Released in June 1979 and retailing for $1,195 (over $100 less than the original Apple II), the II plus was essentially an extension of the Apple II. It came with 48 KB RAM, a new floating-point Basic interpreter in ROM written by Microsoft, and a new auto-start ROM for easier start-up and screen editing.
Despite these rather minor changes, the II+ instantly became a great success for 3 main reasons:
• It was the first personal computer to offer an affordable and reliable floppy disk unit and an easy-to-use operating system, DOS 3.1
• It was also the first serious personal business machine thanks to the new VisiCalc spreadsheet program which was first released on the Apple II+ before any other systems.
• Instead of restricting its advertising campaign to computer enthusiasts and technical magazines, Apple was the first computer Company to advertise in popular magazines, emphasizing the usefulness of a personal computer at home, for business, education and entertainment.
A few months later, a special version of the II+, called II Europlus, was launched in Europe. Special escape sequences allowed users to type all the specific European characters, and the video interface was also adapted to the European PAL standard.
The first release of the Floppy drive OS was called 3.1 instead of the usual 1.0, simply because one of the OS developers updated a revision counter every time he recompiled the source code. The counter had reached 3.1 when the final version was released. The marketing department of Apple also felt that 3.1 sounded like a more advanced and debugged version than a standard 1.0. By the time of the launch of the Apple II+, the DOS version was up to 3.2.1
More than 2,000,000 Apple II+'s were sold between 1979 and 1983, not counting the numerous clones from south America, Asia, and also from the USA.