See
unnumbered acknowledgement (UA) or user agent
(UA).
UCS
See universal character
set (UCS).
UCS-2
A 2-byte (16-bit) encoding
scheme based on ISO/IEC specification 10646-1. UCS-2 defines three
levels of implementation:
Level 1-No combining of encoded elements allowed.
Level 2-Combining of encoded elements is allowed only for Thai,
Indic, Hebrew, and Arabic.
Level 3-Any combination of encoded elements are allowed.
UDC
See user-defined
character (UDC).
UDDS
See user-defined data
stream (UDDS).
UDF
See user-defined
function (UDF).
UDP
See User Datagram
Protocol (UDP).
UDT
See user-defined type
(UDT).
UEP
See user entry procedure
(UEP).
uid
See user identification
number (uid).
UIM
See user interface
manager (UIM).
UIM tag language
Language
supported by the user interface manager to define panels, menus, and help
items.
U interface
In the reference
model for the integrated services digital network (ISDN), the interface that
includes the transmission line between the network terminator 1 (NT1) and the
line transmission termination
(LT).
Ultimedia Business Conferencing
A
licensed program that provides an AS/400 solution for desktop business
conferencing. Ultimedia Business Conferencing is a cooperative
processing application that manages the conference from scheduling to
completion.
unacknowledged service
In
communications, a data transfer service that does not provide for an
acknowledgement from data receiver to data sender that the data was
received. An active data link connection does not need to be
established between receiver and sender before sending the data. Also
known as connectionless
service. Contrast with acknowledged
service.
unary expression
In the C
language, an expression that contains one
operand.
unary operator
In COBOL, a plus
sign (+) or a minus sign (-) that precedes a variable or a left parenthesis in
an arithmetic expression, which has the effect of multiplying the expression
by +1 or -1, respectively.
unattended mode
In AS/400
Operations Console, a state of the system when the local controlling system
can automatically grant access to a remote request for control of the AS/400
system as long as the local controlling system does not have control at the
time of the request.
unavailable
In the basic
assistance level of the Operational Assistant function, to make a device,
controller, line, or network interface inaccessible for its normal, intended
use. Synonymous with vary
off.
UNBIND command
In SNA, a command
used to reset the protocols for a session. Contrast with BIND
command.
unblocked signal
In POSIX, a
condition that allows a signal-handling action associated with a signal to be
performed. See also signal. Contrast with blocked
signal.
UNC
See Universal Naming
Convention (UNC).
uncommitted read
In DB2 UDB for
AS/400, for a read-only cursor, an isolation level that permits any row read
during a unit of work to be changed by application processes that are running
concurrently, and permits any row changed by application processes that are
running concurrently to be read even if that change has not been
committed. For a cursor that can be updated, the uncommitted read level
is identical to cursor stability. See also cursor stability,
read stability, and repeatable read.
unconfirmed service
In OSI, a
service that does not indicate to the sender whether or not data or control
information was properly received. An unconfirmed service involves only
request and indication service primitives. Contrast with confirmed
service.
undelivered message queue
See
dead-letter queue.
underrun
Loss of data caused by
the inability of a transmitting device or channel to provide data to the
communications control logic at a rate that is fast enough for the attached
data link or loop.
unexport
In DCE Remote Procedure
Call (RPC), to remove binding information from a server entry in a name
service database. Contrast with
export.
unformatted
Pertaining to
something that is not defined, organized, or arranged in a required
manner.
unformatted program interface
(1) The part
of 3270 emulation support that allows user application programs to use the
3270 data stream in the form it is received from the host system.
Contrast with formatted program interface.
(2) For the SNA
3270 program interface, the interface for which the 3270 data stream is passed
to the user application program as it was received from the host application
program. No conversion process occurs as in the formatted program
interface. Contrast with formatted program
interface.
unformatted system services (USS)
A
communications function that translates a character-coded command, such as a
LOGON or LOGOFF command, into a field-formatted command for processing by
formatted system services.
Unicode
A product of the Unicode
Consortium, Inc., which is comprised of companies in the data
processing industry. Unicode defines the same character set as the
ISO/IEC 10646 UCS-2 standard and applies certain attributes to the characters
within the standard (such as alphanumeric, case, and directionality) and some
processing rules.
unidentified user
A user of the
OS/400 licensed program who uses the services of OS/400 but who is not
automatically reported on by the license management function of OS/400.
An example of an unidentified user is one who accesses an AS/400 business
computing system through a gateway server that is not
AS/400.
uniform resource locator (URL)
The
address of an item on the World Wide Web. It includes the protocol, the
fully qualified domain name (sometimes called the host name), and the
request. The Web server typically maps the request portion of the URL
to a path and file name. For example, if the URL is
http://www.AS400.ibm.com/icswg.html,
the protocol is http; the fully qualified domain name is
www.AS400.ibm.com; and the request is
icswg.html.
uninterruptible power supply
A source
of power from a battery installed between the commercial power and the system
that keeps the system running, if a commercial power failure occurs, until it
can complete an orderly end to system processing.
union
(1) In the C language, a
variable that can hold any one of several data types, one data type at a
time.
(2) An SQL operation that combines the
results of two subselects. Union is often used to merge lists of values
obtained from several tables.
unique constraint
In DB2 UDB for
AS/400, a rule in which values of the key columns in a table must be
unique. A unique constraint can be defined for either a table or a
file.
unique index
In DB2 UDB for
AS/400, an index that assures that no identical key values are stored in a
table.
unique key
(1) A field or set of
fields in a database file that must be unique, ascending, and cannot contain a
null value. A unique key can become a parent key.
(2) In DB2 UDB for AS/400, a key
that is constrained so that no two of its values are
equal.
unique product
A product that is
uniquely identified to the OS/400 operating system by a product identifier
(product ID) and version, release, and modification identifiers (Vx, Rx,
Mx).
unique-weight sort sequence
A sort
sequence in which each graphic character in the sequence has a weight
different from the weight of every other graphic character in the
sequence.
unit
The defined space within
disk units that is addressed by the system.
unit number
The unique identifier
of a storage unit within a disk unit or a disk unit subsystem configured on
the system.
unit of recovery
A sequence of
operations within a unit of work between commit
points.
unit of work
(1) In advanced
program-to-program communications, the amount of processing that is started
directly or indirectly by a program on the source system.
(2) In MQSeries, a recoverable
sequence of operations performed by an application between two points of
consistency. A unit of work begins when a transaction starts or at a
user-requested syncpoint. It ends either at a user-requested syncpoint
or at the end of a transaction.
(3) In DB2 UDB for AS/400, a
sequence of SQL commands that the database management system (DBMS) treats as
a single entity. The DBMS ensures the consistency of data by verifying
that either all the data changes made during a unit of work are performed or
none of them are performed.
unit-of-work identifier
In
advanced program-to-program communications, a unique label assigned to the
unit of work. The ID is established when the program on the source
system is started and is associated with each job started by that source
system on the target system. The unit-of-work identifier provides a
beginning-to-end audit trail within an APPC
network.
unit-of-work table
In
DataPropagator Relational, a table at the data server that contains commit
records read from the journals associated with the registered tables.
The records include a unit-of-recovery ID that can be used to join the
unit-of-work table and the change data table to produce transaction-consistent
change data.
unit reference code
A group of
numbers displayed on the console or control panel that identifies failing
parts, system or device states, or system or device status
conditions.
universal character set (UCS)
The
ISO9000 standard that allows all data to be represented as 2 bytes (UCS-2) or
4 bytes (UCS-4). Encoding in the UCS-2 form can accommodate the
necessary characters for most of the world's written
languages.
Universal Naming Convention (UNC)
The
server name and netname combined. These names together identify the
resource on the domain.
Universal Serial Bus (USB)
A
Plug-and-Play (Intel standard) interface between a computer and add-on devices
(such as keyboards and printers). USB allows a user to add a new device
to a computer without having to add an adapter card or to turn the computer
off. The model 2890 Integrated Netfinity Server has a Universal Serial
Bus.
Universal Time Coordinated (UTC)
The basis
of standard time throughout the world. Formerly a synonym for
Greenwich mean time
(GMT).
Universal Unique Identifier (UUID)
In DCE
Remote Procedure Call (RPC), an identifier that is immutable and unique across
time and space. A UUID can identify an entity such as an object or an
RPC interface uniquely. See interface UUID, object
UUID, and type UUID.
UNIX operating system
An operating system,
developed by Bell Laboratories, that features multiprogramming in a multiuser
environment. The UNIX operating system was originally developed for use
on minicomputers, but has been adapted for mainframes and
microcomputers. The AIX operating system is IBM's implementation
of the UNIX operating system.
unlike
Pertaining to two or more
different operating environments. For example, unlike distribution is
distribution between DB2 UDB for AS/400 and DB2 UDB
environments.
unlink
In IDDU, to remove the
association between a database file on disk and a file definition in a data
dictionary. Contrast with link.
unload
To rewind tape past the
beginning-of-tape marker.
unlock
To release an object or
system resource that was previously locked, and return it to general
availability.
unmarshaling
In DCE Remote
Procedure Call (RPC), the process by which a stub disassembles incoming
network data and converts it into local data in the appropriate local data
representation. Contrast with
marshaling.
unnumbered
In communications,
pertaining to a frame format that provides additional control functions, such
as XID, DISC, DM, SABM, SABME, UA, and
FRMR.
unnumbered acknowledgement (UA)
In
communications, a data link command or response that acknowledges the receipt
and acceptance of the SABM, SABME, and DISC command protocol data
units.
unordered
In binary
floating-point, the relationship that exists between two values when they
cannot be arranged according to relative value. The relationship
between two values is unordered either when a not-a-number is compared to any
value or when infinity is compared to any value other than
infinity.
unprotected conversation
An LU
6.2 conversation that has a synchronization level of none or
confirm. If conversation errors or failures occur, the resources used
by the application may be in inconsistent states. Contrast with
protected conversation.
unprotected field
A displayed
field for which operators can enter, change, or delete
data.
unprotected logical unit of work identifier (LUWID)
The
logical unit of work identifier that is used in an unprotected
conversation. Also known as a unit-of-work
identifier.
unprotected logical unit of work (LUW)
The
logical unit of work that is used in an unprotected conversation. Also
known as a unit of work.
unprotected storage
The part of
the system auxiliary storage pool (ASP) that is not protected by mirrored
protection or device parity protection.
unresolved import
An import whose
type and name do not yet match the type and name of an
export.
untrusted system
A system in a
network over which you do not have control of
security.
update
To change an object in
some way. See also committable
update.
update authority
A data authority
that allows the user to change the data in an object, such as a journal, a
message queue, or a data area. See also add authority,
delete authority, execute authority, and read
authority.
update file
In RPG, a file from
which a program reads a record, changes data fields in the record, and writes
the record back to the location from which it
came.
update operation
An I/O process
that changes the data in a record.
update propagation
In the DCE
Cell Directory Service (CDS), an immediate attempt to apply a change to all
replicas of the CDS directory in which a change was just made. An
update propagation delivers changes in a more efficient and timely way than a
skulk.
update rule
In DB2 UDB for
AS/400, a condition enforced by the database manager that must be met before a
column can be updated.
update timestamp (UTS)
In the DCE
Cell Directory Service (CDS), an attribute that identifies the time at which
the most recent change was made to any attribute of a particular CDS
name. For directories, the UTS reflects changes made only to attributes
that apply to the actual directory (not one of the
replicas).
update trigger
A trigger that is
associated with an update operation. See trigger and
trigger event.
upgrade
To change or add devices
or software programs.
Upgrade Load Source Utility
(1) For
CISC-to-CISC upgrades, a program, used as part of a 9406 Model-B-to-Model-D or
Model-E or Model-F upgrade, that changes the old load source (external disk
unit) into a nonload source without requiring an installation of the OS/400
program.
(2) For
CISC-to-RISC upgrades, a program that merges the old CISC disk configuration
with the new RISC load source and changes the old load source into a nonload
source unit. Installation of the OS/400 operating system is required on
completion.
upline
Pertaining to controllers
that are above devices, and lines that are above controllers in a
communications configuration. Contrast with
downline.
upload
To send programming
instructions to a host system from an attached
device.
upstream
(1) In the direction
opposite to data flow or toward the source of transmission.
(2) Toward the processor from an
attached unit or end user. Contrast with
downstream.
URC
See unit reference
code.
URL
See uniform resource
locator (URL).
usage type
In OS/400, a license
management function that monitors usage by tracking the number of license
users. Concurrent usage type indicates the usage limit is for the
number of unique jobs using the product at the same time. Registered
usage type indicates the usage limit is for the number of unique license users
registered to use the product.
USB
See
Universal Serial Bus (USB).
use authority
An object authority
that allows the user to run a program or to display the contents of a
file. Use authority combines object operational authority, read
authority, and execute authority. See also add authority,
data authority, delete authority, execute
authority, read authority, and update
authority.
user agent (UA)
In OSI
X.400, one of two basic parts of electronic mail. A user agent
is a program that provides access to the mail system. This program
allows users to compose, send, and receive mail. See also message
transfer agent (MTA).
user ASP
One or more storage
units used to isolate some objects from the other objects that are stored in
the system ASP and other user ASPs. User ASPs are defined by the
user. See also auxiliary storage pool (ASP) and system
ASP.
user-based pricing
A pricing
option that provides the capability for the customer to pay for the licensed
program on the basis of the number of users.
user class
The classification of
a user by the system task, such as security officer, security administrator,
programmer, system operator, and user. Each user class has a set of
special authorities depending on the security level of the system. The
user class determines which options are shown on the IBM-supplied
menus. See also special
authority.
user configuration
In Client
Access, the set of files, created by the Client Access administrator, that
define the user's Client Access configuration and the functions
used. The files include the configuration file and the command
file.
user-controlled environment
An
extended program model (EPM) environment that is explicitly created using the
QPXXCALL program.
user-created data stream
A data
stream that has not been validated by a system program on the AS/400 system
when the data was spooled.
User Datagram Protocol (UDP)
In the
Internet suite of protocols, a protocol that sends datagrams to programs that
are running on other systems.
user default
In the OfficeVision
program, the user-defined values used for mail, calendars, and word processing
if no value is specified.
user-defined character (UDC)
A
character that is created through the Character Generator Utility
(CGU). CGU is an extension of the code page with special user-defined
ideographic characters, symbols, or logos. User-defined characters may
be present in some of the Japanese, Chinese, and Korean code
pages.
user-defined collating sequence
In
Query, a collating sequence defined by the user that replaces the EBCDIC
collating sequence provided by the system for sorting fields in a query
report.
user-defined communications support
An
Operating System/400 function that provides an application program interface
(API). User-defined communications support allows user-written
application programs to call routines to set up and use a communications
protocol over a token-ring, Ethernet, or X.25
network.
user-defined data stream (UDDS)
A data
stream in which the user has defined and embedded all device control
characters.
user-defined edit code
A number
(5 through 9) indicating that editing should be done on a numeric output field
according to a pattern predefined to the system program. User-defined
edit codes can take the place of edit words, so that repetitive coding of the
same edit word is not necessary.
user-defined function (UDF)
A
user-written program than can be called in place of a built-in function within
SQL. DB2 UDB for AS/400 supports the following types of user-defined
functions: external functions, SQL functions, and sourced
functions.
user-defined type (UDT)
In DB2 UDB for
AS/400, a mechanism that can be used to create new data types. A UDT
can extend the capabilities of the built-in data types and capture the unique
semantics of user data.
user-defined word
In COBOL, a
word, required by a clause or a statement, that must be supplied by the user
in a clause or statement.
user dictionary
In the
OfficeVision program, a supplemental spelling dictionary created by a
user. Each user can create as many user dictionaries as needed.
See also spelling
dictionary.
user domain object
An object on
the system that can be accessed directly by a user state program. The
object types that can be either system domain or user domain are:
*USRSPC, *USRIDX, *USRQ, *PGM, *SQLPKG. All other object types are
system domain. See also system domain object, user
state program, and system state
program.
user entry procedure (UEP)
The
entry procedure, written by the application programmer, that is the target of
a dynamic program call. This procedure gets control from the program
entry procedure (PEP). Contrast with program entry
procedure.
user exit
In Backup Recovery and
Media Services, a special operation (*EXIT) available in the control group to
permit automatic processing of predefined user routines during control group
processing.
user ID
See user
identification (user ID).
user ID/address
The two-part
network name used in the system distribution directory and in the office
applications to uniquely identify a user and send electronic
mail.
user identification number (uid)
A
four-byte, unsigned integer (uid) used to identify a user profile.
Contrast with group identification number
(gid).
user identification (user ID)
(1) The name
used to associate the user profile with a user when a user signs on the
system. See also user profile name.
(2) The first part
of a two-part network name used in the system distribution directory and in
the office applications to uniquely identify a user. The network name
is usually the same as the user profile name, but does not need to be.
See also common user identification (common user
ID).
user index
In OS/400 application
programming interfaces, an object that provides a specific order for byte data
according to the value of the data. User index objects reside in the
user domain. The system-recognized identifier for the object type is
*USRIDX.
user interface
Any of the actions
or items that allow a user to interact with and perform operations on a
computer.
user interface manager (UIM)
A function
of the operating system that provides a consistent user interface by providing
comprehensive support for defining and running panels (displays), dialogs, and
online help information.
user message queue
A user-created
object used to receive messages sent from the system, other users, and
application programs.
user name
The name of the user
profile that the system associates with a user when that user signs on the
system. Also known as the user ID.
user password
A unique string of
characters that a system user enters to identify that user to the system, if
the system resources are secured.
user profile
An object with a
unique name that contains the user's password, the list of special
authorities assigned to a user, and the objects the user owns. The
system-recognized identifier for the object type is
*USRPRF.
user profile name
The name or
code that the system associates with a user when he or she signs on the
system. Also known as user ID. See also user identification
(user ID). For SQL, see also authorization
ID.
user queue
In OS/400 application
programming interfaces, an object consisting of a list of messages that
communicate information to other application programs. The
system-recognized identifier for the object type is
*USRQ.
user registry
A collection of
user information, such as user IDs and passwords, that is used as the basis
for security control by a system such as a Web application server.
user shell
An interactive
shell. The user's CICS application program runs directly under
this CICS facility. See also application shell
(SH).
user space
In OS/400 application
programming interfaces, an object consisting of a collection of bytes that can
be used for storing any user-defined information. The system-recognized
identifier for the object type is
*USRSPC.
user state program
A program that
can access objects in the user domain. All user programs on the system
are user domain. A user state program can call only another user state
program. See also system domain object, user domain
object, and system state
program.
user table
(1) A list of user IDs
authorized to an AS/400 finance job.
(2) In DataPropagator Relational,
a table that is owned by a user. A user table can be registered as a
source for a refresh operation or an update
operation.