Specifications
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Appendix A Glossary
clock multiplier A processor feature where the
internal core runs at a higher speed than the moth-
erboard or processor bus. See also overclocking.
clock speed A measurement of the rate at which
the clock signal for a device oscillates, usually
expressed in millions of cycles per second (MHz).
clone Originally referred to an IBM-compatible
computer system that physically as well as electri-
cally emulates the design of one of IBM’s personal
computer systems. More currently, it refers to any
PC system running an Intel or compatible processor
in the 80x86 family.
cluster Also called allocation unit. A group of one
or more sectors on a disk that forms a fundamental
unit of storage to the operating system. Cluster, or
allocation unit, size is determined by the operating
system when the disk is formatted. Larger clusters
generally offer faster system performance but waste
disk space.
CLV (constant linear velocity) An optical
recording format in which the spacing of data is
consistent throughout the disk and the rotational
speed of the disk varies depending on which track
is being read. Additionally, more sectors of data are
placed on the outer tracks compared to the inner
tracks of the disk, which is similar to zone record-
ing on hard drives. CLV drives adjust the rotational
speed to maintain a constant track velocity as the
diameter of the track changes. CLV drives also
rotate more quickly near the center of the disk and
more slowly toward the edge. Rotational adjust-
ment maximizes the amount of data that can be
stored on a disk. CD audio and CD-ROM use CLV
recording. See also CAV.
CMOS (complementary metal-oxide semicon-
ductor) A type of chip design that requires little
power to operate. In PCs, a battery-powered CMOS
memory and clock chip is used to store and main-
tain the clock setting and system configuration
information.
CMYK (cyan magenta yellow black) The
standard four-color model used for printing.
CNR Short for Communications and Networking
Riser, CNR was developed by Intel as a replacement
for the AMR. It enables motherboard makers to
offer low-cost modem, networking, and audio
features through a special expansion slot. Unlike
AMR, a CNR slot can be built as a shared slot with
a PCI slot. See also AMR.
coated media Hard disk platters coated with a
reddish iron-oxide medium on which data is
recorded.
coaxial cable Also called coax cable. A data-
transmission medium noted for its wide band-
width, immunity to interference, and high cost
compared to other types of cable. Signals are trans-
mitted inside a fully shielded environment, in
which an inner conductor is surrounded by a solid
insulating material and then an outer conductor or
shield. Used in many local area network systems,
such as Ethernet and ARCnet.
COBOL (Common Business-Oriented
Language) A high-level computer programming
language used primarily by some larger companies.
It has never achieved popularity on personal and
small business computers.
code page A table used in DOS 3.3 and later that
sets up the keyboard and display characters for vari-
ous foreign languages.
code page switching A DOS feature in versions
3.3 and later that changes the characters displayed
onscreen or printed on an output device. Primarily
used to support foreign-language characters.
Requires an EGA or better video system and an
IBM-compatible graphics printer.
CODEC (coder-decoder) A device that converts
voice signals from their analog form to digital sig-
nals acceptable to more modern digital PBXs and
digital transmission systems. It then converts those
digital signals back to analog so you can hear and
understand what the other party is saying. Also
refers to compression/decompression software used
in the creation of digital audio and video files, such
as MP3 and MPEG, and for videophone programs.
coercivity A measurement in units of oersteds of
the amount of magnetic energy to switch or
“coerce” the flux change in the magnetic recording
media. High-coercivity disk media require a
stronger write current.
cold boot The act of starting or restarting a com-
puter from a powered-off state. If the system is on,
this requires cycling the power off and then back
on. A cold boot causes all RAM to be forcibly
cleared. See also warm boot.
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