【Mitsubishi Electric】 MELCOM EX 830II‚EX 840II‚EX 850II‚EX 860II‚EX 870II‚EX 880II

With the EX830II, EX840II and EX850II, Mitsubishi provided an integrated package of the main unit (central processing unit, main memory unit, channel unit) and input/output control unit (magnetic disk control unit, communications control unit, local work station control unit, local input/output control unit and integrated communications control unit), achieved greater compactness making it possible to build-in a magnetic disk unit up to a maximum of 5GB, and reduced set-up area per system (excluding terminals) by 27~48% compared to the EX830, EX840 and EX850. A power fail-safe feature was added which automatically saved state information during battery back-up when a momentary power failure occurred, so that the job could be resumed automatically after power was restored.

The EX860II, EX870II and EX880II improved performance of the central processing unit, expanded maximum memory capacity, and came with GOS/EA, whose virtual space size was increased from 16MB to 256MB. By using the expansion part as a system shared area, the number of channels which could be connected to the system was increased. Capabilities and performance were also enhanced for online transaction processing and database processing, and response performance was improved in time-sharing systems. A system checkpoint restart function was added to the automatic operation system to make it possible to stop the system in the middle of work, and resume work later.

  EX830II EX840 II EX850 II EX860 II EX870 II EX880 II
Announcement date April 1988 July 1990
Processing performance ratio* 1 1.4 2.4 3.2 4.8 8.1
Main memory Element 1MbitCMOS LSI 1MbitCMOS LSI
Maximum capacity 32MB 48MB 64MB 256MB
Buffer memory 16KB 32KB 64KB 32KB 64KB 128KB
Number of channels: Max. 5 Max.8 Max.16 Max.12 Max.24

* Processing performance is given as the ratio against the EX830.