NEC SP B-Series - Manual (Page 137)

Glossary 15
system board
The main printed circuit board inside the system unit into which other boards and
major chip components, such as the system microprocessor, are connected.
T
tpi
Tracks per inch.
track
Any of many concentric circular regions on a disk for storing data. Tracks are
divided into sectors. One measure of storage density of a disk is tpi.
U
Ultra DMA
A protocol developed by Quantum Corporation and Intel that supports burst mode
data transfer rates of 33.3 MBps. This is twice as fast as the previous disk drive
standard for PCs, and is necessary to take advantage of new, faster Ultra ATA disk
drives. The official name for the protocol is Ultra DMA/33.
USB
Universal Serial Bus. An external bus standard that supports data transfer rates of
12 Mbps (12 million bits per second). A single USB port can be used to connect up
to 127 peripheral devices, such as mice, modems, and keyboards. USB also
supports Plug-and-Play installation and hot plugging. It is expected to eventually
replace serial and parallel ports.
V
VESA
Video Electronics Standards Association. The source of a SuperVGA standard used
on many video boards.
virus
Software that copies itself onto hard drives and diskettes without user intervention,
usually when a diskette is placed into the drive of a computer. Viruses usually
trigger a harmless or destructive occurrence on the system, activated by some preset
condition. Viruses are frequently written with antisocial intent.
VGA
Video Graphics Array. Graphics technology that supports up to 256 K colors and a
graphics resolution of 640 by 480 pixels.
volatile memory
Storage media that loses its data when system power is turned off. Standard
memory and memory added to the system are volatile memory. See nonvolatile
memory.