MS-DOS (Microsoft's Disk Operating System) is an operating system for x86-based personal computers developed mostly by Microsoft. All in all, MS-DOS, its rebranding as IBM PC DOS and some operating systems that try to be compatible with MS-DOS, are sometimes called "DOS" (which is also the generic acronym for the disk operating system). MS-DOS was the main operating system for personal computers compatible with IBM PC during the 80s and early 90s, when it was gradually replaced by operating systems that offer a graphical user interface (GUI), in several generations of the operating system Microsoft Windows graphic.