Glossary 21
virus
Software that copies itself onto hard drives and diskettes without user
intervention, usually when a diskette is placed into the drive of a
computer. Viruses usually trigger a harmless or destructive
occurrence on the system, activated by some preset condition.
Viruses are frequently written with antisocial intent.
VGA
Video Graphics Array. Graphics technology that supports up to
256 K colors and a graphics resolution of 640 by 480 pixels.
volatile memory
Storage media that loses its data when system power is turned off.
Standard memory and memory that you add to the system are volatile
memory. See nonvolatile memory.
VRAM
Video RAM. VRAM is special-purpose memory used by video
adapters. Unlike conventional RAM, VRAM can be accessed by two
different devices simultaneously. This enables a video adapter to
access the VRAM for screen updates at the same time that the CPU
provides new data. VRAM yields better graphics performance but is
more expensive than normal RAM. A special type of VRAM, called
Windows RAM (WRAM), yields even better performance than
conventional VRAM. See SGRAM and WRAM.
W
warm boot
Process of resetting the computer without turning off the power
through keyboard input (pressing Ctrl, Alt, and Del keys
simultaneously) or the reset button. The system returns to an initial or
arbitrarily selected condition.
WRAM
Windows RAM. A type of RAM that supports two ports. This
enables a video adapter to fetch the contents of memory for display at
the same time that new bytes are being pumped into memory. This
results in much faster display than is possible with conventional
single-port RAM. WRAM is similar to VRAM, but achieves even
faster performance at less cost because it supports addressing of large
blocks (windows) of video memory. See VRAM and SGRAM.