Computer Glossary C
Cache Temporary storage area used to speed up different
processes. A web browser keeps recently used web pages on
hard disk cache, so it doesn’t have to download the same page
again. A processor stores recent or frequently used instructions
in chunks of very fast memory called level 1 and 2 caches.
CCD charge-coupled device. A CCD is used by digital cameras
and scanners. It is a grid of light-sensitive cells that store an
electrical charge proportional to the amount of light falling on
them. The charge value in each cell is converted from analogue
to digital and is used to build up a complete image.
CDMA code division multiple access. CDMA is a digital cellular
technology. Unlike GSM, CDMA does not assign a specific
frequency to each user. Instead, every channel uses the full
available spectrum and the frequency is divided using codes.
Chipset A number of integrated circuits which carry out related
tasks. This is the name often given to the core functionality of
a motherboard, or to the chip that powers a graphics card.
client/server A network where all services and facilities such as
email or file and printer sharing are provided to networked, or
client PCs and controlled by separate, purpose-built systems
called servers.
Cmos complementary metal oxide semiconductor. A process
used to make chips, but in a PC is shorthand for a batterypowered
chip on the motherboard, which stores basic system
configurations and clock settings.
Compiler Special program that takes the instructions written in
a programming language and turns them into machine code that
a PC processor can understand.
Composite cable A video cable with yellow connectors on the
end used to view digital cameras on a television.
Cookie A message sent by a web server to a browser and stored
in a text file, usually called cookie.txt. The message is sent back to the browser every time a new request is made at the website. Cookies are mostly used to identify users and create
site visit statistics on types of browser, operating systems and
popular pages.
CPU central processing unit. A microprocessor chip that is the
‘brains’ of a computer. Its many functions include fetching and
carrying out instructions for programs.
CRT cathode ray tube. A monitor technology that works by
moving an electron beam back and forth across the back of the
screen. Each time it passes across the screen it lights up red,
green and blue phosphor dots on the inside of the screen to
make up the images you see.
CMYK cyan, magenta, yellow, keystone black. These are the
four basic colours used by inkjet and laser colour printers.
A huge range of colours are created by a combination of
overlaying and dithering.
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