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.vxd
VxD is the device driver model used in Microsoft Windows/386 2.x, the 386 enhanced mode of Windows 3.x, Windows 9x, and to some extent also by the Novell DOS 7, OpenDOS 7.01, and DR-DOS 7.02 (and higher) multitasker (TASKMGR). VxDs have access to the memory of the kernel and all running processes, as well as raw access to the hardware. Starting with Windows 98, Windows Driver Model was the recommended driver model to write drivers for, with the VxD driver model still being supported for backward compatibility, until Windows Me. Name and design The name "VxD" is an abbreviation for "virtual xxx driver", where "xxx" is some class of hardware device. It derives from the fact that most drivers had filenames of the form vxxxd.386 in Windows 3.x. Some examples are vjoyd.386 (joystick) and vmm.386 ( memory manager). VxDs under Windows 3.x usually have the filename extension .386, while those under Windows 9x have .vxd. Windows 9x VxDs are in Linear Executable format; its code can b ...
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Windows 9x
Windows 9x is a generic term referring to a line of discontinued Microsoft Windows operating systems released from 1995 to 2000 and supported until 2006, which were based on the kernel introduced in Windows 95 and modified in succeeding versions, with its underlying foundation based on MS-DOS. The first version in the 9x series was Windows 95, which was succeeded by Windows 98 and then Windows Me, which was the third and last version of Windows on the 9x line, until the series was superseded by Windows XP. Windows 9x is predominantly known for its use in Desktop computer, home desktops. In 1998, Windows made up 82% of operating system market share. The internal release number for versions of Windows 9x is 4.x. The internal versions for Windows 95, 98, and Me are 4.0, 4.1, and 4.9, respectively. Previous MS-DOS-based versions of Windows used version numbers of Windows 3.x, 3.2 or lower. Windows NT, which was aimed at professional users such as networks and businesses, used a sim ...
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Device Driver
In the context of an operating system, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and other computer programs to access hardware functions without needing to know precise details about the hardware being used. A driver communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device (drives it). Once the device sends data back to the driver, the driver may invoke routines in the original calling program. Drivers are hardware dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface. Purpose The main purpose of device drivers is to provide abstraction b ...
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Interrupt
In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, the processor will suspend its current activities, save its state, and execute a function called an '' interrupt handler'' (or an ''interrupt service routine'', ISR) to deal with the event. This interruption is often temporary, allowing the software to resume normal activities after the interrupt handler finishes, although the interrupt could instead indicate a fatal error. Interrupts are commonly used by hardware devices to indicate electronic or physical state changes that require time-sensitive attention. Interrupts are also commonly used to implement computer multitasking and system calls, especially in real-time computing. Systems that use interrupts in these ways are said to be interrupt-driven. History Hardware interrupts wer ...
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32-bit
In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in a maximum of 32- bit units. Compared to smaller bit widths, 32-bit computers can perform large calculations more efficiently and process more data per clock cycle. Typical 32-bit personal computers also have a 32-bit address bus, permitting up to 4  GiB of RAM to be accessed, far more than previous generations of system architecture allowed. 32-bit designs have been used since the earliest days of electronic computing, in experimental systems and then in large mainframe and minicomputer systems. The first hybrid 16/32-bit microprocessor, the Motorola 68000, was introduced in the late 1970s and used in systems such as the original Apple Macintosh. Fully 32-bit microprocessors such as the HP FOCUS, Motorola 68020 and Intel 80386 were launched in the early to mid 1980s and became dominant by the early 1990s. This gener ...
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NTVDM
Virtual DOS machines (VDM) refer to a technology that allows running 16-bit/32-bit DOS and 16-bit Windows programs when there is already another operating system running and controlling the hardware. Overview Virtual DOS machines can operate either exclusively through typical software emulation methods (e.g. dynamic recompilation) or can rely on the virtual 8086 mode of the Intel 80386 processor, which allows real mode 8086 software to run in a controlled environment by catching all operations which involve accessing protected hardware and forwarding them to the normal operating system (as exceptions). The operating system can then perform an emulation and resume the execution of the DOS software. VDMs generally also implement support for running 16-bit and 32-bit protected mode software ( DOS extenders), which has to conform to the DOS Protected Mode Interface (DPMI). When a DOS program running inside a VDM needs to access a peripheral, Windows will either allow this di ...
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Windows 2000
Windows 2000 is a major release of the Windows NT operating system developed by Microsoft, targeting the server and business markets. It is the direct successor to Windows NT 4.0, and was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on December 15, 1999, and then to retail on February 17, 2000 for all versions, with Windows 2000 Datacenter Server being released to retail on September 26, 2000. Windows 2000 introduces NTFS 3.0, Encrypting File System, and basic and dynamic disk storage. Support for people with disabilities is improved over Windows NT 4.0 with a number of new Assistive technology, assistive technologies, and Microsoft increased support for different languages and Locale (computer software), locale information. The Windows 2000 Server family has additional features, most notably the introduction of Active Directory, which in the years following became a widely used directory service in business environments. Although not pre ...
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