H-8577 Grouped Magnetic Disk Drive

The basic system of this unit was derived from the H-8564 magnetic disk drive, but the surface recording density was doubled, and the number of disks comprising the disk pack was increased to 11, so the capacity per spindle was greatly increased to 30Mbyte. A grouped disk unit was configured by equipping these disk packs with 9 spindles per controller (including spare disks), and thus memory capacity per controller increased dramatically. For the recording media, a disk pack was configured from eleven 14-inch coated disks, and the number of heads was doubled to 20. The worsening of positioning accuracy due to the increased number of heads was resolved by improving the precision/management of each mechanism.