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Glossary
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back door. A secret way of getting into a program, usually only accessible by the original programmer.
backslash key. The "\" key, sometimes confused with the forward slash key "/." The backslash key is used to separate directory names.
backtiming. Method of calculating the in point by subtracting the edit duration from the known outpoint.
badge. A symbol in the corner of a QuickTime movie window which is pressed to bring the standard QuickTime movie controller into view.
balloon help. Beginning with System 7 on the Macintosh, Apple introduced balloon help, which provides small windows of helpful information on the screen.
bandwidth. In network media, refers to the number of bits that can be sent across the cable at any given time. In multimedia, it refers to the frequency range of a video signal, measured in MHz. The bandwidth is directly related to horizontal resolution: the higher number of picture elements defined, the higher the frequency required. The bandwidth describes "how much" information is being transferred. The bandwidth of the Machintosh II video signal can be as high as 33 MHz depending on screen size. By comparison, the bandwidth of broadcast television is 4 MHz High resolution images can be displayed on low resolution monitors, with an obvious loss in quality.
batch file. A special file that contains lists of operating system commands.
baud rate. A measurement of modem speed of transmission named for a French scientist named Baudot who developed an encoding scheme for the French telegraph system in 1877. Often confused with bps (bits per second), the baud rate actually refers to the number of state transitions (from 0 to 1 and 1 to 09) that occur within a single second. Newer compression technologies allow more than 1 bit to be transmitted within a single state transition, so the two measurements are no longer equivalent. A modem transmitting at 9,600 bps might in fact transmit at 2,400 baud.
beta test. This is the second stage of testing (alpha test is the first) a program before releasing it to the general public.
BIN. A three-letter file extension to identify files containing binary data.
binary. A counting system that uses two digits, 0 and 1.
binary file. A file containing bits and bytes of information that only a computer understands. Often identified with the three-letter BIN file extension.
Binary Synchronous Communications (BSC). See bisync.
BIOS. An acronym that stands for Basic Input/Output System. The BIOS is a built-in chip in the computer which contains a set of instructions that tells the computer how to act.
bisync. Short for binary synchronous, a type of synchronous communications used primarily in mainframe networks. The de facto bisync standard is Binary Synchronous Communications (BSC) developed by IBM. The binary part of the name signifies that the data is binary-coded. The synchronous part means that both the sender and receiver must be synchronized before the data transfer can begin.
bit. Short for BInary digiT, the smallest unit of data a computer can store. Bits are expressed as 1 or 0 bitmap.
BITNET. An early nationwide computer network that began in the early 1980s. Bitnet still exists and can be accessed through the Internet.
black level. The level of the video signal that corresponds to the maximum limits of the black areas of the picture.
black, black burst. In video production, black refers to a composite video signal which has composite sync, reference burst, and a black video signal. Used for genlock purposes.
blanking. The porition of the video signal that is off, or black, during the retrace interval of the scan. Blanking occurs between each horizontal line and during the vertical retrace between each field.
block. A collection of information lumped together for convenience. For example, when transferring files using a communications protocol, such as XModem or ZModem, data gets transferred in blocks. In a word processor, a block is a highlighted area of text.
bluetooth. Bluetooth is a computing and telecommunications industry
specification that describes how mobile phones, computers, and personal
digital assistants (PDAs) can easily interconnect with each other and
with home and business phones and computers using a short-range wirelessconnection.
Using this technology, users of cellular phones, pagers, and personal
digital assistants such as the PalmPilot will be able to buy a three-in-one
phone that can double as a portable phone at home or in the office, get
quickly synchronized with information in a desktop or notebook computer,
initiate the sending or receiving of a fax, initiate a print-out, and,
in general, have all mobile and fixed computer devices be totally coordinated.
Bluetooth requires that a low-cost transceiver chip be included in each
device. The tranceiver transmits and receives in a previously unused frequency
band of 2.45 GHz that is available globally (with some variation of bandwidth
in different countries). In addition to data, up to three voice channels
are available. Each device has a unique 48-bit address from theIEEE 802
standard. Connections can be point-to-point or multipoint. The maximum
range is 10 meters. Data can be exchanged at a rate of 1megabit per second
(up to 2 Mbps in the second generation of the technology). A frequency
hop scheme allows devices to communicate even in areas with a great deal
of electromagnetic interference. Built-in encryption and verification
is provided.
The technology got its unusual name in honor of Harald Bluetooth, king
of Denmark in the mid-tenth century. Among other things, Harald is credited
with joining Denmark and part of Norway into a single kingdom before he
died in battle in 986 with his son, Svend Forkbeard.
Bluetooth brick. A Bluetooth brick is a battery-powered,
sealed device that has sensors for monitoring and communicating information
such as temperature or vibration levels. Bluetooth is a standard technology
for short-rangewireless communication. Bluetooth bricks are especially
convenient in industries where cable is difficult to install or requires
frequent replacement because machinery is constantly moving. The bricks,
which weigh about a half pound and are about the size of a paperback book,
can be hung in hard-to-reach places such as on the top of a crane, or
in the middle of a moving conveyor belt. Bluetooth technology suits this
kind of application because the monitoring devices are not sending out
large amounts of data.
In addition to their convenience, Bluetooth bricks are a cost-effective
alternative to cabling. Whereas a cable connecting a sensor device to
a computer network can cost between $25 and $100 a foot, a Bluetooth chip
embedded in the same type of sensor costs between $5 to $10 per device.
Although longer-range Wi-Fi solutions to replacing cable have been explored
by some manufacturers, industry experts predict that Bluetooth technology
will continue to dominate the market because in addition to costing less,
Bluetooth uses less power so batteries last longer.
boolean search. True or false values, often used in programming.
boot. To start up a computer. Derived from the idea that the computer has to "pull itself up by the bootstraps."
bps. A measurement within communications of the number of bits per second transmitted.
brightness. 1. The luminance of the video signal, or the level of brightness on the scale from black to maximum white. One of the three determinants (with hue and saturation) of the color of an image, and the only one of the three that affects a monochrome image. 2. The brightness of a monitor or video projector measured in lumens.
browser. A computer program used to view Web pages written in HTML (Hypertext Markup Language) or other languages.
bubble memory. The type of memory that retains its contents even after the power has gone off. This type of memory is often used in laptop computers that don't have room for a hard drive.
buffer. A temporary holding place reserved in memory, where data is held while in transit to or from a storage device or another location in memory.
bus. An electronic pathway on which information travels between the microprocessor and other important computer parts.
Bus mouse. A mouse that plugs into an expansion board, in contrast to a serial mouse that plugs into a computer's serial port.
byte. 8 bits. The amount of memory to store one character.
