Today, we’re opening the vault—for real. For decades, fragments and unofficial copies of Microsoft’s 6502 BASIC have circulated online, mirrored on retrocomputing sites, and preserved in museum archives. Coders have studied the code, rebuilt it, and even run it in modern systems. Today, for the first time, we’re opening the hatch and officially releasing the code under an open-source license. Microsoft’s first products: From the Altair to the Commodore 64 Microsoft BASIC began in 1975 as the com...