Specifications

Glossary
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BBS (bulletin board system) A computer that
operates with a program and a modem to enable
other computers with modems to communicate
with it, often on a round-the-clock basis. Although
BBSs were once the primary means of distributing
information and software, the Internet has almost
completely replaced BBSs.
benchmark A test or set of tests designed to
compare the performance of hardware or software.
A popular set of benchmarks for PC hardware are
the SYSmark, MobileMark and WebMark series,
available from BAPCO (Business Applications
Performance Corporation—www.bapco.com).
bezel A cosmetic panel that covers the face of a
drive or some other device.
Bézier curve A mathematical method for
describing a curve, often used in illustration and
CAD programs to draw complex shapes.
BGA (ball grid array) A packaging technology
used by Socket 478 Pentium 4 and Celeron proces-
sors, as well as many recent motherboard chipsets
and video card memory chips. BGA uses small
solder balls instead of pin connectors to enable
more signaling paths to exist in a smaller space
and improve signal accuracy.
bidirectional 1) Refers to lines over which data
can move in two directions, such as a data bus or
telephone line. 2) Refers to the capability of a
printer to print from right to left and from left to
right alternately.
binary See base-2.
BIOS (basic input/output system) The part
of an operating system that handles the communi-
cations between the computer and its peripherals.
The BIOS is often burned into read-only memory
(ROM) chips or rewritable flash (EEPROM) memory
chips found on motherboards and expansion cards,
such as video cards and SCSI and ATA/IDE host
adapters. See also firmware.
bipolar A category of semiconductor circuit
design that was used to create the first transistor
and the first integrated circuit. Bipolar and CMOS
are the two major transistor technologies. Almost
all personal computers use CMOS technology
chips. CMOS uses far less energy than bipolar.
bisynchronous (binary synchronous control)
An earlier protocol developed by IBM for software
applications and communicating devices operating
in synchronous environments. The protocol defines
operations at the link level of communications—for
example, the format of data frames exchanged
between modems over a phone line.
bit binary digit Represented logically by 0 or 1
and electrically by 0 volts and (typically) 5 volts.
Other methods are used to represent binary digits
physically (tones, different voltages, lights, and so
on), but the logic is always the same.
bit density Expressed as bits per inch (bpi).
Defines how many bits can be written onto one
linear inch of a track. Sometimes also called linear
density.
bit depth The number of bits used to describe
the color of each pixel on a computer display. For
example, a bit depth of two (2
2
) means the monitor
can display only black and white pixels; a bit depth
of four (2
4
) means the monitor can display 16 dif-
ferent colors; a bit depth of eight (2
8
) allows for 256
colors; and so on.
bitmap A method of storing graphics informa-
tion in memory, in which a bit devoted to each
pixel (picture element) onscreen indicates whether
that pixel is on or off. A bitmap contains a bit for
each point or dot on a video display screen and
enables fine resolution because any point or pixel
onscreen can be addressed. A greater number of bits
can be used to describe each pixel’s color, intensity,
and other display characteristics.
blade server A thin circuit board that contains
processors, memory, and (often) storage and plugs
into a special rack-mounted chassis. Multiple-blade
servers can occupy a single chassis.
BladeCenter A blade server design developed by
IBM that might become the basis for a de facto
blade architecture standard.
blank or blanking interval A period in
which no video signal is received by a monitor
while the videodisc or digital video player searches
for the next video segment or frame to display.
block A string of records, words, or characters
formed for technical or logic reasons and to be
treated as an entity.
Appendix A
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