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V
V.34
Data transmission
standard that provides for up to 33,600 bits per second (bps)
communications over telephone lines. It defines a full-duplex (two-way)
modulation technique and includes error-correcting and
negotiation.
V.90
Data transmission
standard that provides for up to 56,000 bits per second (bps)
communications over telephone lines. The transmission speed from the
client-side modem is 33,600 bps, the same as V.34. The transmission speed
from the host-side modem, such as an Internet service provider (ISP) or
corporate network, is up to 56,000 bps, with an average speed of 40,000 to
50,000 bps. When the host-side modem does not support this standard, the
alternative is V.34.
value
entry
The string of data that
appears in the right pane of a registry window and that defines the value
of the currently selected key. A value entry has three parts: name, data
type, and the value itself.
variable
In programming, a named
storage location capable of containing a certain type of data that can be
modified during program execution.
System environment
variables are defined by Windows 2000 Server and are the same no
matter who is logged on to the computer. Administrator group members can
add new variables or change the values, however.
User environment
variables can be different for each user of a particular computer. They
include any environment variables you want to define or variables defined
by your applications, such as the path where application files are
located.
vector
For Indexing Service, an
ordered series of words or numbers used in a query. For example, a single
document can have (Scott Cooper; Don Hall; Amy Egert) as a vector of
coauthors.
vector
font
A font rendered from a
mathematical model, in which each character is defined as a set of lines
drawn between points. Vector fonts can be cleanly scaled to any size or
aspect ratio.
video
adapter
An expansion board that
plugs into a personal computer to give it display capabilities. A
computer's display capabilities depend on both the logical circuitry
(provided in the video adapter) and the monitor. Each adapter offers
several different video modes. The two basic categories of video modes are
text and graphics. Within the text and graphics modes, some monitors also
offer a choice of resolutions. At lower resolutions a monitor can display
more colors.
Modern adapters contain
memory, so that the computer's RAM is not used for storing displays. In
addition, most adapters have their own graphics coprocessor for performing
graphics calculations. These adapters are often called graphics
accelerators.
virtual
address
In a virtual memory
system, the address the application uses to reference memory. The kernel
and the memory management unit (MMU) translate this address into a
physical address before the memory is actually read or
written.
virtual
container
A container that allows
any LDAP-compliant directory to be accessed through Active
Directory.
virtual IP
address
An IP address that is
shared among the hosts of a Network Load Balancing cluster. A Network Load
Balancing cluster might also use multiple virtual IP addresses, for
example, in a cluster of multihomed Web servers.
virtual local area network
(VLAN)
A logical grouping of
hosts on one or more LANs that allows communication to occur between hosts
as if they were on the same physical LAN.
virtual
memory
Temporary storage used by
a computer to run programs that need more memory than it has. For example,
programs could have access to 4 gigabytes of virtual memory on a
computer's hard drive, even if the computer has only 32 megabytes of RAM.
The program data that does not currently fit in the computer's memory is
saved into paging files.
Virtual Memory
Size
In Task Manager, the
amount of virtual memory, or address space, committed to a
process.
virtual printer
memory
In a PostScript printer,
a part of memory that stores font information. The memory in PostScript
printers is divided into two areas: banded memory and virtual memory. The
banded memory contains graphics and page-layout information needed to
print your documents. The virtual memory contains any font information
that is sent to your printer either when you print a document or when you
download fonts.
virtual private network
(VPN)
The extension of a
private network that encompasses encapsulated, encrypted, and
authenticated links across shared or public networks. VPN connections can
provide remote access and routed connections to private networks over the
Internet.
virus
A program that attempts
to spread from computer to computer and either cause damage (by erasing or
corrupting data) or annoy users (by printing messages or altering what is
displayed on the screen).
VoIP (Voice over Internet
Protocol)
A method for sending
voice over a LAN, a WAN, or the Internet using TCP/IP
packets.
volume
An area of storage on a
hard disk. A volume is formatted by using a file system, such as FAT or
NTFS, and has a drive letter assigned to it. You can view the contents of
a volume by clicking its icon in Windows Explorer or in My Computer. A
single hard disk can have multiple volumes, and volumes can also span
multiple disks.
volume set
A partition consisting of
disk space on one or more physical disks that was created with
Windows NT 4.0 or earlier. You can delete volume sets only with
Windows&nsbsp;2000 or Windows XP. To create new volumes that span
multiple disks, use spanned volumes on dynamic
disks.
volume shadow
copy
A volume that represents
a duplicate of the original volume taken at the time the copy
began.
voluntary
tunnel
A tunnel that is
initiated by the client. It tunnels PPP over IP from the client to the
tunnel server, then the data is forwarded to the target host by the tunnel
server. |
