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

66 Chapter1
Glossary of Terms
SYS account from the backup media. I/O configuration data, the
directory, and user files are loaded from the system disk. UPDATE is
typically used to install a new version of system software or to load
MPE from another computer. Equivalent to the MPE/XL ISL UPDATE
utility UPDATE NOCONFIG option.
use communications subsystems capability (CS capability) A capability assigned
to accounts and users allowing access to the MPE communications
subsystems.
user Anyone logged onto a session, using a local or remote terminal to interact
with the computer. Each user identified by a user and account name can
access files in the logon group.
user asynchronous I/O A method of performing I/O whereby a process launches an I/O
request and continues to execute while the I/O is performed. The process's
buffers should not be changed or used by the process until the system
informs the process that they are free.
user command A set of MPE/iX commands that a user has grouped together to perform
a specific task. A user command is stored in a command file or UDC. UDCs
are first in MPE's search path for commands.
user-defined command (UDC) A command that executes a set of one or more
commands that the user has grouped together into a single, named
procedure file to perform a specific task. See command file.
user-level security The file access modes permitted the user. User-level security must
duplicate, or be a subset of, the file access permitted the user's account and
group.
user logging A facility that enables users and subsystems to record additions and
modifications to files. If necessary, user logging also provides the means
whereby recorded entries can be used to recover the files themselves.
use volumes capability (UV capability) A capability assigned at the account and user
level allowing users to access nonsystem disk volumes.
utility program A program that performs specific functions such as file copying, sorting
and merging, memory dump analysis, or monitoring available disk space.
value added network (VAN) A common carrier service that has been upgraded by a
communications service. Also referred to as a packet switching network.
variable A value that can be changed, as opposed to a constant, usually represented
by a letter or a group of alphanumeric characters.
variable-length record A record whose length (in bytes or words) can vary and is
defined only by a maximum allowable file size. A file with undefined length
records must have a blocking factor of one, and is written without
buffering. One of a set of records that varies in size with respect to each
other.
VINIT An MPE V/E volume initialization subsystem (accessed with the VINIT
command). It contains several commands for online initialization and
formatting of private volumes, serial disks, and foreign disks. Equivalent