This disk unit used a 5.25-inch disk, and employed a voice coil motor and servo track system.
These technologies greatly reduced average seek time to 30ms—1/3 that of the previous unit.
Coated disk technology developed for large disks was applied here to a 5-inch size to achieve both high recording density and high-reliability. At the time, other companies were unable to solve the head crash problem with coated disks, and problems occurred frequently, and thus this unit was highly acclaimed in the market. Starting with this unit, the capacity of 5-inch disk units was continually enhanced for 4 generations.
| Completion date | 1983 |
|---|---|
| Memory capacity per spindle | 51Mbyte |
| BPI | 9,340BPI |
| TPI | 784TPI |
| Surface recording density | 7.3Mbit/square inc |
| Disk size/quantity | 5.25-inch/4 disks |
| Head type/number per actuator | Lightweight MnZn/8 |
| Average access time | 30ms |
| Disk rotation speed | 3,600rpm |
| Data transfer speed | 0.63Mbyte/s |
