gtpd3m0xLibrary Guide with Master Index and Glossary

U

UDD
Universal data display.

UDDC
Universal data display client.

UDDS
Universal data display server.

UDP
User Datagram Protocol.

UFT
Universal format type.

UFT/FTI conversion table
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.

UUID
Universal unique identifier.