V
A testbed for distributed
system research .
VAD See Voice
Activity Detection (VAD) /.
Validation
The process of evaluating software
at the end of the development
process to ensure compliance with
software requirements.
Value
Anything that may be a legitimate
(actual) parameter in a request.
In particular, a value is an instance
of an IDL /i data type.
Vanity Page
A vanity page is a website placed
on-line by an individual, not
for commercial purposes, or as
an informational resource, but
simple because it tells something
about the person that put the
page up.
variable A container,
referrer to with a name=, that
can store a number, a string,
or an object.
VAX A range
of 32-bit computers manufactured
by DEC.
VAX DOCUMENT
A document preparation system
from DEC.
VAX/VMS see
VMS VMS.
VAXset A set
of software development tools
from DEC, including a language-sensitive
editor, compilers etc.
VAXstation A
family of workstations from DEC
based on their VAX computer architecture.
VB Visual Basic
VBR Variable Bit Rate:
An ATM Forum defined service category
which supports variable bit rate
data traffic with average and
peak traffic parameters.
VBScript
A scripting language developed
by Microsoft, with syntax based
on Visual Basic. Only Microsoft
Internet Explorer supports VBScript.
VC
A communications channel that
provides for the sequential unidirectional
transport of ATM cells.
VCAL:
Electronic or virtual Calendar,
developed by the versit consortium
and now controlled by the Internet
Mail Consortium. This open specification
defines the format of electronic
personal calendar entry and scheduling
information.
vCARD:
Elecronic or virtual Card, developed
by the versit consortium and now
controlled by the Internet Mail
Consortium. This open specification
defines the format of an Electronic
Business Card.
VCC Virtual Channel Connection:
A concatenation of VCLs
that extends between the points
where the ATM service users access
the ATM layer. The points at which
the ATM cell payload is passed
to, or received from, the users
of the ATM Layer (i.e., a higher
layer or ATM-entity) for processing
signify the endpoints of a VCC.
VCCs are unidirectional.
VCI
See virtual circuit identifier
(VCI) /.
VCI Virtual Channel Identifier:
A unique numerical tag as defined
by a 16 bit field in the ATM cell
header that identifies a virtual
channel, over which the cell is
to travel.
VCL Virtual Channel Link:
A means of unidirectional transport
of ATM cells between the point
where a VCI value is assigned
and the point where that value
is translated or removed.
VCO Voltage Controlled
Oscillator:
An oscillator whose clock frequency
is determined by the magnitude
of the voltage presented at its
input. The frequency changes when
the voltage changes.
VD Virtual Destination.
Refer to VS/VD.
VDL Vienna Definition
Language: an algebraic definition
language, see VDM VDM.
VDM Vienna Definition
Method: a program development
method based on formal specification
using the Meta-IV language - .
/VDM
VDM Virtual
Device Metafile.
VEE see HP VEE
HP-VEE.
Verification The
process of determining whether
or not the products of a given
phase in the life-cycle fulfill
a set of established requirements.
Verilog A Hardware
Description Language for electronic
design and gate level simulation.
Verilog SA A
French real-time real-time software
engineering company.
Version A variant
of the original value of an object.
See change management change-management
Vertical Frequency
This indicates how many times
per second the monitor can draw
all the lines on an entire screen.
A higher Vertical frequency or
Refresh rate will produce less
flicker.
VF Variance Factor: VF
is a relative measure of cell
rate margin normalized by the
variance of the aggregate cell
rate on the link
VHDL Very High Speed
Integrated Circuit Description
Language:
a high-level VLSI VLSI design
language, now standardised as
IEEE IEEE Std.1076 - . /VHDL
VHE Virtual Home Environment:
a tool for using NFS
NFS on HP UX HP-UX .
VIFF Visualization
Image File Format - . /Graphics
Viola An experimental
hypercard hypercard-like interpreted
hypertext hypertext system by
Pei Y. Wei of Berkeley.
VIP Virtual
Internet Internet Protocol - .
VIPA VMEbus
VMEbus International Physics Association.
Virtual Channel Switch
A network element that connects
VCLs. It terminates VPCs and translates
VCI values. It is directed by
Control Plane functions and relays
the cells of a VC.
Virtual Circuit
A channel or circuit established
between two points on an ATM /a
network. Circuit numbers 0 through
31 are reserved; circuit 5 is
the signalling channel. Virtual
circuits can be Permanent Virtual
Circuit (PVC) /p or Switched Virtual
Circuit (SVC) /s (dynamic).
Virtual Circuit Identifier
(VCI)
The identifier code used with
the virtual path identifier for
routing ATM /a cells /c.
Virtual Memory
A sneaky trick by which Unix pretends
to have more memory than it really
does. When you are not looking,
Unix copies information from memory
to the disk to free up space in
memory. When you need the information
on disk, Unix copies it from the
disk back into memory. Virtual
memory is generally invisible,
except when a program uses it
too enthusiastically; then the
computer spends all its time copying
stuff back and forth to the disk
and no time doing useful work,
a condition called thrashing.
Virtual Path
A group of virtual circuits bundled
together.
Virtual Path Identifier
(VPI)
The identifier code used with
the virtual circuit identifier
for routing ATM /a cells /c.
Virtual Path Switch
A network element that connects
VPLs. It translates VPI (not VCI)
values and is directed by Control
Plane functions. It relays the
cell of the VP.
Virtual Private Network
(VPN)
A service from telephone companies
to provide PBX trunking services,
typically including volume price
discounts.
Virtual Reality Modeling
Language (VRML)
Similar to SGML /s and HTML /h,
the Virtual Reality Modeling Language
(VRML) provides a way to textually
represent objects in a three-dimensional
virtual world, defining color,
size, shape, lighting factors,
and so forth.
VIRTUAL SERVER
A Virtual Server is fully functioning
Web Server that resides within
the same physical location of
a true Web Server. Multiple Virtual
Servers can reside on a single
Web Server. This technology sprang
up in the mid 1990's and has allowed
business and persons to have the
benefits of a Web Server at a
very feasible rate.
Virus
A program that was designed to
do something usually counterproductive
and occasionally destructive,
whether through ignorance or malice,
to your work. Other similar terms
include worm /w and trojan horse
/t.
Visual Basic A
programming language and development
environment for Windows Windows
from Microsoft
Visualisation A
method by which a computer system
presents data to the user
VITA VMEbus
International Trade Association.
VITAL VHDL Initiative
Towards ASIC Libraries
VLAN Virtual Local Area
Network:
Work stations connected to an
intelligent device which provides
the capabilities to define LAN
membership.
VLIW Very Long
Instruction Word.
VLSI Very Large Scale
Integration.
Refers to semiconductor chips
composed of very many tightly
packed logic elements or memories.
VM see VM/CMS
VM/CMS.
VM/CMS Virtual Machine/Conversational
Monitor System:
an IBM operating system
running on 43xx and 30xx series
machines, providing efficient
support for large numbers of interactive
users.
VME Common abbreviation
for VMEbus VMEbus.
VMEbus
A widely accepted backplane interconnection
bus system developed by a consortium
of companies led by Motorola,
now standardized as IEEE IEEE
Std. 1014.
VMS The operating
system offered by DEC as the standard
system for their VAX range of
processors.
Voice Activity Detection
(VAD)
A technology that recognizes when
a person is speaking and when
a person is silent to suppress
sending unnecessary noise across
a telecommunications line.
VoiceXML:
VoiceXML, a makeup language for
speech, is standard being pushed
by the VoiceXML the internet via
a phone, whether wired or not.
VoIP:
Voice over IP is a protocol that
allows the transmission of voice
over Internet networks by using
IP encoding.
VoxML:
A markup language for speech proposed
by Motorola for their telephony
applications.
VP Virtual Path:
A unidirectional logical association
or bundle of VCs.
VPC Virtual Path Connection:
A concatenation of VPLs between
Virtual Path Terminators (VPTs).
VPCs are unidirectional.
VPI See virtual
path identifier (VPI) /.
VPI Virtual Path Identifier:
An eight bit field in the ATM
cell header which indicates the
virtual path over which the cell
should be routed.
VPL Virtual Path Link:
A means of unidirectional transport
of ATM cells between the point
where a VPI value is assigned
and the point where that value
is translated or removed.
VPN See Virtual
Private Network (VPN) /.
VPN Virtual Private Network.
A computer network that appears
to be a dedicated network to a
particular set of users, whilst
in fact using the infrastructure
of public switched networks.
VPT Virtual Path Terminator:
A system that unbundles the Vcs
of a VP for independent processing
of each VC.
VRML See Virtual
Reality Modeling Language (VRML)
/.
VRML Virtual
Reality Modeling Language - .
/VRML
VRTX Virtual Real-Time
Executive:
a real-time real-time operating
system from ReadySystems for the
Motorola 68000 family of microprocessors.
VS Virtual Scheduling:
Virtual Scheduling is a method
to determine the conformance of
an arriving cell. The virtual
scheduling algorithm updates a
Theoretical Arrival Time (TAT),
which is the "nominal"
arrival time of the cell assuming
that the active source sends equally
spaced cells. If the actual arrival
time of a cell is not "too"
early relative to the TAT, then
the cell is conforming. Otherwise
the cell is non-conforming.
VS Virtual Source. Refer
to VS/VD.
VS/VD Virtual Source/Virtual
Destination:
An ABR connection may be divided
into two or more separately controlled
ABR segments. Each ABR control
segment, except the first, is
sourced by a virtual source. A
virtual source implements the
behavior of an ABR source endpoint.
Backwards RM-cells received by
a virtual source are removed from
the connection. Each ABR control
segment, except the last, is terminated
by a virtual destination. A virtual
destination assumes the behavior
of an ABR destination endpoint.
Forward RM-cells received by a
virtual destination are turned
around and not forwarded to the
next segment of the connection.
VSAT Very small
aperture terminal.It is small
satellite terminal used for digital
communications.
VSF Virtual Software
Factory: a product from
Systematica which allows users
to develop CASE tools CASE-tools
appropriate to any software engineering
methodology.
VSNL VIDESH
SANCHAR NIGAM LIMITED
VSX Verification
Suite.for X/open X/open
VTOA Voice and Telephony
Over ATM:
The ATM Forum voice and telephony
over ATM service interoperability
specifications address three applications
for carrying voice over ATM networks;
desktop (or LAN services), trunking
(or WAN services), and mobile
services.
VTS A suite
of test programs for Motif Motif
from OSF OSF.
VUE Visual User Environment:
a desktop manager desktop-manager
for UNIX UNIX from Hewlett-Packard.
VUIT Visual User Interface
Tool:
a WYSIWYG WYSIWYG editor from
DEC for building human interfaces
to applications using OSF OSF/Motif
Motif. It provides an interactive
interface to UIL UIL and the Motif
toolkit.
VxWorks
A real-time real-time software
development environment and multitasking
operating system from Wind River
Systems that uses the VRTX kernel.
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