Tim, get the facts
PERCS is NOT a software project, it is hardware and software. Check out
http://www.darpa.mil/Our_Work/I2O/Programs/High_Productivity_Computing_Systems_%28HPCS%29.aspx
and http://www.ncsa.illinois.edu/BlueWaters/percs.html which, BTW, states:
The Blue Waters sustained-petascale computing system is based on the most advanced technologies under development at IBM, including an advanced processor and memory subsystem, a new interconnect, parallel file system, operating system, programming environment, and system administration tools. These technologies are embodied in the PERCS system design (Productive, Easy-to-use, Reliable Computing System).
Blue Waters is supported by the National Science Foundation. It leverages the investment made by the Defense Advanced Research Projects Agency's High Productivity Computing Systems (HPCS) program, which is supporting the development of PERCS. Blue Waters will be the first production deployment of PERCS technologies, 100 times more powerful than today's general purpose supercomputers but dramatically simpler to use.