Apple II

Launched in April 1977, the same year as the Commodore PET and the Tandy TRS-80 — the three are usually called the 1977 trinity. Steve Wozniak designed it almost single-handedly and squeezed colour graphics, sound and eight expansion slots out of a remarkably small chip count. BASIC lived in ROM, so the machine was useful the moment it was switched on, and Wozniak's 1978 disk controller cost a fraction of the competition's.

The breakthrough came in 1979 with VisiCalc, the first spreadsheet, available only on the Apple II. Suddenly accountants and small businesses were paying thousands of dollars for a computer just to avoid recalculating a column by hand. The line was made until 1993 and sold around six million units — the money that paid for the Macintosh.