MS-DOS (short for Microsoft Disk Operating System) is an operating system commercialize by Microsoft. It was the most commonly used member of the DOS family of operating systems and was the dominant operating system for computers based on the Intel 8086 family of microprocessors, particularly the IBM PC and compatibles, during the 1980s. It was gradually replaced on consumer desktop computers by operating systems offering a graphical user interface (GUI), in particular by various generations of the Microsoft Windows operating system. It was originally known as QDOS (Quick and Dirty Operating System) and 86-DOS.