The NCBI SRA Toolkit enables reading ("dumping") of sequencing files from the SRA database and writing ("loading") files into the .sra format (Note that this is not required for submission). The Toolkit source code is provided in the form of the SRA SDK, and may be compiled with GCC. However, pre-built software executables are available for Linux, Windows, and Mac OS X, and we highly recommend using these pre-built executables whenever possible.