A two-stage
lookup table for decoding FARF4, FARF5, and FARF6 addresses.
UID
User ID.
unary expression
An expression that contains
one operand.
unblocked tape
A tape recorded with
undefined length (format-U) blocks. The logical records on the tape are
usually referred to as unblocked records. An unblocked tape
contains one record for each block. Contrast with blocked
tape.
Unicode
A character coding system designed
to support the interchange, processing, and display of the written texts of
the different languages. The XML4C parser is fully compliant with the
Unicode 3.0 specification. For details about the Unicode
Standard, go to the Unicode Consortium's Web page at http://www.unicode.org.
uniform resource locator (URL)
For Hypertext
Markup Language (HTML) documents and for the World Wide Web, a sequence of
characters that represent information resources. This sequence of
characters includes (a) the abbreviated name of the protocol used to access
the information and (b) the information used by the protocol to locate the
information resource. For example, in the context of the Internet,
these are abbreviated names of some protocols used to access various
information resources: http, ftp,
gopher, telnet, and news; and the Web
address for the IBM home page, which is http://www.ibm.com
union
A variable that can hold any one of
several data types, but only one data type at a time.
union tag
The identifier that names a union
data type.
uniprocessor
A processor with only one
I-stream.
unique collections
Collections in which no
two elements have the same value (such as bags and logs) or the same key (such
as dictionaries and key bags).
unique record
A fixed file record that is
unique to any subsystem user, processor, or I-stream. Contrast with
shared record.
unique resource
A resource that is not
shared among processors, I-stream engines, subsystems, or subsystem
users.
unit of work
A recoverable sequence of
operations performed by an application between two points of
consistency. A unit of work begins when a transaction starts or after a
user-requested syncpoint. It ends at either a user-requested syncpoint
or at the end of a transaction.
unit record status table (URST)
A system
table that contains information indicating the status of all unit record
devices in the system.
universal data display (UDD)
A
component of the TPF C Debugger for VisualAge Client and TPF Assembler
Debugger for VisualAge Client that displays synchronized data for both
debuggers. It consists of a server (UDDS) and a client
(UDDC). See also universal data display server
(UDDS) and universal data display client (UDDC) .
universal data display client (UDDC)
A
component of the universal data display (UDD) that resides on a user's
workstation. It displays data sent to it from the UDDS and also
communicates user requests to the UDDS. See also universal data
display (UDD) and universal data display server (UDDS)
.
universal data display server (UDDS)
A
component of the universal data display (UDD) that communicates to the UDDC
data residing in the address space of the ECB being debugged. See also
universal data display (UDD) and universal data display client
(UDDC) .
universal format type (UFT)
A 6-bit field at
the front of FARF4 and FARF5 addresses and a 16-bit field at the front of
FARF6 addresses. The value in this field is used to determine the size
of the format type indicator (FTI) field of the address. Once the FTI
size is known, its value can be determined. A specific UFT/FTI
combination is related to a specific record type in the TPF system.
universal unique identifier (UUID)
An
attribute that consists of a network address and a timestamp, used to specify
the interface definition.
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.
unmigrated state
In pool file support, a
condition that refers to a processor that has not been IPLed on an image that
contains the pool support provided by 32-way loosely coupled pool
support. See also pool migration and pool
conversion.
unsolicited message processor
A collection
of programs that handle unsolicited messages to terminals or LUs logged to
applications.
update sequence counter
A field used by TPF
collection support (TPFCS) to control updates made to an object.
UPR
User profile record.
URL
Uniform resource locator.
URST
Unit record status table.
User Datagram Protocol (UDP)
An application
interface to Internet Protocol (IP). It adds no reliability, flow
control, or error recovery to IP. It simply serves as a vehicle for
sending and receiving IP datagrams and using ports to direct the
datagrams. See also Transmission Control Protocol
(TCP).
user exit
A point in the TPF system where a
user-written routine can perform installation-unique processing.
user exit vector
See exit
vector.
user expansion area
An area reserved for
application use that is at the end of the C library function work area
contained in the first stack frame.
user global symbol table
In expression
enhancements for the TPF debuggers, a table that contains global symbol
definitions that do not exist in a real-time assembler program. The
global symbol definitions map to system structures that are not referenced in
the real-time assembler program. You can use the user global symbol
table user exit (UGST) to define global symbols.
user ID (UID)
A nonnegative integer that is
used to identify a user.
user profile record (UPR)
In TPF Internet
mail server support, a record that contains account information and the list
of mailboxes for the user.
user symbol override table
In expression
enhancements for the TPF debuggers, a table that contains global symbols that
are used to override symbol definitions in the local symbol table or the
common symbol table. For example, you can define symbol D0 in the
symbol override table as a pointer to the storage block on data level 0 to
override the definition in data macro (DSECT) CPSEQ, which has a value of
0. You can use the user symbol override table user exit (USOT) to
define these global symbols.
UTIL state (utility state)
One of 5 system
states. In utility state, clock management is provided, disk lost
interrupt is active, and commands are the only permitted input.