【Mitsubishi Electric】 MELCOM80 OFFICELAND Series Model 500

Announced by Mitsubishi Electric in 1982, this was the first office computer using a 32-bit architecture. As basic software, this machine was equipped with the newly developed DPS10 which was based on a UNIX kernel.

For main memory, the system used 64 kilobit MOS LSI with a cycle time of 450ns, and its maximum main memory capacity was 8 megabytes. A multiple virtual memory system with a logical space of 16 megabytes was achieved with dynamic address translation (DAT) and operating system support. There were four types of input/output channel -- a program control channel (PCCH), multiplexer channel (MPX), direct memory access (DMA) and integrated storage controller interface (ISC) -- and address translation was done automatically even in data transfer between the storage unit and the input/output devices.

DPS10 provided support for workstation processing, time-sharing processing, remote batch processing and local batch processing, and this was also the first office computer to support online transaction processing. A relational database was also provided.

MELCOM80 OFFICELAND Series Model 500