14 Glossary
H
hertz
(Hz) A unit of frequency equal to one cycle per second.
hexadecimal
A number system that uses 16 as the base. (Place value
indicates powers of 16.) It uses the digits 0-9 and A-F. Used
around computers because a byte (eight binary digits) easily
converts to a two digit hexadecimal number. Hexadecimal
numbers are often indicated with the letter H, a dollar sign, or a
subscripted 16 after the number. Compare binary, decimal.
host adapter
An expansion board that serves as a controller for SCSI
devices.
hot key
Combination of two or three keys (such as
Ctrl-Alt-D
) that you
press simultaneously for a particular function.
hot plugging
The ability to add and remove devices to a computer while the
computer is running and have the operating system
automatically recognize the change. The Universal Serial Bus
(see USB ) external bus standard supports hot plugging. This is
also a feature of PCMCIA. Hot plugging is also called hot
swapping.
I
IDE
Intelligent Drive Electronics. A hard drive type that has
controller electronics built into the drive and delivers high
throughput.