PC DOS Gary Kildall CP/M-80 Digital Research Dorothy McEwen non-disclosure agreement Bill Gates ROM 86-DOS Tim Paterson MS-DOS Microsoft IBM operating system BASIC CP/M
The IBM PC typically came with PC DOS, an operating system based on Gary Kildall's CP/M-80 operating system. In 1980, IBM approached Digital Research, Kildall's company, for a version of CP/M for its upcoming IBM PC. Kildall's wife and business partner, Dorothy McEwen, met with the IBM representatives who were unable to negotiate a standard non-disclosure agreement with her. IBM turned to Bill Gates, who was already providing the ROM BASIC interpreter for the PC. Gates offered to provide 86-DOS, developed by Tim Paterson of Seattle Computer Products. IBM rebranded it as PC DOS, while Microsoft sold variations and upgrades as MS-DOS.
