Disk II

From Computer History Wiki
Jump to: navigation, search



Disk II
Disk II.jpg
Two Disk II drives
Manufacturer: Apple
Year Introduced: 1978
Capacity: 114 KiB (pre-DOS 3.3), 140 KiB (DOS 3.3)


The Disk II was a 5¼-inch floppy disk drive designed by Steve Wozniak and manufactured by Apple Computer. It was first introduced in 1978 at a retail price of US$495 for pre-order; it was later sold for $595 including the controller card and cable. The Disk II was designed specifically for use with the Apple II personal computer family to replace the slower cassette tape storage.

The first drives sold were built using parts from Shugart Drives, but to reduce costs Apple switched to Alps Electric Co. of Japan who built them for half the cost. Early production at Apple was handled by two people, and they produced about thirty drives a day.

Normal storage capacity per disk side was 114KB with DOS 3.2.1 and earlier (13 256-byte sectors per track, 35 tracks per side), or 140KB with DOS 3.3 and the accompanying firmware update for the controller card (16 sectors/track). A Bell & Howell version of the Disk II was also manufactured by Apple in a black case which matched the color of the Bell & Howell version of the Apple II Plus which Apple was already manufacturing. Apple later modernized the appearance of the Disk II to better match the Apple IIe case, and also offered a combination of two Disk II drives in a single unit, called the DuoDisk.


See also

External links