Atari BASIC

Atari BASIC is an interpreter for the BASIC programming language that shipped with the Atari 8-bit family of home computers. Unlike most American BASICs of the home computer era, it is not a derivative of Microsoft BASIC and differs from them in significant ways. It includes keywords for Atari-specific features, and it lacks support for string arrays. The language was first distributed as an 8 KB ROM cartridge for use with the Atari 400 and 800 computers of 1979. Beginning with the 600XL and 800XL in 1983 it was built into the system. Three versions exist: the original cartridge-based version A, the built-in version B for the 600XL and 800XL, and the final version C in late-model XL machines and the XE series. They differ only in stability, with revision C fixing the bugs of the earlier two. Although the Atari machines ran faster than most of their contemporaries, several technical decisions left Atari BASIC near the bottom of performance benchmarks.