Microsoft Windows

"Windows" redirects here. For other uses, see Windows (disambiguation).

Microsoft Windows

File:Windows Vista Desktop.png Screenshot of Windows Vista, the latest release of Microsoft Windows.
Developer	Microsoft Corporation
OS family	MS-DOS-based, Windows NT, Windows 9x, Windows CE, Windows 3.1x, Windows XP, Windows Vista
Working state	Current
Source model	Closed source
Latest release	24H2 (10.0.26100.2605) (December 10, 2024 (2024-12-10)) [±]
Latest preview	Release Preview Channel 24H2 (10.0.26100.2605) (December 10, 2024 (2024-12-10)) [±] Beta Channel 23H2 (10.0.22635.4655) (December 13, 2024 (2024-12-13)) [±] Dev Channel 24H2 (10.0.26120.2705) (December 18, 2024 (2024-12-18)) [±] Canary Channel 10.0.27764.1000 (December 11, 2024 (2024-12-11)) [±] .
License	MS-EULA
Official website	Microsoft Windows

Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces (GUI). Microsoft Windows eventually came to dominate the world's personal computer market, overtaking OS/2 and Mac OS which had been introduced earlier. At the 2004 IDC Directions conference, IDC Vice President Avneesh Saxena stated that Windows had approximately 90% of the client operating system market.

Versions

See also: List of Microsoft Windows versions

The term Windows collectively describes any or all of several generations of Microsoft (MS) operating system (OS) products. These products are generally categorized as follows:

16-bit operating environments

File:Windows 1.0.jpg

The box art of Windows 1.0, the first version Microsoft released to the public.

The early versions of Windows were often thought of as just graphical user interfaces or workstations, mostly because they were started from MS-DOS and used for file system services. However even the earliest 16-bit Windows versions already assumed many typical operating system functions, notably having their own executable file format and providing their own device drivers (timer, graphics, printer, mouse, keyboard and sound) for applications. Unlike MS-DOS, Windows allowed users to execute multiple graphical applications at the same time, through cooperative multitasking. Finally, Windows implemented an elaborate, segment-based, software virtual memory scheme which allowed it to run applications larger than available memory: code segments and resources were swapped in and thrown away when memory became scarce, and data segments moved in memory when a given application had relinquished processor control, typically waiting for user input. Examples include Windows 1.0 (1985) and Windows 2.0 (1987) and its close relative Windows/286.

Hybrid 16/32-bit operating environments

File:Microsoft Windows.svg

A classic Windows logo. Was used from the early 1990s to 1999.

Windows/386 introduced a 32-bit protected mode kernel and virtual machine monitor. For the duration of a Windows session, it created one or more virtual 8086 environments and provided device virtualization for the video card, keyboard, mouse, timer and interrupt controller inside each of them. The user-visible consequence was that it became possible to preemptively multitask multiple MS-DOS environments in separate Windows (graphical applications required switching the window to full screen mode). Windows applications were still multi-tasked cooperatively inside one of such real-mode environments.

Windows 3.0 (1990) and Windows 3.1 (1992) improved the design, mostly thanks to virtual memory and loadable virtual device drivers (VxDs) which allowed them to share arbitrary devices between multitasked DOS windows. Because of this, Windows applications could now run in 16-bit protected mode (when Windows was running in Standard or 386 Enhanced Mode), which gave them access to several megabytes of memory and removed the obligation to participate in the software virtual memory scheme. They still ran inside the same address space, where the segmented memory provided a degree of protection, and multi-tasked cooperatively. For Windows 3.0, Microsoft also rewrote critical operations from C into assembly, making this release faster and less memory-hungry than its predecessors.

Hybrid 16/32-bit operating systems

The Windows logo that was used from late 1999 to 2001.

With the introduction of 32-bit Windows for Workgroups 3.11, Windows could finally stop relying on DOS for file management. Leveraging this, Windows 95 introduced Long File Names, reducing the 8.3 filename to the role of a boot loader. MS-DOS was now bundled with Windows; this notably made it (partially) aware of long file names when its utilities were run from within Windows, but angered the competition. The most important novelty was the possibility of running 32-bit multi-threaded preemptively multitasked graphical programs. However, the necessity of keeping compatibility with 16-bit programs meant the GUI components were still 16-bit only and not fully reentrant, which resulted in reduced performance and stability.

There were three releases of Windows 95 (the first in 1995, then subsequent bug-fix versions in 1996 and 1997, only released to OEMs, which added extra features such as FAT32 support). Microsoft's next OS was Windows 98; there were two versions of this (the first in 1998 and the second, named "Windows 98 Second Edition", in 1999). In 2000, Microsoft released Windows Me (Me standing for Millennium Edition), which used the same core as Windows 98 but adopted the visual appearance of Windows 2000, as well as a new feature called System Restore, allowing the user to set the computer's settings back to an earlier date. It was not a very well-received implementation, and many user problems occurred. Windows Me was considered a stopgap to the day both product lines would be seamlessly merged. Microsoft left little time for Windows Me to become popular before announcing their next version of Windows which would be called Windows XP.

32-bit operating systems

File:Microsoft Windows.png

The Windows logo that was used from 2001 to November 2006.

This family of Windows systems was fashioned and marketed for higher-reliability business use, and was unencumbered by any Microsoft DOS patrimony. The first release was Windows NT 3.1 (1993, numbered "3.1" to match the Windows version and to one-up OS/2 2.1, IBM's flagship OS codeveloped by Microsoft and Windows NT's main competitor at the time), which was followed by NT 3.5 (1994), NT 3.51 (1995), and NT 4.0 (1996); NT 4.0 was the first in this line to implement the Windows 95 user interface. Microsoft then moved to combine their consumer and business operating systems. Their first attempt, Windows 2000, failed to meet their goals, and was released as a business system. The home consumer edition of Windows 2000, codenamed "Windows Neptune," ceased development and Microsoft released Windows Me in its place. Eventually "Neptune" was merged into their new project, Whistler, which later became Windows XP. Since then, a new business system, Windows Server 2003, has expanded the top end of the range, and the newly released Windows Vista will complete it. Windows CE, Microsoft's offering in the mobile and embedded markets, is also a true 32-bit operating system that offers various services for all sub-operating workstations.

64-bit operating systems

File:Winvista.png

The Current Windows Vista Logo

Windows NT included support for several different platforms before the x86-based personal computer became dominant in the professional world. Versions of NT from 3.1 to 4.0 supported DEC Alpha and MIPS R4000, which were 64-bit processors, although the operating system treated them as 32-bit processors.

With the introduction of the Intel Itanium architecture, and later the AMD64/Intel64 (or x64 in Microsoft terminology) architectures, Microsoft released new versions of its more contemporary operating systems to support them. However, Microsoft dropped support for XP on Itanium in 2005. The modern 64-bit Windows family comprises Windows XP Professional x64 Edition for AMD64/Intel64 systems, and Windows Server 2003, in both Itanium and x64 editions. The x64 versions of Windows XP Professional and Server 2003 were released on April 25 2005, while the Itanium versions were released at the same time as their mainstream x86 (32-bit) counterparts. Windows Vista is the first end-user version of Windows that Microsoft has released simultaneously in 32-bit and x64 editions. Vista does not support Itanium.

History

Main article: History of Microsoft Windows

File:Windows1screen.png

A typical Windows 1.0 desktop.

Microsoft has taken two parallel routes in operating systems. One route has been the home user and the other has been the professional IT user. The dual route has generally led to the home versions with more "eye candy" and less functionality in networking and security, and professional versions with less "eye candy" and better networking and security.

The first independent version of Microsoft Windows, version 1.0, released in November 1985, lacked a degree of functionality and achieved little popularity, and was to compete with Apple's own operating system. Windows 1.0 did not provide a complete operating system; rather, it extended MS-DOS. Microsoft Windows version 2.0 was released in November, 1987 and was slightly more popular than its predecessor. Windows 2.03 (release date January 1988) had changed the OS from tiled Windows to overlapping Windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights.

A typical Windows for Workgroups 3.11 desktop.

Microsoft Windows version 3.0, released in 1990, was the first Microsoft Windows version to achieve broad commercial success, selling 2 million copies in the first six months. It featured improvements to the user interface and to multitasking capabilities. It received a facelift in Windows 3.1, made generally available on March 1, 1992. Windows 3.1 support ended on December 31, 2001. In August 1995, Microsoft released Windows 95, which made further changes to the user interface and was the first Windows version to utilize preemptive multitasking. Mainstream support for Windows 95 ended on December 31, 2000 and extended support for Windows 95 ended on December 31, 2001.

In July 1993, Microsoft released Windows NT based on a new kernel. NT was considered to be the professional OS. NT and the Windows non-professional line would later be fused together to create Windows XP.

The next in line was Microsoft Windows 98 released in June 1998. Substantially criticized for its slowness compared with Windows 95, many of its basic problems were later rectified with the release of Windows 98 Second Edition in 1999. Mainstream support for Windows 98 ended on June 30, 2002 and extended support for Windows 98 ended on July 11, 2006.

As part of its professional line, Microsoft released Windows 2000 in February 2000. The consumer version following Windows 98 was Windows Me (Windows Millennium Edition). Released in September 2000, Windows Me attempted to implement a number of new technologies for Microsoft: most notably publicized was "Universal Plug and Play." However, the OS was substantially criticized for its lack of compatibility and stability.

In October 2001, Microsoft released Windows XP, a version built on the Windows NT kernel that also retained the consumer-oriented usability of Windows 95 and its successors. This new version was widely praised in computer magazines. It shipped in two distinct editions, "Home" and "Professional", the former lacking many of the superior security and networking features of the Professional edition. Additionally, the "Media Center" edition was released in 2003, with an emphasis on support for DVD and TV functionality including program recording and a remote control. Mainstream support for Windows XP will continue until April 14, 2009 and extended support will continue until April 8, 2014.

In April 2003, Windows Server 2003 was introduced, replacing the Windows 2000 line of server products with a number of new features and a strong focus on security; this was followed in December 2005 by Windows Server 2003 R2.

Security

File:XPsp2 SecurityCentre FirewallAlert.png

The Windows Security Center was introduced with Windows XP Service Pack 2.

Security has been a hot topic with Windows for many years, and even Microsoft itself has been the victim of security breaches. Due in some part to the widespread usage of Windows on personal computers, as well as a number of technical reasons there is reportedly a fivefold greater amount of malware for Windows than other operating systems such as GNU/Linux, Unix, Mac OS X, and FreeBSD.

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. Windows NT and its successors are designed for security (including on a network) and multi-user PCs, but are not designed with Internet security in mind as much since, when they were first developed, Internet use was less prevalent. These design issues combined with flawed code (such as buffer overflows) and the popularity of Windows means that it is a frequent target of worm and virus writers. Furthermore, until Windows Server 2003 most versions of Windows NT were shipped with important security features disabled by default, and vulnerable (albeit useful) system services enabled by default. In June 2005, Bruce Schneier's Counterpane Internet Security reported that it had seen over 1,000 new viruses and worms in the previous six months.

Microsoft publicly admitted their ongoing security problems shortly after the turn of the century and now claims to regard security as their number one priority. Microsoft releases security patches through its Windows Update service approximately once a month (usually the second Tuesday of the month), although critical updates are made available at shorter intervals when necessary. In Windows 2000 (SP3 and later), Windows XP and Windows Server 2003, updates can be automatically downloaded and installed if the user selects to do so. As a result, Service Pack 2 for Windows XP, as well as Windows Server 2003, was installed by users more quickly than it otherwise might have been.

Windows Defender

On 6 January 2005, Microsoft released a beta version of Microsoft AntiSpyware, based upon the previously released Giant AntiSpyware. On 14 February 2006, Microsoft AntiSpyware became Windows Defender with the release of beta 2. Windows Defender is a freeware program designed to protect against spyware and other unwanted software. Windows XP and Windows Server 2003 users who have genuine copies of Microsoft Windows can freely download the program from Microsoft's web site, and Windows Defender ships as part of Windows Vista.

Third-party analysis

Microsoft Windows has been listed by Symantec as having the "fewest number of patches and the shortest average patch development time of the five operating systems it monitored in the last six months of 2006."[1] Listed in Symantec's 11th Internet Security Threat Report, several operating systems were tested including Red Hat Linux, and Mac OS X.

A study conducted by Kevin Mitnick and marketing communications firm Avantgarde in 2004 found that an unprotected and unpatched Windows XP system lasted only 4 minutes on the Internet before it was compromised. However, it is important to note that this study does not apply to Windows XP systems running the Service Pack 2 update (released in late 2004), which vastly improved the security of Windows XP. The AOL National Cyber Security Alliance Online Safety Study of October 2004 determined that 80% of Windows users were infected by at least one spyware/adware product. Much documentation is available describing how to increase the security of Microsoft Windows products. Typical suggestions include deploying Microsoft Windows behind a hardware or software firewall, running anti-virus and anti-spyware software, and installing patches as they become available through Windows Update.

Microsoft Windows through the years

Date	Product name	Support status
June 1985	Windows 1.01	Cancelled
August 1986	Windows 1.03	Cancelled
December 1987	Windows 2.03	Cancelled
June 1988	Windows 2.1	Cancelled
May 1990	Windows 3.0	Cancelled
April 1992	Windows 3.1	Cancelled
October 1992	Windows For Workgroups 3.1	Cancelled
February 1993	Microsoft Bob	Cancelled
August 1993	Windows NT 3.1	Cancelled
November 1993	Windows For Workgroups 3.11	Cancelled
September 1994	Windows NT 3.5	Cancelled
November 1994	Windows NT 3.51	Cancelled
August 1995	Windows 95	Unsupported as of December 31 2001.
September 1996	Windows NT 4.0	Unsupported as of December 31, 2004.
June 1998	Windows 98	Unsupported as of July 11, 2006
February 2000	Windows 2000	Extended Support
July 2000	Windows Me	Unsupported as of July 11, 2006
October 2001	Windows XP	Unsupported for SP1 as of October 10, 2006 Current for SP2
April 2003	Windows Server 2003	Current
November 2006	Windows Vista	Current

Windows lifecycle policy

Microsoft has stopped releasing updates and hotfixes for many old Windows operating systems, including all versions of Windows 9x and earlier versions of Windows NT. Support for Windows 98, Windows 98 Second Edition and Windows Me ended in July 11, 2006, and Extended Support for Windows NT 4.0 ended in December 31, 2004. Security updates were also discontinued for Windows XP 64-bit Edition after the release of the more recent Windows XP Professional x64 Edition. But most of the updates that Microsoft has released in the past can still be downloaded using Windows Update Catalog.

Windows 2000 is currently in the Extended Support Period, and this period will not end until July 13, 2010. Only security updates will be provided during Extended Support; indicating that no new service packs will be released for Windows 2000.

Emulation software

Emulation allows the use of some Windows applications without using Microsoft Windows. These include:

• Wine - (Wine Is Not an Emulator) an almost-complete free software/open-source software implementation of the Windows API, allowing one to run most Windows applications on x86-based platforms, including GNU/Linux.
• CrossOver - A Wine package with licensed fonts. Its developers are regular contributors to Wine, and focus on Wine running officially supported applications.
• Cedega - TransGaming Technologies' proprietary fork of Wine, which is designed specifically for running games written for Microsoft Windows under GNU/Linux.
• ReactOS - An open-source OS that intends to run the same software as Windows, at an early alpha stage.
• Darwine - This project intends to port and develop Wine as well as other supporting tools that will allow Darwin and Mac OS X users to run Microsoft Windows Applications, and to provide Win32 API compatibility at application source code level.
• E/OS - An open source linux kernel based operating system with the goal of running programs from many OS:es by emulation. Microsoft Windows is one of the targeted operating systems.

See also

General

• Comparison of operating systems
• List of operating systems
• Comparison of Windows and Linux
• Comparison of Windows and Mac OS X

Further reading

• Architecture of the Windows NT operating system line
• List of Microsoft Windows components
• Microsoft Windows topics
• Windows Explorer
• Windows Genuine Advantage
• Windows Media
• Windows Startup Process

External links

Official

• Microsoft's Official Windows Website
• Windows history time line from Microsoft

Programming

• Microsoft Development Network for programming Microsoft Windows
• Windows API tutorial in C++

Reviews and evaluation

• Paul Thurrott's SuperSite for Windows – a comprehensive evaluation of Microsoft's products and technologies
• "Time to Live on the Network" – a security study by Kevin Mitnick and Avantgarde (PDF)
• Windows XP: rough around the edges – an UI review of Windows XP
• AOL/National Cyber Security Alliance Online Safety Study (December 2005) (PDF)

High Performance Computing

• WindowsHPC.net
• WinHPC.org Windows HPC Portal

Other

• Windows history – a Windows history time line graph by Éric Lévénez (detailed, continually updated)
• GUIdebook: Windows Gallery – a website dedicated to preserving and showcasing graphical user interfaces
• Windows 20th Birthday