HITAC S-820

The HITAC S-820 was a family of vector supercomputers developed, manufactured and marketed by Hitachi and announced in July 1987. It was Hitachi's second supercomputer, succeeding the HITAC S-810, and is counted as a second generation Japanese supercomputer. Like the S-810 it combined a scalar processor with a vector processor; the scalar side was based on Hitachi's M-series mainframe processor, so it was compatible with that line's operating system. Its theoretical peak performance was reported as 2 GFLOPS, with a theoretical maximum computational performance of 3 GFLOPS, and its maximum memory was 512 MB. There were five models: the mid-range S-820/60 at 1.5 GFLOPS and the top-end S-820/80 at 3.0 GFLOPS, both announced in July 1987, then the S-820/20 and S-820/40 in May 1988 and the S-820/15 in November 1989. In early 1988 a team from the Institute for Supercomputing Research in Tokyo and Los Alamos National Laboratory benchmarked the S-820/80 against the NEC SX-2, the Cray X-MP/416 and the S-810, and concluded that it was much faster in vector mode than any other supercomputer they had measured.