Gary Kildall develops the first commercially successful operating system for microcomputers. He had developed intergalactic digital research together with his wife. CP/M made it possible for one version of a program to run on a variety of computers. Initially confined to 8-microprocessors and no more than 64 kilobytes of memory, later versions of CP/M added multi user variations and were migrated to 16 bit processors. CP/M increased the market size of both hardware and software by reducing the amount of programming required to install an application on a manufacturers new computer. At one point IBM approached digital research and Microsoft about providing an operating system for their PC. Microsoft won and thus, CP/M was replaced by Microsoft’s system called MS-DOS.