HITAC S-820

In December 1987, Hitachi started shipping its 2nd generation supercomputer series S-820. It achieved world top processing speed as single vector processor, more than three times higher than its predecessor S-810, by adopting unique features such as custom logic-in-memory chip for Vector Register (VR).

Its unique features are as follows.

1. Up to eight vector elementwise pipelines
2. Vector processor linking scheme
   Starting next vector chain before previous vector chain completed to reduce startup overhead.
3. Extended Storage to reduce IO overhead
   Max 12GB DRAM based storage for swapping added to SRAM based main storage(512MB).
4. Video output mechanism directly attached to the Extended Storage for visualization of processed data
5. Custom VR chip containing 7Kbit 2.5ns access time SRAM and logic elements with 2,500 gates
6. 3D structure frame to achieve world top class “performance per installation area”
   Vertical settled back plane with vertical mounted PCBs each containing 72 VR chips.
7. Air Cooling structure that blows under floor cold air from bottom to top

As the facility needed to install it is almost same as mainframe computers, S-820 models were installed not only academic organizations but also financial or manufacturing industries.

In October 2009, S-810 and S-820 were registered as “Earliest Domestic Produced Supercomputers” by essential historical materials for science and technology^☆1, Japan National Museum of Nature and Science.