Applesoft BASIC is a dialect of Microsoft BASIC, developed by Marc McDonald and Ric Weiland, supplied with the Apple II series of computers. It supersedes Integer BASIC and is the BASIC in ROM in all Apple II series computers after the original Apple II model. It is also referred to as FP BASIC (from floating point) because of the Apple DOS command used to invoke it, instead of INT for Integer BASIC.
Applesoft BASIC was supplied by Microsoft and its name is derived from the names of both Apple Computer and Microsoft. Apple employees, including Randy Wigginton, adapted Microsoft's interpreter for the Apple II and added several features. The first version of Applesoft was released in 1977 on cassette tape and lacked proper support for high-resolution graphics. Applesoft II, which was made available on cassette and disk and in the ROM of the Apple II Plus and subsequent models, was released in 1978. It is this latter version, which has some syntax differences and support for the Apple II high-resolution graphics modes, that is usually synonymous with the term "Applesoft."
A compiler for Applesoft BASIC, TASC (The Applesoft Compiler), was released by Microsoft in 1981.
When Steve Wozniak wrote Integer BASIC for the Apple II, he did not implement support for floating-point arithmetic because he was primarily interested in writing games, a task for which integers alone were sufficient. In 1976, Microsoft had developed Microsoft BASIC for the MOS Technology 6502, but at the time there was no production computer that used it. Upon learning that Apple had a 6502 machine, Microsoft asked if the company were interested in licensing BASIC, but Steve Jobs replied that Apple already had one.
The Apple II was unveiled to the public at the West Coast Computer Faire in April 1977 and became available for sale in June. One of the most common customer complaints about the computer was BASIC's lack of floating-point math. Making things more problematic was that the rival Commodore PET personal computer had a floating point-capable BASIC interpreter from the beginning.