Windows XP is the current version of the Windows operating system from the Microsoft Corporation. It became available on October 25, 2001. There are two versions available to purchase, the professional and home editions. The professional edition has everything the home edition offers along with more business applications. It can also support dual processors and more networking features.
Before XP, Microsoft produced two separate lines of operating systems. One line, represented by Windows 98 and Windows Me was designed for desktop computers, while the other line, represented by Windows NT and Windows 2000, was aimed at the server market. Windows XP is Microsoft's attempt to offer a single operating system for all purposes, at the cost of finally deciding to remove support for MS-DOS-based programs from the new operating system.
Windows XP is based on the Windows 2000 code with a newly developed Graphical User Interface (called Luna), which includes slightly redesigned features, some of which appear to have been inspired by modern Linux desktop environments such as KDE. The graphical login screen with user images is one such feature.
It includes a simplified set of the user security features of Windows 2000 and an integrated firewall, which were probably included partially due to increasing competition from Linux. It is also part of an overall effort to secure the operating system after general dissatisfaction with its history of security vulnerabilities.
XP has come under intense criticism and scrutiny due to the integration of many user applications for which there has traditionally been a thriving third party market, such as the firewall and Windows Media Player, as well as its close tying to the Microsoft Passport network which is seen by many computer experts as a security risk and threat to privacy. These features are also widely believed to be a continuance of Microsoft's anticompetitive behavior.
It has also been sharply criticized for its product activation scheme. This takes an audit of certain components on the host computer, creating a unique reference number that is logged by Microsoft before the software can be used permanently (it comes with a 30 day activation period). Installing the software on another computer would generate a different number that would not match the one stored by Microsoft. This would prevent a new license being issued, disabling the software.
see also History of Microsoft Windows