User's Manual

Glossary 249
FILE LOCATI ON: S:\SYSTEMS\Pebble\UG\A00\English\glossary.fm
DELL CONFI DENTI AL – PRELI MI NARY 1/29/03 – FOR PROOF ONLY
U
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 into 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
VI DEO CONTROLLER — The circuitry on a video card or on the system board (in
computers with an integrated video controller) that provides the video capabilities—
in combination with the monitor—for your computer.
VI DEO MEM ORY — 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.
VI DEO 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.
VI DEO RESOLUTI ON — See resolution.
VI RUS — 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. W hen an infected program starts, its embedded virus also starts.