【Mitsubishi Electric】 M2883 Hard Disk Unit

This was a hard disk unit for small computers, announced in 1978 by Mitsubishi Electric. It corresponded to the unit (Model 62GV) incorporated by IBM Corporation into its System 32 and 34, and among equivalent products, it enabled expansion of memory capacity up to 80.8MB, the highest among Japanese manufacturers. Furthermore, a 2.43MB fixed head could be added as an option. Thus a single unit could be simultaneously equipped with high-capacity files as well as high-speed memory. Its features included compactness and maintenance-free performance, and it was used as an external memory device in a wide-range of systems, such as office computers and minicomputers.

This unit had the following features:

  • There were 4 models, ranging from a minimum capacity of 13.4MB to a maximum capacity of 80.8MB, and memory capacity could be selected to suit the application.
  • A fixed head (with a capacity of 0.81MB or 2.43MB) could be mounted in addition to the movable head.
  • The unit maintained compactness, even with a built-in power supply, and could be mounted in a standard 19-inch rack.
  • A completely sealed structure eliminated contamination of the disk surface with dust and made periodic maintenance unnecessary.
Main Specifications of M2883 Hard Disk Unit
Unit memory capacity 13.4MB(model 10),26.9MB(model 20),
53.8MB(model 30),80.8MB(model 40)
Fixed head section:0.81MB or 2.43MB
Track capacity 20,160byte
Recording system MFM
Bit density 6,060bit/inch
Track density Movable head 286track/inch
Fixed head 33.3track/inch
Data transfer speed 996Kbyte/s
Positioning time Min. 10ms,Max. 75ms,Average 38ms
Rotational delay Average 10.12ms
Rotation speed 2,964rpm
Memory media Disk diameter 14-inch
Number of disks 1-4
Number of heads Movable heads 2-12
Fixed heads 0-40
servo heads 1
External dimensions 451mm×178mm×610mm
Weight 30kg

M2883 Hard Disk Unit