NEC Versa 550 Series Service Manual page 117

extended RAM
The area of RAM above the first megabyte of memory in the sys-
tem available for enhancing system performance.
FM synthesis
A technique for synthesizing sound that uses a combination of
modulated sine waves to produce different waveforms.
function key
The set of keys on the keyboard (usually F1 through F12) that let
you get help and error message information or quickly select fre-
quently used commands.
hard disk
A rigid magnetic storage device that provides fast access to stored
data.
hardware
The electrical and mechanical parts from which a computer is
made.
hertz
(Hz) A unit of frequency equal to one cycle per second.
hot key
Combination of two or three keys (such as
simultaneously for a particular function.
) that you press
Ctrl-Alt-D
Glossary 5