Microsoft BASIC

Microsoft BASIC was developed from the project that led to the foundation of Micro-Soft, now known as Microsoft.

History
"Micro-Soft" was founded on April 4, 1975 by Bill Gates and Paul Allen to develop and sell a BASIC interpreter for the Altair 8800. In October 1975, three variants of BASIC became available on paper tape or cassette tape for various memory configurations: 4K BASIC was $150, 8K BASIC was $200, and Extended BASIC was $350. Discounts were available for customers who also bought memory or an I/O board for the Altair computer.

Dialects
In 1977, Microsoft adapted BASIC to run on the MOS Technology 6502 processor. It initially supported 6 digits of floating-point precision and was updated later that year to support 9 digits of precision with version 1.1.

GW-BASIC is a dialect developed by Microsoft for the IBM Personal Computer. It was also bundled with MS-DOS, which became Microsoft's next primary product. The source code to GW-BASIC was published on February 10, 1983 and was released to the open source community on May 21, 2020.