ASCI Blue Pacific

ASCI Blue Pacific was a supercomputer installed at the Lawrence Livermore National Laboratory (LLNL) in Livermore, CA at the end of 1998. It was a collaboration between IBM and LLNL.
It was an IBM RS/6000 SP "massively parallel processing" system. It contained 5,856 PowerPC 604e microprocessors. Its theoretical top performance was 3.9 teraflops. 
It was built as a stage of the Accelerated Strategic Computing Initiative (ASCI) started by the U.S. Department of Energy and the National Nuclear Security Administration to build a simulator to replace live nuclear weapon testing following the moratorium on testing started by President George H. W. Bush in 1992 and extended by Bill Clinton in 1993.