Windows XP

Windows XP is an operating system that was produced by Microsoft for use on personal computers, including home and business desktops, laptops, and media centers. It was first released to computer manufacturers on August 24, 2001, and is the most popular version of Windows, based on installed user base. The name "XP" is short for "eXPerience."

Windows XP was the successor to both Windows 2000 and Windows Me, and was the first consumer-oriented operating system produced by Microsoft to be built on the Windows NT kernel and architecture. Windows XP was released for retail sale on October 25, 2001, and over 400 million copies were in use in January 2006, according to an estimate in that month by an IDC analyst. It was succeeded by Windows Vista, which was released to volume license customers on November 8, 2006, and worldwide to the general public on January 30, 2007. Direct OEM and retail sales of Windows XP ceased on June 30, 2008. Microsoft continued to sell Windows XP through their System Builders (smaller OEMs who sell assembled computers) program until January 31, 2009. XP may continue to be available as these sources run through their inventory or by purchasing Windows 7 Ultimate, Windows 7 Pro, Windows Vista Ultimate or Windows Vista Business, and then downgrading to Windows XP.

The most common editions of the operating system were Windows XP Home Edition, which was targeted at home users, and Windows XP Professional, which offered additional features such as support for Windows Server domains and two physical processors, and was targeted at power users, business and enterprise clients. Windows XP Media Center Edition has additional multimedia features enhancing the ability to record and watch TV shows, view DVD movies, and listen to music. Windows XP Tablet PC Edition was designed to run stylus applications built using the Tablet PC platform.

Windows XP was eventually released for two additional architectures, Windows XP 64-bit Edition for IA-64 (Itanium) processors and Windows XP Professional x64 Edition for x86-64. There is also Windows XP Embedded, a component version of the Windows XP Professional, and editions for specific markets such as Windows XP Starter Edition. By mid 2009, a manufacturer revealed the first Windows XP powered cellular telephone.

The NT-based versions of Windows, which are programmed in C, C++, and assembly, are known for their improved stability and efficiency over the 9x versions of Microsoft Windows. Windows XP presented a significantly redesigned graphical user interface, a change Microsoft promoted as more user-friendly than previous versions of Windows. A new software management facility called Side-by-Side Assembly was introduced to ameliorate the "DLL hell" that plagues 9x versions of Windows. It is also the first version of Windows to use product activation to combat illegal copying. Windows XP had also been criticized by some users for security vulnerabilities, tight integration of applications such as Internet Explorer 6 and Windows Media Player, and for aspects of its default user interface. Later versions with Service Pack 2, Service Pack 3, and Internet Explorer 8 addressed some of these concerns.

During development, the project was codenamed "Whistler", after Whistler, British Columbia, as many Microsoft employees skied at the Whistler-Black comb ski resort.

According to web analytics data generated by W3Schools, as of February 2011, Windows XP is the most widely used operating system for accessing the Internet in the world with a 44.2% market share, having peaked at 76.1% in January 2007.

Editions

The two major editions are Windows XP Home Edition, designed for home users, and Windows XP Professional, designed for business and power-users. XP Professional contains advanced features that the average home user would not use. However, these features are not necessarily missing from XP Home. They are simply disabled, but are there and can become functional. These releases were made available at retail outlets that sell computer software, and were preinstalled on computers sold by major computer manufacturers. As of mid-2008, both editions continue to be sold. A third edition, called Windows XP Media Center Edition was introduced in 2002 and was updated every year until 2006 to incorporate new digital media, broadcast television and Media Center Extender capabilities. Unlike the Home and Professional edition, it was never made available for retail purchase, and was typically either sold through OEM channels, or was preinstalled on computers that were typically marketed as "media center PCs".

Two different 64-bit editions were made available, one designed specifically for Itanium-based workstations, which was introduced in 2001 around the same time as the Home and Professional editions, but was discontinued a few years later when vendors of Itanium hardware stopped selling workstation-class machines due to low sales. The other, called Windows XP Professional x64 Edition, supports the x86-64 extension. x86-64 was implemented first by AMD as "AMD64", found in AMD's Opteron and Athlon 64 chips, and later implemented by Intel as "Intel 64" (formerly known as IA-32e and EM64T), found in Intel's Pentium 4 and later chips.

Windows XP Tablet PC Edition was produced for a class of specially designed notebook/laptop computers called tablet PCs. It is compatible with a pen-sensitive screen, supporting handwritten notes and portrait-oriented screens.

Microsoft also released Windows XP Embedded, an edition for specific consumer electronics, set-top boxes, kiosks/ATMs, medical devices, arcade video games, point-of-sale terminals, and Voice over Internet Protocol (VoIP) components. In July 2006, Microsoft released Windows Fundamentals for Legacy PCs, a thin client version of Windows XP Embedded which targets older machines (as early as the original Pentium). It is only available to Software Assurance customers. It is intended for corporate customers who would like to upgrade to Windows XP to take advantage of its security and management capabilities, but can't afford to purchase new hardware.

Editions for specific markets

Windows XP Starter Edition is a lower-cost edition of Windows XP available in Thailand, Indonesia, Russia, India, Colombia, Brazil, Argentina, Peru, Bolivia, Chile, Mexico, Ecuador, Uruguay and Venezuela. It is similar to Windows XP Home, but is limited to low-end hardware, can only run 3 programs at a time, and has some other features either removed or disabled by default. Each country's edition is also customized for that country, including desktop backgrounds of popular locations, localized help features for those who may not speak English, and other default settings designed for easier use than typical Windows XP installations. The Malaysian version, for example, contains a desktop background of the Kuala Lumpur skyline.

In March 2004, the European Commission fined Microsoft €497 million (US$603 million) and ordered the company to provide a version of Windows without Windows Media Player. The Commission concluded that Microsoft "broke European Union competition law by leveraging its near monopoly in the market for PC operating systems onto the markets for work group server operating systems and for media players". After unsuccessful appeals in 2004 and 2005, Microsoft reached an agreement with the Commission where it would release a court-compliant version, Windows XP Edition N. This version does not include the company's Windows Media Player but instead encourages users to pick and download their own media player. Microsoft wanted to call this version Reduced Media Edition, but EU regulators objected and suggested theEdition N name, with the N signifying "not with Media Player" for both Home and Professional editions of Windows XP. Because it is sold at the same price as the version with Windows Media Player included, Dell, Hewlett-Packard, Lenovo and Fujitsu Siemens have chosen not to stock the product. However, Dell did offer the operating system for a short time. Consumer interest has been low, with roughly 1,500 units shipped to OEMs, and no reported sales to consumers.

In December 2005, the Korean Fair Trade Commission ordered Microsoft to make available editions of Windows XP and Windows Server 2003 that do not contain Windows Media Player or Windows Messenger. Like the European Commission decision, this decision was based on the grounds that Microsoft had abused its dominant position in the market to push other products onto consumers. Unlike that decision, however, Microsoft was also forced to withdraw the non-compliant versions of Windows from the South Korean market. This decision resulted in Microsoft's releasing "K" and "KN" variants of the Home and Professional editions in August 2006.

That same year, Microsoft also released two additional editions of Windows XP Home Edition directed towards subscription-based and pay-as-you-go pricing models. These editions, released as part of Microsoft's FlexGo initiative, are used in conjunction with a hardware component to enforce time limitations on the usage of Windows. Its target market is emerging economies such as Brazil and Vietnam.