【Hitachi】 H-8598 Magnetic Disk Unit

The H-8598 Magnetic Disk Unit was developed as a machine with twice the capacity of the H-8576 (317MB/actuator).
This unit derived its system from the previous generation (H-8576), and was designed for high recording density by greatly enhancing read/write specifications, and enhancing head positioning and the performance of other parts.
In order to achieve high-density recording, MnZn was used as the magnetic head material, and the 2-7 recording system was used for recording modulation.
Using these technologies, recording density in the disk circumferential direction was increased by 2.4 times, and the media transfer speed was greatly increased to 3Mbyte/s. The system of providing two rotary actuators for one spindle was the same as the previous machine, but for the HDA, the unit used an external circulation system for supplying filtered air from the outside.
Each actuator had a capacity of 630MB, and was compatible with the IBM3380.

H-8598 Magnetic Disk Unit Specifications
Completion date October 1982
Memory capacity per unit 2,5Gbyte/DKU
Memory capacity per spindle 1,260Mbyte
BPI 15,000BPI
Surface recording density 9Mbit/square inch
Disk size/quantity 14-inch/11disks
Head type/number per actuator Lightweight MnZn ferrite 20+1(servo)
Average access time 16ms
Disk rotation speed 3,600rpm
Data transfer speed 3Mbyte/s

H-8598 Magnetic Disk Unit