The OpenCatamount source code began as a fork of the Catamount source code developed by Sandia for the Cray Red Storm machine, which as the first prototype of the Cray XT3 platform. It is a snapshot of the Catamount source code from the XT3 repository from April of 2005. Every effort was made to remove all Cray copyrighted code and XT3-specific code. Any code that originated from Cray was removed. This base OpenCatamount code booted on several generic Intel Pentium III and Pentium IV boxes. More recently, we have merged changes made to the production Catamount to support virtual node mode back into OpenCatamount. The latest version of OpenCatamount boots in several different environments, including a quad socket Dell box, the Bachs emulator environment, and VmWare x86 virtual machines. The latest version of OpenCatamount does not contain several enhancements that Cray and Sandia have made over the last year specifically for the production XT3 environment, such as runtime selection of large pages and support for more than 4 GB of main memory.

The source code distribution can be downloaded from the Sandia CCIM download page.