Definition - What does Altair BASIC mean?
Altair BASIC is an interpreter for the BASIC language meant to run on the MITS Altair 8800. It was the first ever product of Microsoft, and was distributed by MITS itself under a contract. It also marked the beginning of the Microsoft BASIC product line. It was written in assembly language using an Intel 8080 emulator running on a PDP-10 machine.
Techopedia explains Altair BASIC
Altair BASIC is essentially the beginning of Microsoft. The MITS Altair 8800 opened up a new world for technology enthusiasts when it was announced in the January 1st issue of Popular Mechanics in 1975, a time when electronic hobbyists were still trying to scrounge up parts from various electronic devices in order to build their own computers. The Altair 8800 was complete, powerful and affordable. Because of the popularity of the Altair, Bill Gates and Paul Allen realized the value of software as an indispensable counterpart to hardware, something that everybody with a computer would need. They then contacted Ed Roberts, the founder of MITS, and told him that they were developing an interpreter, and he agreed to meet them for a demonstration in March 1975.
Gates and Allen recognized that the small footprint of BASIC made it an ideal candidate for the limitations of the first personal computers, which were extremely limited in both processing power and memory. Using the published specifications of Altair, Paul Allen reworked his previously written Intel 8080 emulator that runs on a DEC PDP-10 machine. Allen adapted the emulator based on the Altair programmer guide, and they also hired Monte Davidoff to write the floating-point arithmetic routines for the interpreter. It was immediately accepted by MITS in March of 1975 and then distributed under license as Altair BASIC, the first release was on July 1, 1975. Microsoft (then Micro-Soft) was officially formed in April 4, 1975 right after the successful demonstration of the interpreter.