Windows 'The Operating System'

 Microsoft Windows is a group of several graphical operating system families , all of which are developed , marketed , and sold by Microsoft. Active Windows families include Windows NT and Windows Embedded ; these may encompass subfamilies, e.g. Windows Embedded Compact (Windows CE) or Windows Server. Defunct Windows families include Windows 9x, Windows Mobile and Windows Phone.

The operating system for mainstream personal computers, tablets and smartphones. The latest version is Windows 10. The main competitor of this family is macOS by Apple Inc. for personal computers and Android for mobile devices.

Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces (GUIs). Microsoft Windows came to dominate the world's personal computer (PC) market with over 90% market share , overtaking Mac OS, which had been introduced in 1984. 

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 . On PCs, Windows is still the most popular operating system. However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android , because of the massive growth in sales of Android smartphones. 

In 2014, the number of Windows devices sold was less than 25% that of Android devices sold. This comparision however may not be fully relevant , as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows show one third market share, similar to for end user use.

As of December 2017, the most recent version of Windows for PCs , tablets , smartphones and embedded devices is Windows 10. The most recent versions for server computers is Windows Server 2016. A specialized version of Windows runs on the Xbox One video game console.

Microsoft, the developer of Windows, has registered several trademarks each of which denote a family of Windows operating systems that target a specific sector of the computing industry . As of 2014, the following Windows families are being actively developed.

• Windows NT:- Started as a family of operating system with Windows NT 3.1, an operating system for server computers and workstations. It now consists of three operating system subfamilies that are released almost at the same time and share the same kernel.
• Windows Server: The operating system for server computers. The latest version is Windows Server 2016. Unlike its clients sibling, it has adopted a strong naming scheme. The main competitor of this family is Linux.
• Windows PE: A lightweight version of its Windows sibling meant to operate as a live operating system, used for installing Windows on bare-metal computers (especially on many computers at once), recovery or trouble shooting purposes. The latest version is Windows PE 10.

* The following Windows families are no longer being developed:-

• Windows 9x: An operating system that targeted consumers market. Discontinued because of suboptimal performance. Microsoft now caters to the consumers market with Windows NT.
• Windows Mobile: The predecessor to Windows Phone, it was a mobile phone operating system. The first version was called Pocket PC 2000; the third version, Windows Mobile 2003 is the first version to adopt the Windows Mobile trademark. The last version is Windows Mobile 6.5.
• Windows Phone: An operating system sold only to manufacturers of smartphones. The first version was Windows Phone 7, followed by Windows Phone 8, and the last version Windows Phone 8.1. It was succeeded by Windows 10 Mobile.

The history of Windows dates back to 1981, when Microsoft started work on a program called "Interface Manager". It was announced in November 1983 (after the Apple Lisa, but before the Macintosh) under the name "Windows", but Windows 1.0 was not released until November 1985. Windows 1.0 was to compete with Apple's operating system, but achieved little popularity. 

Windows 1.0 is not a complete operating system; rather, it extends MS-DOS. The shell of Windows 1.0 is a program known as the MS-DOS Executive. Components included Calculator, Calendar, Cardfile, Clipboard viewer, Clock, Control Panel, Notepad, Paint, Reversi, Terminal and Write. Windows 1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows.

Windows 2.0 was released in December 1987, and was more popular than its predecessor. It features several improvements to the user interface and memory management. Windows 2.03 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.Windows 2.0 also introduced more sophisticated keyboard shortcuts and could make use of expanded memory.

Windows 2.1 was released in two different versions:- Windows/286 and Windows/386. Windows/386 uses the virtual 8086 mode of the Intel 80386 to multitask several DOS programs . Windows/286, in spite of its name, runs on both Intel 8086 and Intel 80286 processors. It runs in real mode but can make use of the high memory area.

Windows 3.0, released in 1990, improved the design, mostly because of virtual memory and loadable virtual device drivers that allow Windows to share arbitrary devices between multi-tasked DOS applications. Windows 3.0 applications can run in protected mode, which gives them access to several megabytes of memory without the obligation to participate in the software virtual memory scheme. 

They run inside the same address space , where the segmented memory provides a degree of protection . Windows 3.0 also featured improvements to the user interface. Microsoft rewrote critical operations from C into assembly. Windows 3.0 is the first Microsoft Windows version to achieve broad commercial success, selling 2 million copies in the first six months.

Windows 3.1, made generally available on March 1, 1992, featured a facelift. In August 1993, Windows for Workgroups, a special version with integrated peer-to-peer networking features and a version number of 3.11, was released. It was sold along Windows 3.1. Support for Windows 3.1 ended on December 31, 2001.

Windows 3.2, released 1994, is an updated version of the Chinese version of Windows 3.1. The update was limited to this language version, as it fixed only issues related to the complex writing system of the Chinese language.

The next major consumer-oriented release of Windows, Windows 95, was released on August 24, 1995. While still remaining MS-DOS-based, Windows 95 introduced support for native 32-bit applications, plug and play hardware , preemptive multitasking, long file names of up to 255 characters, and provided increased stability over its predecessors. Windows 95 also introduced a redesigned, object oriented user interface, replacing the previous Program Manager with the Start menu, taskbar, and Windows Explorer shell. Windows 95 was a major commercial success for Microsoft.

On September 14, 2000, Microsoft released Windows ME (Millennium Edition), the last DOS-based version of Windows. Windows ME incorporated visual interface enhancements from its Windows NT-based counter part. Windows 2000, had faster boot times than previous versions expanded multimedia functionality including Windows Media Player 7, Windows Movie Maker, and the Windows Image Acquisition framework for retrieving images from scanners and digital cameras, additional system utilities such as System File Protection and System Restore, and updated home networking tool.

The next major version of Windows NT, Windows XP, was released on October 25, 2001. The introduction of Windows XP aimed to unify the consumer-oriented Windows 9x series with the architecture introduced by Windows NT , a change which Microsoft promised would provide better performance over its DOS-based predecessors. Windows XP would also introduce a redesigned user interface, streamlined multimedia and networking features, Internet Explorer 6, integration with Microsoft's .

After a lengthy development process, Windows Vista was released on November 30, 2006, for volume licensing and January 30, 2007, for consumers. It contained a number of new features, from a redesigned shell and user interface to significant technical changes, with a particular focus on security features. It was available in a number of different editions, and has been subject to some criticism, such as drop of performance, longer boot time.

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. 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 with which Windows Vista was already compatible.

Windows 8, the successor to Windows 7, was released on October 26, 2012. A number of significant changes were made on Windows 8, including the introduction of a user interface based around Microsoft's Metro design language with optimizations for touch-based devices such as tablets and all-in-one PCs. 

These changes include the Start screen, which uses large tiles that are more convenient for touch interactions and allow for the display of continually updated information, and a new class of apps which are designed primarily for use on touch-based devices. Other changes include increased integration with cloud services and other online platforms

On September 30, 2014, Microsoft announced Windows 10 as the successor to Windows 8.1. It was released on July 29, 2015, and addresses shortcomings in the user interface first introduced with Windows 8. Changes include the return of the Start Menu, a virtual desktop system, and the ability to run Windows Store apps within windows on the desktop rather than in full-screen mode.