Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on

August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Windows 2000 for high-end and business users and Windows Me for home users, and is available for any devices running Windows NT 4.0, Windows 98, Windows 2000, or Windows Me that meet the new Windows XP system requirements.

Upon its release, Windows XP received critical acclaim, noting increased performance and stability (especially compared to

Windows Me), a more intuitive user interface, improved hardware support, and expanded multimedia capabilities. Windows XP and Windows Server 2003 were succeeded by Windows Vista and Windows Server 2008, released in 2007 and 2008, respectively. However, some criticisms of Windows XP were its security issues at launch, and many people believed their anti-piracy schemes had gone too far.

On August 24, 2001, Windows XP build 2600 was released to manufacturing (RTM). During a ceremonial media event at 

Microsoft Redmond Campus, copies of the RTM build were given to representatives of several major PC manufacturers in briefcases, who then flew off on decorated helicopters. While PC manufacturers would be able to release devices running XP beginning on September 24, 2001, XP was expected to reach general, retail availability on October 25, 2001. On the same day, Microsoft also announced the final retail pricing of XP's two main editions, "Home" (as a replacement for Windows Me for home computing) and "Professional" (as a replacement for Windows 2000 for high-end users).

Mainstream support for Windows XP ended on April 14, 2009, and extended support ended on April 8, 2014. Windows

Embedded POSReady 2009, based on an embedded version of Windows XP Professional, was the last supported version of Windows based on the Windows XP codebase, and received security updates until April 2019.

 

Features:

• User Interface: While retaining some similarities to previous versions, Windows XP's interface was overhauled with a new

visual appearance, with an increased use of alpha compositing effects, drop shadows, and "visual styles", which completely changed the appearance of the operating system. The number of effects enabled are determined by the operating system based on the computer's processing power, and can be enabled or disabled on a case-by-case basis. XP also added ClearType, a new subpixel rendering system designed to improve the appearance of fonts on liquid-crystal displays. A new set of system icons was also introduced. The default wallpaper, Bliss, is a photo of a landscape in the Napa Valley outside Napa, California, with rolling green hills and a blue sky with stratocumulus and cirrus clouds. Fast user switching allows additional users to log into a Windows XP machine without existing users having to close their programs and log out. Although only one user at the time can use the console (i.e., monitor, keyboard, and mouse), previous users can resume their session once they regain control of the console. Service Pack 2 and Service Pack 3 also introduced new features to Windows XP post-release, including the Windows Security Center, Bluetooth support, Data Execution Prevention, Windows Firewall, and support for SDHC cards that are larger than 4 GB and smaller than 32 GB.

• Infrastructure: Windows XP uses prefetching to improve startup and application launch times. It also became possible

to revert the installation of an updated device driver, should the updated driver produce undesirable results.

• Networking and Internet: Windows XP was originally bundled with Internet Explorer 6, Outlook Express 6, 

Windows Messenger, and MSN Explorer. New networking features were also added, including Internet Connection Firewall, Internet Connection Sharing integration with UPnP, NAT traversal APIs, Quality of Service features, IPv6 and Teredo tunneling, Background Intelligent Transfer Service, extended fax features, network bridging, peer to peer networking, support for most DSL modems, IEEE 802.11 (Wi-Fi) connections with auto configuration and roaming, TAPI 3.1, and networking over FireWire. Remote Assistance and Remote Desktop were also added, which allow users to connect to a computer running Windows XP from across a network or the Internet and access their applications, files, printers, and devices or request help. Improvements were also made to IntelliMirror features such as Offline Files, roaming user profiles and folder redirection.

• Other Features: 

  • Improved application compatibility and shims compared to Windows 2000.

  • DirectX 8.1, upgradeable to DirectX 9.0c.

  • A number of new features in Windows Explorer including task panes, thumbnails, and the option to view photos as a slideshow.

  • Improved imaging features such as Windows Picture and Fax Viewer.

  • Faster start-up, (because of improved Prefetch functions) logon, logoff, hibernation, and application launch sequences.

  • Numerous improvements to increase the system reliability such as improved System Restore, Automated System Recovery, and driver reliability improvements through Device Driver Rollback.

  • Hardware support improvements such as FireWire 800, and improvements to multi-monitor support under the name "DualView".

  • Fast user switching.

  • The ClearType font rendering mechanism, which is designed to improve text readability on liquid-crystal display (LCD) and similar monitors, especially laptops.

  • Side-by-side assemblies and registration-free COM.

  • General improvements to international support such as more locales, languages and scripts, MUI support in Terminal Services, improved Input Method Editors, and National Language Support.

 

​Service Packs:​

• Service Pack 1: Service Pack 1 (SP1) for Windows XP was released on September 9, 2002. It contained over 300 minor, post-RTM bug fixes, along with all security patches released since the original release of XP. SP1 also added USB 2.0 support, the Microsoft Java Virtual Machine, .NET Framework support, and support for technologies used by the then-upcoming Media Center and Tablet PC editions of XP. The most significant change on SP1 was the addition of Set Program Access and Defaults, a settings page which allows programs to be set as default for certain types of activities (such as media players or web browsers) and for access to bundled, Microsoft programs (such as Internet Explorer or Windows Media Player) to be disabled. On February 3, 2003, Microsoft released Service Pack 1a (SP1a). It was the same as SP1, except the Microsoft Java Virtual Machine was excluded.

• Service Pack 2: Service Pack 2 (SP2) for Windows XP Home edition and Professional edition was released on August 25, 2004. Headline features included WPA encryption compatibility for Wi-Fi and usability improvements to the Wi-Fi networking user interface, partial Bluetooth support, and various improvements to security systems. Security-related improvements were made to e-mail and web browsing. Service Pack 2 also added Security Center, an interface that provides a general overview of the system's security status, including the state of the firewall and automatic updates. Third-party firewall and antivirus software can also be monitored from Security Center.

• Service Pack 3: The third and final Service Pack, SP3, was released through different channels between April and June 2008, about a year after the release of Windows Vista, and about a year before the release of Windows 7. Service Pack 3 was not available for Windows XP x64 Edition, which was based on the Windows Server 2003 kernel and, as a result, used its service packs rather than the ones for the other editions. Service Pack 3 included security enhancements over and above those of SP2, including APIs allowing developers to enable Data Execution Prevention for their code, independent of system-wide compatibility enforcement settings, the Security Support Provider Interface, improvements to WPA2 security, and an updated version of the Microsoft Enhanced Cryptographic Provider Module that is FIPS 140-2 certified. In addition, SP3 contains updates to the operating system components of Windows XP Media Center Edition (MCE) and Windows XP Tablet PC Edition, and security updates for .NET Framework version 1.0, which is included in these editions. However, it does not include update rollups for the Windows Media Center application in Windows XP MCE 2005. SP3 also omits security updates for Windows Media Player 10, although the player is included in Windows XP MCE 2005. The Address Bar DeskBand on the Taskbar is no longer included because of antitrust violation concerns.