Glossary: Dell Latitude D620 User's Guide
U
UMA
unified memory allocation System memory dynamically allocated to video.
UPS
uninterruptible power supply A backup power source used when the electrical power fails or
drops to an unacceptable voltage level. A UPS keeps a computer running for a limited amount of time
when there is no electrical power. UPS systems typically provide surge suppression and may also
provide voltage regulation. Small UPS systems provide battery power for a few minutes to enable you
to shut down your computer.
USB
universal serial bus A hardware interface for a low-speed device such as a USB-compatible
keyboard, mouse, joystick, scanner, set of speakers, printer, broadband devices (DSL and cable
modems), imaging devices, or storage devices. Devices are plugged directly in to a 4-pin socket on
your computer or in to a multi-port hub that plugs in to your computer. USB devices can be connected
and disconnected while the computer is turned on, and they can also be daisy-chained together.
UTP
unshielded twisted pair Describes a type of cable used in most telephone networks and some
computer networks. Pairs of unshielded wires are twisted to protect against electromagnetic
interference, rather than relying on a metal sheath around each pair of wires to protect against
interference.
UXGA
ultra extended graphics array A video standard for video cards and controllers that supports
resolutions up to 1600 x 1200.
V
video controller
The circuitry on a video card or on the system board (in computers with an
integrated video controller) that provides the video capabilitiesin combination with the monitorfor your
computer.
video memory
Memory that consists of memory chips dedicated to video functions. Video memory is
usually faster than system memory. The amount of video memory installed primarily influences the
number of colors that a program can display.
video mode
A mode that describes how text and graphics are displayed on a monitor. Graphics-
based software, such as Windows operating systems, displays in video modes that can be defined as
x
horizontal pixels by
y
vertical pixels by
z
colors. Character-based software, such as text editors,
displays in video modes that can be defined as
x
columns by
y
rows of characters.
video resolution
See
resolution
.
virus
A program that is designed to inconvenience you or to destroy data stored on your computer. A
virus program moves from one computer to another through an infected disk, software downloaded
from the Internet, or e-mail attachments. When an infected program starts, its embedded virus also
starts.
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