Steve Wozniak was a colleague of Rod Holt.
The Apple II is an 8-bit home computer , one of the first highly successful mass-produced microcomputer products , designed primarily by Steve Wozniak ( Steve Jobs oversaw the development of the Apple II 's foam-molded plastic case and Rod Holt developed the switching power supply ) . Steve Wozniak . He primarily designed the 1977 Apple II , known as one of the first highly successful mass-produced microcomputers , while Jobs oversaw the development of its unusual case and Rod Holt developed the unique power supply .