Disk II
A 5.25 inch floppy disk drive for the Apple II that Steve Wozniak designed and Apple sold from June 1978 for $495.
Apple investor Mike Markkula found that a checkbook program he wrote loaded too slowly from tape. He asked Steve Wozniak to design a disk drive. Wozniak spent the 1977 Christmas holidays adapting a controller he had sketched at Hewlett-Packard.
His design used about ten times fewer chips than other controllers. The Disk II went on sale in June 1978 for $495 on pre-order. Later Apple sold it for $595 with the controller card and cable.
Why it matters
The Disk II replaced slow cassette tape on the Apple II. Fast loading and saving helped the Apple II run business software. Apple made at least six variants of the basic drive over the life of the Apple II series.
Key facts
- On sale June 1978.
- Priced at $495 on pre-order, later $595 with controller card.
- Designed by Steve Wozniak at Mike Markkula's request.
- Controller used about ten times fewer chips than others.
- Replaced cassette tape storage.
Sources
- Wikipedia, "Disk II", en.wikipedia.org/wiki/Disk_II, accessed October 14, 2026.
- Wikipedia, "Apple II", en.wikipedia.org/wiki/Apple_II, accessed October 14, 2026.