The Apple II Plus shipped with 48KB of standard memory, expandable to 64KB, and introduced Applesoft BASIC built into ROM, replacing the earlier Integer BASIC. Though less revolutionary than the original 1977 Apple II, the Plus extended the platform's commercial momentum, cementing Apple's early lead in a personal computer market that IBM had not yet entered.
By 1980 the original Apple II, unveiled three years earlier at the West Coast Computer Faire, had already proven that a computer could be something other than an industrial or academic instrument, that it could sit on a desk in a living room or small office and run a spreadsheet or play a game. VisiCalc, the first killer app for personal computers, had launched on the Apple II in 1979 and was driving sales among accountants and small business owners who had never previously considered owning a computer.
The Apple II Plus, released March 5, 1980, was an incremental machine rather than a revolutionary one: more memory, Applesoft BASIC in ROM instead of loaded from tape or disk, minor disk controller improvements. But incremental was exactly what a maturing product line needed, and the Plus sold steadily through 1982, helping Apple's revenue climb past $100 million for the first time.
Within a year and a half IBM would enter the personal computer market with its own PC, permanently changing the competitive landscape. But for a crucial window, the unglamorous, beige-boxed Apple II Plus was quietly proving there was real money, not just hobbyist enthusiasm, in personal computing, laying commercial groundwork for the industry's explosive growth through the 1980s.