Users Guide

to the other application program and leave the TSR program resident in memory for later use.
Because MS-DOS is not designed to support multiple programs running simultaneously, TSR programs can sometimes
cause memory conflicts. When troubleshooting, rule out the possibility of such a conflict by rebooting your computer
without starting any TSR programs.
TV
Abbreviation for television.
UL
Abbreviation for Underwriters Laboratories.
UMB
Abbreviation for upper memory blocks. See also conventional memory, HMA, memory manager, and upper memory
area.
upper memory area
The 384 KB of RAM located between 640 KB and 1 MB. If the computer has an Intel386 or higher microprocessor, a
software utility called a memory manager can create UMBs in the upper memory area, in which you can load device
drivers and memory-resident programs. See also conventional memory, HMA, and memory manager.
UPS
Abbreviation for uninterruptible power supply. A battery-powered unit that automatically supplies power to your
computer in the event of an electrical failure.
USOC
Abbreviation for Universal Service Ordering Code.
utility
A program used to manage system resources—memory, disk drives, or printers, for example. The diskcopy command
for duplicating diskettes and the himem.sys device driver for managing extended memory are utilities included in MS-
DOS.
V
Abbreviation for volt(s).
VAC
Abbreviation for volt(s) alternating current.
VCCI
Abbreviation for Voluntary Control Council for Interference.
VDC