NonStop S-Series System Expansion and Reduction Guide

Table Of Contents
Glossary
G-Series Common Glossary
Glossary-114
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undefined. Pertaining to the use of an incorrect value for data or the incorrect behavior of a
program for which the ISO/IEC IS 9945-1:1990 standard imposes no portability
requirements.
undervoltage. A negative change in the amplitude of the voltage.
unicode. A 2-octet (2-byte) character code designed to represent more alphabetic and
graphic characters than allowed by the ASCII character set. When the first octet of a
unicode character is zero, the second octet maps to the ISO 8859-1 (ASCII) character
set. Unicode is the standard character set for encoding characters in implementations
of the Java language and is the default character code set used by several Microsoft
Windows operating systems.
uninterruptible power supply (UPS). The equipment used to provide an uninterruptible
source of power to connected equipment if a main power outage occurs. The basic
components of any UPS system are a rectifier/charger that converts alternating-current
(AC) power to direct-current (DC) power, batteries that store the DC power, and an
inverter that converts the DC power back into AC power for distribution to the load.
unitary segment. See segment.
unmount. To make a fileset inaccessible to the users of a node.
unplanned outage. Time during which a computer system is not capable of doing useful
work because of an unplanned interruption. Unplanned interruptions can include
failures caused by faulty hardware, operator error, or disaster.
unshielded twisted pair (UTP). A transmission medium consisting of two twisted
conductors with no cable shielding. Contrast with shielded twisted pair (STP)
.
unspecified. Pertaining to the use of a correct value for data or the correct behavior of a
program for which the ISO/IEC IS 9945-1:1990 standard imposes no portability
requirements.
UPS. See uninterruptible power supply (UPS).
upward compatibility. The ability of a requester to operate with a server of a later revision
level. In this case, the requester is upward-compatible with the server, and the server is
downward-compatible with the requester. Contrast with downward compatibility
.
User Code (UC). See TNS code space.
user code. A logically distinct part of the HP NonStop™ Kernel operating system that
consists of the code for user processes.
user database. A database within an HP NonStop™ node that contains the user name,
user ID, group ID, initial working directory, and initial user program for each user of the
node.