Windows 95 introduced many features that have been part of the product ever since, including the Start menu, the taskbar, and Windows Explorer (renamed File Explorer in Windows 8). Windows 95, though still being based on MS-DOS, was its own operating system, using a 16-bit DOS-based kernel and a 32-bit user space. The first versions of Windows (1.0 through to 3.11) were graphical shells that ran from MS-DOS. The product line evolved in the 1990s from an operating environment into a fully complete, modern operating system over two lines of development, each with their own separate codebase.
Microsoft introduced Windows as a graphical user interface for MS-DOS, which had been introduced two years earlier. Microsoft Windows was announced by Bill Gates on November 10, 1983. Overview of the version history of Microsoft Windows
