </literallayout>
+                                                </para></listitem>
+                                        </itemizedlist>
+                                    </note>
+                                    </para></listitem>
+                            </itemizedlist></para></listitem>
+                        <listitem><para><emphasis>Set the
+                            <filename>DISPLAY</filename> variable:</emphasis>
+                            You need to set this variable so that you have an X
+                            server available (e.g. start
+                            <filename>vncserver</filename> for a headless machine).
+                            </para></listitem>
+                        <listitem><para><emphasis>Be sure your host's firewall
+                            accepts incoming connections from
+                            192.168.7.0/24:</emphasis>
+                            Some of the tests (in particular DNF tests) start
+                            an HTTP server on a random high number port,
+                            which is used to serve files to the target.
+                            The DNF module serves
+                            <filename>${WORKDIR}/oe-rootfs-repo</filename>
+                            so it can run DNF channel commands.
+                            That means your host's firewall
+                            must accept incoming connections from 192.168.7.0/24,
+                            which is the default IP range used for tap devices
+                            by <filename>runqemu</filename>.</para></listitem>
+                        <listitem><para><emphasis>Be sure your host has the
+                            correct packages installed:</emphasis>
+                            Depending your host's distribution, you need
+                            to have the following packages installed:
+                            <itemizedlist>
+                                <listitem><para>Ubuntu and Debian:
+                                    <filename>sysstat</filename> and
+                                    <filename>iproute2</filename>
+                                    </para></listitem>
+                                <listitem><para>OpenSUSE:
+                                    <filename>sysstat</filename> and
+                                    <filename>iproute2</filename>
+                                    </para></listitem>
+                                <listitem><para>Fedora:
+                                    <filename>sysstat</filename> and
+                                    <filename>iproute</filename>
+                                    </para></listitem>
+                                <listitem><para>CentOS:
+                                    <filename>sysstat</filename> and
+                                    <filename>iproute</filename>
+                                    </para></listitem>
+                            </itemizedlist>
+                        </para></listitem>
+                    </itemizedlist>
+                </para>
+
+                <para>
+                    Once you start running the tests, the following happens:
+                    <orderedlist>
+                        <listitem><para>A copy of the root filesystem is written
+                            to <filename>${WORKDIR}/testimage</filename>.
+                            </para></listitem>
+                        <listitem><para>The image is booted under QEMU using the
+                            standard <filename>runqemu</filename> script.
+                            </para></listitem>
+                        <listitem><para>A default timeout of 500 seconds occurs
+                            to allow for the boot process to reach the login prompt.
+                            You can change the timeout period by setting
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-TEST_QEMUBOOT_TIMEOUT'><filename>TEST_QEMUBOOT_TIMEOUT</filename></ulink>
+                            in the <filename>local.conf</filename> file.
+                            </para></listitem>
+                        <listitem><para>Once the boot process is reached and the
+                            login prompt appears, the tests run.
+                            The full boot log is written to
+                            <filename>${WORKDIR}/testimage/qemu_boot_log</filename>.
+                            </para></listitem>
+                        <listitem><para>Each test module loads in the order found
+                            in <filename>TEST_SUITES</filename>.
+                            You can find the full output of the commands run over
+                            SSH in
+                            <filename>${WORKDIR}/testimgage/ssh_target_log</filename>.
+                            </para></listitem>
+                        <listitem><para>If no failures occur, the task running the
+                            tests ends successfully.
+                            You can find the output from the
+                            <filename>unittest</filename> in the task log at
+                            <filename>${WORKDIR}/temp/log.do_testimage</filename>.
+                            </para></listitem>
+                    </orderedlist>
+                </para>
+            </section>
+
+            <section id='hardware-image-enabling-tests'>
+                <title>Enabling Runtime Tests on Hardware</title>
+
+                <para>
+                    The OpenEmbedded build system can run tests on real
+                    hardware, and for certain devices it can also deploy
+                    the image to be tested onto the device beforehand.
+                </para>
+
+                <para>
+                    For automated deployment, a "master image" is installed
+                    onto the hardware once as part of setup.
+                    Then, each time tests are to be run, the following
+                    occurs:
+                    <orderedlist>
+                        <listitem><para>The master image is booted into and
+                            used to write the image to be tested to
+                            a second partition.
+                            </para></listitem>
+                        <listitem><para>The device is then rebooted using an
+                            external script that you need to provide.
+                            </para></listitem>
+                        <listitem><para>The device boots into the image to be
+                            tested.
+                            </para></listitem>
+                    </orderedlist>
+                </para>
+
+                <para>
+                    When running tests (independent of whether the image
+                    has been deployed automatically or not), the device is
+                    expected to be connected to a network on a
+                    pre-determined IP address.
+                    You can either use static IP addresses written into
+                    the image, or set the image to use DHCP and have your
+                    DHCP server on the test network assign a known IP address
+                    based on the MAC address of the device.
+                </para>
+
+                <para>
+                    In order to run tests on hardware, you need to set
+                    <filename>TEST_TARGET</filename> to an appropriate value.
+                    For QEMU, you do not have to change anything, the default
+                    value is "qemu".
+                    For running tests on hardware, the following options exist:
+                    <itemizedlist>
+                        <listitem><para><emphasis>"simpleremote":</emphasis>
+                            Choose "simpleremote" if you are going to
+                            run tests on a target system that is already
+                            running the image to be tested and is available
+                            on the network.
+                            You can use "simpleremote" in conjunction
+                            with either real hardware or an image running
+                            within a separately started QEMU or any
+                            other virtual machine manager.
+                            </para></listitem>
+                        <listitem><para><emphasis>"SystemdbootTarget":</emphasis>
+                            Choose "SystemdbootTarget" if your hardware is
+                            an EFI-based machine with
+                            <filename>systemd-boot</filename> as bootloader and
+                            <filename>core-image-testmaster</filename>
+                            (or something similar) is installed.
+                            Also, your hardware under test must be in a
+                            DHCP-enabled network that gives it the same IP
+                            address for each reboot.</para>
+                            <para>If you choose "SystemdbootTarget", there are
+                            additional requirements and considerations.
+                            See the
+                            "<link linkend='selecting-systemdboottarget'>Selecting SystemdbootTarget</link>"
+                            section, which follows, for more information.
+                            </para></listitem>
+                        <listitem><para><emphasis>"BeagleBoneTarget":</emphasis>
+                            Choose "BeagleBoneTarget" if you are deploying
+                            images and running tests on the BeagleBone
+                            "Black" or original "White" hardware.
+                            For information on how to use these tests, see the
+                            comments at the top of the BeagleBoneTarget
+                            <filename>meta-yocto-bsp/lib/oeqa/controllers/beaglebonetarget.py</filename>
+                            file.
+                            </para></listitem>
+                        <listitem><para><emphasis>"EdgeRouterTarget":</emphasis>
+                            Choose "EdgeRouterTarget" is you are deploying
+                            images and running tests on the Ubiquiti Networks
+                            EdgeRouter Lite.
+                            For information on how to use these tests, see the
+                            comments at the top of the EdgeRouterTarget
+                            <filename>meta-yocto-bsp/lib/oeqa/controllers/edgeroutertarget.py</filename>
+                            file.
+                            </para></listitem>
+                        <listitem><para><emphasis>"GrubTarget":</emphasis>
+                            Choose the "supports deploying images and running
+                            tests on any generic PC that boots using GRUB.
+                            For information on how to use these tests, see the
+                            comments at the top of the GrubTarget
+                            <filename>meta-yocto-bsp/lib/oeqa/controllers/grubtarget.py</filename>
+                            file.
+                            </para></listitem>
+                        <listitem><para><emphasis>"<replaceable>your-target</replaceable>":</emphasis>
+                            Create your own custom target if you want to run
+                            tests when you are deploying images and running
+                            tests on a custom machine within your BSP layer.
+                            To do this, you need to add a Python unit that
+                            defines the target class under
+                            <filename>lib/oeqa/controllers/</filename> within
+                            your layer.
+                            You must also provide an empty
+                            <filename>__init__.py</filename>.
+                            For examples, see files in
+                            <filename>meta-yocto-bsp/lib/oeqa/controllers/</filename>.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='selecting-systemdboottarget'>
+                <title>Selecting SystemdbootTarget</title>
+
+                <para>
+                    If you did not set <filename>TEST_TARGET</filename> to
+                    "SystemdbootTarget", then you do not need any information
+                    in this section.
+                    You can skip down to the
+                    "<link linkend='qemu-image-running-tests'>Running Tests</link>"
+                    section.
+                </para>
+
+                <para>
+                    If you did set <filename>TEST_TARGET</filename> to
+                    "SystemdbootTarget", you also need to perform a one-time
+                    setup of your master image by doing the following:
+                    <orderedlist>
+                        <listitem><para><emphasis>Set <filename>EFI_PROVIDER</filename>:</emphasis>
+                            Be sure that <filename>EFI_PROVIDER</filename>
+                            is as follows:
+                            <literallayout class='monospaced'>
+     EFI_PROVIDER = "systemd-boot"
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para><emphasis>Build the master image:</emphasis>
+                            Build the <filename>core-image-testmaster</filename>
+                            image.
+                            The <filename>core-image-testmaster</filename>
+                            recipe is provided as an example for a
+                            "master" image and you can customize the image
+                            recipe as you would any other recipe.
+                            </para>
+                            <para>Here are the image recipe requirements:
+                            <itemizedlist>
+                                <listitem><para>Inherits
+                                    <filename>core-image</filename>
+                                    so that kernel modules are installed.
+                                    </para></listitem>
+                                <listitem><para>Installs normal linux utilities
+                                    not busybox ones (e.g.
+                                    <filename>bash</filename>,
+                                    <filename>coreutils</filename>,
+                                    <filename>tar</filename>,
+                                    <filename>gzip</filename>, and
+                                    <filename>kmod</filename>).
+                                    </para></listitem>
+                                <listitem><para>Uses a custom
+                                    Initial RAM Disk (initramfs) image with a
+                                    custom installer.
+                                    A normal image that you can install usually
+                                    creates a single rootfs partition.
+                                    This image uses another installer that
+                                    creates a specific partition layout.
+                                    Not all Board Support Packages (BSPs)
+                                    can use an installer.
+                                    For such cases, you need to manually create
+                                    the following partition layout on the
+                                    target:
+                                    <itemizedlist>
+                                        <listitem><para>First partition mounted
+                                            under <filename>/boot</filename>,
+                                            labeled "boot".
+                                            </para></listitem>
+                                        <listitem><para>The main rootfs
+                                            partition where this image gets
+                                            installed, which is mounted under
+                                            <filename>/</filename>.
+                                            </para></listitem>
+                                        <listitem><para>Another partition
+                                            labeled "testrootfs" where test
+                                            images get deployed.
+                                            </para></listitem>
+                                    </itemizedlist>
+                                    </para></listitem>
+                            </itemizedlist>
+                            </para></listitem>
+                        <listitem><para><emphasis>Install image:</emphasis>
+                            Install the image that you just built on the target
+                            system.
+                            </para></listitem>
+                    </orderedlist>
+                </para>
+
+                <para>
+                    The final thing you need to do when setting
+                    <filename>TEST_TARGET</filename> to "SystemdbootTarget" is
+                    to set up the test image:
+                    <orderedlist>
+                        <listitem><para><emphasis>Set up your <filename>local.conf</filename> file:</emphasis>
+                            Make sure you have the following statements in
+                            your <filename>local.conf</filename> file:
+                            <literallayout class='monospaced'>
+     IMAGE_FSTYPES += "tar.gz"
+     INHERIT += "testimage"
+     TEST_TARGET = "SystemdbootTarget"
+     TEST_TARGET_IP = "192.168.2.3"
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para><emphasis>Build your test image:</emphasis>
+                            Use BitBake to build the image:
+                            <literallayout class='monospaced'>
+     $ bitbake core-image-sato
+                            </literallayout>
+                            </para></listitem>
+                    </orderedlist>
+                </para>
+            </section>
+
+            <section id='power-control'>
+                <title>Power Control</title>
+
+                <para>
+                    For most hardware targets other than "simpleremote",
+                    you can control power:
+                    <itemizedlist>
+                        <listitem><para>
+                            You can use
+                            <filename>TEST_POWERCONTROL_CMD</filename>
+                            together with
+                            <filename>TEST_POWERCONTROL_EXTRA_ARGS</filename>
+                            as a command that runs on the host and does power
+                            cycling.
+                            The test code passes one argument to that command:
+                            off, on or cycle (off then on).
+                            Here is an example that could appear in your
+                            <filename>local.conf</filename> file:
+                            <literallayout class='monospaced'>
+     TEST_POWERCONTROL_CMD = "powercontrol.exp test 10.11.12.1 nuc1"
+                            </literallayout>
+                            In this example, the expect script does the
+                            following:
+                            <literallayout class='monospaced'>
+     ssh test@10.11.12.1 "pyctl nuc1 <replaceable>arg</replaceable>"
+                            </literallayout>
+                            It then runs a Python script that controls power
+                            for a label called <filename>nuc1</filename>.
+                            <note>
+                                You need to customize
+                                <filename>TEST_POWERCONTROL_CMD</filename>
+                                and
+                                <filename>TEST_POWERCONTROL_EXTRA_ARGS</filename>
+                                for your own setup.
+                                The one requirement is that it accepts
+                                "on", "off", and "cycle" as the last argument.
+                            </note>
+                            </para></listitem>
+                        <listitem><para>
+                            When no command is defined, it connects to the
+                            device over SSH and uses the classic reboot command
+                            to reboot the device.
+                            Classic reboot is fine as long as the machine
+                            actually reboots (i.e. the SSH test has not
+                            failed).
+                            It is useful for scenarios where you have a simple
+                            setup, typically with a single board, and where
+                            some manual interaction is okay from time to time.
+                            </para></listitem>
+                    </itemizedlist>
+                    If you have no hardware to automatically perform power
+                    control but still wish to experiment with automated
+                    hardware testing, you can use the dialog-power-control
+                    script that shows a dialog prompting you to perform the
+                    required power action.
+                    This script requires either KDialog or Zenity to be
+                    installed.
+                    To use this script, set the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-TEST_POWERCONTROL_CMD'><filename>TEST_POWERCONTROL_CMD</filename></ulink>
+                    variable as follows:
+                    <literallayout class='monospaced'>
+     TEST_POWERCONTROL_CMD = "${COREBASE}/scripts/contrib/dialog-power-control"
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='serial-console-connection'>
+                <title>Serial Console Connection</title>
+
+                <para>
+                    For test target classes requiring a serial console
+                    to interact with the bootloader (e.g. BeagleBoneTarget,
+                    EdgeRouterTarget, and GrubTarget), you need to
+                    specify a command to use to connect to the serial console
+                    of the target machine by using the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-TEST_SERIALCONTROL_CMD'><filename>TEST_SERIALCONTROL_CMD</filename></ulink>
+                    variable and optionally the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-TEST_SERIALCONTROL_EXTRA_ARGS'><filename>TEST_SERIALCONTROL_EXTRA_ARGS</filename></ulink>
+                    variable.
+                </para>
+
+                <para>
+                    These cases could be a serial terminal program if the
+                    machine is connected to a local serial port, or a
+                    <filename>telnet</filename> or
+                    <filename>ssh</filename> command connecting to a remote
+                    console server.
+                    Regardless of the case, the command simply needs to
+                    connect to the serial console and forward that connection
+                    to standard input and output as any normal terminal
+                    program does.
+                    For example, to use the picocom terminal program on
+                    serial device <filename>/dev/ttyUSB0</filename>
+                    at 115200bps, you would set the variable as follows:
+                    <literallayout class='monospaced'>
+     TEST_SERIALCONTROL_CMD = "picocom /dev/ttyUSB0 -b 115200"
+                    </literallayout>
+                    For local devices where the serial port device disappears
+                    when the device reboots, an additional "serdevtry" wrapper
+                    script is provided.
+                    To use this wrapper, simply prefix the terminal command
+                    with
+                    <filename>${COREBASE}/scripts/contrib/serdevtry</filename>:
+                    <literallayout class='monospaced'>
+     TEST_SERIALCONTROL_CMD = "${COREBASE}/scripts/contrib/serdevtry picocom -b
+115200 /dev/ttyUSB0"
+                    </literallayout>
+                </para>
+            </section>
+        </section>
+
+        <section id="qemu-image-running-tests">
+            <title>Running Tests</title>
+
+            <para>
+                You can start the tests automatically or manually:
+                <itemizedlist>
+                    <listitem><para><emphasis>Automatically running tests:</emphasis>
+                        To run the tests automatically after the
+                        OpenEmbedded build system successfully creates an image,
+                        first set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-TESTIMAGE_AUTO'><filename>TESTIMAGE_AUTO</filename></ulink>
+                        variable to "1" in your <filename>local.conf</filename>
+                        file in the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>:
+                        <literallayout class='monospaced'>
+     TESTIMAGE_AUTO = "1"
+                        </literallayout>
+                        Next, build your image.
+                        If the image successfully builds, the tests run:
+                        <literallayout class='monospaced'>
+     bitbake core-image-sato
+                        </literallayout></para></listitem>
+                    <listitem><para><emphasis>Manually running tests:</emphasis>
+                        To manually run the tests, first globally inherit the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-testimage*'><filename>testimage</filename></ulink>
+                        class by editing your <filename>local.conf</filename>
+                        file:
+                        <literallayout class='monospaced'>
+    INHERIT += "testimage"
+                        </literallayout>
+                        Next, use BitBake to run the tests:
+                        <literallayout class='monospaced'>
+     bitbake -c testimage <replaceable>image</replaceable>
+                        </literallayout></para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                All test files reside in
+                <filename>meta/lib/oeqa/runtime</filename> in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
+                A test name maps directly to a Python module.
+                Each test module may contain a number of individual tests.
+                Tests are usually grouped together by the area
+                tested (e.g tests for systemd reside in
+                <filename>meta/lib/oeqa/runtime/systemd.py</filename>).
+            </para>
+
+            <para>
+                You can add tests to any layer provided you place them in the
+                proper area and you extend
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBPATH'><filename>BBPATH</filename></ulink>
+                in the <filename>local.conf</filename> file as normal.
+                Be sure that tests reside in
+                <filename><replaceable>layer</replaceable>/lib/oeqa/runtime</filename>.
+                <note>
+                    Be sure that module names do not collide with module names
+                    used in the default set of test modules in
+                    <filename>meta/lib/oeqa/runtime</filename>.
+                </note>
+            </para>
+
+            <para>
+                You can change the set of tests run by appending or overriding
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-TEST_SUITES'><filename>TEST_SUITES</filename></ulink>
+                variable in <filename>local.conf</filename>.
+                Each name in <filename>TEST_SUITES</filename> represents a
+                required test for the image.
+                Test modules named within <filename>TEST_SUITES</filename>
+                cannot be skipped even if a test is not suitable for an image
+                (e.g. running the RPM tests on an image without
+                <filename>rpm</filename>).
+                Appending "auto" to <filename>TEST_SUITES</filename> causes the
+                build system to try to run all tests that are suitable for the
+                image (i.e. each test module may elect to skip itself).
+            </para>
+
+            <para>
+                The order you list tests in <filename>TEST_SUITES</filename>
+                is important and influences test dependencies.
+                Consequently, tests that depend on other tests should be added
+                after the test on which they depend.
+                For example, since the <filename>ssh</filename> test
+                depends on the
+                <filename>ping</filename> test, "ssh" needs to come after
+                "ping" in the list.
+                The test class provides no re-ordering or dependency handling.
+                <note>
+                    Each module can have multiple classes with multiple test
+                    methods.
+                    And, Python <filename>unittest</filename> rules apply.
+                </note>
+            </para>
+
+            <para>
+                Here are some things to keep in mind when running tests:
+                <itemizedlist>
+                    <listitem><para>The default tests for the image are defined
+                        as:
+                        <literallayout class='monospaced'>
+     DEFAULT_TEST_SUITES_pn-<replaceable>image</replaceable> = "ping ssh df connman syslog xorg scp vnc date rpm dnf dmesg"
+                        </literallayout></para></listitem>
+                    <listitem><para>Add your own test to the list of the
+                        by using the following:
+                        <literallayout class='monospaced'>
+     TEST_SUITES_append = " mytest"
+                        </literallayout></para></listitem>
+                    <listitem><para>Run a specific list of tests as follows:
+                        <literallayout class='monospaced'>
+     TEST_SUITES = "test1 test2 test3"
+                        </literallayout>
+                        Remember, order is important.
+                        Be sure to place a test that is dependent on another test
+                        later in the order.</para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id="exporting-tests">
+            <title>Exporting Tests</title>
+
+            <para>
+                You can export tests so that they can run independently of
+                the build system.
+                Exporting tests is required if you want to be able to hand
+                the test execution off to a scheduler.
+                You can only export tests that are defined in
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-TEST_SUITES'><filename>TEST_SUITES</filename></ulink>.
+            </para>
+
+            <para>
+                If your image is already built, make sure the following are set
+                in your <filename>local.conf</filename> file:
+                <literallayout class='monospaced'>
+     INHERIT +="testexport"
+     TEST_TARGET_IP = "<replaceable>IP-address-for-the-test-target</replaceable>"
+     TEST_SERVER_IP = "<replaceable>IP-address-for-the-test-server</replaceable>"
+                </literallayout>
+                You can then export the tests with the following BitBake
+                command form:
+                <literallayout class='monospaced'>
+     $ bitbake <replaceable>image</replaceable> -c testexport
+                </literallayout>
+                Exporting the tests places them in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                in
+                <filename>tmp/testexport/</filename><replaceable>image</replaceable>,
+                which is controlled by the
+                <filename>TEST_EXPORT_DIR</filename> variable.
+            </para>
+
+            <para>
+                You can now run the tests outside of the build environment:
+                <literallayout class='monospaced'>
+     $ cd tmp/testexport/<replaceable>image</replaceable>
+     $ ./runexported.py testdata.json
+                </literallayout>
+            </para>
+
+            <para>
+                Here is a complete example that shows IP addresses and uses
+                the <filename>core-image-sato</filename> image:
+                <literallayout class='monospaced'>
+     INHERIT +="testexport"
+     TEST_TARGET_IP = "192.168.7.2"
+     TEST_SERVER_IP = "192.168.7.1"
+                </literallayout>
+                Use BitBake to export the tests:
+                <literallayout class='monospaced'>
+     $ bitbake core-image-sato -c testexport
+                </literallayout>
+                Run the tests outside of the build environment using the
+                following:
+                <literallayout class='monospaced'>
+     $ cd tmp/testexport/core-image-sato
+     $ ./runexported.py testdata.json
+                </literallayout>
+            </para>
+        </section>
+
+        <section id="qemu-image-writing-new-tests">
+            <title>Writing New Tests</title>
+
+            <para>
+                As mentioned previously, all new test files need to be in the
+                proper place for the build system to find them.
+                New tests for additional functionality outside of the core
+                should be added to the layer that adds the functionality, in
+                <filename><replaceable>layer</replaceable>/lib/oeqa/runtime</filename>
+                (as long as
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-BBPATH'><filename>BBPATH</filename></ulink>
+                is extended in the layer's
+                <filename>layer.conf</filename> file as normal).
+                Just remember the following:
+                <itemizedlist>
+                    <listitem><para>Filenames need to map directly to test
+                        (module) names.
+                        </para></listitem>
+                    <listitem><para>Do not use module names that
+                        collide with existing core tests.
+                        </para></listitem>
+                    <listitem><para>Minimally, an empty
+                        <filename>__init__.py</filename> file must exist
+                        in the runtime directory.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                To create a new test, start by copying an existing module
+                (e.g. <filename>syslog.py</filename> or
+                <filename>gcc.py</filename> are good ones to use).
+                Test modules can use code from
+                <filename>meta/lib/oeqa/utils</filename>, which are helper
+                classes.
+            </para>
+
+            <note>
+                Structure shell commands such that you rely on them and they
+                return a single code for success.
+                Be aware that sometimes you will need to parse the output.
+                See the <filename>df.py</filename> and
+                <filename>date.py</filename> modules for examples.
+            </note>
+
+            <para>
+                You will notice that all test classes inherit
+                <filename>oeRuntimeTest</filename>, which is found in
+                <filename>meta/lib/oetest.py</filename>.
+                This base class offers some helper attributes, which are
+                described in the following sections:
+            </para>
+
+            <section id='qemu-image-writing-tests-class-methods'>
+                <title>Class Methods</title>
+
+                <para>
+                    Class methods are as follows:
+                    <itemizedlist>
+                        <listitem><para><emphasis><filename>hasPackage(pkg)</filename>:</emphasis>
+                            Returns "True" if <filename>pkg</filename> is in the
+                            installed package list of the image, which is based
+                            on the manifest file that is generated during the
+                            <filename>do_rootfs</filename> task.
+                            </para></listitem>
+                        <listitem><para><emphasis><filename>hasFeature(feature)</filename>:</emphasis>
+                            Returns "True" if the feature is in
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></ulink>
+                            or
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></ulink>.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='qemu-image-writing-tests-class-attributes'>
+                <title>Class Attributes</title>
+
+                <para>
+                    Class attributes are as follows:
+                    <itemizedlist>
+                        <listitem><para><emphasis><filename>pscmd</filename>:</emphasis>
+                            Equals "ps -ef" if <filename>procps</filename> is
+                            installed in the image.
+                            Otherwise, <filename>pscmd</filename> equals
+                            "ps" (busybox).
+                            </para></listitem>
+                        <listitem><para><emphasis><filename>tc</filename>:</emphasis>
+                            The called test context, which gives access to the
+                            following attributes:
+                            <itemizedlist>
+                                <listitem><para><emphasis><filename>d</filename>:</emphasis>
+                                    The BitBake datastore, which allows you to
+                                    use stuff such as
+                                    <filename>oeRuntimeTest.tc.d.getVar("VIRTUAL-RUNTIME_init_manager")</filename>.
+                                    </para></listitem>
+                                <listitem><para><emphasis><filename>testslist</filename> and <filename>testsrequired</filename>:</emphasis>
+                                    Used internally.
+                                    The tests do not need these.
+                                    </para></listitem>
+                                <listitem><para><emphasis><filename>filesdir</filename>:</emphasis>
+                                    The absolute path to
+                                    <filename>meta/lib/oeqa/runtime/files</filename>,
+                                    which contains helper files for tests meant
+                                    for copying on the target such as small
+                                    files written in C for compilation.
+                                    </para></listitem>
+                                <listitem><para><emphasis><filename>target</filename>:</emphasis>
+                                    The target controller object used to deploy
+                                    and start an image on a particular target
+                                    (e.g. Qemu, SimpleRemote, and
+                                    SystemdbootTarget).
+                                    Tests usually use the following:
+                                    <itemizedlist>
+                                        <listitem><para><emphasis><filename>ip</filename>:</emphasis>
+                                            The target's IP address.
+                                            </para></listitem>
+                                        <listitem><para><emphasis><filename>server_ip</filename>:</emphasis>
+                                            The host's IP address, which is
+                                            usually used by the DNF test
+                                            suite.
+                                            </para></listitem>
+                                        <listitem><para><emphasis><filename>run(cmd, timeout=None)</filename>:</emphasis>
+                                            The single, most used method.
+                                            This command is a wrapper for:
+                                            <filename>ssh root@host "cmd"</filename>.
+                                            The command returns a tuple:
+                                            (status, output), which are what
+                                            their names imply - the return code
+                                            of "cmd" and whatever output
+                                            it produces.
+                                            The optional timeout argument
+                                            represents the number of seconds the
+                                            test should wait for "cmd" to
+                                            return.
+                                            If the argument is "None", the
+                                            test uses the default instance's
+                                            timeout period, which is 300
+                                            seconds.
+                                            If the argument is "0", the test
+                                            runs until the command returns.
+                                            </para></listitem>
+                                        <listitem><para><emphasis><filename>copy_to(localpath, remotepath)</filename>:</emphasis>
+                                            <filename>scp localpath root@ip:remotepath</filename>.
+                                            </para></listitem>
+                                        <listitem><para><emphasis><filename>copy_from(remotepath, localpath)</filename>:</emphasis>
+                                            <filename>scp root@host:remotepath localpath</filename>.
+                                            </para></listitem>
+                                    </itemizedlist></para></listitem>
+                            </itemizedlist></para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id='qemu-image-writing-tests-instance-attributes'>
+                <title>Instance Attributes</title>
+
+                <para>
+                    A single instance attribute exists, which is
+                    <filename>target</filename>.
+                    The <filename>target</filename> instance attribute is
+                    identical to the class attribute of the same name, which
+                    is described in the previous section.
+                    This attribute exists as both an instance and class
+                    attribute so tests can use
+                    <filename>self.target.run(cmd)</filename> in instance
+                    methods instead of
+                    <filename>oeRuntimeTest.tc.target.run(cmd)</filename>.
+                </para>
+            </section>
+        </section>
+
+        <section id='installing-packages-in-the-dut-without-the-package-manager'>
+            <title>Installing Packages in the DUT Without the Package Manager</title>
+
+            <para>
+                When a test requires a package built by BitBake, it is possible
+                to install that package.
+                Installing the package does not require a package manager be
+                installed in the device under test (DUT).
+                It does, however, require an SSH connection and the target must
+                be using the <filename>sshcontrol</filename> class.
+                <note>
+                    This method uses <filename>scp</filename> to copy files
+                    from the host to the target, which causes permissions and
+                    special attributes to be lost.
+                </note>
+            </para>
+
+            <para>
+                A JSON file is used to define the packages needed by a test.
+                This file must be in the same path as the file used to define
+                the tests.
+                Furthermore, the filename must map directly to the test
+                module name with a <filename>.json</filename> extension.
+            </para>
+
+            <para>
+                The JSON file must include an object with the test name as
+                keys of an object or an array.
+                This object (or array of objects) uses the following data:
+                <itemizedlist>
+                    <listitem><para>"pkg" - A mandatory string that is the
+                        name of the package to be installed.
+                        </para></listitem>
+                    <listitem><para>"rm" - An optional boolean, which defaults
+                        to "false", that specifies to remove the package after
+                        the test.
+                        </para></listitem>
+                    <listitem><para>"extract" - An optional boolean, which
+                        defaults to "false", that specifies if the package must
+                        be extracted from the package format.
+                        When set to "true", the package is not automatically
+                        installed into the DUT.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Following is an example JSON file that handles test "foo"
+                installing package "bar" and test "foobar" installing
+                packages "foo" and "bar".
+                Once the test is complete, the packages are removed from the
+                DUT.
+                <literallayout class='monospaced'>
+     {
+         "foo": {
+             "pkg": "bar"
+         },
+         "foobar": [
+             {
+                 "pkg": "foo",
+                 "rm": true
+             },
+             {
+                 "pkg": "bar",
+                 "rm": true
+             }
+         ]
+     }
+                </literallayout>
+            </para>
+        </section>
+    </section>
+
+    <section id='usingpoky-debugging-tools-and-techniques'>
+        <title>Debugging Tools and Techniques</title>
+
+        <para>
+            The exact method for debugging build failures depends on the nature
+            of the problem and on the system's area from which the bug
+            originates.
+            Standard debugging practices such as comparison against the last
+            known working version with examination of the changes and the
+            re-application of steps to identify the one causing the problem are
+            valid for the Yocto Project just as they are for any other system.
+            Even though it is impossible to detail every possible potential
+            failure, this section provides some general tips to aid in
+            debugging given a variety of situations.
+            <note><title>Tip</title>
+                A useful feature for debugging is the error reporting tool.
+                Configuring the Yocto Project to use this tool causes the
+                OpenEmbedded build system to produce error reporting commands as
+                part of the console output.
+                You can enter the commands after the build completes to log
+                error information into a common database, that can help you
+                figure out what might be going wrong.
+                For information on how to enable and use this feature, see the
+                "<link linkend='using-the-error-reporting-tool'>Using the Error Reporting Tool</link>"
+                section.
+            </note>
+        </para>
+
+        <para>
+            The following list shows the debugging topics in the remainder of
+            this section:
+            <itemizedlist>
+                <listitem><para>
+                    "<link linkend='dev-debugging-viewing-logs-from-failed-tasks'>Viewing Logs from Failed Tasks</link>"
+                    describes how to find and view logs from tasks that
+                    failed during the build process.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='dev-debugging-viewing-variable-values'>Viewing Variable Values</link>"
+                    describes how to use the BitBake <filename>-e</filename>
+                    option to examine variable values after a recipe has been
+                    parsed.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='viewing-package-information-with-oe-pkgdata-util'>Viewing Package Information with <filename>oe-pkgdata-util</filename></link>"
+                    describes how to use the
+                    <filename>oe-pkgdata-util</filename> utility to query
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PKGDATA_DIR'><filename>PKGDATA_DIR</filename></ulink>
+                    and display package-related information for built
+                    packages.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='dev-viewing-dependencies-between-recipes-and-tasks'>Viewing Dependencies Between Recipes and Tasks</link>"
+                    describes how to use the BitBake <filename>-g</filename>
+                    option to display recipe dependency information used
+                    during the build.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='dev-viewing-task-variable-dependencies'>Viewing Task Variable Dependencies</link>"
+                    describes how to use the
+                    <filename>bitbake-dumpsig</filename> command in
+                    conjunction with key subdirectories in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                    to determine variable dependencies.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='dev-debugging-taskrunning'>Running Specific Tasks</link>"
+                    describes how to use several BitBake options (e.g.
+                    <filename>-c</filename>, <filename>-C</filename>, and
+                    <filename>-f</filename>) to run specific tasks in the
+                    build chain.
+                    It can be useful to run tasks "out-of-order" when trying
+                    isolate build issues.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='dev-debugging-bitbake'>General BitBake Problems</link>"
+                    describes how to use BitBake's <filename>-D</filename>
+                    debug output option to reveal more about what BitBake is
+                    doing during the build.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='dev-debugging-buildfile'>Building with No Dependencies</link>"
+                    describes how to use the BitBake <filename>-b</filename>
+                    option to build a recipe while ignoring dependencies.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='recipe-logging-mechanisms'>Recipe Logging Mechanisms</link>"
+                    describes how to use the many recipe logging functions
+                    to produce debugging output and report errors and warnings.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='debugging-parallel-make-races'>Debugging Parallel Make Races</link>"
+                    describes how to debug situations where the build consists
+                    of several parts that are run simultaneously and when the
+                    output or result of one part is not ready for use with a
+                    different part of the build that depends on that output.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='platdev-gdb-remotedebug'>Debugging With the GNU Project Debugger (GDB) Remotely</link>"
+                    describes how to use GDB to allow you to examine running
+                    programs, which can help you fix problems.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='debugging-with-the-gnu-project-debugger-gdb-on-the-target'>Debugging with the GNU Project Debugger (GDB) on the Target</link>"
+                    describes how to use GDB directly on target hardware for
+                    debugging.
+                    </para></listitem>
+                <listitem><para>
+                    "<link linkend='dev-other-debugging-others'>Other Debugging Tips</link>"
+                    describes miscellaneous debugging tips that can be useful.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <section id='dev-debugging-viewing-logs-from-failed-tasks'>
+            <title>Viewing Logs from Failed Tasks</title>
+
+            <para>
+                You can find the log for a task in the file
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink><filename>}/temp/log.do_</filename><replaceable>taskname</replaceable>.
+                For example, the log for the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-compile'><filename>do_compile</filename></ulink>
+                task of the QEMU minimal image for the x86 machine
+                (<filename>qemux86</filename>) might be in
+                <filename>tmp/work/qemux86-poky-linux/core-image-minimal/1.0-r0/temp/log.do_compile</filename>.
+                To see the commands
+                <ulink url='&YOCTO_DOCS_REF_URL;#bitbake-term'>BitBake</ulink>
+                ran to generate a log, look at the corresponding
+                <filename>run.do_</filename><replaceable>taskname</replaceable>
+                file in the same directory.
+            </para>
+
+            <para>
+                <filename>log.do_</filename><replaceable>taskname</replaceable>
+                and
+                <filename>run.do_</filename><replaceable>taskname</replaceable>
+                are actually symbolic links to
+                <filename>log.do_</filename><replaceable>taskname</replaceable><filename>.</filename><replaceable>pid</replaceable>
+                and
+                <filename>log.run_</filename><replaceable>taskname</replaceable><filename>.</filename><replaceable>pid</replaceable>,
+                where <replaceable>pid</replaceable> is the PID the task had
+                when it ran.
+                The symlinks always point to the files corresponding to the most
+                recent run.
+            </para>
+        </section>
+
+        <section id='dev-debugging-viewing-variable-values'>
+            <title>Viewing Variable Values</title>
+
+            <para>
+                Sometimes you need to know the value of a variable as a
+                result of BitBake's parsing step.
+                This could be because some unexpected behavior occurred
+                in your project.
+                Perhaps an attempt to
+                <ulink url='&YOCTO_DOCS_BB_URL;#modifying-existing-variables'>modify a variable</ulink>
+                did not work out as expected.
+            </para>
+
+            <para>
+                BitBake's <filename>-e</filename> option is used to display
+                variable values after parsing.
+                The following command displays the variable values after the
+                configuration files (i.e. <filename>local.conf</filename>,
+                <filename>bblayers.conf</filename>,
+                <filename>bitbake.conf</filename> and so forth) have been
+                parsed:
+                <literallayout class='monospaced'>
+     $ bitbake -e
+                </literallayout>
+                The following command displays variable values after a specific
+                recipe has been parsed.
+                The variables include those from the configuration as well:
+                <literallayout class='monospaced'>
+     $ bitbake -e recipename
+                </literallayout>
+                <note><para>
+                    Each recipe has its own private set of variables
+                    (datastore).
+                    Internally, after parsing the configuration, a copy of the
+                    resulting datastore is made prior to parsing each recipe.
+                    This copying implies that variables set in one recipe will
+                    not be visible to other recipes.</para>
+
+                    <para>Likewise, each task within a recipe gets a private
+                    datastore based on the recipe datastore, which means that
+                    variables set within one task will not be visible to
+                    other tasks.</para>
+                </note>
+            </para>
+
+            <para>
+                In the output of <filename>bitbake -e</filename>, each
+                variable is preceded by a description of how the variable
+                got its value, including temporary values that were later
+                overriden.
+                This description also includes variable flags (varflags) set on
+                the variable.
+                The output can be very helpful during debugging.
+            </para>
+
+            <para>
+                Variables that are exported to the environment are preceded by
+                <filename>export</filename> in the output of
+                <filename>bitbake -e</filename>.
+                See the following example:
+                <literallayout class='monospaced'>
+     export CC="i586-poky-linux-gcc -m32 -march=i586 --sysroot=/home/ulf/poky/build/tmp/sysroots/qemux86"
+                </literallayout>
+            </para>
+
+            <para>
+                In addition to variable values, the output of the
+                <filename>bitbake -e</filename> and
+                <filename>bitbake -e</filename>&nbsp;<replaceable>recipe</replaceable>
+                commands includes the following information:
+                <itemizedlist>
+                    <listitem><para>
+                        The output starts with a tree listing all configuration
+                        files and classes included globally, recursively listing
+                        the files they include or inherit in turn.
+                        Much of the behavior of the OpenEmbedded build system
+                        (including the behavior of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#normal-recipe-build-tasks'>normal recipe build tasks</ulink>)
+                        is implemented in the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-base'><filename>base</filename></ulink>
+                        class and the classes it inherits, rather than being
+                        built into BitBake itself.
+                        </para></listitem>
+                    <listitem><para>
+                        After the variable values, all functions appear in the
+                        output.
+                        For shell functions, variables referenced within the
+                        function body are expanded.
+                        If a function has been modified using overrides or
+                        using override-style operators like
+                        <filename>_append</filename> and
+                        <filename>_prepend</filename>, then the final assembled
+                        function body appears in the output.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='viewing-package-information-with-oe-pkgdata-util'>
+            <title>Viewing Package Information with <filename>oe-pkgdata-util</filename></title>
+
+            <para>
+                You can use the <filename>oe-pkgdata-util</filename>
+                command-line utility to query
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-PKGDATA_DIR'><filename>PKGDATA_DIR</filename></ulink>
+                and display various package-related information.
+                When you use the utility, you must use it to view information
+                on packages that have already been built.
+            </para>
+
+            <para>
+                Following are a few of the available
+                <filename>oe-pkgdata-util</filename> subcommands.
+                <note>
+                    You can use the standard * and ? globbing wildcards as part
+                    of package names and paths.
+                </note>
+                <itemizedlist>
+                    <listitem><para>
+                        <filename>oe-pkgdata-util list-pkgs [</filename><replaceable>pattern</replaceable><filename>]</filename>:
+                        Lists all packages that have been built, optionally
+                        limiting the match to packages that match
+                        <replaceable>pattern</replaceable>.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>oe-pkgdata-util list-pkg-files&nbsp;</filename><replaceable>package</replaceable><filename>&nbsp;...</filename>:
+                        Lists the files and directories contained in the given
+                        packages.
+                        <note>
+                            <para>
+                            A different way to view the contents of a package is
+                            to look at the
+                            <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink><filename>}/packages-split</filename>
+                            directory of the recipe that generates the
+                            package.
+                            This directory is created by the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>
+                            task and has one subdirectory for each package the
+                            recipe generates, which contains the files stored in
+                            that package.</para>
+                            <para>
+                            If you want to inspect the
+                            <filename>${WORKDIR}/packages-split</filename>
+                            directory, make sure that
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-rm-work'><filename>rm_work</filename></ulink>
+                            is not enabled when you build the recipe.
+                            </para>
+                            </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>oe-pkgdata-util find-path&nbsp;</filename><replaceable>path</replaceable><filename>&nbsp;...</filename>:
+                        Lists the names of the packages that contain the given
+                        paths.
+                        For example, the following tells us that
+                        <filename>/usr/share/man/man1/make.1</filename>
+                        is contained in the <filename>make-doc</filename>
+                        package:
+                        <literallayout class='monospaced'>
+     $ oe-pkgdata-util find-path /usr/share/man/man1/make.1
+     make-doc: /usr/share/man/man1/make.1
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>oe-pkgdata-util lookup-recipe&nbsp;</filename><replaceable>package</replaceable><filename>&nbsp;...</filename>:
+                        Lists the name of the recipes that
+                        produce the given packages.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                For more information on the <filename>oe-pkgdata-util</filename>
+                command, use the help facility:
+                <literallayout class='monospaced'>
+     $ oe-pkgdata-util &dash;&dash;help
+     $ oe-pkgdata-util <replaceable>subcommand</replaceable> --help
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='dev-viewing-dependencies-between-recipes-and-tasks'>
+            <title>Viewing Dependencies Between Recipes and Tasks</title>
+
+            <para>
+                Sometimes it can be hard to see why BitBake wants to build other
+                recipes before the one you have specified.
+                Dependency information can help you understand why a recipe is
+                built.
+            </para>
+
+            <para>
+                To generate dependency information for a recipe, run the
+                following command:
+                <literallayout class='monospaced'>
+     $ bitbake -g <replaceable>recipename</replaceable>
+                </literallayout>
+                This command writes the following files in the current
+                directory:
+                <itemizedlist>
+                    <listitem><para>
+                        <filename>pn-buildlist</filename>: A list of
+                        recipes/targets involved in building
+                        <replaceable>recipename</replaceable>.
+                        "Involved" here means that at least one task from the
+                         recipe needs to run when building
+                        <replaceable>recipename</replaceable> from scratch.
+                        Targets that are in
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-ASSUME_PROVIDED'><filename>ASSUME_PROVIDED</filename></ulink>
+                        are not listed.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>task-depends.dot</filename>: A graph showing
+                        dependencies between tasks.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                The graphs are in
+                <ulink url='https://en.wikipedia.org/wiki/DOT_%28graph_description_language%29'>DOT</ulink>
+                format and can be converted to images (e.g. using the
+                <filename>dot</filename> tool from
+                <ulink url='http://www.graphviz.org/'>Graphviz</ulink>).
+                <note><title>Notes</title>
+                    <itemizedlist>
+                        <listitem><para>
+                            DOT files use a plain text format.
+                            The graphs generated using the
+                            <filename>bitbake -g</filename> command are often so
+                            large as to be difficult to read without special
+                            pruning (e.g. with Bitbake's
+                            <filename>-I</filename> option) and processing.
+                            Despite the form and size of the graphs, the
+                            corresponding <filename>.dot</filename> files can
+                            still be possible to read and provide useful
+                            information.
+                            </para>
+
+                            <para>As an example, the
+                            <filename>task-depends.dot</filename> file contains
+                            lines such as the following:
+                            <literallayout class='monospaced'>
+     "libxslt.do_configure" -> "libxml2.do_populate_sysroot"
+                            </literallayout>
+                            The above example line reveals that the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-configure'><filename>do_configure</filename></ulink>
+                            task in <filename>libxslt</filename> depends on the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-populate_sysroot'><filename>do_populate_sysroot</filename></ulink>
+                            task in <filename>libxml2</filename>, which is a
+                            normal
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+                            dependency between the two recipes.
+                            </para></listitem>
+                        <listitem><para>
+                            For an example of how <filename>.dot</filename>
+                            files can be processed, see the
+                            <filename>scripts/contrib/graph-tool</filename>
+                            Python script, which finds and displays paths
+                            between graph nodes.
+                            </para></listitem>
+                    </itemizedlist>
+                </note>
+            </para>
+
+            <para>
+                You can use a different method to view dependency information
+                by using the following command:
+                <literallayout class='monospaced'>
+     $ bitbake -g -u taskexp <replaceable>recipename</replaceable>
+                </literallayout>
+                This command displays a GUI window from which you can view
+                build-time and runtime dependencies for the recipes involved in
+                building <replaceable>recipename</replaceable>.
+            </para>
+        </section>
+
+        <section id='dev-viewing-task-variable-dependencies'>
+            <title>Viewing Task Variable Dependencies</title>
+
+            <para>
+                As mentioned in the
+                "<ulink url='&YOCTO_DOCS_BB_URL;#checksums'>Checksums (Signatures)</ulink>"
+                section of the BitBake User Manual, BitBake tries to
+                automatically determine what variables a task depends on so
+                that it can rerun the task if any values of the variables
+                change.
+                This determination is usually reliable.
+                However, if you do things like construct variable names at
+                runtime, then you might have to manually declare dependencies
+                on those variables using <filename>vardeps</filename> as
+                described in the
+                "<ulink url='&YOCTO_DOCS_BB_URL;#variable-flags'>Variable Flags</ulink>"
+                section of the BitBake User Manual.
+            </para>
+
+            <para>
+                If you are unsure whether a variable dependency is being
+                picked up automatically for a given task, you can list the
+                variable dependencies BitBake has determined by doing the
+                following:
+                <orderedlist>
+                    <listitem><para>
+                        Build the recipe containing the task:
+                        <literallayout class='monospaced'>
+     $ bitbake <replaceable>recipename</replaceable>
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        Inside the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-STAMPS_DIR'><filename>STAMPS_DIR</filename></ulink>
+                        directory, find the signature data
+                        (<filename>sigdata</filename>) file that corresponds
+                        to the task.
+                        The <filename>sigdata</filename> files contain a pickled
+                        Python database of all the metadata that went into
+                        creating the input checksum for the task.
+                        As an example, for the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-fetch'><filename>do_fetch</filename></ulink>
+                        task of the <filename>db</filename> recipe, the
+                        <filename>sigdata</filename> file might be found in the
+                        following location:
+                        <literallayout class='monospaced'>
+     ${BUILDDIR}/tmp/stamps/i586-poky-linux/db/6.0.30-r1.do_fetch.sigdata.7c048c18222b16ff0bcee2000ef648b1
+                        </literallayout>
+                        For tasks that are accelerated through the shared state
+                        (<ulink url='&YOCTO_DOCS_OM_URL;#shared-state-cache'>sstate</ulink>)
+                        cache, an additional <filename>siginfo</filename> file
+                        is written into
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-SSTATE_DIR'><filename>SSTATE_DIR</filename></ulink>
+                        along with the cached task output.
+                        The <filename>siginfo</filename> files contain exactly
+                        the same information as <filename>sigdata</filename>
+                        files.
+                        </para></listitem>
+                    <listitem><para>
+                        Run <filename>bitbake-dumpsig</filename> on the
+                        <filename>sigdata</filename> or
+                        <filename>siginfo</filename> file.
+                        Here is an example:
+                        <literallayout class='monospaced'>
+     $ bitbake-dumpsig ${BUILDDIR}/tmp/stamps/i586-poky-linux/db/6.0.30-r1.do_fetch.sigdata.7c048c18222b16ff0bcee2000ef648b1
+                        </literallayout>
+                        In the output of the above command, you will find a
+                        line like the following, which lists all the (inferred)
+                        variable dependencies for the task.
+                        This list also includes indirect dependencies from
+                        variables depending on other variables, recursively.
+                        <literallayout class='monospaced'>
+     Task dependencies: ['PV', 'SRCREV', 'SRC_URI', 'SRC_URI[md5sum]', 'SRC_URI[sha256sum]', 'base_do_fetch']
+                        </literallayout>
+                        <note>
+                            Functions (e.g. <filename>base_do_fetch</filename>)
+                            also count as variable dependencies.
+                            These functions in turn depend on the variables they
+                            reference.
+                        </note>
+                        The output of <filename>bitbake-dumpsig</filename> also
+                        includes the value each variable had, a list of
+                        dependencies for each variable, and
+                        <ulink url='&YOCTO_DOCS_BB_URL;#var-BB_HASHBASE_WHITELIST'><filename>BB_HASHBASE_WHITELIST</filename></ulink>
+                        information.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                There is also a <filename>bitbake-diffsigs</filename> command
+                for comparing two <filename>siginfo</filename> or
+                <filename>sigdata</filename> files.
+                This command can be helpful when trying to figure out what
+                changed between two versions of a task.
+                If you call <filename>bitbake-diffsigs</filename> with just one
+                file, the command behaves like
+                <filename>bitbake-dumpsig</filename>.
+            </para>
+
+            <para>
+                You can also use BitBake to dump out the signature construction
+                information without executing tasks by using either of the
+                following BitBake command-line options:
+                <literallayout class='monospaced'>
+     &dash;&dash;dump-signatures=<replaceable>SIGNATURE_HANDLER</replaceable>
+     -S <replaceable>SIGNATURE_HANDLER</replaceable>
+                </literallayout>
+                <note>
+                    Two common values for
+                    <replaceable>SIGNATURE_HANDLER</replaceable> are "none" and
+                    "printdiff", which dump only the signature or compare the
+                    dumped signature with the cached one, respectively.
+                </note>
+                Using BitBake with either of these options causes BitBake to
+                dump out <filename>sigdata</filename> files in the
+                <filename>stamps</filename> directory for every task it would
+                have executed instead of building the specified target package.
+            </para>
+        </section>
+
+        <section id='dev-viewing-metadata-used-to-create-the-input-signature-of-a-shared-state-task'>
+            <title>Viewing Metadata Used to Create the Input Signature of a Shared State Task</title>
+
+            <para>
+                Seeing what metadata went into creating the input signature
+                of a shared state (sstate) task can be a useful debugging
+                aid.
+                This information is available in signature information
+                (<filename>siginfo</filename>) files in
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SSTATE_DIR'><filename>SSTATE_DIR</filename></ulink>.
+                For information on how to view and interpret information in
+                <filename>siginfo</filename> files, see the
+                "<link linkend='dev-viewing-task-variable-dependencies'>Viewing Task Variable Dependencies</link>"
+                section.
+            </para>
+
+            <para>
+                For conceptual information on shared state, see the
+                "<ulink url='&YOCTO_DOCS_OM_URL;#shared-state'>Shared State</ulink>"
+                section in the Yocto Project Overview and Concepts Manual.
+            </para>
+        </section>
+
+        <section id='dev-invalidating-shared-state-to-force-a-task-to-run'>
+            <title>Invalidating Shared State to Force a Task to Run</title>
+
+            <para>
+                The OpenEmbedded build system uses
+                <ulink url='&YOCTO_DOCS_OM_URL;#overview-checksums'>checksums</ulink>
+                and
+                <ulink url='&YOCTO_DOCS_OM_URL;#shared-state'>shared state</ulink>
+                cache to avoid unnecessarily rebuilding tasks.
+                Collectively, this scheme is known as "shared state code."
+            </para>
+
+            <para>
+                As with all schemes, this one has some drawbacks.
+                It is possible that you could make implicit changes to your
+                code that the checksum calculations do not take into
+                account.
+                These implicit changes affect a task's output but do not
+                trigger the shared state code into rebuilding a recipe.
+                Consider an example during which a tool changes its output.
+                Assume that the output of <filename>rpmdeps</filename>
+                changes.
+                The result of the change should be that all the
+                <filename>package</filename> and
+                <filename>package_write_rpm</filename> shared state cache
+                items become invalid.
+                However, because the change to the output is
+                external to the code and therefore implicit,
+                the associated shared state cache items do not become
+                invalidated.
+                In this case, the build process uses the cached items
+                rather than running the task again.
+                Obviously, these types of implicit changes can cause
+                problems.
+            </para>
+
+            <para>
+                To avoid these problems during the build, you need to
+                understand the effects of any changes you make.
+                Realize that changes you make directly to a function
+                are automatically factored into the checksum calculation.
+                Thus, these explicit changes invalidate the associated
+                area of shared state cache.
+                However, you need to be aware of any implicit changes that
+                are not obvious changes to the code and could affect
+                the output of a given task.
+            </para>
+
+            <para>
+                When you identify an implicit change, you can easily
+                take steps to invalidate the cache and force the tasks
+                to run.
+                The steps you can take are as simple as changing a
+                function's comments in the source code.
+                For example, to invalidate package shared state files,
+                change the comment statements of
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>
+                or the comments of one of the functions it calls.
+                Even though the change is purely cosmetic, it causes the
+                checksum to be recalculated and forces the build system to
+                run the task again.
+                <note>
+                    For an example of a commit that makes a cosmetic
+                    change to invalidate shared state, see this
+                    <ulink url='&YOCTO_GIT_URL;/cgit.cgi/poky/commit/meta/classes/package.bbclass?id=737f8bbb4f27b4837047cb9b4fbfe01dfde36d54'>commit</ulink>.
+                </note>
+            </para>
+        </section>
+
+        <section id='dev-debugging-taskrunning'>
+            <title>Running Specific Tasks</title>
+
+            <para>
+                Any given recipe consists of a set of tasks.
+                The standard BitBake behavior in most cases is:
+                <filename>do_fetch</filename>,
+                <filename>do_unpack</filename>,
+                <filename>do_patch</filename>,
+                <filename>do_configure</filename>,
+                <filename>do_compile</filename>,
+                <filename>do_install</filename>,
+                <filename>do_package</filename>,
+                <filename>do_package_write_*</filename>, and
+                <filename>do_build</filename>.
+                The default task is <filename>do_build</filename> and any tasks
+                on which it depends build first.
+                Some tasks, such as <filename>do_devshell</filename>, are not
+                part of the default build chain.
+                If you wish to run a task that is not part of the default build
+                chain, you can use the <filename>-c</filename> option in
+                BitBake.
+                Here is an example:
+                <literallayout class='monospaced'>
+     $ bitbake matchbox-desktop -c devshell
+                </literallayout>
+            </para>
+
+            <para>
+                The <filename>-c</filename> option respects task dependencies,
+                which means that all other tasks (including tasks from other
+                recipes) that the specified task depends on will be run before
+                the task.
+                Even when you manually specify a task to run with
+                <filename>-c</filename>, BitBake will only run the task if it
+                considers it "out of date".
+                See the
+                "<ulink url='&YOCTO_DOCS_OM_URL;#stamp-files-and-the-rerunning-of-tasks'>Stamp Files and the Rerunning of Tasks</ulink>"
+                section in the Yocto Project Overview and Concepts Manual for
+                how BitBake determines whether a task is "out of date".
+            </para>
+
+            <para>
+                If you want to force an up-to-date task to be rerun (e.g.
+                because you made manual modifications to the recipe's
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>
+                that you want to try out), then you can use the
+                <filename>-f</filename> option.
+                <note>
+                    The reason <filename>-f</filename> is never required when
+                    running the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-devshell'><filename>do_devshell</filename></ulink>
+                    task is because the
+                    <filename>[</filename><ulink url='&YOCTO_DOCS_BB_URL;#variable-flags'><filename>nostamp</filename></ulink><filename>]</filename>
+                    variable flag is already set for the task.
+                </note>
+                The following example shows one way you can use the
+                <filename>-f</filename> option:
+                <literallayout class='monospaced'>
+     $ bitbake matchbox-desktop
+               .
+               .
+     make some changes to the source code in the work directory
+               .
+               .
+     $ bitbake matchbox-desktop -c compile -f
+     $ bitbake matchbox-desktop
+                </literallayout>
+            </para>
+
+            <para>
+                This sequence first builds and then recompiles
+                <filename>matchbox-desktop</filename>.
+                The last command reruns all tasks (basically the packaging
+                tasks) after the compile.
+                BitBake recognizes that the <filename>do_compile</filename>
+                task was rerun and therefore understands that the other tasks
+                also need to be run again.
+            </para>
+
+            <para>
+                Another, shorter way to rerun a task and all
+                <ulink url='&YOCTO_DOCS_REF_URL;#normal-recipe-build-tasks'>normal recipe build tasks</ulink>
+                that depend on it is to use the <filename>-C</filename>
+                option.
+                <note>
+                    This option is upper-cased and is separate from the
+                    <filename>-c</filename> option, which is lower-cased.
+                </note>
+                Using this option invalidates the given task and then runs the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-build'><filename>do_build</filename></ulink>
+                task, which is the default task if no task is given, and the
+                tasks on which it depends.
+                You could replace the final two commands in the previous example
+                with the following single command:
+                <literallayout class='monospaced'>
+     $ bitbake matchbox-desktop -C compile
+                </literallayout>
+                Internally, the <filename>-f</filename> and
+                <filename>-C</filename> options work by tainting (modifying) the
+                input checksum of the specified task.
+                This tainting indirectly causes the task and its
+                dependent tasks to be rerun through the normal task dependency
+                mechanisms.
+                <note>
+                    BitBake explicitly keeps track of which tasks have been
+                    tainted in this fashion, and will print warnings such as the
+                    following for builds involving such tasks:
+                    <literallayout class='monospaced'>
+     WARNING: /home/ulf/poky/meta/recipes-sato/matchbox-desktop/matchbox-desktop_2.1.bb.do_compile is tainted from a forced run
+                    </literallayout>
+                    The purpose of the warning is to let you know that the work
+                    directory and build output might not be in the clean state
+                    they would be in for a "normal" build, depending on what
+                    actions you took.
+                    To get rid of such warnings, you can remove the work
+                    directory and rebuild the recipe, as follows:
+                    <literallayout class='monospaced'>
+     $ bitbake matchbox-desktop -c clean
+     $ bitbake matchbox-desktop
+                    </literallayout>
+                </note>
+            </para>
+
+            <para>
+                You can view a list of tasks in a given package by running the
+                <filename>do_listtasks</filename> task as follows:
+                <literallayout class='monospaced'>
+     $ bitbake matchbox-desktop -c listtasks
+                </literallayout>
+                The results appear as output to the console and are also in the
+                file <filename>${WORKDIR}/temp/log.do_listtasks</filename>.
+            </para>
+        </section>
+
+        <section id='dev-debugging-bitbake'>
+            <title>General BitBake Problems</title>
+
+            <para>
+                You can see debug output from BitBake by using the
+                <filename>-D</filename> option.
+                The debug output gives more information about what BitBake
+                is doing and the reason behind it.
+                Each <filename>-D</filename> option you use increases the
+                logging level.
+                The most common usage is <filename>-DDD</filename>.
+            </para>
+
+            <para>
+                The output from
+                <filename>bitbake -DDD -v</filename> <replaceable>targetname</replaceable>
+                can reveal why BitBake chose a certain version of a package or
+                why BitBake picked a certain provider.
+                This command could also help you in a situation where you think
+                BitBake did something unexpected.
+            </para>
+        </section>
+
+        <section id='dev-debugging-buildfile'>
+            <title>Building with No Dependencies</title>
+
+            <para>
+                To build a specific recipe (<filename>.bb</filename> file),
+                you can use the following command form:
+                <literallayout class='monospaced'>
+     $ bitbake -b <replaceable>somepath</replaceable>/<replaceable>somerecipe</replaceable>.bb
+                </literallayout>
+                This command form does not check for dependencies.
+                Consequently, you should use it only when you know existing
+                dependencies have been met.
+                <note>
+                    You can also specify fragments of the filename.
+                    In this case, BitBake checks for a unique match.
+                </note>
+            </para>
+        </section>
+
+        <section id='recipe-logging-mechanisms'>
+            <title>Recipe Logging Mechanisms</title>
+
+            <para>
+                The Yocto Project provides several logging functions for
+                producing debugging output and reporting errors and warnings.
+                For Python functions, the following logging functions exist.
+                All of these functions log to
+                <filename>${T}/log.do_</filename><replaceable>task</replaceable>,
+                and can also log to standard output (stdout) with the right
+                settings:
+                <itemizedlist>
+                    <listitem><para>
+                        <filename>bb.plain(</filename><replaceable>msg</replaceable><filename>)</filename>:
+                        Writes <replaceable>msg</replaceable> as is to the
+                        log while also logging to stdout.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>bb.note(</filename><replaceable>msg</replaceable><filename>)</filename>:
+                        Writes "NOTE: <replaceable>msg</replaceable>" to the
+                        log.
+                        Also logs to stdout if BitBake is called with "-v".
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>bb.debug(</filename><replaceable>level</replaceable><filename>,&nbsp;</filename><replaceable>msg</replaceable><filename>)</filename>:
+                        Writes "DEBUG: <replaceable>msg</replaceable>" to the
+                        log.
+                        Also logs to stdout if the log level is greater than or
+                        equal to <replaceable>level</replaceable>.
+                        See the
+                        "<ulink url='&YOCTO_DOCS_BB_URL;#usage-and-syntax'>-D</ulink>"
+                        option in the BitBake User Manual for more information.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>bb.warn(</filename><replaceable>msg</replaceable><filename>)</filename>:
+                        Writes "WARNING: <replaceable>msg</replaceable>" to the
+                        log while also logging to stdout.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>bb.error(</filename><replaceable>msg</replaceable><filename>)</filename>:
+                        Writes "ERROR: <replaceable>msg</replaceable>" to the
+                        log while also logging to standard out (stdout).
+                        <note>
+                            Calling this function does not cause the task to fail.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>bb.fatal(</filename><replaceable>msg</replaceable><filename>)</filename>:
+                        This logging function is similar to
+                        <filename>bb.error(</filename><replaceable>msg</replaceable><filename>)</filename>
+                        but also causes the calling task to fail.
+                        <note>
+                            <filename>bb.fatal()</filename> raises an exception,
+                            which means you do not need to put a "return"
+                            statement after the function.
+                        </note>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                The same logging functions are also available in shell
+                functions, under the names
+                <filename>bbplain</filename>, <filename>bbnote</filename>,
+                <filename>bbdebug</filename>, <filename>bbwarn</filename>,
+                <filename>bberror</filename>, and <filename>bbfatal</filename>.
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-logging'><filename>logging</filename></ulink>
+                class implements these functions.
+                See that class in the
+                <filename>meta/classes</filename> folder of the
+                <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                for information.
+            </para>
+
+            <section id='logging-with-python'>
+                <title>Logging With Python</title>
+
+                <para>
+                    When creating recipes using Python and inserting code that
+                    handles build logs, keep in mind the goal is to have
+                    informative logs while keeping the console as "silent" as
+                    possible.
+                    Also, if you want status messages in the log, use the
+                    "debug" loglevel.
+                </para>
+
+                <para>
+                    Following is an example written in Python.
+                    The code handles logging for a function that determines the
+                    number of tasks needed to be run.
+                    See the
+                    "<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-listtasks'><filename>do_listtasks</filename></ulink>"
+                    section for additional information:
+                    <literallayout class='monospaced'>
+     python do_listtasks() {
+         bb.debug(2, "Starting to figure out the task list")
+         if noteworthy_condition:
+             bb.note("There are 47 tasks to run")
+         bb.debug(2, "Got to point xyz")
+         if warning_trigger:
+             bb.warn("Detected warning_trigger, this might be a problem later.")
+         if recoverable_error:
+             bb.error("Hit recoverable_error, you really need to fix this!")
+         if fatal_error:
+             bb.fatal("fatal_error detected, unable to print the task list")
+         bb.plain("The tasks present are abc")
+         bb.debug(2, "Finished figuring out the tasklist")
+     }
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='logging-with-bash'>
+                <title>Logging With Bash</title>
+
+                <para>
+                    When creating recipes using Bash and inserting code that
+                    handles build logs, you have the same goals - informative
+                    with minimal console output.
+                    The syntax you use for recipes written in Bash is similar
+                    to that of recipes written in Python described in the
+                    previous section.
+                </para>
+
+                <para>
+                    Following is an example written in Bash.
+                    The code logs the progress of the <filename>do_my_function</filename> function.
+                    <literallayout class='monospaced'>
+     do_my_function() {
+         bbdebug 2 "Running do_my_function"
+         if [ exceptional_condition ]; then
+             bbnote "Hit exceptional_condition"
+         fi
+         bbdebug 2  "Got to point xyz"
+         if [ warning_trigger ]; then
+             bbwarn "Detected warning_trigger, this might cause a problem later."
+         fi
+         if [ recoverable_error ]; then
+             bberror "Hit recoverable_error, correcting"
+         fi
+         if [ fatal_error ]; then
+             bbfatal "fatal_error detected"
+         fi
+         bbdebug 2 "Completed do_my_function"
+     }
+                    </literallayout>
+                </para>
+            </section>
+        </section>
+
+        <section id='debugging-parallel-make-races'>
+            <title>Debugging Parallel Make Races</title>
+
+            <para>
+                A parallel <filename>make</filename> race occurs when the build
+                consists of several parts that are run simultaneously and
+                a situation occurs when the output or result of one
+                part is not ready for use with a different part of the build
+                that depends on that output.
+                Parallel make races are annoying and can sometimes be difficult
+                to reproduce and fix.
+                However, some simple tips and tricks exist that can help
+                you debug and fix them.
+                This section presents a real-world example of an error
+                encountered on the Yocto Project autobuilder and the process
+                used to fix it.
+                <note>
+                    If you cannot properly fix a <filename>make</filename> race
+                    condition, you can work around it by clearing either the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKE'><filename>PARALLEL_MAKE</filename></ulink>
+                    or
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKEINST'><filename>PARALLEL_MAKEINST</filename></ulink>
+                    variables.
+                </note>
+            </para>
+
+            <section id='the-failure'>
+                <title>The Failure</title>
+
+                <para>
+                    For this example, assume that you are building an image that
+                    depends on the "neard" package.
+                    And, during the build, BitBake runs into problems and
+                    creates the following output.
+                    <note>
+                        This example log file has longer lines artificially
+                        broken to make the listing easier to read.
+                    </note>
+                    If you examine the output or the log file, you see the
+                    failure during <filename>make</filename>:
+                    <literallayout class='monospaced'>
+     | DEBUG: SITE files ['endian-little', 'bit-32', 'ix86-common', 'common-linux', 'common-glibc', 'i586-linux', 'common']
+     | DEBUG: Executing shell function do_compile
+     | NOTE: make -j 16
+     | make --no-print-directory all-am
+     | /bin/mkdir -p include/near
+     | /bin/mkdir -p include/near
+     | /bin/mkdir -p include/near
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/types.h include/near/types.h
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/log.h include/near/log.h
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/plugin.h include/near/plugin.h
+     | /bin/mkdir -p include/near
+     | /bin/mkdir -p include/near
+     | /bin/mkdir -p include/near
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/tag.h include/near/tag.h
+     | /bin/mkdir -p include/near
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/adapter.h include/near/adapter.h
+     | /bin/mkdir -p include/near
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/ndef.h include/near/ndef.h
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/tlv.h include/near/tlv.h
+     | /bin/mkdir -p include/near
+     | /bin/mkdir -p include/near
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/setting.h include/near/setting.h
+     | /bin/mkdir -p include/near
+     | /bin/mkdir -p include/near
+     | /bin/mkdir -p include/near
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/device.h include/near/device.h
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/nfc_copy.h include/near/nfc_copy.h
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/snep.h include/near/snep.h
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/version.h include/near/version.h
+     | ln -s /home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/work/i586-poky-linux/neard/
+       0.14-r0/neard-0.14/include/dbus.h include/near/dbus.h
+     | ./src/genbuiltin nfctype1 nfctype2 nfctype3 nfctype4 p2p > src/builtin.h
+     | i586-poky-linux-gcc  -m32 -march=i586 --sysroot=/home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/
+       build/build/tmp/sysroots/qemux86 -DHAVE_CONFIG_H -I. -I./include -I./src -I./gdbus  -I/home/pokybuild/
+       yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/sysroots/qemux86/usr/include/glib-2.0
+       -I/home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/tmp/sysroots/qemux86/usr/
+       lib/glib-2.0/include  -I/home/pokybuild/yocto-autobuilder/yocto-slave/nightly-x86/build/build/
+       tmp/sysroots/qemux86/usr/include/dbus-1.0 -I/home/pokybuild/yocto-autobuilder/yocto-slave/
+       nightly-x86/build/build/tmp/sysroots/qemux86/usr/lib/dbus-1.0/include  -I/home/pokybuild/yocto-autobuilder/
+       yocto-slave/nightly-x86/build/build/tmp/sysroots/qemux86/usr/include/libnl3
+       -DNEAR_PLUGIN_BUILTIN -DPLUGINDIR=\""/usr/lib/near/plugins"\"
+       -DCONFIGDIR=\""/etc/neard\"" -O2 -pipe -g -feliminate-unused-debug-types -c
+       -o tools/snep-send.o tools/snep-send.c
+     | In file included from tools/snep-send.c:16:0:
+     | tools/../src/near.h:41:23: fatal error: near/dbus.h: No such file or directory
+     |  #include &lt;near/dbus.h&gt;
+     |                        ^
+     | compilation terminated.
+     | make[1]: *** [tools/snep-send.o] Error 1
+     | make[1]: *** Waiting for unfinished jobs....
+     | make: *** [all] Error 2
+     | ERROR: oe_runmake failed
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='reproducing-the-error'>
+                <title>Reproducing the Error</title>
+
+                <para>
+                    Because race conditions are intermittent, they do not
+                    manifest themselves every time you do the build.
+                    In fact, most times the build will complete without problems
+                    even though the potential race condition exists.
+                    Thus, once the error surfaces, you need a way to reproduce
+                    it.
+                </para>
+
+                <para>
+                    In this example, compiling the "neard" package is causing
+                    the problem.
+                    So the first thing to do is build "neard" locally.
+                    Before you start the build, set the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKE'><filename>PARALLEL_MAKE</filename></ulink>
+                    variable in your <filename>local.conf</filename> file to
+                    a high number (e.g. "-j 20").
+                    Using a high value for <filename>PARALLEL_MAKE</filename>
+                    increases the chances of the race condition showing up:
+                    <literallayout class='monospaced'>
+     $ bitbake neard
+                    </literallayout>
+                </para>
+
+                <para>
+                    Once the local build for "neard" completes, start a
+                    <filename>devshell</filename> build:
+                    <literallayout class='monospaced'>
+     $ bitbake neard -c devshell
+                    </literallayout>
+                    For information on how to use a
+                    <filename>devshell</filename>, see the
+                    "<link linkend='platdev-appdev-devshell'>Using a Development Shell</link>"
+                    section.
+                </para>
+
+                <para>
+                    In the <filename>devshell</filename>, do the following:
+                    <literallayout class='monospaced'>
+     $ make clean
+     $ make tools/snep-send.o
+                    </literallayout>
+                    The <filename>devshell</filename> commands cause the failure
+                    to clearly be visible.
+                    In this case, a missing dependency exists for the "neard"
+                    Makefile target.
+                    Here is some abbreviated, sample output with the
+                    missing dependency clearly visible at the end:
+                    <literallayout class='monospaced'>
+     i586-poky-linux-gcc  -m32 -march=i586 --sysroot=/home/scott-lenovo/......
+        .
+        .
+        .
+     tools/snep-send.c
+     In file included from tools/snep-send.c:16:0:
+     tools/../src/near.h:41:23: fatal error: near/dbus.h: No such file or directory
+      #include &lt;near/dbus.h&gt;
+                       ^
+     compilation terminated.
+     make: *** [tools/snep-send.o] Error 1
+     $
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='creating-a-patch-for-the-fix'>
+                <title>Creating a Patch for the Fix</title>
+
+                <para>
+                    Because there is a missing dependency for the Makefile
+                    target, you need to patch the
+                    <filename>Makefile.am</filename> file, which is generated
+                    from <filename>Makefile.in</filename>.
+                    You can use Quilt to create the patch:
+                    <literallayout class='monospaced'>
+     $ quilt new parallelmake.patch
+     Patch patches/parallelmake.patch is now on top
+     $ quilt add Makefile.am
+     File Makefile.am added to patch patches/parallelmake.patch
+                    </literallayout>
+                    For more information on using Quilt, see the
+                    "<link linkend='using-a-quilt-workflow'>Using Quilt in Your Workflow</link>"
+                    section.
+                </para>
+
+                <para>
+                    At this point you need to make the edits to
+                    <filename>Makefile.am</filename> to add the missing
+                    dependency.
+                    For our example, you have to add the following line
+                    to the file:
+                    <literallayout class='monospaced'>
+     tools/snep-send.$(OBJEXT): include/near/dbus.h
+                    </literallayout>
+                </para>
+
+                <para>
+                    Once you have edited the file, use the
+                    <filename>refresh</filename> command to create the patch:
+                    <literallayout class='monospaced'>
+     $ quilt refresh
+     Refreshed patch patches/parallelmake.patch
+                    </literallayout>
+                    Once the patch file exists, you need to add it back to the
+                    originating recipe folder.
+                    Here is an example assuming a top-level
+                    <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                    named <filename>poky</filename>:
+                    <literallayout class='monospaced'>
+     $ cp patches/parallelmake.patch poky/meta/recipes-connectivity/neard/neard
+                    </literallayout>
+                    The final thing you need to do to implement the fix in the
+                    build is to update the "neard" recipe (i.e.
+                    <filename>neard-0.14.bb</filename>) so that the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                    statement includes the patch file.
+                    The recipe file is in the folder above the patch.
+                    Here is what the edited <filename>SRC_URI</filename>
+                    statement would look like:
+                    <literallayout class='monospaced'>
+     SRC_URI = "${KERNELORG_MIRROR}/linux/network/nfc/${BPN}-${PV}.tar.xz \
+                file://neard.in \
+                file://neard.service.in \
+                file://parallelmake.patch \
+               "
+                    </literallayout>
+                </para>
+
+                <para>
+                    With the patch complete and moved to the correct folder and
+                    the <filename>SRC_URI</filename> statement updated, you can
+                    exit the <filename>devshell</filename>:
+                    <literallayout class='monospaced'>
+     $ exit
+                    </literallayout>
+                </para>
+            </section>
+
+            <section id='testing-the-build'>
+                <title>Testing the Build</title>
+
+                <para>
+                    With everything in place, you can get back to trying the
+                    build again locally:
+                    <literallayout class='monospaced'>
+     $ bitbake neard
+                    </literallayout>
+                    This build should succeed.
+                </para>
+
+                <para>
+                    Now you can open up a <filename>devshell</filename> again
+                    and repeat the clean and make operations as follows:
+                    <literallayout class='monospaced'>
+     $ bitbake neard -c devshell
+     $ make clean
+     $ make tools/snep-send.o
+                    </literallayout>
+                    The build should work without issue.
+                </para>
+
+                <para>
+                    As with all solved problems, if they originated upstream,
+                    you need to submit the fix for the recipe in OE-Core and
+                    upstream so that the problem is taken care of at its
+                    source.
+                    See the
+                    "<link linkend='how-to-submit-a-change'>Submitting a Change to the Yocto Project</link>"
+                    section for more information.
+                </para>
+            </section>
+        </section>
+
+        <section id="platdev-gdb-remotedebug">
+            <title>Debugging With the GNU Project Debugger (GDB) Remotely</title>
+
+            <para>
+                GDB allows you to examine running programs, which in turn helps
+                you to understand and fix problems.
+                It also allows you to perform post-mortem style analysis of
+                program crashes.
+                GDB is available as a package within the Yocto Project and is
+                installed in SDK images by default.
+                See the
+                "<ulink url='&YOCTO_DOCS_REF_URL;#ref-images'>Images</ulink>"
+                chapter in the Yocto Project Reference Manual for a description of
+                these images.
+                You can find information on GDB at
+                <ulink url="http://sourceware.org/gdb/"/>.
+                <note><title>Tip</title>
+                    For best results, install debug (<filename>-dbg</filename>)
+                    packages for the applications you are going to debug.
+                    Doing so makes extra debug symbols available that give you
+                    more meaningful output.
+                </note>
+            </para>
+
+            <para>
+                Sometimes, due to memory or disk space constraints, it is not
+                possible to use GDB directly on the remote target to debug
+                applications.
+                These constraints arise because GDB needs to load the debugging
+                information and the binaries of the process being debugged.
+                Additionally, GDB needs to perform many computations to locate
+                information such as function names, variable names and values,
+                stack traces and so forth - even before starting the debugging
+                process.
+                These extra computations place more load on the target system
+                and can alter the characteristics of the program being debugged.
+            </para>
+
+            <para>
+                To help get past the previously mentioned constraints, you can
+                use gdbserver, which runs on the remote target and does not
+                load any debugging information from the debugged process.
+                Instead, a GDB instance processes the debugging information that
+                is run on a remote computer - the host GDB.
+                The host GDB then sends control commands to gdbserver to make
+                it stop or start the debugged program, as well as read or write
+                memory regions of that debugged program.
+                All the debugging information loaded and processed as well
+               as all the heavy debugging is done by the host GDB.
+                Offloading these processes gives the gdbserver running on the
+                target a chance to remain small and fast.
+            </para>
+
+            <para>
+                Because the host GDB is responsible for loading the debugging
+                information and for doing the necessary processing to make
+                actual debugging happen, you have to make sure the host can
+                access the unstripped binaries complete with their debugging
+                information and also be sure the target is compiled with no
+                optimizations.
+                The host GDB must also have local access to all the libraries
+                used by the debugged program.
+                Because gdbserver does not need any local debugging information,
+                the binaries on the remote target can remain stripped.
+                However, the binaries must also be compiled without optimization
+                so they match the host's binaries.
+            </para>
+
+            <para>
+                To remain consistent with GDB documentation and terminology,
+                the binary being debugged on the remote target machine is
+                referred to as the "inferior" binary.
+                For documentation on GDB see the
+                <ulink url="http://sourceware.org/gdb/documentation/">GDB site</ulink>.
+            </para>
+
+            <para>
+                The following steps show you how to debug using the GNU project
+                debugger.
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Configure your build system to construct the
+                        companion debug filesystem:</emphasis></para>
+
+                        <para>In your <filename>local.conf</filename> file, set
+                        the following:
+                        <literallayout class='monospaced'>
+     IMAGE_GEN_DEBUGFS = "1"
+     IMAGE_FSTYPES_DEBUGFS = "tar.bz2"
+                        </literallayout>
+                        These options cause the OpenEmbedded build system
+                        to generate a special companion filesystem fragment,
+                        which contains the matching source and debug symbols to
+                        your deployable filesystem.
+                        The build system does this by looking at what is in the
+                        deployed filesystem, and pulling the corresponding
+                        <filename>-dbg</filename> packages.</para>
+
+                        <para>The companion debug filesystem is not a complete
+                        filesystem, but only contains the debug fragments.
+                        This filesystem must be combined with the full filesystem
+                        for debugging.
+                        Subsequent steps in this procedure show how to combine
+                        the partial filesystem with the full filesystem.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Configure the system to include gdbserver in
+                        the target filesystem:</emphasis></para>
+
+                        <para>Make the following addition in either your
+                        <filename>local.conf</filename> file or in an image
+                        recipe:
+                        <literallayout class='monospaced'>
+     IMAGE_INSTALL_append = " gdbserver"
+                        </literallayout>
+                        The change makes sure the <filename>gdbserver</filename>
+                        package is included.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Build the environment:</emphasis></para>
+
+                        <para>Use the following command to construct the image
+                        and the companion Debug Filesystem:
+                        <literallayout class='monospaced'>
+     $ bitbake <replaceable>image</replaceable>
+                        </literallayout>
+                        Build the cross GDB component and make it available
+                        for debugging.
+                        Build the SDK that matches the image.
+                        Building the SDK is best for a production build
+                        that can be used later for debugging, especially
+                        during long term maintenance:
+                        <literallayout class='monospaced'>
+     $ bitbake -c populate_sdk <replaceable>image</replaceable>
+                        </literallayout></para>
+
+                        <para>Alternatively, you can build the minimal
+                        toolchain components that match the target.
+                        Doing so creates a smaller than typical SDK and only
+                        contains a minimal set of components with which to
+                        build simple test applications, as well as run the
+                        debugger:
+                        <literallayout class='monospaced'>
+     $ bitbake meta-toolchain
+                        </literallayout></para>
+
+                        <para>A final method is to build Gdb itself within
+                        the build system:
+                        <literallayout class='monospaced'>
+     $ bitbake gdb-cross-<replaceable>architecture</replaceable>
+                        </literallayout>
+                        Doing so produces a temporary copy of
+                        <filename>cross-gdb</filename> you can use for
+                        debugging during development.
+                        While this is the quickest approach, the two previous
+                        methods in this step are better when considering
+                        long-term maintenance strategies.
+                        <note>
+                            If you run
+                            <filename>bitbake gdb-cross</filename>, the
+                            OpenEmbedded build system suggests the actual
+                            image (e.g. <filename>gdb-cross-i586</filename>).
+                            The suggestion is usually the actual name you want
+                            to use.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Set up the</emphasis>&nbsp;<filename>debugfs</filename></para>
+
+                        <para>Run the following commands to set up the
+                        <filename>debugfs</filename>:
+                        <literallayout class='monospaced'>
+     $ mkdir debugfs
+     $ cd debugfs
+     $ tar xvfj <replaceable>build-dir</replaceable>/tmp-glibc/deploy/images/<replaceable>machine</replaceable>/<replaceable>image</replaceable>.rootfs.tar.bz2
+     $ tar xvfj <replaceable>build-dir</replaceable>/tmp-glibc/deploy/images/<replaceable>machine</replaceable>/<replaceable>image</replaceable>-dbg.rootfs.tar.bz2
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Set up GDB</emphasis></para>
+
+                        <para>Install the SDK (if you built one) and then
+                        source the correct environment file.
+                        Sourcing the environment file puts the SDK in your
+                        <filename>PATH</filename> environment variable.</para>
+
+                        <para>If you are using the build system, Gdb is
+                        located in
+                        <replaceable>build-dir</replaceable>/tmp/sysroots/<replaceable>host</replaceable>/usr/bin/<replaceable>architecture</replaceable>/<replaceable>architecture</replaceable>-gdb
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Boot the target:</emphasis></para>
+
+                        <para>For information on how to run QEMU, see the
+                        <ulink url='http://wiki.qemu.org/Documentation/GettingStartedDevelopers'>QEMU Documentation</ulink>.
+                        <note>
+                            Be sure to verify that your host can access the
+                            target via TCP.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Debug a program:</emphasis></para>
+
+                        <para>Debugging a program involves running gdbserver
+                        on the target and then running Gdb on the host.
+                        The example in this step debugs
+                        <filename>gzip</filename>:
+                        <literallayout class='monospaced'>
+     root@qemux86:~# gdbserver localhost:1234 /bin/gzip —help
+                        </literallayout>
+                        For additional gdbserver options, see the
+                        <ulink url='https://www.gnu.org/software/gdb/documentation/'>GDB Server Documentation</ulink>.
+                        </para>
+
+                        <para>After running gdbserver on the target, you need
+                        to run Gdb on the host and configure it and connect to
+                        the target.
+                        Use these commands:
+                        <literallayout class='monospaced'>
+     $ cd <replaceable>directory-holding-the-debugfs-directory</replaceable>
+     $ <replaceable>arch</replaceable>-gdb
+
+     (gdb) set sysroot debugfs
+     (gdb) set substitute-path /usr/src/debug debugfs/usr/src/debug
+     (gdb) target remote <replaceable>IP-of-target</replaceable>:1234
+                        </literallayout>
+                        At this point, everything should automatically load
+                        (i.e. matching binaries, symbols and headers).
+                        <note>
+                            The Gdb <filename>set</filename> commands in the
+                            previous example can be placed into the users
+                           <filename>~/.gdbinit</filename> file.
+                            Upon starting, Gdb automatically runs whatever
+                            commands are in that file.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Deploying without a full image
+                        rebuild:</emphasis></para>
+
+                        <para>In many cases, during development you want a
+                        quick method to deploy a new binary to the target and
+                        debug it, without waiting for a full image build.
+                        </para>
+
+                        <para>One approach to solving this situation is to
+                        just build the component you want to debug.
+                        Once you have built the component, copy the
+                        executable directly to both the target and the
+                        host <filename>debugfs</filename>.</para>
+
+                        <para>If the binary is processed through the debug
+                        splitting in OpenEmbedded, you should also
+                        copy the debug items (i.e. <filename>.debug</filename>
+                        contents and corresponding
+                        <filename>/usr/src/debug</filename> files)
+                        from the work directory.
+                        Here is an example:
+                        <literallayout class='monospaced'>
+     $ bitbake bash
+     $ bitbake -c devshell bash
+     $ cd ..
+     $ scp packages-split/bash/bin/bash <replaceable>target</replaceable>:/bin/bash
+     $ cp -a packages-split/bash-dbg/* <replaceable>path</replaceable>/debugfs
+                        </literallayout>
+                        </para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+
+        <section id='debugging-with-the-gnu-project-debugger-gdb-on-the-target'>
+            <title>Debugging with the GNU Project Debugger (GDB) on the Target</title>
+
+            <para>
+                The previous section addressed using GDB remotely for debugging
+                purposes, which is the most usual case due to the inherent
+                hardware limitations on many embedded devices.
+                However, debugging in the target hardware itself is also
+                possible with more powerful devices.
+                This section describes what you need to do in order to support
+                using GDB to debug on the target hardware.
+            </para>
+
+            <para>
+                To support this kind of debugging, you need do the following:
+                <itemizedlist>
+                    <listitem><para>
+                        Ensure that GDB is on the target.
+                        You can do this by adding "gdb" to
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_INSTALL'><filename>IMAGE_INSTALL</filename></ulink>:
+                        <literallayout class='monospaced'>
+     IMAGE_INSTALL_append = " gdb"
+                        </literallayout>
+                        Alternatively, you can add "tools-debug" to
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></ulink>:
+                        <literallayout class='monospaced'>
+     IMAGE_FEATURES_append = " tools-debug"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        Ensure that debug symbols are present.
+                        You can make sure these symbols are present by
+                        installing <filename>-dbg</filename>:
+                        <literallayout class='monospaced'>
+     IMAGE_INSTALL_append = " <replaceable>packagename</replaceable>-dbg"
+                        </literallayout>
+                        Alternatively, you can do the following to include all
+                        the debug symbols:
+                        <literallayout class='monospaced'>
+     IMAGE_FEATURES_append = " dbg-pkgs"
+                        </literallayout>
+                        </para></listitem>
+                </itemizedlist>
+                <note>
+                    To improve the debug information accuracy, you can reduce
+                    the level of optimization used by the compiler.
+                    For example, when adding the following line to your
+                    <filename>local.conf</filename> file, you will reduce
+                    optimization from
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-FULL_OPTIMIZATION'><filename>FULL_OPTIMIZATION</filename></ulink>
+                    of "-O2" to
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-DEBUG_OPTIMIZATION'><filename>DEBUG_OPTIMIZATION</filename></ulink>
+                    of "-O -fno-omit-frame-pointer":
+                    <literallayout class='monospaced'>
+     DEBUG_BUILD = "1"
+                    </literallayout>
+                    Consider that this will reduce the application's performance
+                    and is recommended only for debugging purposes.
+                </note>
+            </para>
+        </section>
+
+        <section id='dev-other-debugging-others'>
+            <title>Other Debugging Tips</title>
+
+            <para>
+                Here are some other tips that you might find useful:
+                <itemizedlist>
+                    <listitem><para>
+                        When adding new packages, it is worth watching for
+                        undesirable items making their way into compiler command
+                        lines.
+                        For example, you do not want references to local system
+                        files like
+                        <filename>/usr/lib/</filename> or
+                        <filename>/usr/include/</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        If you want to remove the <filename>psplash</filename>
+                        boot splashscreen,
+                        add <filename>psplash=false</filename> to  the kernel
+                        command line.
+                        Doing so prevents <filename>psplash</filename> from
+                        loading and thus allows you to see the console.
+                        It is also possible to switch out of the splashscreen by
+                        switching the virtual console (e.g. Fn+Left or Fn+Right
+                        on a Zaurus).
+                        </para></listitem>
+                    <listitem><para>
+                        Removing
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-TMPDIR'><filename>TMPDIR</filename></ulink>
+                        (usually <filename>tmp/</filename>, within the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>)
+                        can often fix temporary build issues.
+                        Removing <filename>TMPDIR</filename> is usually a
+                        relatively cheap operation, because task output will be
+                        cached in
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-SSTATE_DIR'><filename>SSTATE_DIR</filename></ulink>
+                        (usually <filename>sstate-cache/</filename>, which is
+                        also in the Build Directory).
+                        <note>
+                            Removing <filename>TMPDIR</filename> might be a
+                            workaround rather than a fix.
+                            Consequently, trying to determine the underlying
+                            cause of an issue before removing the directory is
+                            a good idea.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        Understanding how a feature is used in practice within
+                        existing recipes can be very helpful.
+                        It is recommended that you configure some method that
+                        allows you to quickly search through files.</para>
+
+                        <para>Using GNU Grep, you can use the following shell
+                        function to recursively search through common
+                        recipe-related files, skipping binary files,
+                        <filename>.git</filename> directories, and the
+                        Build Directory (assuming its name starts with
+                        "build"):
+                        <literallayout class='monospaced'>
+     g() {
+         grep -Ir \
+              --exclude-dir=.git \
+              --exclude-dir='build*' \
+              --include='*.bb*' \
+              --include='*.inc*' \
+              --include='*.conf*' \
+              --include='*.py*' \
+              "$@"
+     }
+                        </literallayout>
+                        Following are some usage examples:
+                        <literallayout class='monospaced'>
+     $ g FOO    # Search recursively for "FOO"
+     $ g -i foo # Search recursively for "foo", ignoring case
+     $ g -w FOO # Search recursively for "FOO" as a word, ignoring e.g. "FOOBAR"
+                        </literallayout>
+                        If figuring out how some feature works requires a lot of
+                        searching, it might indicate that the documentation
+                        should be extended or improved.
+                        In such cases, consider filing a documentation bug using
+                        the Yocto Project implementation of
+                        <ulink url='https://bugzilla.yoctoproject.org/'>Bugzilla</ulink>.
+                        For information on how to submit a bug against
+                        the Yocto Project, see the Yocto Project Bugzilla
+                        <ulink url='&YOCTO_WIKI_URL;/wiki/Bugzilla_Configuration_and_Bug_Tracking'>wiki page</ulink>
+                        and the
+                        "<link linkend='submitting-a-defect-against-the-yocto-project'>Submitting a Defect Against the Yocto Project</link>"
+                        section.
+                        <note>
+                            The manuals might not be the right place to document
+                            variables that are purely internal and have a
+                            limited scope (e.g. internal variables used to
+                            implement a single <filename>.bbclass</filename>
+                            file).
+                        </note>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+    </section>
+
+    <section id='making-changes-to-the-yocto-project'>
+        <title>Making Changes to the Yocto Project</title>
+
+        <para>
+            Because the Yocto Project is an open-source, community-based
+            project, you can effect changes to the project.
+            This section presents procedures that show you how to submit
+            a defect against the project and how to submit a change.
+        </para>
+
+        <section id='submitting-a-defect-against-the-yocto-project'>
+            <title>Submitting a Defect Against the Yocto Project</title>
+
+            <para>
+                Use the Yocto Project implementation of
+                <ulink url='http://www.bugzilla.org/about/'>Bugzilla</ulink>
+                to submit a defect (bug) against the Yocto Project.
+                For additional information on this implementation of Bugzilla see the
+                "<ulink url='&YOCTO_DOCS_REF_URL;#resources-bugtracker'>Yocto Project Bugzilla</ulink>"
+                section in the Yocto Project Reference Manual.
+                For more detail on any of the following steps, see the Yocto Project
+                <ulink url='&YOCTO_WIKI_URL;/wiki/Bugzilla_Configuration_and_Bug_Tracking'>Bugzilla wiki page</ulink>.
+            </para>
+
+            <para>
+                Use the following general steps to submit a bug"
+
+                <orderedlist>
+                    <listitem><para>
+                        Open the Yocto Project implementation of
+                        <ulink url='&YOCTO_BUGZILLA_URL;'>Bugzilla</ulink>.
+                        </para></listitem>
+                    <listitem><para>
+                        Click "File a Bug" to enter a new bug.
+                        </para></listitem>
+                    <listitem><para>
+                        Choose the appropriate "Classification", "Product", and
+                        "Component" for which the bug was found.
+                        Bugs for the Yocto Project fall into one of several
+                        classifications, which in turn break down into several
+                        products and components.
+                        For example, for a bug against the
+                        <filename>meta-intel</filename> layer, you would choose
+                        "Build System, Metadata &amp; Runtime", "BSPs", and
+                        "bsps-meta-intel", respectively.
+                        </para></listitem>
+                    <listitem><para>
+                        Choose the "Version" of the Yocto Project for which you found
+                        the bug (e.g. &DISTRO;).
+                        </para></listitem>
+                    <listitem><para>
+                        Determine and select the "Severity" of the bug.
+                        The severity indicates how the bug impacted your work.
+                        </para></listitem>
+                    <listitem><para>
+                        Choose the "Hardware" that the bug impacts.
+                        </para></listitem>
+                    <listitem><para>
+                        Choose the "Architecture" that the bug impacts.
+                        </para></listitem>
+                    <listitem><para>
+                        Choose a "Documentation change" item for the bug.
+                        Fixing a bug might or might not affect the Yocto Project
+                        documentation.
+                        If you are unsure of the impact to the documentation, select
+                        "Don't Know".
+                        </para></listitem>
+                    <listitem><para>
+                        Provide a brief "Summary" of the bug.
+                        Try to limit your summary to just a line or two and be sure
+                        to capture the essence of the bug.
+                        </para></listitem>
+                    <listitem><para>
+                        Provide a detailed "Description" of the bug.
+                        You should provide as much detail as you can about the context,
+                        behavior, output, and so forth that surrounds the bug.
+                        You can even attach supporting files for output from logs by
+                        using the "Add an attachment" button.
+                        </para></listitem>
+                    <listitem><para>
+                        Click the "Submit Bug" button submit the bug.
+                        A new Bugzilla number is assigned to the bug and the defect
+                        is logged in the bug tracking system.
+                        </para></listitem>
+                </orderedlist>
+                Once you file a bug, the bug is processed by the Yocto Project Bug
+                Triage Team and further details concerning the bug are assigned
+                (e.g. priority and owner).
+                You are the "Submitter" of the bug and any further categorization,
+                progress, or comments on the bug result in Bugzilla sending you an
+                automated email concerning the particular change or progress to the
+                bug.
+            </para>
+        </section>
+
+        <section id='how-to-submit-a-change'>
+            <title>Submitting a Change to the Yocto Project</title>
+
+            <para>
+                Contributions to the Yocto Project and OpenEmbedded are very welcome.
+                Because the system is extremely configurable and flexible, we recognize
+                that developers will want to extend, configure or optimize it for
+                their specific uses.
+            </para>
+
+            <para>
+                The Yocto Project uses a mailing list and a patch-based workflow
+                that is similar to the Linux kernel but contains important
+                differences.
+                In general, a mailing list exists through which you can submit
+                patches.
+                You should send patches to the appropriate mailing list so that they
+                can be reviewed and merged by the appropriate maintainer.
+                The specific mailing list you need to use depends on the
+                location of the code you are changing.
+                Each component (e.g. layer) should have a
+                <filename>README</filename> file that indicates where to send
+                the changes and which process to follow.
+            </para>
+
+            <para>
+                You can send the patch to the mailing list using whichever approach
+                you feel comfortable with to generate the patch.
+                Once sent, the patch is usually reviewed by the community at large.
+                If somebody has concerns with the patch, they will usually voice
+                their concern over the mailing list.
+                If a patch does not receive any negative reviews, the maintainer of
+                the affected layer typically takes the patch, tests it, and then
+                based on successful testing, merges the patch.
+            </para>
+
+            <para id='figuring-out-the-mailing-list-to-use'>
+                The "poky" repository, which is the Yocto Project's reference build
+                environment, is a hybrid repository that contains several
+                individual pieces (e.g. BitBake, Metadata, documentation,
+                and so forth) built using the combo-layer tool.
+                The upstream location used for submitting changes varies by
+                component:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>Core Metadata:</emphasis>
+                        Send your patch to the
+                        <ulink url='http://lists.openembedded.org/mailman/listinfo/openembedded-core'>openembedded-core</ulink>
+                        mailing list.  For example, a change to anything under
+                        the <filename>meta</filename> or
+                        <filename>scripts</filename> directories should be sent
+                        to this mailing list.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>BitBake:</emphasis>
+                        For changes to BitBake (i.e. anything under the
+                        <filename>bitbake</filename> directory), send your patch
+                        to the
+                        <ulink url='http://lists.openembedded.org/mailman/listinfo/bitbake-devel'>bitbake-devel</ulink>
+                        mailing list.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>"meta-*" trees:</emphasis>
+                        These trees contain Metadata.
+                        Use the
+                        <ulink url='https://lists.yoctoproject.org/listinfo/poky'>poky</ulink>
+                        mailing list.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                For changes to other layers hosted in the Yocto Project source
+                repositories (i.e. <filename>yoctoproject.org</filename>), tools,
+                and the Yocto Project documentation, use the
+                <ulink url='https://lists.yoctoproject.org/listinfo/yocto'>Yocto Project</ulink>
+                general mailing list.
+                <note>
+                    Sometimes a layer's documentation specifies to use a
+                    particular mailing list.
+                    If so, use that list.
+                </note>
+                For additional recipes that do not fit into the core Metadata, you
+                should determine which layer the recipe should go into and submit
+                the change in the manner recommended by the documentation (e.g.
+                the <filename>README</filename> file) supplied with the layer.
+                If in doubt, please ask on the Yocto general mailing list or on
+                the openembedded-devel mailing list.
+            </para>
+
+            <para>
+                You can also push a change upstream and request a maintainer to
+                pull the change into the component's upstream repository.
+                You do this by pushing to a contribution repository that is upstream.
+                See the
+                "<ulink url='&YOCTO_DOCS_OM_URL;#gs-git-workflows-and-the-yocto-project'>Git Workflows and the Yocto Project</ulink>"
+                section in the Yocto Project Overview and Concepts Manual for additional
+                concepts on working in the Yocto Project development environment.
+            </para>
+
+            <para>
+                Two commonly used testing repositories exist for
+                OpenEmbedded-Core:
+                <itemizedlist>
+                    <listitem><para>
+                        <emphasis>"ross/mut" branch:</emphasis>
+                        The "mut" (master-under-test) tree
+                        exists in the <filename>poky-contrib</filename> repository
+                        in the
+                        <ulink url='&YOCTO_GIT_URL;'>Yocto Project source repositories</ulink>.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>"master-next" branch:</emphasis>
+                        This branch is part of the main
+                        "poky" repository in the Yocto Project source repositories.
+                        </para></listitem>
+                </itemizedlist>
+                Maintainers use these branches to test submissions prior to merging
+                patches.
+                Thus, you can get an idea of the status of a patch based on
+                whether the patch has been merged into one of these branches.
+                <note>
+                    This system is imperfect and changes can sometimes get lost in the
+                    flow.
+                    Asking about the status of a patch or change is reasonable if the
+                    change has been idle for a while with no feedback.
+                    The Yocto Project does have plans to use
+                    <ulink url='https://en.wikipedia.org/wiki/Patchwork_(software)'>Patchwork</ulink>
+                    to track the status of patches and also to automatically preview
+                    patches.
+                </note>
+            </para>
+
+            <para>
+                The following sections provide procedures for submitting a change.
+            </para>
+
+            <section id='pushing-a-change-upstream'>
+                <title>Using Scripts to Push a Change Upstream and Request a Pull</title>
+
+                <para>
+                    Follow this procedure to push a change to an upstream "contrib"
+                    Git repository:
+                    <note>
+                        You can find general Git information on how to push a change
+                        upstream in the
+                        <ulink url='http://git-scm.com/book/en/v2/Distributed-Git-Distributed-Workflows'>Git Community Book</ulink>.
+                    </note>
+                    <orderedlist>
+                        <listitem><para>
+                            <emphasis>Make Your Changes Locally:</emphasis>
+                            Make your changes in your local Git repository.
+                            You should make small, controlled, isolated changes.
+                            Keeping changes small and isolated aids review,
+                            makes merging/rebasing easier and keeps the change
+                            history clean should anyone need to refer to it in
+                            future.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Stage Your Changes:</emphasis>
+                            Stage your changes by using the <filename>git add</filename>
+                            command on each file you changed.
+                            </para></listitem>
+                        <listitem><para id='making-sure-you-have-correct-commit-information'>
+                            <emphasis>Commit Your Changes:</emphasis>
+                            Commit the change by using the
+                            <filename>git commit</filename> command.
+                            Make sure your commit information follows standards by
+                            following these accepted conventions:
+                            <itemizedlist>
+                                <listitem><para>
+                                    Be sure to include a "Signed-off-by:" line in the
+                                    same style as required by the Linux kernel.
+                                    Adding this line signifies that you, the submitter,
+                                    have agreed to the Developer's Certificate of
+                                    Origin 1.1 as follows:
+                                    <literallayout class='monospaced'>
+     Developer's Certificate of Origin 1.1
+
+     By making a contribution to this project, I certify that:
+
+     (a) The contribution was created in whole or in part by me and I
+         have the right to submit it under the open source license
+         indicated in the file; or
+
+     (b) The contribution is based upon previous work that, to the best
+         of my knowledge, is covered under an appropriate open source
+         license and I have the right under that license to submit that
+         work with modifications, whether created in whole or in part
+         by me, under the same open source license (unless I am
+         permitted to submit under a different license), as indicated
+         in the file; or
+
+     (c) The contribution was provided directly to me by some other
+         person who certified (a), (b) or (c) and I have not modified
+         it.
+
+     (d) I understand and agree that this project and the contribution
+         are public and that a record of the contribution (including all
+         personal information I submit with it, including my sign-off) is
+         maintained indefinitely and may be redistributed consistent with
+         this project or the open source license(s) involved.
+                                    </literallayout>
+                                    </para></listitem>
+                                <listitem><para>
+                                    Provide a single-line summary of the change.
+                                    and,
+                                    if more explanation is needed, provide more
+                                    detail in the body of the commit.
+                                    This summary is typically viewable in the
+                                    "shortlist" of changes.
+                                    Thus, providing something short and descriptive
+                                    that gives the reader a summary of the change is
+                                    useful when viewing a list of many commits.
+                                    You should prefix this short description with the
+                                    recipe name (if changing a recipe), or else with
+                                    the short form path to the file being changed.
+                                    </para></listitem>
+                                <listitem><para>
+                                    For the body of the commit message, provide
+                                    detailed information that describes what you
+                                    changed, why you made the change, and the approach
+                                    you used.
+                                    It might also be helpful if you mention how you
+                                    tested the change.
+                                    Provide as much detail as you can in the body of
+                                    the commit message.
+                                    <note>
+                                        You do not need to provide a more detailed
+                                        explanation of a change if the change is
+                                        minor to the point of the single line
+                                        summary providing all the information.
+                                    </note>
+                                    </para></listitem>
+                                <listitem><para>
+                                    If the change addresses a specific bug or issue
+                                    that is associated with a bug-tracking ID,
+                                    include a reference to that ID in your detailed
+                                    description.
+                                    For example, the Yocto Project uses a specific
+                                    convention for bug references - any commit that
+                                    addresses a specific bug should use the following
+                                    form for the detailed description.
+                                    Be sure to use the actual bug-tracking ID from
+                                    Bugzilla for
+                                    <replaceable>bug-id</replaceable>:
+                                    <literallayout class='monospaced'>
+     Fixes [YOCTO #<replaceable>bug-id</replaceable>]
+
+     <replaceable>detailed description of change</replaceable>
+                                    </literallayout>
+                                    </para></listitem>
+                            </itemizedlist>
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Push Your Commits to a "Contrib" Upstream:</emphasis>
+                            If you have arranged for permissions to push to an
+                            upstream contrib repository, push the change to that
+                            repository:
+                            <literallayout class='monospaced'>
+     $ git push <replaceable>upstream_remote_repo</replaceable> <replaceable>local_branch_name</replaceable>
+                            </literallayout>
+                            For example, suppose you have permissions to push into the
+                            upstream <filename>meta-intel-contrib</filename>
+                            repository and you are working in a local branch named
+                            <replaceable>your_name</replaceable><filename>/README</filename>.
+                            The following command pushes your local commits to the
+                            <filename>meta-intel-contrib</filename> upstream
+                            repository and puts the commit in a branch named
+                            <replaceable>your_name</replaceable><filename>/README</filename>:
+                            <literallayout class='monospaced'>
+     $ git push meta-intel-contrib <replaceable>your_name</replaceable>/README
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para id='push-determine-who-to-notify'>
+                            <emphasis>Determine Who to Notify:</emphasis>
+                            Determine the maintainer or the mailing list
+                            that you need to notify for the change.</para>
+
+                            <para>Before submitting any change, you need to be sure
+                            who the maintainer is or what mailing list that you need
+                            to notify.
+                            Use either these methods to find out:
+                            <itemizedlist>
+                                <listitem><para>
+                                    <emphasis>Maintenance File:</emphasis>
+                                    Examine the <filename>maintainers.inc</filename>
+                                    file, which is located in the
+                                    <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                                    at
+                                    <filename>meta/conf/distro/include</filename>,
+                                    to see who is responsible for code.
+                                    </para></listitem>
+                                <listitem><para>
+                                    <emphasis>Search by File:</emphasis>
+                                    Using <ulink url='&YOCTO_DOCS_OM_URL;#git'>Git</ulink>,
+                                    you can enter the following command to bring up a
+                                    short list of all commits against a specific file:
+                                    <literallayout class='monospaced'>
+     git shortlog -- <replaceable>filename</replaceable>
+                                    </literallayout>
+                                    Just provide the name of the file for which you
+                                    are interested.
+                                    The information returned is not ordered by history
+                                    but does include a list of everyone who has
+                                    committed grouped by name.
+                                    From the list, you can see who is responsible for
+                                    the bulk of the changes against the file.
+                                    </para></listitem>
+                                <listitem><para>
+                                    <emphasis>Examine the List of Mailing Lists:</emphasis>
+                                    For a list of the Yocto Project and related mailing
+                                    lists, see the
+                                    "<ulink url='&YOCTO_DOCS_REF_URL;#resources-mailinglist'>Mailing lists</ulink>"
+                                    section in the Yocto Project Reference Manual.
+                                    </para></listitem>
+                            </itemizedlist>
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Make a Pull Request:</emphasis>
+                            Notify the maintainer or the mailing list that you have
+                            pushed a change by making a pull request.</para>
+
+                            <para>The Yocto Project provides two scripts that
+                            conveniently let you generate and send pull requests to the
+                            Yocto Project.
+                            These scripts are <filename>create-pull-request</filename>
+                            and <filename>send-pull-request</filename>.
+                            You can find these scripts in the
+                            <filename>scripts</filename> directory within the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                            (e.g. <filename>~/poky/scripts</filename>).
+                            </para>
+
+                            <para>Using these scripts correctly formats the requests
+                            without introducing any whitespace or HTML formatting.
+                            The maintainer that receives your patches either directly
+                            or through the mailing list needs to be able to save and
+                            apply them directly from your emails.
+                            Using these scripts is the preferred method for sending
+                            patches.</para>
+
+                            <para>First, create the pull request.
+                            For example, the following command runs the script,
+                            specifies the upstream repository in the contrib directory
+                            into which you pushed the change, and provides a subject
+                            line in the created patch files:
+                            <literallayout class='monospaced'>
+     $ ~/poky/scripts/create-pull-request -u meta-intel-contrib -s "Updated Manual Section Reference in README"
+                            </literallayout>
+                            Running this script forms
+                            <filename>*.patch</filename> files in a folder named
+                            <filename>pull-</filename><replaceable>PID</replaceable>
+                            in the current directory.
+                            One of the patch files is a cover letter.</para>
+
+                            <para>Before running the
+                            <filename>send-pull-request</filename> script, you must
+                            edit the cover letter patch to insert information about
+                            your change.
+                            After editing the cover letter, send the pull request.
+                            For example, the following command runs the script and
+                            specifies the patch directory and email address.
+                            In this example, the email address is a mailing list:
+                            <literallayout class='monospaced'>
+     $ ~/poky/scripts/send-pull-request -p ~/meta-intel/pull-10565 -t meta-intel@yoctoproject.org
+                            </literallayout>
+                            You need to follow the prompts as the script is
+                            interactive.
+                            <note>
+                                For help on using these scripts, simply provide the
+                                <filename>-h</filename> argument as follows:
+                                <literallayout class='monospaced'>
+     $ poky/scripts/create-pull-request -h
+     $ poky/scripts/send-pull-request -h
+                                </literallayout>
+                            </note>
+                            </para></listitem>
+                    </orderedlist>
+                </para>
+            </section>
+
+            <section id='submitting-a-patch'>
+                <title>Using Email to Submit a Patch</title>
+
+                <para>
+                    You can submit patches without using the
+                    <filename>create-pull-request</filename> and
+                    <filename>send-pull-request</filename> scripts described in the
+                    previous section.
+                    However, keep in mind, the preferred method is to use the scripts.
+                </para>
+
+                <para>
+                    Depending on the components changed, you need to submit the email
+                    to a specific mailing list.
+                    For some guidance on which mailing list to use, see the
+                    <link linkend='figuring-out-the-mailing-list-to-use'>list</link>
+                    at the beginning of this section.
+                    For a description of all the available mailing lists, see the
+                    "<ulink url='&YOCTO_DOCS_REF_URL;#resources-mailinglist'>Mailing Lists</ulink>"
+                    section in the Yocto Project Reference Manual.
+                </para>
+
+                <para>
+                    Here is the general procedure on how to submit a patch through
+                    email without using the scripts:
+                    <orderedlist>
+                        <listitem><para>
+                            <emphasis>Make Your Changes Locally:</emphasis>
+                            Make your changes in your local Git repository.
+                            You should make small, controlled, isolated changes.
+                            Keeping changes small and isolated aids review,
+                            makes merging/rebasing easier and keeps the change
+                            history clean should anyone need to refer to it in
+                            future.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Stage Your Changes:</emphasis>
+                            Stage your changes by using the <filename>git add</filename>
+                            command on each file you changed.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Commit Your Changes:</emphasis>
+                            Commit the change by using the
+                            <filename>git commit --signoff</filename> command.
+                            Using the <filename>--signoff</filename> option identifies
+                            you as the person making the change and also satisfies
+                            the Developer's Certificate of Origin (DCO) shown earlier.
+                            </para>
+
+                            <para>When you form a commit, you must follow certain
+                            standards established by the Yocto Project development
+                            team.
+                            See
+                            <link linkend='making-sure-you-have-correct-commit-information'>Step 3</link>
+                            in the previous section for information on how to
+                            provide commit information that meets Yocto Project
+                            commit message standards.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Format the Commit:</emphasis>
+                            Format the commit into an email message.
+                            To format commits, use the
+                            <filename>git format-patch</filename> command.
+                            When you provide the command, you must include a revision
+                            list or a number of patches as part of the command.
+                            For example, either of these two commands takes your most
+                            recent single commit and formats it as an email message in
+                            the current directory:
+                            <literallayout class='monospaced'>
+     $ git format-patch -1
+                            </literallayout>
+                            or
+                            <literallayout class='monospaced'>
+     $ git format-patch HEAD~
+                            </literallayout></para>
+
+                            <para>After the command is run, the current directory
+                            contains a numbered <filename>.patch</filename> file for
+                            the commit.</para>
+
+                            <para>If you provide several commits as part of the
+                            command, the <filename>git format-patch</filename> command
+                            produces a series of numbered files in the current
+                            directory – one for each commit.
+                            If you have more than one patch, you should also use the
+                            <filename>--cover</filename> option with the command,
+                            which generates a cover letter as the first "patch" in
+                            the series.
+                            You can then edit the cover letter to provide a
+                            description for the series of patches.
+                            For information on the
+                            <filename>git format-patch</filename> command,
+                            see <filename>GIT_FORMAT_PATCH(1)</filename> displayed
+                            using the <filename>man git-format-patch</filename>
+                            command.
+                            <note>
+                                If you are or will be a frequent contributor to the
+                                Yocto Project or to OpenEmbedded, you might consider
+                                requesting a contrib area and the necessary associated
+                                rights.
+                            </note>
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Import the Files Into Your Mail Client:</emphasis>
+                            Import the files into your mail client by using the
+                            <filename>git send-email</filename> command.
+                            <note>
+                                In order to use <filename>git send-email</filename>,
+                                you must have the proper Git packages installed on
+                                your host.
+                                For Ubuntu, Debian, and Fedora the package is
+                                <filename>git-email</filename>.
+                            </note></para>
+
+                            <para>The <filename>git send-email</filename> command
+                            sends email by using a local or remote Mail Transport Agent
+                            (MTA) such as <filename>msmtp</filename>,
+                            <filename>sendmail</filename>, or through a direct
+                            <filename>smtp</filename> configuration in your Git
+                            <filename>~/.gitconfig</filename> file.
+                            If you are submitting patches through email only, it is
+                            very important that you submit them without any whitespace
+                            or HTML formatting that either you or your mailer
+                            introduces.
+                            The maintainer that receives your patches needs to be able
+                            to save and apply them directly from your emails.
+                            A good way to verify that what you are sending will be
+                            applicable by the maintainer is to do a dry run and send
+                            them to yourself and then save and apply them as the
+                            maintainer would.</para>
+
+                            <para>The <filename>git send-email</filename> command is
+                            the preferred method for sending your patches using
+                            email since there is no risk of compromising whitespace
+                            in the body of the message, which can occur when you use
+                            your own mail client.
+                            The command also has several options that let you
+                            specify recipients and perform further editing of the
+                            email message.
+                            For information on how to use the
+                            <filename>git send-email</filename> command,
+                            see <filename>GIT-SEND-EMAIL(1)</filename> displayed using
+                            the <filename>man git-send-email</filename> command.
+                            </para></listitem>
+                    </orderedlist>
+                </para>
+            </section>
+        </section>
+    </section>
+
+    <section id='working-with-licenses'>
+        <title>Working With Licenses</title>
+
+        <para>
+            As mentioned in the
+            "<ulink url='&YOCTO_DOCS_OM_URL;#licensing'>Licensing</ulink>"
+            section in the Yocto Project Overview and Concepts Manual,
+            open source projects are open to the public and they
+            consequently have different licensing structures in place.
+            This section describes the mechanism by which the
+            <ulink url='&YOCTO_DOCS_REF_URL;#build-system-term'>OpenEmbedded build system</ulink>
+            tracks changes to licensing text and covers how to maintain open
+            source license compliance during your project's lifecycle.
+            The section also describes how to enable commercially licensed
+            recipes, which by default are disabled.
+        </para>
+
+        <section id="usingpoky-configuring-LIC_FILES_CHKSUM">
+            <title>Tracking License Changes</title>
+
+            <para>
+                The license of an upstream project might change in the future.
+                In order to prevent these changes going unnoticed, the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></ulink>
+                variable tracks changes to the license text. The checksums are
+                validated at the end of the configure step, and if the
+                checksums do not match, the build will fail.
+            </para>
+
+            <section id="usingpoky-specifying-LIC_FILES_CHKSUM">
+                <title>Specifying the <filename>LIC_FILES_CHKSUM</filename> Variable</title>
+
+                <para>
+                    The <filename>LIC_FILES_CHKSUM</filename>
+                    variable contains checksums of the license text in the
+                    source code for the recipe.
+                    Following is an example of how to specify
+                    <filename>LIC_FILES_CHKSUM</filename>:
+                    <literallayout class='monospaced'>
+     LIC_FILES_CHKSUM = "file://COPYING;md5=xxxx \
+                         file://licfile1.txt;beginline=5;endline=29;md5=yyyy \
+                         file://licfile2.txt;endline=50;md5=zzzz \
+                         ..."
+                    </literallayout>
+                    <note><title>Notes</title>
+                        <itemizedlist>
+                            <listitem><para>
+                                When using "beginline" and "endline", realize
+                                that line numbering begins with one and not
+                                zero.
+                                Also, the included lines are inclusive (i.e.
+                                lines five through and including 29 in the
+                                previous example for
+                                <filename>licfile1.txt</filename>).
+                                </para></listitem>
+                            <listitem><para>
+                                When a license check fails, the selected license
+                                text is included as part of the QA message.
+                                Using this output, you can determine the exact
+                                start and finish for the needed license text.
+                                </para></listitem>
+                        </itemizedlist>
+                    </note>
+                </para>
+
+                <para>
+                    The build system uses the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>
+                    variable as the default directory when searching files
+                    listed in <filename>LIC_FILES_CHKSUM</filename>.
+                    The previous example employs the default directory.
+                </para>
+
+                <para>
+                    Consider this next example:
+                    <literallayout class='monospaced'>
+     LIC_FILES_CHKSUM = "file://src/ls.c;beginline=5;endline=16;\
+                                         md5=bb14ed3c4cda583abc85401304b5cd4e"
+     LIC_FILES_CHKSUM = "file://${WORKDIR}/license.html;md5=5c94767cedb5d6987c902ac850ded2c6"
+                    </literallayout>
+                </para>
+
+                <para>
+                    The first line locates a file in
+                    <filename>${S}/src/ls.c</filename> and isolates lines five
+                    through 16 as license text.
+                    The second line refers to a file in
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink>.
+                </para>
+
+                <para>
+                    Note that <filename>LIC_FILES_CHKSUM</filename> variable is
+                    mandatory for all recipes, unless the
+                    <filename>LICENSE</filename> variable is set to "CLOSED".
+                </para>
+            </section>
+
+            <section id="usingpoky-LIC_FILES_CHKSUM-explanation-of-syntax">
+                <title>Explanation of Syntax</title>
+
+                <para>
+                    As mentioned in the previous section, the
+                    <filename>LIC_FILES_CHKSUM</filename> variable lists all
+                    the important files that contain the license text for the
+                    source code.
+                    It is possible to specify a checksum for an entire file,
+                    or a specific section of a file (specified by beginning and
+                    ending line numbers with the "beginline" and "endline"
+                    parameters, respectively).
+                    The latter is useful for source files with a license
+                    notice header, README documents, and so forth.
+                    If you do not use the "beginline" parameter, then it is
+                    assumed that the text begins on the first line of the file.
+                    Similarly, if you do not use the "endline" parameter,
+                    it is assumed that the license text ends with the last
+                    line of the file.
+                </para>
+
+                <para>
+                    The "md5" parameter stores the md5 checksum of the license
+                    text.
+                    If the license text changes in any way as compared to
+                    this parameter then a mismatch occurs.
+                    This mismatch triggers a build failure and notifies
+                    the developer.
+                    Notification allows the developer to review and address
+                    the license text changes.
+                    Also note that if a mismatch occurs during the build,
+                    the correct md5 checksum is placed in the build log and
+                    can be easily copied to the recipe.
+                </para>
+
+                <para>
+                    There is no limit to how many files you can specify using
+                    the <filename>LIC_FILES_CHKSUM</filename> variable.
+                    Generally, however, every project requires a few
+                    specifications for license tracking.
+                    Many projects have a "COPYING" file that stores the
+                    license information for all the source code files.
+                    This practice allows you to just track the "COPYING"
+                    file as long as it is kept up to date.
+                    <note><title>Tips</title>
+                        <itemizedlist>
+                            <listitem><para>
+                                If you specify an empty or invalid "md5"
+                                parameter,
+                                <ulink url='&YOCTO_DOCS_REF_URL;#bitbake-term'>BitBake</ulink>
+                                returns an md5 mis-match
+                                error and displays the correct "md5" parameter
+                                value during the build.
+                                The correct parameter is also captured in
+                                the build log.
+                                </para></listitem>
+                            <listitem><para>
+                                If the whole file contains only license text,
+                                you do not need to use the "beginline" and
+                               "endline" parameters.
+                               </para></listitem>
+                        </itemizedlist>
+                    </note>
+                </para>
+            </section>
+        </section>
+
+        <section id="enabling-commercially-licensed-recipes">
+            <title>Enabling Commercially Licensed Recipes</title>
+
+            <para>
+                By default, the OpenEmbedded build system disables
+                components that have commercial or other special licensing
+                requirements.
+                Such requirements are defined on a
+                recipe-by-recipe basis through the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE_FLAGS'><filename>LICENSE_FLAGS</filename></ulink>
+                variable definition in the affected recipe.
+                For instance, the
+                <filename>poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly</filename>
+                recipe contains the following statement:
+                <literallayout class='monospaced'>
+     LICENSE_FLAGS = "commercial"
+                </literallayout>
+                Here is a slightly more complicated example that contains both
+                an explicit recipe name and version (after variable expansion):
+                <literallayout class='monospaced'>
+     LICENSE_FLAGS = "license_${PN}_${PV}"
+                </literallayout>
+	            In order for a component restricted by a
+                <filename>LICENSE_FLAGS</filename> definition to be enabled and
+                included in an image, it needs to have a matching entry in the
+                global
+	            <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE_FLAGS_WHITELIST'><filename>LICENSE_FLAGS_WHITELIST</filename></ulink>
+                variable, which is a variable typically defined in your
+                <filename>local.conf</filename> file.
+                For example, to enable the
+                <filename>poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly</filename>
+	            package, you could add either the string
+	            "commercial_gst-plugins-ugly" or the more general string
+	            "commercial" to <filename>LICENSE_FLAGS_WHITELIST</filename>.
+                See the
+                "<link linkend='license-flag-matching'>License Flag Matching</link>"
+                section for a full
+                explanation of how <filename>LICENSE_FLAGS</filename> matching
+                works.
+                Here is the example:
+                <literallayout class='monospaced'>
+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly"
+                </literallayout>
+	            Likewise, to additionally enable the package built from the
+                recipe containing
+	            <filename>LICENSE_FLAGS = "license_${PN}_${PV}"</filename>,
+                and assuming that the actual recipe name was
+                <filename>emgd_1.10.bb</filename>, the following string would
+                enable that package as well as the original
+                <filename>gst-plugins-ugly</filename> package:
+                <literallayout class='monospaced'>
+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly license_emgd_1.10"
+                </literallayout>
+	            As a convenience, you do not need to specify the complete
+                license string in the whitelist for every package.
+                You can use an abbreviated form, which consists
+                of just the first portion or portions of the license
+                string before the initial underscore character or characters.
+                A partial string will match any license that contains the
+                given string as the first portion of its license.
+                For example, the following whitelist string will also match
+                both of the packages previously mentioned as well as any other
+                packages that have licenses starting with "commercial" or
+                "license".
+                <literallayout class='monospaced'>
+     LICENSE_FLAGS_WHITELIST = "commercial license"
+                </literallayout>
+            </para>
+
+            <section id="license-flag-matching">
+                <title>License Flag Matching</title>
+
+                <para>
+		            License flag matching allows you to control what recipes
+                    the OpenEmbedded build system includes in the build.
+                    Fundamentally, the build system attempts to match
+                    <filename>LICENSE_FLAGS</filename> strings found in recipes
+                    against <filename>LICENSE_FLAGS_WHITELIST</filename>
+                    strings found in the whitelist.
+                    A match causes the build system to include a recipe in the
+                    build, while failure to find a match causes the build
+                    system to exclude a recipe.
+                </para>
+
+                <para>
+                    In general, license flag matching is simple.
+                    However, understanding some concepts will help you
+                    correctly and effectively use matching.
+                </para>
+
+                <para>
+                    Before a flag
+                    defined by a particular recipe is tested against the
+                    contents of the whitelist, the expanded string
+                    <filename>_${PN}</filename> is appended to the flag.
+                    This expansion makes each
+                    <filename>LICENSE_FLAGS</filename> value recipe-specific.
+                    After expansion, the string is then matched against the
+                    whitelist.
+                    Thus, specifying
+                    <filename>LICENSE_FLAGS = "commercial"</filename>
+                    in recipe "foo", for example, results in the string
+                    <filename>"commercial_foo"</filename>.
+                    And, to create a match, that string must appear in the
+                    whitelist.
+                </para>
+
+                <para>
+                    Judicious use of the <filename>LICENSE_FLAGS</filename>
+                    strings and the contents of the
+                    <filename>LICENSE_FLAGS_WHITELIST</filename> variable
+                    allows you a lot of flexibility for including or excluding
+                    recipes based on licensing.
+                    For example, you can broaden the matching capabilities by
+                    using license flags string subsets in the whitelist.
+                    <note>
+                        When using a string subset, be sure to use the part of
+                        the expanded string that precedes the appended
+                        underscore character (e.g.
+                        <filename>usethispart_1.3</filename>,
+                        <filename>usethispart_1.4</filename>, and so forth).
+                    </note>
+                    For example, simply specifying the string "commercial" in
+                    the whitelist matches any expanded
+                    <filename>LICENSE_FLAGS</filename> definition that starts
+                    with the string "commercial" such as "commercial_foo" and
+                    "commercial_bar", which are the strings the build system
+                    automatically generates for hypothetical recipes named
+                    "foo" and "bar" assuming those recipes simply specify the
+                    following:
+                    <literallayout class='monospaced'>
+     LICENSE_FLAGS = "commercial"
+                    </literallayout>
+                    Thus, you can choose to exhaustively
+                    enumerate each license flag in the whitelist and
+                    allow only specific recipes into the image, or
+                    you can use a string subset that causes a broader range of
+                    matches to allow a range of recipes into the image.
+                </para>
+
+                <para>
+                    This scheme works even if the
+                    <filename>LICENSE_FLAGS</filename> string already
+                    has <filename>_${PN}</filename> appended.
+                    For example, the build system turns the license flag
+                    "commercial_1.2_foo" into "commercial_1.2_foo_foo" and
+                    would match both the general "commercial" and the specific
+                    "commercial_1.2_foo" strings found in the whitelist, as
+                    expected.
+                </para>
+
+                <para>
+                    Here are some other scenarios:
+                    <itemizedlist>
+                        <listitem><para>
+                            You can specify a versioned string in the recipe
+                            such as "commercial_foo_1.2" in a "foo" recipe.
+                            The build system expands this string to
+                            "commercial_foo_1.2_foo".
+                            Combine this license flag with a whitelist that has
+                            the string "commercial" and you match the flag
+                            along with any other flag that starts with the
+                            string "commercial".
+                            </para></listitem>
+                        <listitem><para>
+                            Under the same circumstances, you can use
+                            "commercial_foo" in the whitelist and the build
+                            system not only matches "commercial_foo_1.2" but
+                            also matches any license flag with the string
+                            "commercial_foo", regardless of the version.
+                            </para></listitem>
+                        <listitem><para>
+                            You can be very specific and use both the
+                            package and version parts in the whitelist (e.g.
+                            "commercial_foo_1.2") to specifically match a
+                            versioned recipe.
+                            </para></listitem>
+                    </itemizedlist>
+                </para>
+            </section>
+
+            <section id="other-variables-related-to-commercial-licenses">
+                <title>Other Variables Related to Commercial Licenses</title>
+
+                <para>
+                    Other helpful variables related to commercial
+                    license handling exist and are defined in the
+                    <filename>poky/meta/conf/distro/include/default-distrovars.inc</filename> file:
+                    <literallayout class='monospaced'>
+     COMMERCIAL_AUDIO_PLUGINS ?= ""
+     COMMERCIAL_VIDEO_PLUGINS ?= ""
+                    </literallayout>
+                    If you want to enable these components, you can do so by
+                    making sure you have statements similar to the following
+                    in your <filename>local.conf</filename> configuration file:
+                    <literallayout class='monospaced'>
+     COMMERCIAL_AUDIO_PLUGINS = "gst-plugins-ugly-mad \
+        gst-plugins-ugly-mpegaudioparse"
+     COMMERCIAL_VIDEO_PLUGINS = "gst-plugins-ugly-mpeg2dec \
+        gst-plugins-ugly-mpegstream gst-plugins-bad-mpegvideoparse"
+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly commercial_gst-plugins-bad commercial_qmmp"
+                    </literallayout>
+                    Of course, you could also create a matching whitelist
+                    for those components using the more general "commercial"
+                    in the whitelist, but that would also enable all the
+                    other packages with <filename>LICENSE_FLAGS</filename>
+                    containing "commercial", which you may or may not want:
+                    <literallayout class='monospaced'>
+     LICENSE_FLAGS_WHITELIST = "commercial"
+                    </literallayout>
+                </para>
+
+                <para>
+                    Specifying audio and video plugins as part of the
+                    <filename>COMMERCIAL_AUDIO_PLUGINS</filename> and
+                    <filename>COMMERCIAL_VIDEO_PLUGINS</filename> statements
+                    (along with the enabling
+                    <filename>LICENSE_FLAGS_WHITELIST</filename>) includes the
+                    plugins or components into built images, thus adding
+                    support for media formats or components.
+                </para>
+            </section>
+        </section>
+
+        <section id='maintaining-open-source-license-compliance-during-your-products-lifecycle'>
+            <title>Maintaining Open Source License Compliance During Your Product's Lifecycle</title>
+
+            <para>
+                One of the concerns for a development organization using open source
+                software is how to maintain compliance with various open source
+                licensing during the lifecycle of the product.
+                While this section does not provide legal advice or
+                comprehensively cover all scenarios, it does
+                present methods that you can use to
+                assist you in meeting the compliance requirements during a software
+                release.
+            </para>
+
+            <para>
+                With hundreds of different open source licenses that the Yocto
+                Project tracks, it is difficult to know the requirements of each
+                and every license.
+                However, the requirements of the major FLOSS licenses can begin
+                to be covered by
+                assuming that three main areas of concern exist:
+                <itemizedlist>
+                    <listitem><para>Source code must be provided.</para></listitem>
+                    <listitem><para>License text for the software must be
+                        provided.</para></listitem>
+                    <listitem><para>Compilation scripts and modifications to the
+                        source code must be provided.
+                        </para></listitem>
+                </itemizedlist>
+                There are other requirements beyond the scope of these
+                three and the methods described in this section
+                (e.g. the mechanism through which source code is distributed).
+            </para>
+
+            <para>
+                As different organizations have different methods of complying with
+                open source licensing, this section is not meant to imply that
+                there is only one single way to meet your compliance obligations,
+                but rather to describe one method of achieving compliance.
+                The remainder of this section describes methods supported to meet the
+                previously mentioned three requirements.
+                Once you take steps to meet these requirements,
+                and prior to releasing images, sources, and the build system,
+                you should audit all artifacts to ensure completeness.
+                <note>
+                    The Yocto Project generates a license manifest during
+                    image creation that is located
+                    in <filename>${DEPLOY_DIR}/licenses/<replaceable>image_name-datestamp</replaceable></filename>
+                    to assist with any audits.
+                </note>
+            </para>
+
+            <section id='providing-the-source-code'>
+                <title>Providing the Source Code</title>
+
+                <para>
+                    Compliance activities should begin before you generate the
+                    final image.
+                    The first thing you should look at is the requirement that
+                    tops the list for most compliance groups - providing
+                    the source.
+                    The Yocto Project has a few ways of meeting this
+                    requirement.
+                </para>
+
+                <para>
+                    One of the easiest ways to meet this requirement is
+                    to provide the entire
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-DL_DIR'><filename>DL_DIR</filename></ulink>
+                    used by the build.
+                    This method, however, has a few issues.
+                    The most obvious is the size of the directory since it includes
+                    all sources used in the build and not just the source used in
+                    the released image.
+                    It will include toolchain source, and other artifacts, which
+                    you would not generally release.
+                    However, the more serious issue for most companies is accidental
+                    release of proprietary software.
+                    The Yocto Project provides an
+                    <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-archiver'><filename>archiver</filename></ulink>
+                    class to help avoid some of these concerns.
+                </para>
+
+                <para>
+                    Before you employ <filename>DL_DIR</filename> or the
+                    <filename>archiver</filename> class, you need to decide how
+                    you choose to provide source.
+                    The source <filename>archiver</filename> class can generate
+                    tarballs and SRPMs and can create them with various levels of
+                    compliance in mind.
+                </para>
+
+                <para>
+                    One way of doing this (but certainly not the only way) is to
+                    release just the source as a tarball.
+                    You can do this by adding the following to the
+                    <filename>local.conf</filename> file found in the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>:
+                    <literallayout class='monospaced'>
+     INHERIT += "archiver"
+     ARCHIVER_MODE[src] = "original"
+                    </literallayout>
+                    During the creation of your image, the source from all
+                    recipes that deploy packages to the image is placed within
+                    subdirectories of
+                    <filename>DEPLOY_DIR/sources</filename> based on the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE</filename></ulink>
+                    for each recipe.
+                    Releasing the entire directory enables you to comply with
+                    requirements concerning providing the unmodified source.
+                    It is important to note that the size of the directory can
+                    get large.
+                </para>
+
+                <para>
+                    A way to help mitigate the size issue is to only release
+                    tarballs for licenses that require the release of
+                    source.
+                    Let us assume you are only concerned with GPL code as
+                    identified by running the following script:
+                    <literallayout class='monospaced'>
+     # Script to archive a subset of packages matching specific license(s)
+     # Source and license files are copied into sub folders of package folder
+     # Must be run from build folder
+     #!/bin/bash
+     src_release_dir="source-release"
+     mkdir -p $src_release_dir
+     for a in tmp/deploy/sources/*; do
+        for d in $a/*; do
+           # Get package name from path
+           p=`basename $d`
+           p=${p%-*}
+           p=${p%-*}
+           # Only archive GPL packages (update *GPL* regex for your license check)
+           numfiles=`ls tmp/deploy/licenses/$p/*GPL* 2> /dev/null | wc -l`
+           if [ $numfiles -gt 1 ]; then
+              echo Archiving $p
+              mkdir -p $src_release_dir/$p/source
+              cp $d/* $src_release_dir/$p/source 2> /dev/null
+              mkdir -p $src_release_dir/$p/license
+              cp tmp/deploy/licenses/$p/* $src_release_dir/$p/license 2> /dev/null
+           fi
+        done
+     done
+                    </literallayout>
+                    At this point, you could create a tarball from the
+                    <filename>gpl_source_release</filename> directory and
+                    provide that to the end user.
+                    This method would be a step toward achieving compliance
+                    with section 3a of GPLv2 and with section 6 of GPLv3.
+                </para>
+            </section>
+
+            <section id='providing-license-text'>
+                <title>Providing License Text</title>
+
+                <para>
+                    One requirement that is often overlooked is inclusion
+                    of license text.
+                    This requirement also needs to be dealt with prior to
+                    generating the final image.
+                    Some licenses require the license text to accompany
+                    the binary.
+                    You can achieve this by adding the following to your
+                    <filename>local.conf</filename> file:
+                    <literallayout class='monospaced'>
+     COPY_LIC_MANIFEST = "1"
+     COPY_LIC_DIRS = "1"
+     LICENSE_CREATE_PACKAGE = "1"
+                    </literallayout>
+                    Adding these statements to the configuration file ensures
+                    that the licenses collected during package generation
+                    are included on your image.
+                    <note>
+                        <para>Setting all three variables to "1" results in the
+                        image having two copies of the same license file.
+                        One copy resides in
+                        <filename>/usr/share/common-licenses</filename> and
+                        the other resides in
+                        <filename>/usr/share/license</filename>.</para>
+
+                        <para>The reason for this behavior is because
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-COPY_LIC_DIRS'><filename>COPY_LIC_DIRS</filename></ulink>
+                        and
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-COPY_LIC_MANIFEST'><filename>COPY_LIC_MANIFEST</filename></ulink>
+                        add a copy of the license when the image is built but do
+                        not offer a path for adding licenses for newly installed
+                        packages to an image.
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE_CREATE_PACKAGE'><filename>LICENSE_CREATE_PACKAGE</filename></ulink>
+                        adds a separate package and an upgrade path for adding
+                        licenses to an image.</para>
+                    </note>
+                </para>
+
+                <para>
+                    As the source <filename>archiver</filename> class has already
+                    archived the original
+                    unmodified source that contains the license files,
+                    you would have already met the requirements for inclusion
+                    of the license information with source as defined by the GPL
+                    and other open source licenses.
+                </para>
+            </section>
+
+            <section id='providing-compilation-scripts-and-source-code-modifications'>
+                <title>Providing Compilation Scripts and Source Code Modifications</title>
+
+                <para>
+                    At this point, we have addressed all we need to
+                    prior to generating the image.
+                    The next two requirements are addressed during the final
+                    packaging of the release.
+                </para>
+
+                <para>
+                    By releasing the version of the OpenEmbedded build system
+                    and the layers used during the build, you will be providing both
+                    compilation scripts and the source code modifications in one
+                    step.
+                </para>
+
+                <para>
+                    If the deployment team has a
+                    <ulink url='&YOCTO_DOCS_BSP_URL;#bsp-layers'>BSP layer</ulink>
+                    and a distro layer, and those those layers are used to patch,
+                    compile, package, or modify (in any way) any open source
+                    software included in your released images, you
+                    might be required to release those layers under section 3 of
+                    GPLv2 or section 1 of GPLv3.
+                    One way of doing that is with a clean
+                    checkout of the version of the Yocto Project and layers used
+                    during your build.
+                    Here is an example:
+                    <literallayout class='monospaced'>
+     # We built using the &DISTRO_NAME_NO_CAP; branch of the poky repo
+     $ git clone -b &DISTRO_NAME_NO_CAP; git://git.yoctoproject.org/poky
+     $ cd poky
+     # We built using the release_branch for our layers
+     $ git clone -b release_branch git://git.mycompany.com/meta-my-bsp-layer
+     $ git clone -b release_branch git://git.mycompany.com/meta-my-software-layer
+     # clean up the .git repos
+     $ find . -name ".git" -type d -exec rm -rf {} \;
+                    </literallayout>
+                    One thing a development organization might want to consider
+                    for end-user convenience is to modify
+                    <filename>meta-poky/conf/bblayers.conf.sample</filename> to
+                    ensure that when the end user utilizes the released build
+                    system to build an image, the development organization's
+                    layers are included in the <filename>bblayers.conf</filename>
+                    file automatically:
+                    <literallayout class='monospaced'>
+     # POKY_BBLAYERS_CONF_VERSION is increased each time build/conf/bblayers.conf
+     # changes incompatibly
+     POKY_BBLAYERS_CONF_VERSION = "2"
+
+     BBPATH = "${TOPDIR}"
+     BBFILES ?= ""
+
+     BBLAYERS ?= " \
+       ##OEROOT##/meta \
+       ##OEROOT##/meta-poky \
+       ##OEROOT##/meta-yocto-bsp \
+       ##OEROOT##/meta-mylayer \
+       "
+                    </literallayout>
+                    Creating and providing an archive of the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink>
+                    layers (recipes, configuration files, and so forth)
+                    enables you to meet your
+                    requirements to include the scripts to control compilation
+                    as well as any modifications to the original source.
+                </para>
+            </section>
+        </section>
+
+        <section id='copying-licenses-that-do-not-exist'>
+            <title>Copying Licenses that Do Not Exist</title>
+
+            <para>
+                Some packages, such as the linux-firmware package, have many
+                licenses that are not in any way common.
+                You can avoid adding a lot of these types of common license
+                files, which are only applicable to a specific package, by using
+                the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-NO_GENERIC_LICENSE'><filename>NO_GENERIC_LICENSE</filename></ulink>
+                variable.
+                Using this variable also avoids QA errors when you use a
+                non-common, non-CLOSED license in a recipe.
+            </para>
+
+            <para>
+                The following is an example that uses the
+                <filename>LICENSE.Abilis.txt</filename>
+                file as the license from the fetched source:
+                <literallayout class='monospaced'>
+     NO_GENERIC_LICENSE[Firmware-Abilis] = "LICENSE.Abilis.txt"
+                </literallayout>
+            </para>
+        </section>
+    </section>
+
+    <section id='using-the-error-reporting-tool'>
+        <title>Using the Error Reporting Tool</title>
+
+        <para>
+            The error reporting tool allows you to
+            submit errors encountered during builds to a central database.
+            Outside of the build environment, you can use a web interface to
+            browse errors, view statistics, and query for errors.
+            The tool works using a client-server system where the client
+            portion is integrated with the installed Yocto Project
+            <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+            (e.g. <filename>poky</filename>).
+            The server receives the information collected and saves it in a
+            database.
+        </para>
+
+        <para>
+            A live instance of the error reporting server exists at
+            <ulink url='http://errors.yoctoproject.org'></ulink>.
+            This server exists so that when you want to get help with
+            build failures, you can submit all of the information on the
+            failure easily and then point to the URL in your bug report
+            or send an email to the mailing list.
+            <note>
+                If you send error reports to this server, the reports become
+                publicly visible.
+            </note>
+        </para>
+
+        <section id='enabling-and-using-the-tool'>
+            <title>Enabling and Using the Tool</title>
+
+            <para>
+                By default, the error reporting tool is disabled.
+                You can enable it by inheriting the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-report-error'><filename>report-error</filename></ulink>
+                class by adding the following statement to the end of
+                your <filename>local.conf</filename> file in your
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                <literallayout class='monospaced'>
+     INHERIT += "report-error"
+                </literallayout>
+            </para>
+
+            <para>
+                By default, the error reporting feature stores information in
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-LOG_DIR'><filename>LOG_DIR</filename></ulink><filename>}/error-report</filename>.
+                However, you can specify a directory to use by adding the following
+                to your <filename>local.conf</filename> file:
+                <literallayout class='monospaced'>
+     ERR_REPORT_DIR = "path"
+                </literallayout>
+                Enabling error reporting causes the build process to collect
+                the errors and store them in a file as previously described.
+                When the build system encounters an error, it includes a
+                command as part of the console output.
+                You can run the command to send the error file to the server.
+                For example, the following command sends the errors to an
+                upstream server:
+                <literallayout class='monospaced'>
+     $ send-error-report /home/brandusa/project/poky/build/tmp/log/error-report/error_report_201403141617.txt
+                </literallayout>
+                In the previous example, the errors are sent to a public
+                database available at
+                <ulink url='http://errors.yoctoproject.org'></ulink>, which is
+                used by the entire community.
+                If you specify a particular server, you can send the errors
+                to a different database.
+                Use the following command for more information on available
+                options:
+                <literallayout class='monospaced'>
+     $ send-error-report --help
+                </literallayout>
+            </para>
+
+            <para>
+                When sending the error file, you are prompted to review the
+                data being sent as well as to provide a name and optional
+                email address.
+                Once you satisfy these prompts, the command returns a link
+                from the server that corresponds to your entry in the database.
+                For example, here is a typical link:
+                <literallayout class='monospaced'>
+     http://errors.yoctoproject.org/Errors/Details/9522/
+                </literallayout>
+                Following the link takes you to a web interface where you can
+                browse, query the errors, and view statistics.
+             </para>
+        </section>
+
+        <section id='disabling-the-tool'>
+            <title>Disabling the Tool</title>
+
+            <para>
+                To disable the error reporting feature, simply remove or comment
+                out the following statement from the end of your
+                <filename>local.conf</filename> file in your
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                <literallayout class='monospaced'>
+     INHERIT += "report-error"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='setting-up-your-own-error-reporting-server'>
+            <title>Setting Up Your Own Error Reporting Server</title>
+
+            <para>
+                If you want to set up your own error reporting server, you
+                can obtain the code from the Git repository at
+                <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/error-report-web/'></ulink>.
+                Instructions on how to set it up are in the README document.
+            </para>
+        </section>
+     </section>
+
+    <section id="dev-using-wayland-and-weston">
+        <title>Using Wayland and Weston</title>
+
+        <para>
+            <ulink url='http://en.wikipedia.org/wiki/Wayland_(display_server_protocol)'>Wayland</ulink>
+            is a computer display server protocol that
+            provides a method for compositing window managers to communicate
+            directly with applications and video hardware and expects them to
+            communicate with input hardware using other libraries.
+            Using Wayland with supporting targets can result in better control
+            over graphics frame rendering than an application might otherwise
+            achieve.
+        </para>
+
+        <para>
+            The Yocto Project provides the Wayland protocol libraries and the
+            reference
+            <ulink url='http://en.wikipedia.org/wiki/Wayland_(display_server_protocol)#Weston'>Weston</ulink>
+            compositor as part of its release.
+            You can find the integrated packages in the
+            <filename>meta</filename> layer of the
+            <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
+            Specifically, you can find the recipes that build both Wayland
+            and Weston at <filename>meta/recipes-graphics/wayland</filename>.
+        </para>
+
+        <para>
+            You can build both the Wayland and Weston packages for use only
+            with targets that accept the
+            <ulink url='https://en.wikipedia.org/wiki/Mesa_(computer_graphics)'>Mesa 3D and Direct Rendering Infrastructure</ulink>,
+            which is also known as Mesa DRI.
+            This implies that you cannot build and use the packages if your
+            target uses, for example, the
+            <trademark class='registered'>Intel</trademark> Embedded Media
+            and Graphics Driver
+            (<trademark class='registered'>Intel</trademark> EMGD) that
+            overrides Mesa DRI.
+            <note>
+                Due to lack of EGL support, Weston 1.0.3 will not run
+                directly on the emulated QEMU hardware.
+                However, this version of Weston will run under X emulation
+                without issues.
+            </note>
+        </para>
+
+        <para>
+            This section describes what you need to do to implement Wayland and
+            use the Weston compositor when building an image for a supporting
+            target.
+        </para>
+
+        <section id="enabling-wayland-in-an-image">
+            <title>Enabling Wayland in an Image</title>
+
+            <para>
+                To enable Wayland, you need to enable it to be built and enable
+                it to be included (installed) in the image.
+            </para>
+
+            <section id="enable-building">
+                <title>Building</title>
+
+                <para>
+                    To cause Mesa to build the <filename>wayland-egl</filename>
+                    platform and Weston to build Wayland with Kernel Mode
+                    Setting
+                    (<ulink url='https://wiki.archlinux.org/index.php/Kernel_Mode_Setting'>KMS</ulink>)
+                    support, include the "wayland" flag in the
+                    <ulink url="&YOCTO_DOCS_REF_URL;#var-DISTRO_FEATURES"><filename>DISTRO_FEATURES</filename></ulink>
+                    statement in your <filename>local.conf</filename> file:
+                    <literallayout class='monospaced'>
+     DISTRO_FEATURES_append = " wayland"
+                    </literallayout>
+                    <note>
+                        If X11 has been enabled elsewhere, Weston will build
+                        Wayland with X11 support
+                    </note>
+                </para>
+            </section>
+
+            <section id="enable-installation-in-an-image">
+                <title>Installing</title>
+
+                <para>
+                    To install the Wayland feature into an image, you must
+                    include the following
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-CORE_IMAGE_EXTRA_INSTALL'><filename>CORE_IMAGE_EXTRA_INSTALL</filename></ulink>
+                    statement in your <filename>local.conf</filename> file:
+                    <literallayout class='monospaced'>
+     CORE_IMAGE_EXTRA_INSTALL += "wayland weston"
+                    </literallayout>
+                </para>
+            </section>
+        </section>
+
+        <section id="running-weston">
+            <title>Running Weston</title>
+
+            <para>
+                To run Weston inside X11, enabling it as described earlier and
+                building a Sato image is sufficient.
+                If you are running your image under Sato, a Weston Launcher
+                appears in the "Utility" category.
+            </para>
+
+            <para>
+                Alternatively, you can run Weston through the command-line
+                interpretor (CLI), which is better suited for development work.
+                To run Weston under the CLI, you need to do the following after
+                your image is built:
+                <orderedlist>
+                    <listitem><para>
+                        Run these commands to export
+                        <filename>XDG_RUNTIME_DIR</filename>:
+                        <literallayout class='monospaced'>
+     mkdir -p /tmp/$USER-weston
+     chmod 0700 /tmp/$USER-weston
+     export XDG_RUNTIME_DIR=/tmp/$USER-weston
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        Launch Weston in the shell:
+                        <literallayout class='monospaced'>
+     weston
+                        </literallayout></para></listitem>
+                </orderedlist>
+            </para>
+        </section>
+    </section>
+</chapter>
+
+<!--
+vim: expandtab tw=80 ts=4
+-->