MPE/iX Glossary of Terms and Acronyms (32650-90887)

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Glossary of Terms
transaction management facility Ensures data consistency and integrity by providing
transaction locking. Transaction locking ensures that only one transaction
at a time is allowed to update given data, and all changes that are part of a
transaction must be completed before the changes are committed to a
permanent record. When a transaction abnormally ends (before it is
actually complete), the changes made from the beginning of the
transaction to the abort point are undone. The database is restored to the
state it was in just prior to the beginning of the transaction.
transient space Disk space used for temporary processes such as stacks and operating
system data structures.
translation lookaside buffer (TLB) The translation lookaside buffer (TLB) is a
high-speed random access memory (RAM) buffer. It optimizes the task of
translating virtual addresses to physical addresses. The MPE/iX processor
generates 48-bit virtual addresses and memory access is provided by
28-bit physical (real) addresses.
transparent Unseen by the user. A process or action with which the user need not be
concerend.
transport backup Transport refers to the movement of files between MPE V/E and
MPE/iX systems using backup media. MPE/iX backup and recovery
provides a compatibility option with which an MPE V/E-compatible tape
may be created or read.
transport layer Layer four of the Open Systems Interconnection (OSI) network model.
The transport layer provides for transport of messages between end-users.
tuple A row, record, or data entry in a DBCore relation.
unconfiguring a device The process of logically removing a device from the system.
unblocked record A physical record that contains just one logical record. The opposite of
blocked record.
undefined-length records See variable-length records.
unit number A part of an address used for devices. A number whose meaning is
software-dependent and device-dependent, but which is often used to
specify a particular disk drive in a device with a multidrive controller.
UNIX An operating system developed by AT&T Bell Laboratories.
Hewlett-Packard's implementation of UNIX is called HP-UX.
UNKNOWN A disk pack without a volume label recognized by MPE/iX.
unscratch a volume To make data available on a previously "scratched" volume. See
scratch a volume.
UPDATE 1. The MPE/XL ISL UPDATE utility performs a system load from tape. It
replaces the current base system files on disk, and optionally replaces
configuration files. The ISL UPDATE CONFIG option is equivalent to the
MPE V/E COLDSTART procedure, and the UPDATE NOCONFIG option
is equivalent to the MPE V/E UPDATE operation.
2. An MPE V/E coldload option that loads all files in the PUB group of the