In 1983, Microsoft announced the development of Windows, a graphical user interface (GUI) for its own operating system (MS-DOS). 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 3.0, Windows 3.1x, Windows 95, Windows 98, and Windows ME. Windows for Workgroups 3.11 added 32-bit networking.