Windows XP

Windows XP is an operating system produced by Microsoft as part of the Windows NT family of operating systems. It was the successor to both Windows 2000 for professional users and Windows Me for home users. It was released to manufacturing on August 24, 2001, and broadly released for retail sale on October 25, 2001. Development of Windows XP began in the late 1990s as "Neptune", an operating system (OS) built on the Windows NT kernel which was intended specifically for mainstream consumer use. An updated version of Windows 2000 was also originally planned for the business market; however, in January 2000, both projects were scrapped in favor of a single OS codenamed "Whistler", which would serve as a single OS platform for both consumer and business markets. As such, Windows XP was the first consumer edition of Windows not to be based on MS-DOS. Upon its release, Windows XP received critical acclaim, with critics noting increased performance and stability (especially in comparison to Windows Me), a more intuitive user interface, improved hardware support, and expanded multimedia capabilities. However, some industry reviewers were concerned by the new licensing model and product activation system.

Extended support for Windows XP ended on April 8, 2014, after which the operating system ceased receiving further support or security updates (with exceptional security updates, to address major malware threats, such as BlueKeep) to most users. Windows Embedded POSReady 2009, based on Windows XP Professional, received security updates until April 2019. Unofficial methods were made available to apply the updates to other editions of Windows XP. Microsoft officially discouraged this practice, citing incompatibility issues. By August 2019, Microsoft (and others) had ended support for games on Windows XP.

As of October 2020, 0.8% of Windows PCs run Windows XP, and 0.29% of all devices across all platforms run Windows XP. A few countries still have double-digit use, e.g. Armenia, where it is being replaced by Windows 10, with both operating systems having over 40% use.

Development
In the late 1990s, initial development of what would become Windows XP was focused on two individual products: "Odyssey", which was reportedly intended to succeed the future Windows 2000; and "Neptune", which was reportedly a consumer-oriented operating system using the Windows NT architecture, succeeding the MS-DOS-based Windows 98.

However, the projects proved to be too ambitious. In January 2000, shortly prior to the official release of Windows 2000, technology writer Paul Thurrott reported that Microsoft had shelved both Neptune and Odyssey in favor of a new product codenamed "Whistler", after Whistler, British Columbia, as many Microsoft employees skied at the Whistler-Blackcomb ski resort. The goal of Whistler was to unify both the consumer and business-oriented Windows lines under a single, Windows NT platform: Thurrott stated that Neptune had become "a black hole when all the features that were cut from Windows Me were simply re-tagged as Neptune features. And since Neptune and Odyssey would be based on the same code-base anyway, it made sense to combine them into a single project".

At PDC on July 13, 2000, Microsoft announced that Whistler would be released during the second half of 2001, and also unveiled the first preview build, 2250. The build notably introduced an early version of Windows XP's visual styles system.

Microsoft released the first beta build of Whistler, build 2296, on October 31, 2000. Subsequent builds gradually introduced features that users of the release version of Windows XP would recognize, such as Internet Explorer 6.0, the Microsoft Product Activation system and the Bliss desktop background.

Whistler was officially unveiled during a media event on February 5, 2001, under the name Windows XP, where XP stands for "eXPerience".

Release
In June 2001, Microsoft indicated that it was planning to, in conjunction with Intel and other PC makers, spend at least 1 billion US dollars on marketing and promoting Windows XP. The theme of the campaign, "Yes You Can", was designed to emphasize the platform's overall capabilities. Microsoft had originally planned to use the slogan "Prepare to Fly", but it was replaced because of sensitivity issues in the wake of the September 11 attacks.

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" and "Professional".