Microsoft Windows is a series of graphical interfaceoperating systems developed, marketed, and sold byMicrosoft.Microsoft introduced an operating environmentnamed Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest ingraphical user interfaces (GUIs). Microsoft Windows came to dominate the world's personal computer market, overtaking Mac OS, which had been introduced in 1984.The most recent client version of Windows isWindows 7; the most recent server version isWindows Server 2008 R2; the most recent mobileversion is Windows Phone 7.5.The history of Windows dates back to September 1981, when Chase Bishop, a computer scientist, designed the first model of an electronic device and project "Interface Manager" was started. It was announced in November 1983 (after the Apple Lisa, but before theMacintosh) under the name "Windows", but Windows 1.0 was not released until November 1985. Theshell of Windows 1.0 was a program known as theMS-DOS Executive. Other supplied programs wereCalculator, Calendar, Cardfile, Clipboard viewer, Clock, Control Panel, Notepad, Paint, Reversi,Terminal, and Write. Windows 1.0 did not allow overlapping windows. Instead all windows were tiled. Only dialog boxes could appear over other windows.Windows 2.0 was released in October 1987 and featured several improvements to the user interface and memory management. Windows 2.0 allowed application windows to overlap each other and also introduced more sophisticated keyboard shortcuts. It could also make use of expanded memory.Windows 2.1 was released in two different versions: Windows/386 employed the 386 virtual 8086 mode to multitask several DOS programs, and the paged memory model to emulate expanded memory using availableextended memory. Windows/286 (which, despite its name, would run on the 8086) still ran in real mode, but could make use of the high memory area.The early versions of Windows were often thought of as simply graphical user interfaces, mostly because they ran on top of MS-DOS and used it for file system services. However, even the earliest 16-bit Windows versions already assumed many typical operating system functions; notably, having their own executable file format and providing their own device drivers (timer, graphics, printer, mouse, keyboard and sound) for applications. UnlikeMS-DOS, Windows allowed users to execute multiple graphical applications at the same time, through cooperative multitasking. Windows implemented an elaborate, segment-based, software virtual memory scheme, which allowed it to run applications larger than available memory: code segments and resources were swapped in and thrown away when memory became scarce, and data segments moved in memory when a given application had relinquished processor control.
Windows NT family
The NT family of Windows systems was fashioned and marketed for higher reliability business use. The first release was NT 3.1 (1993), numbered "3.1" to match the consumer Windows version, which was followed by NT 3.5 (1994), NT 3.51 (1995), NT 4.0 (1996), and Windows 2000, which is the last NT-based Windows release that does not include Microsoft Product Activation. Windows NT 4.0 was the first in this line to implement the "Windows 95" user interface (and the first to include Windows 95's built-in 32-bit runtimes).
Microsoft then moved to combine their consumer and business operating systems with Windows XP that was released on October 25, 2001. It came both in home and professional versions (and later niche market versions fortablet PCs and media centers); they also diverged release schedules for server operating systems. Windows Server 2003, released a year and a half after Windows XP, brought Windows Server up to date with Windows XP. After a lengthy development process, Windows Vista was released on November 30, 2006 for volume licensing and January 30, 2007 for consumers. And its server counterpart, Windows Server 2008 was released in early 2008. On July 22, 2009, Windows 7 and Windows Server 2008 R2 were released as RTM (release to manufacturing) while the former was released to the public 3 months later on October 22, 2009.
64-bit operating systems
Windows NT included support for several different platforms before the x86-based personal computer became dominant in the professional world. Versions of NT from 3.1 to 4.0 variously supported PowerPC, DEC Alpha and MIPS R4000, some of which were 64-bit processors, although the operating system treated them as 32-bit processors.
With the introduction of the Intel Itanium architecture (also known as IA-64), Microsoft released new versions of Windows to support it. Itanium versions of Windows XP and Windows Server 2003 were released at the same time as their mainstream x86 (32-bit) counterparts. On April 25, 2005, Microsoft released Windows XP Professional x64 Edition and Windows Server 2003 x64 Editions to support the x86-64 (or x64 in Microsoft terminology) architecture. Microsoft dropped support for the Itanium version of Windows XP in 2005. Windows Vista was the first end-user version of Windows that Microsoft released simultaneously in x86 and x64 editions. Windows Vista does not support the Itanium architecture. The modern 64-bit Windows family comprises AMD64/Intel64 versions of Windows 7 and Windows Server 2008, in both Itanium and x64 editions. Windows Server 2008 R2 drops the 32-bit version, although Windows 7 does not.
Windows CE
Windows CE (officially known as Windows Embedded Compact), is an edition of Windows that runs on minimalistic computers, like satellite navigation systems and some mobile phones. Windows Embedded Compact is based on its own dedicated kernel, dubbed Windows CE kernel. Microsoft licenses Windows CE to OEMs and device makers. The OEMs and device makers can modify and create their own user interfaces and experiences, while Windows CE provides the technical foundation to do so.
Windows CE was used in the Dreamcast along with Sega's own proprietary OS for the console. Windows CE is the core from which Windows Mobile is derived. Microsoft's latest mobile OS, Windows Phone, is based on components from both Windows CE 6.0 R3 and the current Windows CE 7.0.
Windows Embedded Compact is not to be confused with Windows XP Embedded or Windows NT 4.0 Embedded, modular editions of Windows based on Windows NT kernel.
History
The first version of Microsoft Windows, version 1.0, released in November 1985, lacked a degree of functionality, achieved little popularity and was to compete with Apple's own operating system. Windows 1.0 is not a complete operating system; rather, it extendsMS-DOS. Microsoft Windows version 2.0 was released in November 1987 and was slightly more popular than its predecessor. Windows 2.03 (release date January 1988) had changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights.
The Windows family tree.
Microsoft Windowsversion 3.0, released in 1990, was the first Microsoft Windows version to achieve broad commercial success, selling 2 million copies in the first six months. It featured improvements to the user interface and to multitasking capabilities. It received a facelift in Windows 3.1, made generally available on March 1, 1992. Windows 3.1 support ended on December 31, 2001.
In July 1993, Microsoft released Windows NT based on a new kernel. Windows NT 3.1 was the first release of Windows NT. NT was considered to be the professional OS and was the first Windows version to utilizepreemptive multitasking. Windows NT would later be retooled to also function as a home operating system, with Windows XP.
On August 24, 1995, Microsoft released Windows 95, a new, and major, consumer version that made further changes to the user interface, and also used preemptive multitasking. Windows 95 was designed to replace not only Windows 3.1, but also Windows for Workgroups, and MS-DOS. It was also the first Windows operating system to use Plug and Play capabilities. The changes Windows 95 brought to the desktop were revolutionary, as opposed to evolutionary, such as those in Windows 98 and Windows Me. Mainstream support for Windows 95 ended on December 31, 2000 and extended support for Windows 95 ended on December 31, 2001.
Next in the consumer line was Microsoft Windows 98 released on June 25, 1998. It was followed with the release of Windows 98 Second Edition (Windows 98 SE) in 1999. Mainstream support for Windows 98 ended on June 30, 2002 and extended support for Windows 98 ended on July 11, 2006.
As part of its "professional" line, Microsoft released Windows 2000 in February 2000. During 2004 part of the Source Code for Windows 2000 was leaked onto the Internet. This was bad for Microsoft as the same kernel used in Windows 2000 was used in Windows XP. The consumer version following Windows 98 was Windows Me(Windows Millennium Edition). Released in September 2000, Windows Me implemented a number of new technologies for Microsoft: most notably publicized was "Universal Plug and Play". Windows Me was heavily criticized due to slowness, freezes and hardware problems.
In October 2001, Microsoft released Windows XP, a version built on the Windows NT kernel that also retained the consumer-oriented usability of Windows 95 and its successors. This new version was widely praised in computer magazines. It shipped in two distinct editions, "Home" and "Professional", the former lacking many of the superior security and networking features of the Professional edition. Additionally, the first "Media Center" edition was released in 2002, with an emphasis on support for DVD and TV functionality including program recording and a remote control. Mainstream support for Windows XP ended on April 14, 2009. Extended support will continue until April 8, 2014.
In April 2003, Windows Server 2003 was introduced, replacing the Windows 2000 line of server products with a number of new features and a strong focus on security; this was followed in December 2005 by Windows Server 2003 R2.
On January 30, 2007, Microsoft released Windows Vista. It contains a number of new features, from a redesigned shell and user interface to significant technical changes, with a particular focus on security features. It is available in a number of different editions, and has been subject to some criticism.
On October 22, 2009, Microsoft released Windows 7. Unlike its predecessor, Windows Vista, which introduced a large number of new features, Windows 7 was intended to be a more focused, incremental upgrade to the Windows line, with the goal of being compatible with applications and hardware which Windows Vista was not at the time. Windows 7 has multi-touch support, a redesigned Windows shell with a new taskbar, referred to as the Superbar, a home networking system called HomeGroup, and performance improvements.
On 29 February 2012, Microsoft released Windows 8 Consumer Preview, the beta version of Windows 8, build 8250. For the first time since Windows 95, the Start button is no longer available on the taskbar, though the Start screen is still triggered by clicking the bottom-left corner of the screen and by clicking Start in the Charm. Windows president Steven Sinofsky said more than 100,000 changes had been made since the developer version went public. In the first day of its release, Windows 8 Consumer Preview was downloaded over one million times. Like the Developer Preview, the Consumer Preview is set to expire on the 15 January 2013.
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