System information

Glossary
g-5
Glossary
backbone Cable on which two or more stations or networks may be attached,
typically used to link computer networks at one site with those at
another. Smaller branch networks are sometimes called ribs.
backplane The backplane provides direct current (DC) power distribution and
connections for all logic cards.
backup To copy files to a second medium (disk or tape) as a precaution in
case the first medium fails.
backup diskette A diskette that contains duplicate information from an original
diskette. The backup diskette is used in case information on the
original diskette is unintentionally changed or destroyed (D).
bandwidth (1) The amount of data that can be sent over a given circuit. (2) A
measure of how fast a network can move information, usually
measured in Hertz (Hz).
baud The unit of signaling speed, expressed as the maximum number of
times per second the signal can change the state of the transmission
line or other medium. The units of baud are seconds to the negative 1
power. Note: With Fibre Channel scheme, a signal event represents a
single transmission bit.
BB_Credit See buffer-to-buffer credit.
ber See bit error rate.
bezel A removable panel that covers empty drive bays and port cards.
bidirectional In Fibre Channel protocol, the capability to simultaneously
communicate at maximum speeds in both directions over a link.
bit Abbreviated as b. (1) Binary digit, the smallest unit of data in
computing, with a value of zero or one (D). (2) A bit is the basic data
unit of all digital computers. It is usually part of a data byte or data
word; however, a single bit can be used to control or read logic
ON/OFF functions. (3) A bit is a single digit in a binary number. Bits
are the basic unit of information capacity on a computer storage
device. Eight bits equals one byte.
bit density Expressed as bits per inch (bpi), the number of bits that can be written
on one inch of track on a disk surface.