viewer ~ VxD
A/B Switch box ~ America On-line AMI BIOS ~ Arithmetic Operation ARP ~ AVI Backbone ~ Bit Image Bit Map ~ Boot Disk Boot Drive ~ Bytes Per Inch C++ ~ Carrier Frequency carrier system ~ certification CGI ~ Chooser extension cipher ~ Clipper Chip clock ~ color color bits ~ communications satellite communications server ~ computer security CON ~ copy copy program ~ cycle time daemon ~ defragmentation demand paging ~ digitize DikuMUD ~ disk disk buffer ~ Document Style Semantics and Specification Language document window ~ dynamic Web page Easter egg ~ erase erase head ~ ezine F2F ~ finger2 firewall ~ font suitcase footer ~ FYI Game Control Adapter ~ GUI HAL ~ hot key1 hot key2 ~ Hz i486DX ~ internal modem internet ~ ISO 9660 ISO/OSI model ~ just-in-time K1 ~ knowledge base L1 cache ~ LU luggable computer ~ LZW compression MAC ~ MILNET mime ~ msec MTBF ~ MYOB named anchor ~ network drive Network File System ~ number crunching object ~ overwrite mode P5 ~ PC/XT keyboard PDA ~ pipeline processing piracy ~ preventive maintenance preview ~ pwd quasi-language ~ QWERTY keyboard R&D ~ registration marks Registry ~ RFI RF shielding ~ run-time library SAA ~ server error server push-pull ~ soft return software ~ style sheet stylus ~ System T1 ~ ToggleKeys token ~ typography UART ~ uupc V.120 ~ view2 viewer ~ VxD w3 ~ WinG WINS ~ WWW X.25 ~ X Windows Yahoo! ~ yotta- Z39.50 standard ~ Zulu time
viewer
n. An application that displays or otherwise outputs a file in the same way as the application that created the file. An example of a viewer is a program to display the images stored in GIF or JPEG files. See also GIF, JPEG.
virtual address
n. In a virtual memory system, the address the application uses to reference memory. The memory management unit (MMU) translates this address into a physical address before the memory is actually read or written to. See also physical address, virtual memory. Compare real address.
virtual channel
n. In Asynchronous Transfer Mode (ATM), the path taken by data sent from one sender to one receiver. See also ATM (definition 1), virtual path (definition 2).
virtual circuit
n. A communications link that appears to be a direct connection between sender and receiver, although physically the link can be routed through a more circuitous path.
virtual community
n. See online community.
Virtual Control Program Interface
n. A specification for MS-DOS programs to allow access to extended memory under a multitasking environment (for example, Microsoft Windows) for 80386, and higher-level processors. See also 80386DX, extended memory, multitasking. Compare protected mode. Acronym: VCPI.
virtual desktop
n. A desktop enhancement tool that provides access to the desktop when it is covered by open windows or that expands the size of the working desktop. See also desktop.
virtual device
n. A device that can be referenced but that does not physically exist. Virtual-memory addressing, for example, uses magnetic disk storage to simulate memory larger than that physically available.
virtual device driver
n. Software in Windows 95 that manages a hardware or software system resource. If a resource retains information from one access to the next that affects the way it behaves when accessed (for example, a disk controller with its status information and buffers), a virtual device driver must exist for it. Virtual device drivers are described using three-letter abbreviations beginning with V and ending with D; the middle letter indicates the type of device, such as D for a display, P for a printer, T for a timer, and x when the type of device is not under discussion. See also device driver. Acronym: VxD.
virtual LAN
n. Short for virtual local area network. A local area network consisting of groups of hosts that are on physically different segments but that communicate as though they were on the same wire. See also LAN.
virtual machine
n. Software that mimics the performance of a hardware device, such as a program that allows applications written for an Intel processor to be run on a Motorola chip. Acronym: VM.
virtual memory
n. Memory that appears to an application to be larger and more uniform than it is. Virtual memory may be partially simulated by secondary storage such as a hard disk. Applications access memory through virtual addresses, which are translated (mapped) by special hardware and software onto physical addresses. Also called disk memory. See also paging, segmentation. Acronym: VM.
virtual name space
n. The set of all hierarchical sequences of names that can be used by an application to locate objects. One such sequence of names defines a path through the virtual name space, regardless of whether the hierarchy of names reflects the actual arrangement of objects around the system. For example, the virtual name space of a Web server consists of all possible URLs on the network on which it runs. See also URL.
virtual path
n. 1. A sequence of names that is used to locate a file and that has the same form as a pathname in the file system but is not necessarily the actual sequence of directory names under which the file is located. The part of a URL that follows the server name is a virtual path. For example, if the directory c:\bar\sinister\forces\distance on the server miles is shared on the local area network at foo.com under the name \\miles\baz and contains the file elena.html, that file may be returned by a Web request for http://miles.foo.com/baz/elena.html. 2. In Asynchronous Transfer Mode (ATM), a set of virtual channels that are switched together as a unit through the network. See also ATM (definition 1), virtual channel.
virtual printer
n. A feature in many operating systems that allows printer output to be saved to a file until a printer becomes available.
virtual private network
n. 1. A set of nodes on a public network such as the Internet that communicate among themselves using encryption technology so that their messages are as safe from being intercepted and understood by unauthorized users as if the nodes were connected by private lines. 2. A wide area network formed of permanent virtual circuits (PVCs) on another network, especially a network using technologies such as ATM or frame relay. See also ATM (definition 1), frame relay, PVC. Acronym: VPN.
virtual reality
n. A simulated 3-D environment that a user can experience and manipulate as if it were physical. The user sees the environment on display screens, possibly mounted in a special pair of goggles. Special input devices, such as gloves or suits fitted with motion sensors, detect the user's actions. Acronym: VR.
virtual real mode
n. A feature of the Intel 80386 (SX and DX) and higher microprocessors that allows them to emulate several 8086 (real-mode) environments simultaneously. The microprocessor provides a set of virtual registers and virtual memory space to each virtual 8086 environment. A program running in a virtual 8086 environment is completely protected from other virtual 8086 environments in the system and behaves as if it had control of the entire system. Also called 86 mode, V86 mode, virtual 8086 mode, virtual 86 mode. See also real mode.
virtual world
n. 1. A 3-D modeled environment, often created in VRML, where a user can interact with the viewer to change variables. See also viewer, VRML. 2. An electronic environment that has no basis in the physical world. Multiuser dungeons (MUDs), talkers, and chat rooms are often considered virtual worlds. See also chat1 (definition 1), MUD, talker.
virus
n. An intrusive program that infects computer files by inserting in those files copies of itself. The copies are usually executed when the file is loaded into memory, allowing them to infect still other files, and so on. Viruses often have damaging side effects--sometimes intentionally, sometimes not. For example, some viruses can destroy a computer's hard disk or take up memory space that could otherwise be used by programs. See also Good Times virus, Trojan horse, worm.
virus signature
n. A portion of unique computer code contained in a virus. Antivirus programs search for known virus signatures to identify infected programs and files. See also virus.
Visual Basic
n. A high-level, visual-programming version of Basic. Visual Basic was developed by Microsoft for building Windows-based applications. See also Basic, Visual Basic for Applications, Visual Basic Scripting Edition, visual programming.
Visual Basic for Applications
n. A macro-language version of Visual Basic that is used to program many Windows 95 applications and is included with several Microsoft applications. See also macro language, Visual Basic. Acronym: VBA.
Visual Basic Script
n. See Visual Basic, Scripting Edition.
Visual Basic, Scripting Edition
n. A subset of the Visual Basic for Applications programming language, optimized for Web-related programming. As with JavaScript, code for Visual Basic, Scripting Edition is embedded in HTML documents. This version is included with the Internet Explorer Web browser. Also called VBScript. See also Visual Basic for Applications. See Visual Basic Script.
Visual C++
n. A Microsoft application development system for the programming language C++ that runs under MS-DOS and Windows. Visual C++ is a visual programming environment. See also visual programming. Compare Visual Basic, Visual J++.
Visual J++
n. Microsoft's Java visual programming environment, which can be used to create applets and applications in the Java language. See also applet, Java, Java applet, visual programming.
visual programming
n. A method of programming using a programming environment or language in which basic program components can be selected through menu choices, buttons, icons, and other predetermined methods.
VL bus
n. Short for VESA local bus. A type of local bus architecture introduced by the Video Electronics Standards Association. The VL bus specification allows up to three VL bus slots to be built into a PC motherboard and allows for bus mastering (wherein "intelligent" adapter cards can do some processing independently of the CPU). A VL bus slot consists of a standard connector plus an additional 16-bit Micro Channel Architecture connector and must be built into the motherboard by the manufacturer. Standard connectors cannot simply be converted to VL bus slots. A non-VL bus adapter card can be used in a VL bus slot, but it cannot use the local bus and so performs as it normally would in a non-VL bus slot. Also called VL local bus. See also local bus, PCI local bus.
VM
n. Acronym for Virtual Machine. An operating system for IBM mainframes that provides virtual-machine capability. VM was developed by IBM customers and later taken over by IBM itself under the name OS/VM. See virtual machine, virtual memory.
voice-capable modem
n. A modem that can support voice messaging applications along with its data-handling functions.
voice mail
n. A system that records and stores telephone messages in a computer's memory. Unlike a simple answering machine, a voice mail system has separate mailboxes for multiple users, each of whom can copy, store, or redistribute messages.
voice modem
n. A modulation/demodulation device that supports a switch to change between telephony and data transmission modes. Such a device might contain a built-in loudspeaker and microphone for voice communication, but more often it uses the computer's sound card. See also modem, sound card, telephony.
voice-net
n. A term used on the Internet to refer to the telephone system, often preceding the user's telephone number in an e-mail signature.
volume
n. 1. A disk or tape that stores computer data. Sometimes, large hard disks are divided into several volumes, each of which is treated as a separate disk. 2. The loudness of an audio signal.
volume label
n. A name for a disk or tape. MS-DOS systems, which seldom use disk names except in directory listings, use the term volume label. Apple Macintosh systems, which often refer to disks by name, use the term volume name.
volume serial number
n. The optional identifying volume number of a disk or tape. MS-DOS systems use the term volume serial number. Apple Macintosh systems use the term volume reference number. A volume serial number is not the same as a volume label or volume name. Compare volume label.
VPD
n. Acronym for virtual printer device driver. See virtual device driver.
VRML
n. Acronym for Virtual Reality Modeling Language. A scene description language for creating 3-D interactive Web graphics similar to those found in some video games, allowing the user to "move around" within a graphic image and interact with objects. VRML, a subset of Silicon Graphics' Inventor File Format (ASCII), was created by Mark Pesce and Tony Parisi in 1994. VRML files can be created in a text editor, although CAD packages, modeling and animation packages, and VRML authoring software are the tools preferred by most VRML authors. VRML files reside on an HTTP server; links to these files can be embedded in HTML documents, or users can access the VRML files directly. To view VRML Web pages, users need a VRML-enabled browser, such as WebSpace from Silicon Graphics, or a VRML plug-in for Internet Explorer or Netscape Navigator. See also 3-D graphic, HTML document, HTTP server (definition 1).
V series
n. See CCITT V series.
VT-52, VT-100, VT-200
n. A popular set of control codes used in terminals with those model numbers that were originally manufactured by Digital Equipment Corporation. Appropriate software can enable a microcomputer to use these codes to emulate such terminals.
VTD
n. Acronym for virtual timer device driver. See virtual device driver.
VxD
n. See virtual device driver.
A/B Switch box ~ America On-line AMI BIOS ~ Arithmetic Operation ARP ~ AVI Backbone ~ Bit Image Bit Map ~ Boot Disk Boot Drive ~ Bytes Per Inch C++ ~ Carrier Frequency carrier system ~ certification CGI ~ Chooser extension cipher ~ Clipper Chip clock ~ color color bits ~ communications satellite communications server ~ computer security CON ~ copy copy program ~ cycle time daemon ~ defragmentation demand paging ~ digitize DikuMUD ~ disk disk buffer ~ Document Style Semantics and Specification Language document window ~ dynamic Web page Easter egg ~ erase erase head ~ ezine F2F ~ finger2 firewall ~ font suitcase footer ~ FYI Game Control Adapter ~ GUI HAL ~ hot key1 hot key2 ~ Hz i486DX ~ internal modem internet ~ ISO 9660 ISO/OSI model ~ just-in-time K1 ~ knowledge base L1 cache ~ LU luggable computer ~ LZW compression MAC ~ MILNET mime ~ msec MTBF ~ MYOB named anchor ~ network drive Network File System ~ number crunching object ~ overwrite mode P5 ~ PC/XT keyboard PDA ~ pipeline processing piracy ~ preventive maintenance preview ~ pwd quasi-language ~ QWERTY keyboard R&D ~ registration marks Registry ~ RFI RF shielding ~ run-time library SAA ~ server error server push-pull ~ soft return software ~ style sheet stylus ~ System T1 ~ ToggleKeys token ~ typography UART ~ uupc V.120 ~ view2 viewer ~ VxD w3 ~ WinG WINS ~ WWW X.25 ~ X Windows Yahoo! ~ yotta- Z39.50 standard ~ Zulu time