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Microsoft Windows logo. Usage restricted. Trademarks on this page belong to their owner(s). See Image use policy.Microsoft Windows is a range of commercial operating environments for personal computers. The range was first introduced by Microsoft in 1985 and eventually has come to dominate the world personal computer market. All recent versions of Windows are fully-fledged operating systems.
1 Versions
The term Windows is used as a collective term for several generations of products, which can be classified into the following categories:
- 16-bit Operating environments. Although they are often thought of as just graphical user interfaces or desktops, mostly because they use MS-DOS for filesystem services, 16-bit Windows versions already have their own executable file format and provide their own device drivers (graphics, printer, mouse, keyboard and sound). Most important, from the beginning they allow the user to (non-preemptively) multi-task graphical applications, something which competitors like GEM do not offer. Finally, they implement an elaborated segment-based software virtual memory scheme, which allows to run applications larger than available memory: code segments and resources are swapped in and thrown away when useless or memory becomes scarce and data segments move in memory when a given application has relinquished processor control. Examples include Windows 1.0 (1985) and Windows 2.0 (1987) and its close relative Windows/286.
- Hybrid 16/32-bit operating environments. Windows/386 introduced a 32-bit protected mode kernel and virtual machineIn general terms, a virtual machine in computer science is software that creates an environment between the computer platform and the end user in which the end user can operate software. Specifically, the term virtual machine has several distinct meanings monitor. For the duration of a Windows session, it provided a device virtualization for the disk controllerIn control theory, a controller is a device that attempts to control states or outputs of a dynamic system. Generally, this is accomplished using feedback to reject disturbances to the system. This is called closed-loop control. Open-loop control is also, video card, keyboard, mouse, timer and interruptIn computer engineering, an interrupt is a signal from a device which typically results in a context switch: that is, the processor sets aside what it's doing and does something else. Digital computers usually provide a way to start software routines in r controller. The user-visible consequence was that it became possible to preemptively multitask multiple MS-DOS environments in separate windows (graphical applications required switching the window to full screen mode). Windows applications were still multi-tasked cooperatively inside one of such real-mode environments. Windows 3.0 (1990) and Windows 3.1 (1992) perfected the design, notably thanks to virtual memoryVirtual memory is a computer design feature that permits software to use more memory than the computer physically possesses. In technical terms, it allows software to run in a memory address space whose size and addressing are not necessarily tied to the and loadable virtual device drivers ( VxDIn Microsoft computing, a VxD is a virtual device driver''. They run under the Windows 3. x, Windows 95 and Windows 98 operating systems, and have access to the memory of the kernel and all running processes, as well as raw access to the hardware. Prior ts) which allowed them to share arbitrary devices between multitasked DOS windows. Most important, Windows applications could now run in 16-bit protected mode (when Windows was running in Standard or 386 Enhanced Mode), which gave them access to several megabytes of memory and removed the obligation to participate in the software virtual memory scheme. They still ran inside the same address space, where the segmented memory provided a degree of protection, and multi-tasked cooperatively. For Windows 3.0 Microsoft also rewrote critical operations from CThe C Programming Language Brian Kernighan and Dennis Ritchie, the original edition that served for many years as an informal specification of the language The C programming language is a low-level standardized programming language developed in the early into assembly, making this release faster and less memory-hungry than its predecessors.
- Hybrid 16/32-bit operating system. With the introduction of 32-Bit File Access in Windows for Workgroups 3.11, Windows could finally stop relying on DOS for file management. Leveraging this, Windows 95 introduced Long File Names, reducing the 8.3 DOS to the role of a boot loader. MS-DOS was now bundled with Windows; this notably allowed to make it (partially) aware of long file names when its utilities were run from within Windows, but angered the competition. The most important novelty was however the possibility of running 32-bit multi-threaded preemptively multitasked graphical programs. There were three releases of Windows 95 (the first in 1995, then subsequent bug-fix versions in 1996 and 1997, only released to OEMs, which added extra features such as FAT32 support). Microsoft's next OS was Windows 98; there were two versions of this (the first in 1998 and the second, named "Windows 98 Second Edition", in 1999). This was an evolutionary enhancement, in much the same relation to Windows 95 as Windows 3.1 had been to 3.0. In 2000, Microsoft released Windows Me, which used the same core as Windows 98 but adopted the visual appearance of Windows 2000. Compared to previous upgrades, comparatively few people bothered to switch to ME: by this time most power users had already jumped over to the NT family.
- 32-bit operating systems originally designed and marketed for higher-reliability business use with no DOS heritage. The first release was Windows NT 3.1 (1993, numbered "3.1" to match the Windows version and to 1-up OS/2 2.1, its new competitor that it was based on), which was followed by NT 3.5 (1994), NT 3.51 (1995) and NT 4.0 (1996), which introduced the Windows 95 interface. Microsoft then moved to combine their consumer and business operating systems. Their first attempt, Windows 2000, failed to meet their goals, and was released as a business system. The home consumer edition of Windows 2000, codenamed "Windows Neptune", ceased development and Microsoft released Windows ME in its place. Eventually "Neptune" was merged into their new project, Whistler, which later became Windows XP. XP finally rendered DOS obsolete, and since then a new business system, Windows Server 2003, has expanded the top end of the range, and the forthcoming Windows Longhorn will complete it. Windows CE, Microsoft's offering in the mobile and embedded markets, is also a true 32-bit operating system.
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