poky/documentation/sdk-manual/sdk-intro.xml - openbmc/openbmc - Gitiles

 <!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='sdk-intro'>
 <title>Introduction</title>

 <section id='sdk-manual-intro'>
     <title>Introduction</title>

     <para>
         Welcome to the Yocto Project Application Development and the
         Extensible Software Development Kit (eSDK) manual.
         This manual provides information that explains how to use both the
         Yocto Project extensible and standard SDKs to develop
         applications and images.
         <note>
             Prior to the 2.0 Release of the Yocto Project, application
             development was primarily accomplished through the use of the
             Application Development Toolkit (ADT) and the availability
             of stand-alone cross-development toolchains and other tools.
             With the 2.1 Release of the Yocto Project, application development
             has transitioned to within a tool-rich extensible SDK and the more
             traditional standard SDK.
         </note>
     </para>

     <para>
         All SDKs consist of the following:
         <itemizedlist>
             <listitem><para>
                 <emphasis>Cross-Development Toolchain</emphasis>:
                 This toolchain contains a compiler, debugger, and various
                 miscellaneous tools.
                 </para></listitem>
             <listitem><para>
                 <emphasis>Libraries, Headers, and Symbols</emphasis>:
                 The libraries, headers, and symbols are specific to the image
                 (i.e. they match the image).
                 </para></listitem>
             <listitem><para>
                 <emphasis>Environment Setup Script</emphasis>:
                 This <filename>*.sh</filename> file, once run, sets up the
                 cross-development environment by defining variables and
                 preparing for SDK use.
                 </para></listitem>
         </itemizedlist>
     </para>

     <para>
         Additionally, an extensible SDK has tools that allow you to easily add
         new applications and libraries to an image, modify the source of an
         existing component, test changes on the target hardware, and easily
         integrate an application into the
         <ulink url='&YOCTO_DOCS_REF_URL;#build-system-term'>OpenEmbedded build system</ulink>.
     </para>

     <para>
         You can use an SDK to independently develop and test code
         that is destined to run on some target machine.
         SDKs are completely self-contained.
         The binaries are linked against their own copy of
         <filename>libc</filename>, which results in no dependencies
         on the target system.
         To achieve this, the pointer to the dynamic loader is
         configured at install time since that path cannot be dynamically
         altered.
         This is the reason for a wrapper around the
         <filename>populate_sdk</filename> and
         <filename>populate_sdk_ext</filename> archives.
     </para>

     <para>
         Another feature for the SDKs is that only one set of cross-compiler
         toolchain binaries are produced for any given architecture.
         This feature takes advantage of the fact that the target hardware can
         be passed to <filename>gcc</filename> as a set of compiler options.
         Those options are set up by the environment script and contained in
         variables such as
         <ulink url='&YOCTO_DOCS_REF_URL;#var-CC'><filename>CC</filename></ulink>
         and
         <ulink url='&YOCTO_DOCS_REF_URL;#var-LD'><filename>LD</filename></ulink>.
         This reduces the space needed for the tools.
         Understand, however, that every target still needs a sysroot because
         those binaries are target-specific.
     </para>

     <para>
         The SDK development environment consists of the following:
         <itemizedlist>
             <listitem><para>
                 The self-contained SDK, which is an
                 architecture-specific cross-toolchain and
                 matching sysroots (target and native) all built by the
                 OpenEmbedded build system (e.g. the SDK).
                 The toolchain and sysroots are based on a
                 <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink>
                 configuration and extensions,
                 which allows you to cross-develop on the host machine for the
                 target hardware.
                 Additionally, the extensible SDK contains the
                 <filename>devtool</filename> functionality.
                 </para></listitem>
             <listitem><para>
                 The Quick EMUlator (QEMU), which lets you simulate
                 target hardware.
                 QEMU is not literally part of the SDK.
                 You must build and include this emulator separately.
                 However, QEMU plays an important role in the development
                 process that revolves around use of the SDK.
                 </para></listitem>
         </itemizedlist>
     </para>

     <para>
         In summary, the extensible and standard SDK share many features.
         However, the extensible SDK has powerful development tools to help you
         more quickly develop applications.
         Following is a table that summarizes the primary differences between
         the standard and extensible SDK types when considering which to
         build:
         <informaltable frame='none'>
             <tgroup cols='3' align='left' colsep='1' rowsep='1'>
                 <colspec colname='c1' colwidth='1*'/>
                 <colspec colname='c2' colwidth='1*'/>
                 <colspec colname='c3' colwidth='1*'/>
                 <thead>
                     <row>
                         <entry align="left"><emphasis>Feature</emphasis></entry>
                         <entry align="left"><emphasis>Standard SDK</emphasis></entry>
                         <entry align="left"><emphasis>Extensible SDK</emphasis></entry>
                     </row>
                 </thead>
                 <tbody>
                     <row>
                         <entry align="left">Toolchain</entry>
                         <entry align="left">Yes</entry>
                         <entry align="left">Yes*</entry>
                     </row>
                     <row>
                         <entry align="left">Debugger</entry>
                         <entry align="left">Yes</entry>
                         <entry align="left">Yes*</entry>
                     </row>
                     <row>
                         <entry align="left">Size</entry>
                         <entry align="left">100+ MBytes</entry>
                         <entry align="left">1+ GBytes (or 300+ MBytes for minimal w/toolchain)</entry>
                     </row>
                     <row>
                         <entry align="left"><filename>devtool</filename></entry>
                         <entry align="left">No</entry>
                         <entry align="left">Yes</entry>
                     </row>
                     <row>
                         <entry align="left">Build Images</entry>
                         <entry align="left">No</entry>
                         <entry align="left">Yes</entry>
                     </row>
                     <row>
                         <entry align="left">Updateable</entry>
                         <entry align="left">No</entry>
                         <entry align="left">Yes</entry>
                     </row>
                     <row>
                         <entry align="left">Managed Sysroot**</entry>
                         <entry align="left">No</entry>
                         <entry align="left">Yes</entry>
                     </row>
                     <row>
                         <entry align="left">Installed Packages</entry>
                         <entry align="left">No***</entry>
                         <entry align="left">Yes****</entry>
                     </row>
                     <row>
                         <entry align="left">Construction</entry>
                         <entry align="left">Packages</entry>
                         <entry align="left">Shared State</entry>
                     </row>
                 </tbody>
             </tgroup>
         </informaltable>
         <literallayout class='monospaced'>
      * Extensible SDK contains the toolchain and debugger if <ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_EXT_TYPE'><filename>SDK_EXT_TYPE</filename></ulink> is "full" or <ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_INCLUDE_TOOLCHAIN'><filename>SDK_INCLUDE_TOOLCHAIN</filename></ulink> is "1", which is the default.

      ** Sysroot is managed through the use of <filename>devtool</filename>.  Thus, it is less likely that you will corrupt your SDK sysroot when you try to add additional libraries.

      *** You can add runtime package management to the standard SDK but it is not supported by default.

      **** You must build and make the shared state available to extensible SDK users for "packages" you want to enable users to install.
         </literallayout>
     </para>

     <section id='the-cross-development-toolchain'>
         <title>The Cross-Development Toolchain</title>

         <para>
             The
             <ulink url='&YOCTO_DOCS_REF_URL;#cross-development-toolchain'>Cross-Development Toolchain</ulink>
             consists of a cross-compiler, cross-linker, and cross-debugger
             that are used to develop user-space applications for targeted
             hardware.
             Additionally, for an extensible SDK, the toolchain also has
             built-in <filename>devtool</filename> functionality.
             This toolchain is created by running a SDK installer script
             or through a
             <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
             that is based on your metadata configuration or extension for
             your targeted device.
             The cross-toolchain works with a matching target sysroot.
         </para>
     </section>

     <section id='sysroot'>
         <title>Sysroots</title>

         <para>
             The native and target sysroots contain needed headers and libraries
             for generating binaries that run on the target architecture.
             The target sysroot is based on the target root filesystem image
             that is built by the OpenEmbedded build system and uses the same
             metadata configuration used to build the cross-toolchain.
         </para>
     </section>

     <section id='the-qemu-emulator'>
         <title>The QEMU Emulator</title>

         <para>
             The QEMU emulator allows you to simulate your hardware while
             running your application or image.
             QEMU is not part of the SDK but is made available a number of
             different ways:
             <itemizedlist>
                 <listitem><para>
                     If you have cloned the <filename>poky</filename> Git
                     repository to create a
                     <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
                     and you have sourced the environment setup script, QEMU is
                     installed and automatically available.
                     </para></listitem>
                 <listitem><para>
                     If you have downloaded a Yocto Project release and unpacked
                     it to create a Source Directory and you have sourced the
                     environment setup script, QEMU is installed and
                     automatically available.
                     </para></listitem>
                 <listitem><para>
                     If you have installed the cross-toolchain tarball and you
                     have sourced the toolchain's setup environment script, QEMU
                     is also installed and automatically available.
                     </para></listitem>
             </itemizedlist>
         </para>
     </section>
 </section>

 <section id='sdk-development-model'>
     <title>SDK Development Model</title>

     <para>
         Fundamentally, the SDK fits into the development process as follows:
         <imagedata fileref="figures/sdk-environment.png" align="center" width="6in" depth="5in" scalefit="100" />
         The SDK is installed on any machine and can be used to develop
         applications, images, and kernels.
         An SDK can even be used by a QA Engineer or Release Engineer.
         The fundamental concept is that the machine that has the SDK installed
         does not have to be associated with the machine that has the
         Yocto Project installed.
         A developer can independently compile and test an object on their
         machine and then, when the object is ready for integration into an
         image, they can simply make it available to the machine that has the
         Yocto Project.
         Once the object is available, the image can be rebuilt using the
         Yocto Project to produce the modified image.
     </para>

     <para>
         You just need to follow these general steps:
         <orderedlist>
             <listitem><para>
                 <emphasis>Install the SDK for your target hardware:</emphasis>
                 For information on how to install the SDK, see the
                 "<link linkend='sdk-installing-the-sdk'>Installing the SDK</link>"
                 section.
                 </para></listitem>
             <listitem><para>
                 <emphasis>Download or Build the Target Image:</emphasis>
                 The Yocto Project supports several target architectures
                 and has many pre-built kernel images and root filesystem
                 images.</para>

                 <para>If you are going to develop your application on
                 hardware, go to the
                 <ulink url='&YOCTO_MACHINES_DL_URL;'><filename>machines</filename></ulink>
                 download area and choose a target machine area
                 from which to download the kernel image and root filesystem.
                 This download area could have several files in it that
                 support development using actual hardware.
                 For example, the area might contain
                 <filename>.hddimg</filename> files that combine the
                 kernel image with the filesystem, boot loaders, and
                 so forth.
                 Be sure to get the files you need for your particular
                 development process.</para>

                 <para>If you are going to develop your application and
                 then run and test it using the QEMU emulator, go to the
                 <ulink url='&YOCTO_QEMU_DL_URL;'><filename>machines/qemu</filename></ulink>
                 download area.
                 From this area, go down into the directory for your
                 target architecture (e.g. <filename>qemux86_64</filename>
                 for an <trademark class='registered'>Intel</trademark>-based
                 64-bit architecture).
                 Download the kernel, root filesystem, and any other files you
                 need for your process.
                 <note>
                     To use the root filesystem in QEMU, you need to extract it.
                     See the
                     "<link linkend='sdk-extracting-the-root-filesystem'>Extracting the Root Filesystem</link>"
                     section for information on how to extract the root
                     filesystem.
                 </note>
                 </para></listitem>
             <listitem><para>
                 <emphasis>Develop and Test your Application:</emphasis>
                 At this point, you have the tools to develop your application.
                 If you need to separately install and use the QEMU emulator,
                 you can go to
                 <ulink url='http://wiki.qemu.org/Main_Page'>QEMU Home Page</ulink>
                 to download and learn about the emulator.
                 See the
                 "<ulink url='&YOCTO_DOCS_DEV_URL;#dev-manual-qemu'>Using the Quick EMUlator (QEMU)</ulink>"
                 chapter in the Yocto Project Development Tasks Manual
                 for information on using QEMU within the Yocto
                 Project.
                 </para></listitem>
         </orderedlist>
     </para>

     <para>
         The remainder of this manual describes how to use the extensible
         and standard SDKs.
         Information also exists in appendix form that describes how you can
         build, install, and modify an SDK.
     </para>
 </section>

 </chapter>
 <!--
 vim: expandtab tw=80 ts=4
 -->
	<!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='sdk-intro'>
	<title>Introduction</title>

	<section id='sdk-manual-intro'>
	<title>Introduction</title>

	<para>
	Welcome to the Yocto Project Application Development and the
	Extensible Software Development Kit (eSDK) manual.
	This manual provides information that explains how to use both the
	Yocto Project extensible and standard SDKs to develop
	applications and images.
	<note>
	Prior to the 2.0 Release of the Yocto Project, application
	development was primarily accomplished through the use of the
	Application Development Toolkit (ADT) and the availability
	of stand-alone cross-development toolchains and other tools.
	With the 2.1 Release of the Yocto Project, application development
	has transitioned to within a tool-rich extensible SDK and the more
	traditional standard SDK.
	</note>
	</para>

	<para>
	All SDKs consist of the following:
	<itemizedlist>
	<listitem><para>
	<emphasis>Cross-Development Toolchain</emphasis>:
	This toolchain contains a compiler, debugger, and various
	miscellaneous tools.
	</para></listitem>
	<listitem><para>
	<emphasis>Libraries, Headers, and Symbols</emphasis>:
	The libraries, headers, and symbols are specific to the image
	(i.e. they match the image).
	</para></listitem>
	<listitem><para>
	<emphasis>Environment Setup Script</emphasis>:
	This <filename>*.sh</filename> file, once run, sets up the
	cross-development environment by defining variables and
	preparing for SDK use.
	</para></listitem>
	</itemizedlist>
	</para>

	<para>
	Additionally, an extensible SDK has tools that allow you to easily add
	new applications and libraries to an image, modify the source of an
	existing component, test changes on the target hardware, and easily
	integrate an application into the
	<ulink url='&YOCTO_DOCS_REF_URL;#build-system-term'>OpenEmbedded build system</ulink>.
	</para>

	<para>
	You can use an SDK to independently develop and test code
	that is destined to run on some target machine.
	SDKs are completely self-contained.
	The binaries are linked against their own copy of
	<filename>libc</filename>, which results in no dependencies
	on the target system.
	To achieve this, the pointer to the dynamic loader is
	configured at install time since that path cannot be dynamically
	altered.
	This is the reason for a wrapper around the
	<filename>populate_sdk</filename> and
	<filename>populate_sdk_ext</filename> archives.
	</para>

	<para>
	Another feature for the SDKs is that only one set of cross-compiler
	toolchain binaries are produced for any given architecture.
	This feature takes advantage of the fact that the target hardware can
	be passed to <filename>gcc</filename> as a set of compiler options.
	Those options are set up by the environment script and contained in
	variables such as
	<ulink url='&YOCTO_DOCS_REF_URL;#var-CC'><filename>CC</filename></ulink>
	and
	<ulink url='&YOCTO_DOCS_REF_URL;#var-LD'><filename>LD</filename></ulink>.
	This reduces the space needed for the tools.
	Understand, however, that every target still needs a sysroot because
	those binaries are target-specific.
	</para>

	<para>
	The SDK development environment consists of the following:
	<itemizedlist>
	<listitem><para>
	The self-contained SDK, which is an
	architecture-specific cross-toolchain and
	matching sysroots (target and native) all built by the
	OpenEmbedded build system (e.g. the SDK).
	The toolchain and sysroots are based on a
	<ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink>
	configuration and extensions,
	which allows you to cross-develop on the host machine for the
	target hardware.
	Additionally, the extensible SDK contains the
	<filename>devtool</filename> functionality.
	</para></listitem>
	<listitem><para>
	The Quick EMUlator (QEMU), which lets you simulate
	target hardware.
	QEMU is not literally part of the SDK.
	You must build and include this emulator separately.
	However, QEMU plays an important role in the development
	process that revolves around use of the SDK.
	</para></listitem>
	</itemizedlist>
	</para>

	<para>
	In summary, the extensible and standard SDK share many features.
	However, the extensible SDK has powerful development tools to help you
	more quickly develop applications.
	Following is a table that summarizes the primary differences between
	the standard and extensible SDK types when considering which to
	build:
	<informaltable frame='none'>
	<tgroup cols='3' align='left' colsep='1' rowsep='1'>
	<colspec colname='c1' colwidth='1*'/>
	<colspec colname='c2' colwidth='1*'/>
	<colspec colname='c3' colwidth='1*'/>
	<thead>
	<row>
	<entry align="left"><emphasis>Feature</emphasis></entry>
	<entry align="left"><emphasis>Standard SDK</emphasis></entry>
	<entry align="left"><emphasis>Extensible SDK</emphasis></entry>
	</row>
	</thead>
	<tbody>
	<row>
	<entry align="left">Toolchain</entry>
	<entry align="left">Yes</entry>
	<entry align="left">Yes*</entry>
	</row>
	<row>
	<entry align="left">Debugger</entry>
	<entry align="left">Yes</entry>
	<entry align="left">Yes*</entry>
	</row>
	<row>
	<entry align="left">Size</entry>
	<entry align="left">100+ MBytes</entry>
	<entry align="left">1+ GBytes (or 300+ MBytes for minimal w/toolchain)</entry>
	</row>
	<row>
	<entry align="left"><filename>devtool</filename></entry>
	<entry align="left">No</entry>
	<entry align="left">Yes</entry>
	</row>
	<row>
	<entry align="left">Build Images</entry>
	<entry align="left">No</entry>
	<entry align="left">Yes</entry>
	</row>
	<row>
	<entry align="left">Updateable</entry>
	<entry align="left">No</entry>
	<entry align="left">Yes</entry>
	</row>
	<row>
	<entry align="left">Managed Sysroot**</entry>
	<entry align="left">No</entry>
	<entry align="left">Yes</entry>
	</row>
	<row>
	<entry align="left">Installed Packages</entry>
	<entry align="left">No***</entry>
	<entry align="left">Yes****</entry>
	</row>
	<row>
	<entry align="left">Construction</entry>
	<entry align="left">Packages</entry>
	<entry align="left">Shared State</entry>
	</row>
	</tbody>
	</tgroup>
	</informaltable>
	<literallayout class='monospaced'>
	* Extensible SDK contains the toolchain and debugger if <ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_EXT_TYPE'><filename>SDK_EXT_TYPE</filename></ulink> is "full" or <ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_INCLUDE_TOOLCHAIN'><filename>SDK_INCLUDE_TOOLCHAIN</filename></ulink> is "1", which is the default.

	** Sysroot is managed through the use of <filename>devtool</filename>. Thus, it is less likely that you will corrupt your SDK sysroot when you try to add additional libraries.

	*** You can add runtime package management to the standard SDK but it is not supported by default.

	**** You must build and make the shared state available to extensible SDK users for "packages" you want to enable users to install.
	</literallayout>
	</para>

	<section id='the-cross-development-toolchain'>
	<title>The Cross-Development Toolchain</title>

	<para>
	The
	<ulink url='&YOCTO_DOCS_REF_URL;#cross-development-toolchain'>Cross-Development Toolchain</ulink>
	consists of a cross-compiler, cross-linker, and cross-debugger
	that are used to develop user-space applications for targeted
	hardware.
	Additionally, for an extensible SDK, the toolchain also has
	built-in <filename>devtool</filename> functionality.
	This toolchain is created by running a SDK installer script
	or through a
	<ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
	that is based on your metadata configuration or extension for
	your targeted device.
	The cross-toolchain works with a matching target sysroot.
	</para>
	</section>

	<section id='sysroot'>
	<title>Sysroots</title>

	<para>
	The native and target sysroots contain needed headers and libraries
	for generating binaries that run on the target architecture.
	The target sysroot is based on the target root filesystem image
	that is built by the OpenEmbedded build system and uses the same
	metadata configuration used to build the cross-toolchain.
	</para>
	</section>

	<section id='the-qemu-emulator'>
	<title>The QEMU Emulator</title>

	<para>
	The QEMU emulator allows you to simulate your hardware while
	running your application or image.
	QEMU is not part of the SDK but is made available a number of
	different ways:
	<itemizedlist>
	<listitem><para>
	If you have cloned the <filename>poky</filename> Git
	repository to create a
	<ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
	and you have sourced the environment setup script, QEMU is
	installed and automatically available.
	</para></listitem>
	<listitem><para>
	If you have downloaded a Yocto Project release and unpacked
	it to create a Source Directory and you have sourced the
	environment setup script, QEMU is installed and
	automatically available.
	</para></listitem>
	<listitem><para>
	If you have installed the cross-toolchain tarball and you
	have sourced the toolchain's setup environment script, QEMU
	is also installed and automatically available.
	</para></listitem>
	</itemizedlist>
	</para>
	</section>
	</section>

	<section id='sdk-development-model'>
	<title>SDK Development Model</title>

	<para>
	Fundamentally, the SDK fits into the development process as follows:
	<imagedata fileref="figures/sdk-environment.png" align="center" width="6in" depth="5in" scalefit="100" />
	The SDK is installed on any machine and can be used to develop
	applications, images, and kernels.
	An SDK can even be used by a QA Engineer or Release Engineer.
	The fundamental concept is that the machine that has the SDK installed
	does not have to be associated with the machine that has the
	Yocto Project installed.
	A developer can independently compile and test an object on their
	machine and then, when the object is ready for integration into an
	image, they can simply make it available to the machine that has the
	Yocto Project.
	Once the object is available, the image can be rebuilt using the
	Yocto Project to produce the modified image.
	</para>

	<para>
	You just need to follow these general steps:
	<orderedlist>
	<listitem><para>
	<emphasis>Install the SDK for your target hardware:</emphasis>
	For information on how to install the SDK, see the
	"<link linkend='sdk-installing-the-sdk'>Installing the SDK</link>"
	section.
	</para></listitem>
	<listitem><para>
	<emphasis>Download or Build the Target Image:</emphasis>
	The Yocto Project supports several target architectures
	and has many pre-built kernel images and root filesystem
	images.</para>

	<para>If you are going to develop your application on
	hardware, go to the
	<ulink url='&YOCTO_MACHINES_DL_URL;'><filename>machines</filename></ulink>
	download area and choose a target machine area
	from which to download the kernel image and root filesystem.
	This download area could have several files in it that
	support development using actual hardware.
	For example, the area might contain
	<filename>.hddimg</filename> files that combine the
	kernel image with the filesystem, boot loaders, and
	so forth.
	Be sure to get the files you need for your particular
	development process.</para>

	<para>If you are going to develop your application and
	then run and test it using the QEMU emulator, go to the
	<ulink url='&YOCTO_QEMU_DL_URL;'><filename>machines/qemu</filename></ulink>
	download area.
	From this area, go down into the directory for your
	target architecture (e.g. <filename>qemux86_64</filename>
	for an <trademark class='registered'>Intel</trademark>-based
	64-bit architecture).
	Download the kernel, root filesystem, and any other files you
	need for your process.
	<note>
	To use the root filesystem in QEMU, you need to extract it.
	See the
	"<link linkend='sdk-extracting-the-root-filesystem'>Extracting the Root Filesystem</link>"
	section for information on how to extract the root
	filesystem.
	</note>
	</para></listitem>
	<listitem><para>
	<emphasis>Develop and Test your Application:</emphasis>
	At this point, you have the tools to develop your application.
	If you need to separately install and use the QEMU emulator,
	you can go to
	<ulink url='http://wiki.qemu.org/Main_Page'>QEMU Home Page</ulink>
	to download and learn about the emulator.
	See the
	"<ulink url='&YOCTO_DOCS_DEV_URL;#dev-manual-qemu'>Using the Quick EMUlator (QEMU)</ulink>"
	chapter in the Yocto Project Development Tasks Manual
	for information on using QEMU within the Yocto
	Project.
	</para></listitem>
	</orderedlist>
	</para>

	<para>
	The remainder of this manual describes how to use the extensible
	and standard SDKs.
	Information also exists in appendix form that describes how you can
	build, install, and modify an SDK.
	</para>
	</section>

	</chapter>
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