Altair BASIC - Versions and Distribution

Versions and Distribution

Roberts agreed to distribute the interpreter. He also hired Gates and Allen to maintain and improve it, causing Gates to take a leave of absence from Harvard. They produced several versions: the original 4K BASIC and later 8K BASIC, Extended Basic, Extended ROM BASIC, and Disk BASIC.

As they expected, the Altair was very popular with hobbyists such as the Homebrew Computer Club. Altair BASIC, as MITS's preferred BASIC interpreter, was also popular. However, the hobbyists took a "share-alike" approach to software and thought nothing of copying the BASIC interpreter for other hobbyists. Homebrew member Dan Sokol was especially prolific; after somehow obtaining a pre-market tape of the interpreter, he made 25 copies and distributed them at the next Homebrew meeting, urging recipients to make more copies. Gates responded in 1976 with a strongly worded Open Letter to Hobbyists that accused the copiers of theft and declared that he could not continue developing computer software that people did not pay for. Many hobbyists reacted defensively to the letter.

Under the terms of the purchase agreement, MITS would receive the rights to the interpreter after it had paid a certain amount in royalties. However, Microsoft had developed versions of the interpreter for other systems such as the Motorola 6800. When they decided to leave MITS, a dispute arose over whether the full amount had been paid and whether the agreement applied to the other versions. Microsoft and MITS took the dispute to an arbitrator, who much to Roberts' surprise decided in favor of Microsoft. BASIC interpreters remained the core of Microsoft's business until the early 1980s, when it shifted to MS-DOS.