Windows XP

Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops, and media centers. It was released in 2001. The name "XP" is short for "eXPerience."

Windows XP is the successor to both Windows 2000 Professional and Windows Me, and is the first consumer-oriented operating system produced by Microsoft to be built on the Windows NT kernel and architecture. Windows XP was first released on October 25, 2001, and over 400 million copies were in use in January 2006, according to an estimate in that month by an IDC analyst. It was succeeded by Windows Vista, which was released to volume license customers on November 8, 2006, and worldwide to the general public on January 30, 2007. Direct OEM and retail sales of Windows XP ceased on June 30, 2008. Microsoft continued to sell XP through their System Builders (smaller OEMs who sell assembled computers) program until January 31, 2009. XP may continue to be available as these sources run through their inventory or by purchasing Windows Vista Ultimate or Business and then downgrading to Windows XP.

The most common editions of the operating system are Windows XP Home Edition, which is targeted at home users, and Windows XP Professional, which offers additional features such as support for Windows Server domains and two physical processors, and is targeted at power users, business and enterprise clients. Windows XP Media Center Edition has additional multimedia features enhancing the ability to record and watch TV shows, view DVD movies, and listen to music. Windows XP Tablet PC Edition is designed to run stylus applications built using the Tablet PC platform.

Windows XP was eventually released for two additional architectures, Windows XP 64-bit Edition for IA-64 (Itanium) processors and Windows XP Professional x64 Edition for x86-64. There is also Windows XP Embedded, a component version of the Windows XP Professional, and editions for specific markets such as Windows XP Starter Edition. By mid 2009, a manufacturer revealed the first Windows XP powered cellular telephone.

The NT-based versions of Windows are known for their improved stability and efficiency over the 9x versions of Microsoft Windows. Windows XP presents a significantly redesigned graphical user interface, a change Microsoft promoted as more user-friendly than previous versions of Windows. A new software management facility called Side-by-Side Assembly was introduced to ameliorate the "DLL hell" that plagues 9x versions of Windows. It is also the first version of Windows to use product activation to combat illegal copying, a restriction that did not sit well with some users and privacy advocates. Windows XP has also been criticized by some users for security vulnerabilities, tight integration of applications such as Internet Explorer 6 and Windows Media Player, and for aspects of its default user interface. Later versions with Service Pack 2, Service Pack 3, and Internet Explorer 8 addressed some of these concerns.

During development, the project was codenamed "Whistler", after Whistler, British Columbia, as many Microsoft employees skied at the Whistler-Blackcomb ski resort.

As of the end of January 2010, Windows XP is the most widely used operating system in the world with a 59.4% market share, having peaked at 76.1% in January 2007.

Windows 2.1x

Windows 2.1x is a family of Microsoft Windows graphical user interface-based operating environments.

Less than a year after the release of Windows 2.0, Windows/286 2.10 and Windows/386 2.10 were released on 27 May 1988. These versions can take advantage of the specific features of the Intel 80286 and Intel 80386 processors.
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Edition
Two editions of Windows 2.10 were released, both of which could take advantage of the Intel processor for which they were designed.


Windows/286
Windows/286 takes advantage of the HMA to increase the memory available to Windows programs. It introduced the himem.sys DOS driver for this purpose. It also includes support for several EMS boards, although this support is not related to the 80286 processor. The segmented nature of Windows programs is quite suited to the usage of EMS, as portions of code and data can be made visible in the first megabyte of memory accessible to real-mode programs only when the program using them is given control. Microsoft encouraged users to configure their computers with only 256KB of main memory, leaving the address space from 256-640KB available for dynamic mapping of EMS memory.

Despite its name, Windows/286 was fully operational on an 8088 or 8086 processor. Windows/286 would simply not use the high memory area since none exist on an 8086-class processor; however, EMS could still be used, if present. A few PC vendors shipped Windows/286 with 8086 hardware; an example was IBM's PS/2 Model 25, which had an option to ship with a "DOS 4.00 and Windows kit" for educational markets, which included word processing and presentation software useful for students, which resulted in some confusion when purchasers of this system received a box labeled Windows/286 with a machine that was definitely less than an 80286.

Windows/386
Windows/386 is much more advanced. It introduced a protected mode kernel, above which the GUI and applications run as a virtual 8086 mode task. It allows several MS-DOS programs to run in parallel in "virtual 8086" CPU mode, rather than always suspending background applications. (Windows applications could already run in parallel through cooperative multitasking.) Each DOS application can use as much low memory as is available before Windows is started, minus a few kilobytes of overhead. Windows/386 also provides EMS emulation, using the memory management features of the 80386 to make RAM beyond 640K behave like the banked memory previously only supplied by add-in cards and used by popular DOS applications. (By overwriting the WIN200.BIN file with COMMAND.COM, it is possible to use the EMS emulation in DOS without starting the Windows GUI.) There is no disk-based virtual memory, so multiple DOS programs have to fit inside the available physical memory; therefore, Microsoft suggested buying additional memory and cards if necessary.

Neither of these versions work with DOS memory managers like CEMM or QEMM or with DOS extenders, which have their own extended memory management and run in protected mode as well. This was remedied in version 3.0, which is compatible with VCPI in "standard mode" and with DPMI in "386 enhanced" mode. Windows 3.0 also has the capability of using the DWEMM Direct Write Enhanced Memory Module. This is what enables the far faster and sleek graphical user interface.
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Windows 2.11
In March 1989, Windows 2.11 was released in Windows/286 and Windows/386 editions, with some minor changes in memory management, AppleTalk support and faster printing and updated printer drivers.

Windows 2.11 was superseded by Windows 3.0 in May 1990.

Windows 2.0

Windows 2.0 was a 16-bit Microsoft Windows graphical user interface-based operating environment that superseded Windows 1.0. Windows 2.0 was supplemented by Windows/286 and Windows/386 in 1988. Windows 2.0, Windows/286 and Windows/386 were superseded by Windows 3.0 in May 1990.
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History

Application support

The first Windows versions of Microsoft Word and Microsoft Excel ran on Windows 2.0. Third-party developer support for Windows increased substantially with this version (some shipped the Windows Runtime software with their applications, for customers who had not purchased the full version of Windows). However, most developers still maintained DOS versions of their applications, as Windows users were still a distinct minority of their market.

Applications shipping with Windows 2.0:

* CALC.EXE
* CALENDAR.EXE
* CARDFILE.EXE
* CLIPBRD.EXE
* CLOCK.EXE
* CONTROL.EXE
* CVTPAINT.EXE
* MSDOS.EXE
* MSDOSD.EXE
* NOTEPAD.EXE
* PAINT.EXE
* REVERSI.EXE
* TERMINAL.EXE
* WRITE.EXE

Legal conflict with Apple

On 17 March 1988, Apple filed suit against Microsoft and Hewlett-Packard, accusing them of violating copyrights Apple held on the Macintosh System Software.[1] Apple claimed the "look and feel" of the Macintosh operating system, taken as a whole, was protected by copyright and that Windows 2.0 violated this copyright by looking extremely similar to it.
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Features
Windows 2.0 allowed application windows to overlap each other unlike its predecessor Windows 1.0, which could display only tiled windows. Windows 2.0 also introduced more sophisticated keyboard-shortcuts and the terminology of "Minimize" and "Maximize", as opposed to "Iconize" and "Zoom" in Windows 1.0.