Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It is a processor-independent, multiprocessing, multi-user operating system. The first version of Windows NT was Windows NT 3.1 and was produced for workstations and server computers. It was intended to complement consumer versions of Windows (including Windows 1.0 through Windows 3.1x) that were based on MS-DOS. Gradually, the Windows NT family was expanded into Microsoft's general-purpose operating system product line for all personal computers, deprecating the Windows 9x family.