This was a high-capacity removable magnetic disk unit announced by Mitsubishi Electric in 1973. It was a equivalent of the IBM3330 magnetic disk unit, and had a memory capacity of 100MB per spindle and a high-speed positioning mechanism which required 30ms on average. This unit was used for data files for mid-size to large computers such as the MELCOM 7000 Series and COSMO Series.
This unit had the following features:
- It exploited high-density magnetic recording technology to achieve a track density of 192track/inch and a bit density of 4040bit/inch, and used the MFM (Modified Frequency Modulation) system to achieve the high capacity.
- Positioning at higher speed and precision was enabled by using a track-servo system which employed a linear motor in place of the conventional hydraulic positioning system.
- A rotational position detection mechanism and high-reliability automatic maintenance functions reduced the burden on the disk controller and improved availability. Diagnostic programs enabled self-diagnosis.
- By using Mitsubishi's unique self-pressing magnetic head technology, the system simplified and lightened the head pressing/holding mechanism, and realized faster access times.
|Unit memory capacity
|Data transfer speed
|IBM3336 or the equivalent
Disk diameter : 14inch(356mm)
Number of disks : 10 + 2(protected)
Data recording sides : 19
servo sides: 1
Number of cylinders : 404 + 7(spare)
Weight : 9kg
|External dimensions(Width x Height x Depth)
The M2837, its enhanced model, was announced in 1975. It achieved a memory capacity of 200MB by doubling the track density to 370track/inch, and setting the number of cylinders to 808 + 7 (spare).
The M2838F, further enhanced model, was announced in 1979. It achieved a memory capacity of 300MB by increasing the bit density 1.5 times to 6,060bit/inch, and adopting a track capacity of 20,160 bytes.