Microsoft Alive
A BASIC interpreter for the Altair became an empire — MS-DOS, Windows, Office, and now the cloud. The company the entire software industry once organized itself in relation to.
Gates and Allen wrote Altair BASIC on a Harvard PDP-10 in 1975 and licensed it to MITS — the founding transaction. The pivotal deal was IBM's PC in 1980: Microsoft bought QDOS for $50,000, licensed it to IBM as PC-DOS, and kept the right to sell it to clone makers.
Windows, Office, the browser wars, the antitrust case (settled 2001), then Nadella's pivot to Azure and open source — the company that was once 'the Evil Empire' now owns GitHub and contributes to Linux.