2. In 1983, Microsoft announced the development of Windows, a graphical user interface (GUI) for its own operating system (MS-DOS), which had shipped for IBM PC and compatible computers since 1981. The product line has changed from a GUI product to a modern operating system over two families of design, each with its own codebase and default file system. The 3.x and 4.x family includes Windows 3.11, Windows 95, Windows 98, and Windows Me. Windows for Workgroups 3.11 achieved the breakthrough from 16- to 32-bit networking and 32-bit disk access. Windows 95 completed the migration to 32-bit code and started an entirely new user interface, most of which is still used today. Windows NT family started with NT 3.1 in 1993. Modern Windows operating system versions are based on the newer Windows NT kernel that was originally intended for OS/2. Windows runs on IA-32, x86-64, and Itanium processors. Earlier versions also ran on the i860, Alpha, MIPS, FairchildClipper, and PowerPC architectures. Some work was done to port it to the SPARC architecture. The NT kernel borrows many techniques from VMS. With NT4.0 in 1996 the shell changed from Program Manager to Explorer. CPU support included PowerPC, MIPS, and DEC Alpha for earlier versions of NT, but focuses on Itanium, 386, 486, and x64 today. Microsoft is also working to bring Windows NT onto ARM in the next release of Windows.
3. Windows Vista was released on 30 November 2006 to business customers, consumer versions following on 30 January 2007. Windows Vista intended to have enhanced security by introducing a new restricted user mode called User Account Control, replacing the "administrator-by-default" philosophy of Windows XP. One major difference between Vista and earlier versions of Windows, Windows 95 and later, is that the original start button was replaced with just the Windows icon. Vista also features new graphics features, the Windows AeroGUI, new applications (such as Windows Calendar, Windows DVD Maker and some new games including Chess, Mahjong, and Purble Place),[16]Internet Explorer 7, Windows Media Player 11, and a large number of underlying architectural changes. Windows Vista ships in six editions:[17] Starter (only available in developing countries) Home Basic Home Premium Business Enterprise (only available to large businesses and enterprises) Ultimate (combines both Home Premium and Enterprise) All editions (except Starter edition) are currently available in both 32-bit and 64-bit versions. The biggest advantage of the 64-bit version is breaking the 4 gigabyte memory barrier, which 32-bit computers cannot fully access.
4. Windows Server 2008, released on 27 February 2008, was originally known as Windows Server Codename "Longhorn". Windows Server 2008 builds on the technological and security advances first introduced with Windows Vista, and is significantly more modular than its predecessor, Windows Server 2003. Windows Server 2008 ships in ten editions: Windows Server 2008 Standard Edition (32-bit and 64-bit) Windows Server 2008 Enterprise Edition (32-bit and 64-bit) Windows Server 2008 Datacenter Edition (32-bit and 64-bit) Windows HPC Server 2008 Windows Web Server 2008 (32-bit and 64-bit) Windows Storage Server 2008 (32-bit and 64-bit) Windows Small Business Server 2008 (64-bit only) Windows Essential Business Server 2008 (32-bit and 64-bit) Windows Server 2008 for Itanium-based Systems Windows Server 2008 Foundation Server
