Microsoft Windows, commonly referred to as Windows, is a group of several proprietary graphical operating system families, all of
which are developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. Active Microsoft Windows
families include Windows NT and Windows IoT; these may encompass subfamilies, e.g. Windows Server or Windows Embedded Compact (Windows CE).
Defunct Microsoft Windows families include Windows 9x, Windows Mobile and Windows Phone.
Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in
response to the growing interest in graphical user interfaces (GUIs). Microsoft Windows came to dominate the world's personal computer
(PC) market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. Apple came to see Windows as an unfair
encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh (eventually settled in court in
Microsoft's favor in 1993). On PCs, Windows is still the most popular operating system. However, in 2014, Microsoft admitted losing the
majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones. In 2014, the
number of Windows devices sold was less than 25% that of Android devices sold. This comparison, however, may not be fully relevant, as the
two operating systems traditionally target different platforms. Still, numbers for server use of Windows (that are comparable to
competitors) show one third market share, similar to that for end user use.
As of February 2020, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10. The most recent version
for server computers is Windows Server, version 2004. A specialized version of Windows also runs on the Xbox One video game console.