Characterization of HPC

NSA's HPC can handle enormous input data volumes. For the division between scalar and vector operations, 30 per cent scalar to 70 per cent vector is typical, although vector operations sometimes approach 90 per cent. Little natural parallelism is found in much of the code we are running because the roots of the code come from design and implementations on serial systems. The code has been ported and patched across 6600s, 7600s, CRAY-1s, X-MPs, and right up the line. We would like to redo much of that code, but that would present a real challenge.

An important characteristic of our implementation is that both batch and interactive operations are done concurrently in each complex with much of the software development. Some of these operations are permanent and long-term, whereas others are experimental. The complexes support a large research community. Although interactive efforts are basically day operations, many batch activities require operating the systems 24 hours a day, seven days a week.