Operating instructions

computers for precision and economy. An electronic circuit that can detect the
difference between two states (on–off, 0–1) is easier and more inexpensive to
build than one that could detect the differences among ten states (0–9).
biometric device Hardware device used to support authentication, which
works by scanning and remembering unique aspects of a user’s various body
parts (e.g., retina, iris, face, or fingerprint) using some form of sensing device
such as a retinal scanner.
BIOS (basic input/output system) Classically, the software routines burned
onto the system ROM of a PC. More commonly seen as any software that di
-
rectly controls a particular piece of hardware. A set of programs encoded in
Read-Only Memory (ROM) on computers. These programs handle startup op
-
erations and low-level control of hardware such as disk drives, the keyboard,
and monitor.
bit A bit is a single binary digit, the smallest unit of information handled by
a computer.
bit depth The number of colors a video card is capable of producing. Com-
mon bit depths are 16-bit and 32-bit, representing 65,536 colors and 16.7
million colors respectively.
Blu-ray Disc An optical disc format that stores 25 or 50 GB of data, designed
to be the replacement media for DVD. Competes with HD DVD.
boot To initiate an automatic routine that clears the memory, loads the oper
-
ating system, and prepares the computer for use. The term is derived from “pull
yourself up by your bootstraps.” PCs must do that because RAM doesn’t retain
program instructions when power is turned off. A cold boot occurs when the PC
is physically switched on. A warm boot loads a fresh OS without turning off the
computer, lessening the strain on the electronic circuitry. To do a warm boot,
press the
CTRL-ALT-DELETE keys at the same time twice in rapid succession (the
three-fingered salute).
boot sector The first sector on an PC hard drive or floppy disk, track 0. The
boot-up software in ROM tells the computer to load whatever program is found
there. If a system disk is read, the program in the boot record directs the com
-
puter to the root directory to load the operating system.
Passport / Mike Meyers‘ A+ Certification Passport / Meyers / 226308-3 / Glossary
10 MIKE MEYERS’ A+ CERTIFICATION PASSPORT
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