For years, unofficial copies of Microsoft's 6502 BASIC have been available online and in archives. Coders have studied and run this code on modern systems. Now, Microsoft is officially releasing the 6502 BASIC code under an open-source license for the first time. Microsoft BASIC originated in 1975 as the company's initial product, an interpreter for the Intel 8080. This codebase was later adapted for various 8-bit processors, including the MOS 6502. Bill Gates and Ric Weiland completed the 6502 port in 1976. Commodore licensed this version in 1977 for their PET computers, and later the VIC-20 and Commodore 64. The released version, labeled "1.1," includes fixes to the garbage collector made in 1978. These fixes were jointly implemented by a Commodore engineer and Bill Gates. This specific version is the one that shipped with the PET computers as "BASIC V2." It even contains a hidden Easter egg confirmed by Bill Gates himself.