What is full form of MS DOS

The term DOS can refer to any operating system, but it is most often used as a short-form for MS-DOS (Microsoft Disk Operating System). Originally, designed by Microsoft for IBM, MS-DOS was the standard operating system for IBM-compatible personal computers. It is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, it’s rebranding as IBM PC DOS, and some operating systems attempting to be compatible with MS-DOS, are sometimes referred to as ‘DOS’. MS-DOS was the main operating system for IBM PC compatible personal computers during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various variations of the graphical Microsoft Windows operating system.