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Toshiba PORTEGE M400 User Manual

Page 241

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User’s Manual

Glossary--4

Glossary

bit: Derived from "binary digit," the basic unit of information used by the

computer. It is either zero or one. Eight bits is one byte. See also

byte.

board: A circuit board. An internal card containing electronic components,

called chips, which perform a specific function or increase the

capabilities of the system.

boot: Short for bootstrap. A program that starts or restarts the computer.

The program reads instructions from a storage device into the

computer’s memory.

bps: Bits per second. Typically used to describe the data transmission

speed of a modem.

buffer: The portion of the computer’s memory where data is temporarily

stored. Buffers often compensate for differences in the rate of flow

from one device to another.

bus: An interface for transmission of signals, data or electric power.
byte: The representation of a single character. A sequence of eight bits

treated as a single unit; also the smallest addressable unit within the

system.

C

cache memory: High speed memory which stores data that increases

processor speed and data transfer rate. When the CPU reads data

from main memory, it stores a copy of this data in cache memory.

The next time the CPU needs that same data, it looks for it in the

cache memory rather than the main memory, which saves time. The

computer has two cache levels. Level one is incorporated into the

processor and level two resides in external memory.

capacity: The amount of data that can be stored on a magnetic storage

device such as a floppy disk or hard disk. It is usually described in

terms of kilobytes (KB), where one KB = 1024 bytes and megabytes

(MB), where one MB = 1024 KB.

card: Synonym for board. See board.
CardBus: An industry standard bus for 32-bit PC cards.
CD-ROM: A Compact Disc-Read Only Memory is a high capacity disc that

can be read from but not written to. The CD-ROM drive uses a laser,

rather than magnetic heads, to read data from the disc.

CD-R: A Compact Disc-Recordable disc can be written once and read

many times. See also CD-ROM.

CD-RW: A Compact Disc-ReWritable disc can be rewritten many times.

See also CD-ROM.

character: Any letter, number, punctuation mark, or symbol used by the

computer. Also synonymous with byte.

chassis: The frame containing the computer.
chip: A small semiconductor containing computer logic and circuitry for

processing, memory, input/output functions and controlling other

chips.

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