Glossary 99
Glossary
AC adapter
The AC (or alternating current) adapter regulates current
coming into your computer from the wall outlet. The current
at the wall outlet is alternating current and needs to be
changed by the adapter to DC (direct current) before your
computer can use it for power.
BIOS
BIOS stands for basic input/output system. The BIOS is
software (often called firmware) that is independent of any
operating system. It enables the computer to communicate
with the screen, keyboard, and other peripheral devices
without using programs on the hard disk.
The BIOS on your computer is flash BIOS, which means that
it has been recorded on a flash memory chip that can be
updated if needed.
Boot
To start your computer. A cold boot resets the entire
computer and runs through all computer self-tests. A warm
boot clears out computer memory only.
Boot disk
A disk containing operating system programs required to
start your computer. A boot disk can be a floppy disk, hard
drive, or compact disc.
Byte
The basic unit of measure for computer memory. A
character—such as a letter of the alphabet—uses one byte of
memory. Computer memory is often measured in kilobytes
(1,024 bytes) or megabytes (1,048,576 bytes).
Each byte is made up of eight bits. For more information on
bytes and bits, see an introductory book on computers.
Cache memory
Cache is very fast, zero-wait-state memory located between
the microprocessor and main memory. Cache reduces the
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