Glossary 3
CPU
(Central Processing Unit) See microprocessor.
CRT
(Cathode-Ray Tube) The type of video display used in monitors for desktop computers.
D DC
(Direct Current) The type of current available in the rechargeable battery packs used in
portable computers. See also AC.
default
The factory setting your computer uses unless you instruct it otherwise. For example, when
powering up, the computer will boot from the default drive.
density
The capacity of information (bytes) that can be packed onto a storage device, such as a
floppy disk.
device driver
A software program that a computer must use to recognize and operate certain hardware,
such as a mouse or a video monitor.
disk drive
A device that stores data on a hard or floppy disk. A floppy disk drive requires a floppy disk
to be inserted; a hard disk drive has a permanently encased hard disk.
DOS
(Disk Operating System) See operating system.
DRAM
(Dynamic RAM) See RAM.
E ECC
(Error Checking and Correction) A method of detecting and correcting errors.
EEPROM
(Electrically Erasable Programmable Read-Only Memory) A type of memory device that
stores password and configuration information.
EGA
(Enhanced Graphics Adapter) A type of video display system that provides medium-
resolution text and graphics on TTL monochrome, color, and enhanced color monitors.