【Mitsubishi Electric】 MELCOM-COSMO 900II

Announced in 1979, this was the high-end machine in Mitsubishi Electric's MELCOM-COSMO Series. It employed world class high-speed logic LSI and many kinds of hardware innovations to increase its speed.

The system was equipped with high-speed ECL logic elements with a gate delay time of 0.75ns and ECL LSI with 250-300 functions per chip. It achieved a machine cycle time of 70ns, and enabled execution of instructions in each clock cycle by using high-speed buffer memory (with a high-capacity of 32 kilobytes) and a pipeline system. Access time for the main memory unit (max. 8MB) was 560ns, and the read width was 8 bytes. The system could access 64 bytes of data at once using an 8-way interleave system, and it achieved a high-speed data transfer rate of 114 megabytes/second.

The system was equipped with service processors and system consoles in two sets, and these could be used simultaneously as an operator console and maintenance console. The maintenance console also served as a backup in case of trouble with the operator console.

For the operating system, Mitsubishi enhanced UTS/VS to allow it to handle any mixtures of Japanese characters, kanji (Chinese characters) and kana, and true Japanese language data processing was adopted for batch, TSS and workstation processing. The system could also provide messages to operators in voice. An automatic operation system made it possible to operate the machine automatically according to a schedule, 24 hours a day.
In 1981, a model was announced which expanded the high-speed buffer memory in the basic processing unit to 64 kilobytes, and a model was announced which allowed a tightly coupled multi-processor configuration with one additional basic processing unit.