In 1983, Microsoft announced the development of Windows, a graphical user interface (GUI) for its own operating system (MS-DOS), which had shipped for IBM PC and compatible computers since 1981. The product line has changed from a GUI product to a modern operating system over two families of design, each with its own codebase and default file system.
The 3.x and 4.x family includes Windows 3.11, Windows 95, Windows 98, and Windows Me. Windows for Workgroups 3.11 achieved the breakthrough from 16- to 32-bit networking and 32-bit disk access. Windows 95 completed the migration to 32-bit code and started an entirely new user interface, most of which is still used today.