The OS Wars Begin
The battle for which company and OS will rule the PC starts with the beginning of the PC itself. Mention “DOS” and Microsoft DOS will come to mind, but there are plenty of variants. Enter Digital Research’s CP/M-86. CP/M was the original “DOS,” shipped with most non-proprietary machines. IBM originally planned to use CP/M-86 with the PC, but negotiations went sour when IBM wanted to pay Digital Research a one-time fee, rather than on-going royalties.
Meanwhile, Microsoft had purchased a clone of CP/M86 from Seattle Computer Products, 86-DOS (aka QDOS – Quick and Dirty Operating System). This was re-branded to MS-DOS and IBM’s PC DOS, available for the PC. After Digital Research threatened legal action, IBM gave customers the option to buy either CP/M-86 or MS-DOS/ PC DOS. MS-DOS/PC DOS was the substantially cheaper option, and outsold CP/M-86 in overwhelming numbers.
IBM and Microsoft’s MSDOS/PC DOS partnership wouldn’t last long, with the two products gradually diverging over the years, with different features and compatibility. PC DOS was designed for genuine IBM hardware, and as IBM compatibles took over the market, the more generic MS-DOS would become ubiquitous. Regardless, both versions would stay in production until the turn of the century.