When I look back at that era now I am amazed at how Gary Killdall failed to capitalize on his amazing position as the creator of CP/M, which was the dominant 8-bit OS and ran on numerous popular platforms, like the 8080, 8086, Z80, and the 68000. When IBM entered the PC market, Killdall and IBM could not come to an agreement so MS stepped in and licensed then purchased an imitation of CP/M called 86-DOS, which IBM offered in addition their own PC DOS. Killdall's company created an 8086 OS called CP/M-86 but it was more expensive than IBM's PC DOS and never took off. IBM did not want the liability of having contested code, so they let MS hold that bag and the rest is history.