Glossary 1
*ORVVDU\
The following list defines or identifies
technical terms, abbreviations, and acro-
nyms used in Dell® user documents.

AC

Abbreviation for alternating current.

APC

Abbreviation for American Power
Conversion.

backup

A copy of a program or data file. As a
precaution, you should back up your com-
puter’s hard-disk drive on a regular basis.
Before making a change to the configura-
tion of your computer, you should back up
important start-up files, such as win.ini
and system.ini for the Microsoft®
Windows® 95 operating system.

BBS

Abbreviation for bulletin board service.

BIOS

Acronym for basic input/output system.
Your computer’s BIOS contains programs
stored on a ROM chip. The BIOS controls
the following:
Communications between the
microprocessor and peripheral
devices, such as the keyboard and
the video adapter
Miscellaneous functions, such as
system messages
The BIOS is a layer of software that iso-
lates the operating system and application
programs from the system’s hardware.
By using the BIOS, the compatibility of
these programs is enhanced.

block

A typical unit of disk storage consisting of
a small number of sectors. This term usu-
ally refers to the fundamental unit of
storage provided by an operating system.
See also block size and striping.

block size

The size of a block. See also block and
striping.

bus

A bus forms an information pathway be-
tween the components of a computer.
Your computer contains an expansion bus
that allows the microprocessor to com-
municate with controllers for all the
various peripheral devices connected to
the computer. Your computer also con-
tains an address bus and a data bus for
communications between the micro-
processor and RAM.

byte

Eight bits of information, the basic data
unit used by your computer.

cache

To facilitate quicker data retrieval, a stor-
age area for keeping a copy of data or
instructions. For example, your comput-
er’s BIOS may cache ROM code in faster
RAM. Or, a disk-cache utility may reserve
RAM in which to store frequently access-
ed information from your computer’s disk
drives; when a program makes a request
to a disk drive for data that is in the cache,