【Hitachi】 H-8589-11 Magnetic Disk Drive

The H-8589-11 disk drive was developed as a successor unit with twice the capacity of the previous generation in order to meet the increasing need for higher capacity.
The basic system of this unit was the same as that of the H-8589-1, but track pitch was halved by improving the design precision of each part. This doubled the surface recording density compared to the previous unit, and enabled a capacity of 200Mbyte per replaceable disk pack. Also, seek time was improved by 17% from the previous 30ms to 25ms by improving the seek system.
Each DKU has two spindles, and four DKUs were linked and connected to a single disk controller to create a subsystem capacity of 1,600Mbyte per house.
This unit had media compatibility with the IBM3330-1 disk unit, and disk packs could be exchanged between the two.

H-8589-11 Magnetic Disk Drive Unit Specifications
Completion date June 1975
Memory capacity per unit 400Mbyte/DKU
Memory capacity per spindle 200Mbyte
BPI 4,400BPI
Surface recording density 1.8Mbit/square inch
Disk size/quantity 14-inch/10 disks
Head type/number per actuator Heavyweight inductive/19+1(servo)
Average access time 25ms
Disk rotation speed 3,600rpm
Data transfer speed 806Kbyte/s

H-8589-11 Magnetic Disk Drive