Microsoft Windows is a range of operating environments for personal computers. The range was first introduced by Microsoft in 1985 and eventually came to dominate the world personal computer market. All recent versions of Windows are fully-fledged operating systems.

Table of contents
1 Versions
2 Interface
3 Popularity
4 Security
5 Contemporary Versions
6 Initiatives
7 Versions for particular devices
8 See also
9 Emulation Software


The term Windows is used as a collective term for numerous very different products, falling into four broad categories:

  • 8-bit Operating environments. These simply provided a graphical user interface or desktop, and required a separate operating system to provide essential services, such as disk access, monitoring the keyboard for input, and so on. Examples include GEOS (1980). None of them were functional without the C64-ROM.

  • 16-bit Operating environments. These simply provided a graphical user interface or desktop, and required a separate operating system to provide essential services, such as disk access, monitoring the keyboard for input, and so on. Examples include Windows 1.0 (1985), Windows 2.0 (1987) and its close relatives Windows 286 and Windows 386, Windows 3.0 (1990), and Windows 3.1 (1992). None of them were functional without DOS.

  • Hybrid 16/32-bit bundled operating system and environment. These Windows versions still required DOS for basic functionality but integrated a version of Microsoft's MS-DOS into the package, so that it was not possible to buy Windows without also buying Microsoft DOS. Examples include the three versions of Windows 95 (first version in 1995, subsequent bug-fix versions in 1996 and 1997) and three versions of Windows 98 (1998, 1999, and 2000). The final version of the three was billed as Windows ME, but its membership of the Windows 98 family was not advertised.

  • True 32-bit operating systems originally designed and marketed for higher-reliability business use with no DOS heritage. Examples include Windows NT 3.1 (1992, numbered "3.1" to match the Windows version, and because it was based on what was about to be OS/2 3.0), NT 3.51, NT 4.0, Windows 2000, Windows XP, and Windows Server 2003.

  • 64-bit operating systems are one of the newest operating systems, compatible with Intel's IA-64, the Intel Architecture 64-bit. Examples of Windows 64-bit OSes are Windows XP 64 Bit Edition and Windows Server 2003.


The most obvious feature of the more recent Windows versions (since Windows 95 and NT 4.0) is the desktop, which is essentially a Microsoft version of IBM's 1992 OS/2 Presentation Manager. The Windows desktop has produced a significant change in the way people and computers interact: it is possible to perform many common tasks with very little computer knowledge, including some quite complex ones.

Modern operating systems need to cater for the vastly increased user base with a lower average computer skill level and the increased power and complexity of modern computer systems. So some technically savvy users accuse the Windows interface of isolating the user from too much of the inner workings of the computer, making it more difficult to control and configure some system features. But this has always been an issue to some extent with GUI operating systems, and, to a lesser extent, almost all operating systems, by definition.


Windows has achieved enormous market penetration. Windows is thought to be installed on over 90% of personal computers at present. In fact, Windows comes pre-installed on most computers, making it the default choice for much of the market. Most consumers do not delete Windows and install another operating system, though this is an option.


Security has been a major issue with Windows family products for many years. Most modern operating systems were designed for security in a multi-user and/or networked environment and have a relatively small number of security issues. Windows was originally designed for ease-of-use on a single-user PC without a network connection, and did not have security features built in from the outset. As a result, Windows has been successfully targeted by hackers and virus writers time and time again. The Blaster worm of August 2003 is a recent example.

Microsoft publicly admitted their ongoing security problems shortly after the turn of the century and (according to their press statements) now regard security as the number one priority.

Thus far, there is no implementation that signals the new emphasis is bearing fruit. However, there has been heavy speculation about the controversial Palladium system to tie software and the data in it to hardware that Microsoft may implement in later versions of Windows.

Contemporary Versions

Windows XP and Windows Server 2003 are the current versions of Windows. Windows XP is designed for desktop computers, while Windows Server 2003 is designed for servers and comes in four different versions: Web Edition, Standard Edition, Enterprise Edition and Datacenter Edition. Web Edition is designed mostly for web hosting, while Datacenter is the flagship product for extremely high end infrastructure. Standard and Enterprise fall in the middle.


Microsoft has a number of new initiatives planned or in progress: .NET, Palladium and the "Longhorn" operating system, which is due in or around 2005, although some Microsoft executives have indicated that a 2006 release is likely. There is some current speculation that Microsoft may use .NET and Longhorn as a way of moving away from the Windows brand. It is suggested that this may help Microsoft avoid the consequences of antitrust actions, as it will be able to claim that the Windows successor is an entirely new product, and not subject to any regulation applied to Windows. Further down the road, there is the "Blackcomb" operating system, which is due sometime around 2008, and will have both a client (for the average user) and server version.

Versions for particular devices

See also

Emulation Software

Use some Windows applications without purchasing a copy of Windows