diff --git a/sys_file.hpp b/sys_file.hpp
new file mode 100644
index 0000000..5a2bb85
--- /dev/null
+++ b/sys_file.hpp
@@ -0,0 +1,90 @@
+#pragma once
+
+#include "sys.hpp"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <string>
+
+namespace binstore
+{
+
+/**
+ * @brief Represents a file that supports read/write semantics
+ * TODO: leverage stdplus's support for smart file descriptors when it's ready.
+ */
+class SysFile
+{
+  public:
+    virtual ~SysFile() = default;
+
+    /**
+     * @brief Reads content at pos to char* buffer
+     * @param pos The byte pos into the file to read from
+     * @param count How many bytes to read
+     * @param buf Output data
+     * @returns The size of data read
+     * @throws std::system_error if read operation cannot be completed
+     */
+    virtual size_t readToBuf(size_t pos, size_t count, char* buf) const = 0;
+
+    /**
+     * @brief Reads content at pos
+     * @param pos The byte pos into the file to read from
+     * @param count How many bytes to read
+     * @returns The data read in a vector, whose size might be smaller than
+     *          count if there is not enough to read.
+     * @throws std::system_error if read operation cannot be completed
+     */
+    virtual std::string readAsStr(size_t pos, size_t count) const = 0;
+
+    /**
+     * @brief Reads all the content in file after pos
+     * @param pos The byte pos to read from
+     * @returns The data read in a vector, whose size might be smaller than
+     *          count if there is not enough to read.
+     * @throws std::system_error if read operation cannot be completed
+     */
+    virtual std::string readRemainingAsStr(size_t pos) const = 0;
+
+    /**
+     * @brief Writes all of data into file at pos
+     * @param pos The byte pos to write
+     * @returns void
+     * @throws std::system_error if write operation cannot be completed or
+     *         not all of the bytes can be written
+     */
+    virtual void writeStr(const std::string& data, size_t pos) = 0;
+};
+
+class SysFileImpl : public SysFile
+{
+  public:
+    /**
+     * @brief Constructs sysFile specified by path and offset
+     * @param path The file path
+     * @param offset The byte offset relatively. Reading a sysfile at position 0
+     *     actually reads underlying file at 'offset'
+     * @param sys Syscall operation interface
+     */
+    explicit SysFileImpl(const std::string& path, size_t offset = 0,
+                         const internal::Sys* sys = &internal::sys_impl);
+    ~SysFileImpl();
+    SysFileImpl() = delete;
+    SysFileImpl(const SysFileImpl&) = delete;
+    SysFileImpl& operator=(SysFileImpl) = delete;
+
+    size_t readToBuf(size_t pos, size_t count, char* buf) const override;
+    std::string readAsStr(size_t pos, size_t count) const override;
+    std::string readRemainingAsStr(size_t pos) const override;
+    void writeStr(const std::string& data, size_t pos) override;
+
+  private:
+    int fd_;
+    size_t offset_;
+    void lseek(size_t pos) const;
+    const internal::Sys* sys;
+};
+
+} // namespace binstore