Windows 7 (codenamed Vienna, formerly Blackcomb) is a personal computer operating system developed by Microsoft. It is a part of Windows NT family of operating systems. Windows 7 was released to manufacturing on 22 July 2009, and became generally available on 22 October 2009,less than three years after the release of its predecessor, Windows Vista. Windows 7's server counterpart, Windows Server 2008 R2, was released at the same time.