【Hitachi】 HITAC M-66X Processor Group

This was a processor group of large general-purpose machines, and was comprised of four models: the M-660D, M-660H, M-660K and M-662K.

The M-660H was a large machine, positioned as the successor of the M-260H, and the processor was miniaturized with fewer gates by using an efficient logic system. At the same time, 1 megabit DRAM was installed for the first time in a domestic machine in order to reduce the machine cycle to the greatest extent possible. Using logic systems for greater speed, such as look-ahead control and a high-speed decimal operation mechanism, these processors achieved world-class high-performance and space/power-savings.

The M-660K was the higher-end model of the M-660H. It could also be field upgraded to the M-662K.
The M-662K was a dyadic processor with two instruction processors. It was the top-end model among M-66X processors, and its performance was about 3.5 times better than the M-660D.
The M-660D was the entry model for the M-66X Processor Group. It could be field upgraded to higher-end models.

Hitachi also produced the M-660 Processor Group E Models, which were enhanced versions of these machines.

M-68X Processor Group Configuration Specifications
  M-660D M-660H M-660K M-662K
Number of instruction processors 1 2
Buffer memory capacity 32KB 64KB 64KBx2
Main memory capacity 32-256MB 64-256MB
Number of channels 8-32 16-32
Announcement date March 1987 August 1986 March 1987