This archive contains almost everything you need to build the IOMD ROM image. It includes the build environment and full source code (including all of the latest changes in CVS). Note: there are a handful of build tools which are part of a commercial product, the "Acorn C/C++ Tools":https://www.riscosopen.org/content/sales so you will need to have that in order to do a build. Once your Acorn Tools are correctly installed, you should run the file @RiscOS.Library.InstallTools@ to copy the relevant tools into this IOMD build tree. See our more detailed build documentation "here":https://www.riscosopen.org/wiki/documentation/pages/Technical+notes.