Glossary 261

bus — An electrical circuit that connects the central processing unit (CPU) with other parts of the computer, such as the video adapter, disk drives, and ports. It is the pathway through which data flows from one device to another. See also bus speed, frontside bus.

bus speed — The speed at which the central processing unit (CPU) communicates with the other parts of the computer.

byte — A sequence of eight bits. A byte is the smallest addressable

unit of data. See also bit, gigabyte, kilobyte, megabyte.

C

cache — A section of very fast memory in which frequently used

 

 

information is duplicated for quick access. Accessing data from

 

cache is faster than accessing it from the computer’s main

 

memory. See also CPU cache, L1 cache, L2 cache.

 

CD — An individual compact disc. See also CD-ROM.

 

CD-ROM (compact disc read-only memory) — A form of high-

 

capacity storage that uses laser optics instead of magnetic means

 

for reading data. See also CD. Compare DVD-ROM.

 

central processing unit (CPU) — The chip that functions as the

 

“brain” of the computer. It takes information from outside

 

sources, such as memory or keyboard input, processes the

 

information, and sends the results to another device that uses the

 

information.

 

character — Any letter, number, or symbol you can use on the

 

computer. Some characters are non-printing characters, such as a

 

paragraph break in a word-processing program. A character

 

occupies one byte of computer storage.

 

chip — A small piece of silicon containing computer logic and

 

circuits for processing, memory, input/output, and/or control

 

functions. Chips are mounted on printed circuit boards.

 

click — To press and release the control button or mouse button

 

without moving the cursor with the TouchPad or mouse. In the

 

operating system, this refers to the left mouse button or primary

 

control button, unless otherwise stated. See also double-click.