Microsoft Windows is a series of popular proprietary operating environments and operating systems created by Microsoft for use on personal computers and servers. Microsoft first introduced an operating environment named Windows in November, 1985, as an add-on to MS-DOS. This was in response to the growing trend of graphical user interfaces such as the Apple Macintosh. Microsoft Windows eventually came to dominate the world personal computer market with market analysts like IDC estimating that Windows has around 90% of the client operating system market. All recent versions of Windows are fully-fledged operating systems.