Glossary 15
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.
Wwarm 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.
write
To record or store information to a storage device.
write-back
Also called copy back. A cache strategy where write operations to data stored in the internal
microprocessor L1 cache aren’t copied to system memory until absolutely necessary. In
contrast, a write-through cache performs all write operations in parallel; data is written to
system memory and the L1 cache simultaneously. Write-back caching yields somewhat
better performance than write-through caching because it reduces the number of write
operations to main memory. See cache and write-through.
write-through
Also write-thru. Write-through characterizes a cache strategy where data is always written
into system memory when data is written by the CPU. See cache and write back.