What is Microsoft Windows?

Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing trend of graphical user interfaces (GUI) popularized by the Macintosh. Microsoft Windows eventually came to dominate the world's personal computer market. At the 2004 IDC Directions conference, IDC Vice President Avneesh Saxena stated that Windows had approximately 90% of the client operating system market.