In computing, a window is a graphical control element. It consists of a visual area containing some of the graphical user interface of the program it belongs to and is framed by a window decoration. It usually has a rectangular shape  that can overlap with the area of other windows. It displays the output of and may allow input to one or more processes. Windows are primarily associated with graphical displays, where they can be manipulated with a pointer by employing some kind of pointing device. Text-only displays can also support windowing, as a way to maintain multiple independent display areas, such as multiple buffers in Emacs.
It was the successor to both Windows for professional users and Windows Me for home users. It was released to manufacturing on August 24, , and broadly released for retail sale on October 25, Development of Windows XP began in the late s 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 was also originally planned for the business market; however, in January , 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. 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, , after which the operating system ceased receiving further support or security updates with exceptional security updates being made e. At least a few countries have double-digit use, e.
Microsoft Windows , commonly referred to as Windows , is a group of several proprietary graphical operating system families, all of which are developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. Microsoft introduced an operating environment named Windows on November 20, , as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces GUIs. Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh eventually settled in court in Microsoft's favor in On PCs, Windows is still the most popular operating system. However, in , Microsoft admitted losing the majority of the overall operating system market to Android ,  because of the massive growth in sales of Android smartphones. This comparison, however, may not be fully relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows that are comparable to competitors show one third market share, similar to that for end user use.
A window is an opening in a wall , door , roof or vehicle that allows the passage of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent material, a sash set in a frame  in the opening; the sash and frame are also referred to as a window. Windows often have a latch or similar mechanism to lock the window shut or to hold it open by various amounts. The Romans were the first known to use glass for windows, a technology likely first produced in Roman Egypt , in Alexandria ca. Paper windows were economical and widely used in ancient China , Korea and Japan.