Specifications

Glossary
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dual-core processor A processor that contains
two distinct physical processor cores in a single
package. This type of processor provides most
of the benefits of dual processor designs at a
lower cost.
dual independent bus (DIB) architecture
A processor technology with the existence of two
independent buses on the processor—the L2 cache
bus and the processor-to-main memory system bus.
The processor can use both buses simultaneously,
thus getting as much as two times more data into
and out of the processor than a single bus architec-
ture processor. The Intel Pentium Pro, Pentium II,
and newer processors from Intel and AMD (such as
the AMD Athlon and Duron) have DIB architecture.
dual scan display A lower-quality but economi-
cal type of LCD color display that has an array of
transistors running down the x and y axes of two
sides of the screen. The number of transistors deter-
mines the screen’s resolution.
dumb terminal A screen and keyboard device
with no inherent processing power connected to a
computer that is usually remotely located.
duplex Indicates a communications channel
capable of carrying signals in both directions.
Duron A low-cost version of the Athlon proces-
sor with less L2 cache. Available in the Socket A
(462-pin) chip package.
DVD (digital versatile disc) Originally called
digital video disc, DVD is a type of high-capacity
CD-ROM disc and drive format with up to 28 times
the capacity of a standard CD-ROM. The disc is the
same diameter as a CD-ROM but can be recorded
on both sides and on two layers for each side. Each
side holds 4.7GB on a single layer disc, whereas
dual-layer versions hold 8.5GB per side, for a maxi-
mum of 17GB total if both sides and both layers
are used, which is the equivalent of 28 CD-ROMs.
DVD drives can read standard audio CDs and
CD-ROMs.
DVD burner Popular term for a rewritable DVD
drive, particularly one that uses DVD-R/RW or
DVD+R/RW media.
DVD-A A DVD format designed to support high-
quality music and audio. DVD-A uses 24-bit sam-
pling at 96KHz, significantly better than CD audio
(16-bit at 44.1KHz). Unlike DVD, DVD-A discs can
be played on conventional CD players but produce
the highest quality only when played on DVD-A
players.
DVD-R A writeable DVD format compatible with
standalone DVD players and DVD-ROM drives.
DVD-R was introduced by Pioneer and was released
to the DVD Forum (www.dvdforum.org) in July
1997. It uses a wobbled-groove recording process to
store 4.7GB of data and is optimized for sequential
data access. See also DVD-RW.
DVD-R DL A dual-layer DVD format based on
DVD-R that supports up to 8.5GB of data. See also
DVD-R.
DVD+R A writeable DVD format compatible with
standalone DVD players and DVD-ROM drives.
DVD+R was developed by the DVD+RW Alliance
(www.dvdrw.com), whose members include
Microsoft, Sony, HP, and Dell. In addition, it is sup-
ported by second-generation DVD+RW drives and
holds 4.7GB of data. DVD+R/RW are the most com-
patible, fastest, most capable, and most popular of
all the recordable DVD formats. See also DVD+RW.
DVD+R DL A dual-layer DVD format based on
DVD+R that supports up to 8.5GB of data. See also
DVD+R.
DVD-RAM A rewritable DVD format developed
by Panasonic, Toshiba, and Hitachi and supported
by the DVD Forum. DVD-RAM is the oldest DVD
rewritable format, but because the media uses a
caddy and has a lower reflectivity than normal
DVD media, DVD-RAM discs are not compatible
with other types of DVD drives or with standalone
DVD players. Older DVD-RAM drives use media in
caddies, but newer drives do not use caddies.
DVD-RW A rewritable DVD format developed by
Pioneer and released to the DVD Forum in
November 1999. It uses a phase-change technology
similar to CD-RW. As with most CD-RW media and
drives, the entire disc must be formatted before it
can be used. Its write speed is also lower than
DVD+RW, and the entire disc must be erased before
it can be used to store new data. See also DVD-R.
DVD+RW A rewritable DVD format developed
by the DVD+RW Alliance; the first DVD+RW drives
were released in 2001. DVD+RW uses a phase-
change technology similar to CD-RW and DVD-RW.
Appendix A
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