molecules, and the greater the impact on your eardrum. Amplitude is measured in deci-
bels. See also frequency.
analog-to-digital converter A chip in a sound card that converts analog sound waves
to the digital audio format. See also digital-to-analog converter and sampling.
APM See Advanced Power Management.
AppData An environment variable that stores the folder that contains the current user’s
application data (usually
application compatibility A set of concepts and technologies that enable Windows XP
to adjust its settings or behavior to compensate for the shortcomings of legacy programs.
See also Compatibility mode.
application-specific path A path to an executable file in which the path is also
associated with the primary name of the executable filename. This enables a user to
launch the executable by entering just the primary name in the Run dialog box or
ARP See Address Resolution Protocol.
backup job A backup file that includes a list of files to back up, the type of backup to
use (full, differential, or incremental), and the backup destination.
base priority A ranking that determines the relative frequency with which a program
gets processor cycles. A program given a higher frequency gets more cycles, which improves
the program’s performance.
baud rate The number of signal changes (which might be variations in voltage or
frequency, depending on the modulation standard being used) per second that can be
exchanged between two modems. In most cases, this isn’t the same as bps.
bit rate The quality of a digital audio recording, usually measured in Kbps.
bitmap An array of bits (pixels) that contains data that describes the colors found in
blue screen of death A screen with white text on a blue background that displays an
error message after a system crash.
Bluetooth A wireless networking standard that uses radio frequencies to set up a
communications link between devices to create an ad hoc wireless network.
boot code A portion of the master boot record that runs the core operating system files.
BOOT.INI A hidden text located in the %SystemRoot% folder that holds the startup
options that appear in the Windows XP OS Choices menu.
bps Bits per second. The rate at which a modem or other communications device trans-
APPENDIX D Glossary752