Windows - technical definition

The most widely used operating system for desktop and laptop computers. Developed by Microsoft, Windows primarily runs on x86-based CPUs, although some versions run on Intel's Itanium CPUs. Windows provides a graphical user interface and desktop environment in which applications are displayed in resizable, movable windows on screen.

Windows comes in both client and server versions, all of which support networking, the difference being that the server versions are designed to be dedicated servers. The client versions of Windows may also share data over the network and can be configured to grant access to all or specific files only. Windows PCs are used to access a variety of servers on the network, including Windows servers, Unix, Linux and NetWare servers, as well as mainframes. See operating system.

Windows How to's

All the Windows "how to's" in this encyclopedia have a "Win" prefix in front of their name in order to group them together in the index; for example, Win Change window appearance and Win Finding files. For fundamentals on how to work with Windows, see Win abc's.

Following is a summary of Windows versions.

Windows NT Lineage (32 & 64 bit)

Windows 7
The successor to Windows Vista, expected in 2009. See Windows 7.

Windows Vista (2006) - MS Version 6.0
The current client version of Windows, which comes in several flavors (see Windows Vista). Windows Server 2008 is the server version (code named Longhorn Server). See Windows Server 2008.

Windows XP (2001) - MS Version 5.1
Windows XP was the previous version of Windows, available in Home and Professional versions, the latter adding more security and administrative capabilities. There were also versions of XP that ran on AMD's 64-bit CPUs and Intel's 64-bit Itaniums. See Windows XP.

Windows 2000 (2000) - MS Version 5.0
Windows 2000 is an updated version of Windows NT 4 for client and server. It added numerous enhancements including Plug and Play and Active Directory. Windows 2000 comes in one workstation version and three server versions. There are server versions that support AMD's 64-bit CPUs and Intel's 64-bit Itaniums. See Windows 2000.

Windows NT (1993) - MS Versions 3.1, 3.5, 4.0
Windows NT 3.1 was a completely new 32-bit OS with separate client and server versions. Introduced during the reign of Windows 3.1 and two years before Windows 95, it used the same Program Manager user interface as Windows 3.1, but provided greater stability. In 1996, Windows NT 4.0 switched to the Windows 95 Start menu and Taskbar interface, but did not include Plug and Play. NT Server gained significant market share, while NT Workstation (client version) was used by the professional user and did not impact the Windows 95/98 market. See Windows NT.

Windows 95 Lineage (32 bit)

Windows ME (2000) - MS Version 4.9
An upgrade to Windows 98. ME had a shorter boot time, but no longer could be booted into DOS only (DOS sessions could still be run in a Windows window). See Windows ME.

Windows 98 (1998) - MS Version 4.1
Windows 98 was an upgrade to Windows 95 that tightly integrated the Internet Explorer Web browser with the OS. In 1999, Windows 98 Second Edition fixed numerous bugs and upgraded its applications. See Windows 98 and Windows Second Edition.

Windows 95 (1995) - MS Version 4.0
Windows 95 was the first 32-bit Windows operating system and a major upgrade from Windows 3.1. It used an entirely different user interface that incorporated the now-common Start menu and Taskbar. It was also the first time the computer booted directly into Windows, rather than being loaded after booting up in DOS. See Windows 95.

Windows DOS Lineage (16 bit)

Windows 3.1 (1992) - MS Version 3.x
An upgrade to Windows 3.0 that provided a more stable and faster environment. It evolved into Windows for Workgroups Version 3.11, which added peer-to-peer networking and was the last 16-bit Windows version. See Windows 3.1.

Windows 3.0 (1990) - MS Version 3.x
The first popular version of Windows. It provided a new and colorful user interface that was far superior to earlier versions. The PC was still booted up in DOS, but Windows included a DOS extender that broke the one megabyte memory barrier, a major breakthrough for that time. Windows 3.0 was widely used to multitask DOS applications. See Windows 3.0.

Windows 2.0/286/386 (1987) - MS Version 2.0
Windows 2.0 introduced overlapping, resizable windows with more flexibility. Soon after, Windows/386 was released for Intel's 386 CPU, which could run multiple DOS applications simultaneously (Windows 2.0 was then renamed Windows/286). Windows was starting to become more useful, and a handful of companies adopted it as an operating environment. See Windows 2.0.

Windows 1.0 (1985) - MS Version 1.0
The first version of Windows introduced the "MS-DOS Executive," which was a DOS application that ran applications in side-by-side windows. It barely made a dent in the market. See Windows 1.0.

                    Word
     Windows        Size   Year   Built-in
     Version       (bits)  Intro  Networking

     NT Lineage

     Windows Server 32/64  2008     yes
     Windows Vista  32/64  2006     yes
     Windows Server 32/64  2003     yes
     Windows XP     32/64  2001     yes
     Windows 2000   32     2000     yes
     Windows NT     32     1993     yes

     95 Lineage

     Windows ME     32     2000     yes
     Windows 98     32     1998     yes
     Windows 95     32     1995     yes

     DOS Lineage

     WfW 3.1        16     1992     yes
     Windows 3.1    16     1992     no
     Windows 3.0    16     1990     no
     Windows/386    16     1987     no
     Windows 2.0    16     1987     no
     Windows 1.0    16     1985     no