Bill Gates and Paul Allen adapted BASIC for the Altair 8800.
In 1975, the Altair 8800 appeared on the cover of Popular Electronics and attracted worldwide attention as a low-cost hobbyist microcomputer. Gates and Allen recognized that users would need software to make the machine useful rather than programming it entirely in machine code.
They developed an interpreter for BASIC, a beginner-friendly programming language originally created at Dartmouth College. The Altair version was written for the machine’s limited memory and was demonstrated to MITS, the Altair’s manufacturer, without the two programmers initially having an actual Altair computer available.
MITS agreed to distribute the software as Altair BASIC. The project became Microsoft’s first product and helped establish the company’s business model: selling software licenses separately from computer hardware.