V

Volt

V.21, V.22, V.22BIS, V.32, V.32BIS, V.42, V.42BIS, V.54

CCITT specifications for modems. See CCITT.

VALIDATE

To check that a file is authentic and has not been altered. Most validation methods rely on computing a statistic based on all the data in the file, which is unlikely to remain constant if the file itself is changed.

VALUE-ADDED RESELLER

This term often refers to a reseller of computer products who also provides both integration and software customization services to business clients, or a company which resells hardware and software packages to developers and/or end-users.

VAMPIRE TAP

Used to connect a transceiver to standard coax cable ("Thick" coax) without cutting the cable and installing connectors. When you tighten the tap down over the cable, a pin pierces the cable's jacket, and makes the connection.

VAN

Value Added Network

VAP

Value-Added Process

VAPORWARE

A term used to describe software or hardware that has been announced or advertised by suppliers, but is not available or doesn't work. Most computer products spend 2 to 6 months in this state. Some never leave it.

VAR

See Value-Added Reseller.

VARIABLE CALLBACK

A type of Callback in which the telephone number to be dialed changes according to the location of the workstation. See Callback.

VARIABLE DATA RATE VIDEO

In digital systems, the ability to vary the amount of data processed per frame to match image quality and transmission bandwidth requirements. DVI symmetrical and asymmetrical systems can compress video at variable data rates.

VARP

VINES Address Resolution Protocol

VAXSTATION

A graphics workstation based on the MicroVAX that supports a wide range of monochrome and color workstation applications. The VAXstation is available in both disk-based and diskless configurations, and serves as a remote graphics terminal when connected to the MicroVAX Information Processor over the Ethernet channel.

Viaual Basic

VBA

Visual Basic for Applications

VCPI

See Virtual Control Program Interface.

VCR

See Video Cassette Recorder.

VCS

Verilog Compiled Simulator (Logic simulation acronym)

VCXO

Voltage Controlled Oscillator

VDC

Vehicle Dynamic Control

VDI

See Video Device Interface.

VDRV

See Variable Data Rate Video.

VECTOR

A software interrupt. See interrupt.

VECTOR FONTS

A set of lines that connect points to form characters.

VECTOR GRAPHICS

Images defined by sets of straight lines, defined by the locations of the end points.

VELOCITY OF PROPAGATION

Indicates the speed of transmission in the cable as it relates to transmission in air, and it is inversely proportional to time delay. The closer its value is to 100 percent, the better the velocity of propagation and the lower the time delay. See Time Delay.

VELVEETA

A Usenet posting, often commercial in nature, excessively cross-posted to a large number of newsgroups. Similar to Spam.

VERONICA

A serch engine for locating files stored on remote gopher servers.

VERTICAL REDUNDANCY CHECK

(VRC) An error-checking method that adds a check or parity bit to each character in a message so the number of 1 bits, including the parity bit, in each character is odd (odd parity) or even (even parity).

VESA

See Video Electronics Standards Association.

VFRP

VINES Fragmentation Protocol

VGA

See Video Graphics Array.

VHDL

VHSIC Hardware Descriptive Language (Logic simulation acronym)

VHF

Fcc defined as 30 to 300MHz (TV 2 to 13 and most FM radio).

VHSIC

Very High-Speed Integrated Circuit (Logic simulation acronym)

Screen oriented editor based on EX

VIA

Plated through hole used on circuit boards. A drilled hole in the substrate subsequently plated through with copper. Allows topside metal traces to connect with bottom-side metal traces.

VIA-FTP

VIA Systems-File Transfer Protocol

VICP

VINES Internet Control Protocol

VIDCAP

Microsoft's Video For Windows program to capture video input to RAM or hard disk memory.

VIDEO CASSETTE RECORDER

(VCR) An analog magnetic recording and playback machine. Generally used for recording and viewing full-motion video.

VIDEO DEVICE INTERFACE

(VDI) A software driver interface that improves video quality by increasing playback frame rates and enhancing motion smoothness and picture sharpness. VDI was developed by Intel and will be broadly licensed to the industry.

VIDEO ELECTRONICS STANDARDS ASSOCIATION

(VESA) A 32-bit local bus standard that is compatible with both ISA and EISA cards. Many manufacturers of local bus adapters use this standard because of its speed.

VIDEO GRAPHICS ARRAY

Standard IBM PC video display. Provides medium resolution text and graphics. VGA pixel resolution is 640X480.

VIDEO1

The default video compression algorithm in Microsoft's Video for Windows. Can produce 8- or 16-bit video sequences.

VIDICON

A generic name for a TV camera tube. It provides an analog voltage output corresponding to the intensity of the incoming light.

VIENNA VIRUS

Infects only .COM files. The virus corrupts one .COM file in six, rather than infecting it. Files corrupted by the virus cause a warm reboot when executed.

VIM

(Vi IMproved) "Charityware" that runs on UNIX, Amiga, DOS, and Windows.

VINES

Virtual Networking System

VIP

VINES Internet Protocol

VIPC

VINES Interprocess Communications

VIRTUAL COMMUNICATION

Communication between corresponding layers of two computers in a network. For example, between layer 7 of one computer and layer 7 of another. Data is not transmitted directly between the corresponding layers.

VIRTUAL CONTROL PROGRAM INTERFACE

(VCPI) An 80386 memory management standard created by Phar Lap Software in conjunction with other software developers to provide an interface between applications using MS-DOS Extenders on an 80386 machine and applications using 386 expanded memory managers. For example, the 386 expanded memory managers QEMM, 386MAX, and CEMM support the VCPI specification.

VIRTUAL DEVICE

A device that software can refer to but that doesn't physically exist.

VIRTUAL LAN

A network consisting of individual workstations connected through the LAN Distance product. It operates just as a physically connect LAN, through the applications and LAN protocols supported transparently across the LAN Distance connections.

VIRTUAL LOADING MODULE

(VLM) Support software modules that are dynamically loaded when VLM.EXE is loaded. A modular executable program that runs at each DOS workstation and enables communication with the NetWare server. Support software modules that are dynamically loaded when VLM.EXE is loaded. A VLM file has a VLM filename extension. For example, the IPX VLM file is IPXNCP.VLM. These files are used with the NetWare DOS Requester which is composed of several VLMs. These VLMs replace, and provide backward compatibility with, NetWare shells used in previous NetWare versions. There are two types of VLMs: child VLMs and multiplexor VLMs.

VIRTUAL MACHINE

(VM) Software that mimics the performance of a hardware device. For Intel 80386 and higher processors, a virtual machine is protected memory space that is created through the processor's hardware capabilities.

VIRTUAL MEMORY

A technique of simulating additional memory for an application to use. Applications access the memory through virtual addresses, which are mapped onto physical addresses on the disk. Two common ways to implement virtual memory are paging and segmentation (which was used by 80286 and earlier Intel processors to address memory).

VIRTUAL MEMORY MANAGER

(VMM) The facility in Windows 386 enhanced mode that manages the task of swapping data in and out of virtual memory for multiple non-Windows applications running virtual machines. The Windows VMM can manage paging in up to 48 MB of virtual memory.

VIRTUAL TELE-COMMUNICATION ACCESS METHOD

(VTAM) An IBM protocol fpr software tha controls communications in an SNA network, employed by NCP. See ACF/VTAM.

VIRUS

A software program or code fragment that attaches itself to another program in computer memory or on a disk, and spreads from one program to another. Viruses may damage data, take over system resources which are then not available to authorized users, cause the computer to crash, display messages, or lie dormant.

VISA

VISA Protocol

VISUAL PROGRAMMING

The use of graphical development tools and visual metaphors to create software.

VITAL

VHDL Initiative Toward ASIC Libraries. (Logic simulation acronym)

VLF

FCC defined as 10 to 30kHz

VLM

See Virtual Loading Module.

VLSI

Very Large-Scale Integration

See Virtual Machine.

VMM

See Virtual Memory Manager.

VMR

Voice Mudulation Recognition

VMS

Virtual Memory System

VMTP

Versatile Message Transaction Protocol

VRC

See Vertical Redundancy Check.

VRTP

VINES Routing Update Protocol

VSAT

Very Small Aperture Terminal

VSPP

VINES Sequenced Packet Protocol

Virtual Terminal

VTAM

See Virtual Telecommunications Access Method.