This was a processor group of ultra-large general-purpose machines, comprised of 4 models (the M-680H, M-682H, M-683H and M-684H) plus the M-680D entry model.
At the time, the M-680H was in the world's top class in terms of speed, being 2--2.5 times faster than the previous M-280H in business processing, and 2--3 times faster than the previous M-280H in scientific and engineering calculations. By developing semiconductors with ultra-high integration, as well as the latest mounting technology and logic system technology, Hitachi realized a true "all LSI machine". Ultra high-speed processing was made possible by more sophisticated pipeline control, high-speed arithmetic mechanisms, high-speed decimal operation capability, high-speed buffer memory, and a 3-level memory configuration which provided high-capacity working memory. This was the only air-cooled system among competing machines in the same class.
The M-682H was a dyadic processor with two instruction processors, and had processing capacity about 1.7--1.9 times that of the M-680H.
The M-683H was comprised of three instruction processors. It could also operate with high availability due to the duplication of key processor mechanisms.
The M-684H was comprised of four instruction processors. Key processor mechanisms were duplicated, just as in the M-683H.
Hitachi also produced the M-680 Processor Group E Models, which were enhanced versions of these machines.
|Number of instruction processors||1||2||3||4|
|Buffer memory capacity||128KB||256KB||256KBx2||256KBx3||256KBx4|
|Main memory capacity||32-512MB||64-512MB||128-512MB|
|Number of channels||16-64||32-64||48-128||64-128|
|Announcement date||May 1986||March 1985||May 1986|