ASCI Red -- Experiences and lessons learned with a massively parallel teraFLOP supercomputer

The Accelerated Strategic Computing Initiative (ASCI) program involves Sandia, Los Alamos and Lawrence Livermore National Laboratories. At Sandia National Laboratories, ASCI applications include large deformation transient dynamics, shock propagation, electromechanics, and abnormal thermal environments. In order to resolve important physical phenomena in these problems, it is estimated that meshes ranging from 10{sup 6} to 10{sup 9} grid points will be required. The ASCI program is relying on the use of massively parallel supercomputers initially capable of delivering over 1 TFLOPs to perform such demanding computations. The ASCI Red machine at Sandia National Laboratories consists of over 4,500 computational nodes with a peak computational rate of 1.8 TFLOPs, 567 GBytes of memory, and 2 TBytes of disk storage. Regardless of the peak FLOP rate, there are many issues surrounding the use of massively parallel supercomputers in a production environment. These issues include parallel I/O, mesh generation, visualization, archival storage, high-bandwidth networking and the development of parallel algorithms. In order to illustrate these issues and their solution with respect to ASCI Red, demonstration calculations of time-dependent buoyancy-dominated plumes, electromechanics, and shock propagation will be presented.