Microsoft Windows
Microsoft Windows is a family of proprietary operating systems designed by Microsoft Corporation and primarily targeted to Intel architecture based computers, with an estimated 88.9 percent total usage share on Web connected computers.[10][16][17][18] The newest version is Windows 8.1 for workstations and Windows Server 2012 R2 for servers. Windows 7 recently overtook Windows XP as most used OS.
Microsoft Windows originated in 1985 as an operating environment running on top of MS-DOS, which was the standard operating system shipped on most Intel architecture personal computers at the time. In 1995, Windows 95 was released which only used MS-DOS as a bootstrap. For backwards compatibility, Win9x could run real-mode MS-DOS[22][23] and 16 bits Windows 3.x[24]drivers. Windows ME, released in 2000, was the last version in the Win9x family. Later versions have all been based on the Windows NT kernel. Current client versions of Windows run on IA-32,x86-64 and 32-bit ARM microprocessors.[25] In addition Itanium is still supported in older server version Windows Server 2008 R2. In the past, Windows NT supported additional architectures.
Server editions of Windows are widely used. In recent years, Microsoft has expended significant capital in an effort to promote the use of Windows as a server operating system. However, Windows' usage on servers is not as widespread as on personal computers, as Windows competes against Linux and BSD for server market share.[26][27]The first PC that used windows operating system was the IBM Personal System/2.