Specifications

Glossary
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volume label An identifier or name of up to 11
characters that names a disk.
VPN (virtual private network) A private net-
work operated within a public network. To main-
tain privacy, VPNs use access control and
encryption.
VRAM (video random-access memory)
VRAM chips are modified DRAMs on video boards
that enable simultaneous access by the host system’s
processor and the processor on the video board. A
large amount of information therefore can be trans-
ferred quickly between the video board and system
processor. Sometimes also called dual-ported RAM. It
has been replaced by SDRAM, SGRAM, and DDR
SDRAM on recent high-performance video cards.
VxD (virtual device driver) A special type of
Windows driver. VxDs run at the most privileged
CPU mode (ring 0) and enable low-level interaction
with the hardware and internal Windows functions.
W3C (World Wide Web Consortium) Sets
standards for HTML, XML, and the Web.
wafer A thin, circular piece of silicon either 8"
(200mm) or 12" (300mm) in diameter from which
processors, memory, and other semiconductor elec-
tronics are manufactured.
wait states One or more pause cycles added
during certain system operations that require the
processor to wait until memory or some other sys-
tem component can respond. Adding wait states
enables a high-speed processor to synchronize with
lower-cost, slower components. A system that runs
with “zero wait states” requires none of these cycles
because of the use of faster memory or other com-
ponents in the system. The widespread use of L1
and L2 memory caches has made the issue of wait
states largely irrelevant. See also L1 cache and L2
cache.
warm boot Rebooting a system by means of a
software command rather than turning the power
off and back on. See also cold boot.
watt (W) A unit of electrical power. One watt is
expended when 1 ampere of direct current flows
through a resistance of 1 ohm.
wave table synthesis A method of creating
synthetic sound on a sound card that uses actual
musical instrument sounds sampled and stored on
ROM (or RAM) on the sound card or in system
RAM. The sound card then modifies this sample to
create any note necessary for that instrument.
Produces much better sound quality than FM
synthesis.
webcam An inexpensive (usually under $100)
video camera that plugs into a USB or an IEEE
1394/FireWire port for use with video chat, web-
sites, or email programs.
Whetstone A benchmark program developed in
1976 and designed to simulate arithmetic-intensive
programs used in scientific computing. Remains
completely CPU-bound and performs no I/O or sys-
tem calls. Originally written in ALGOL, although
the C and Pascal versions became more popular by
the late 1980s. The speed at which a system per-
forms floating-point operations often is measured
in units of Whetstones.
White Book A standard specification developed
by Philips and JVC in 1993 for storing MPEG stan-
dard video on CDs. This is an extension of the Red
Book standard for digital audio, Yellow Book stan-
dard for CD-ROM, Green Book standard for CD-I,
and Orange Book standard for CD write-once.
Whitney technology A term referring to a
magnetic disk design that usually has oxide or
thin film media, thin-film read/write heads, low
floating-height sliders, and low-mass actuator arms
that together allow higher bit densities than the
older Winchester technology. Whitney technology
first was introduced with the IBM 3370 disk drive,
circa 1979.
Wi-Fi Name for IEEE 802.11–compliant network
hardware that also meets the interoperability stan-
dards of the Wireless Ethernet Compatibility
Alliance (WECA). Despite the presence of Wi-Fi
approval for various brands of hardware, achieving
the simplest setup and operation is still easier if
you purchase Wi-Fi wireless NICs and access points
that support the same standard (802.11a, b, g, or n)
from the same vendor. See also 802.11.
Appendix A
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