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table: In RPG, a series of elements with like characteristics. A table can be searched for a uniquely identified element, but elements in a table cannot be accessed by their position relative to other elements.; In COBOL, a set of logically consecutive data items that are defined in the Data Division with the OCCURS clause.; In a relational database, a database object that consists of a specific number of columns and is used to store an unordered set of rows. See also view.; An orderly arrangement of data in rows and columns that can contain numbers, text, or a combination of both.
table designator: An exposed name used to qualify a column name. See also exposed name.
table element: In COBOL, a data item that can be referred to in a table.
table file: In RPG, an input file that contains a table.
table function: A function that receives a set of arguments and that returns a table to the SQL statement that references the function. A table function can be referenced only in the FROM clause of a subselect. See also function, user-defined function, routine.
table reference character (TRC): A numeric character corresponding to the order in which font character sets have been specified. The TRC is used to select a font character set during printing.
tab stop: In VisualAge® RPG, a control setting that determines if a control can be selected by using the tab key.
tachometer: A part that determines speed of rotation.
tag: The statements of the user interface manager (UIM) tag language. Tags describe the actions, format, and data of the panel. Tags are used to define the formatting of help information.
tag content: The text associated with a tag.
tail: In REXX, the part of a compound symbol that follows the stem. A tail can consist of constant symbols, simple symbols, and periods.
tangent: The single point at which a straight line meets a curve or surface.
tape cartridge: A case containing a reel of magnetic tape that can be put into a tape unit without stringing the tape between reels.
tape controller: A logic card located in some tape units that controls input/output tape devices and synchronizes their operation with the operation of the system as a whole.
tape drive: A device used to move magnetic tapes, as well as to read and write information onto those tapes.
tape file: A device file to support a tape device.
tape library: A device that includes a selection of cartridges in a common (secure) area within access of one or more automated removable media (ARM).
tape mark: A unique mark written on the tape to distinguish file boundaries.
tape reel: A round device on which magnetic tape is wound.
tape unit: The physical enclosure containing the tape drive.
tape volume: The recording space on a single tape cartridge or reel.
target: In SEU, a line command, such as B (Before) or A (After), that specifies the destination for other line commands such as C (Copy) or M (Move).; In VisualAge RPG, a part that receives a target event from a source part whenever the state of the source part changes.; The program or system to which a request for files or processing is sent.
target data queue program: In System i® Access, a series of programs that receive requests for data manipulation from the source data queue program. Target data queue programs also send data and replies (to previous requests) to the source data queue program.
target directory: In VisualAge RPG, the directory in which the compiled VRPG application is stored.
target distributed data manager (TDDM): In a distributed data management network, programming support that translates the DDM requests received from a source system into data management or SQL requests on the target (or remote) system. See also source distributed data manager.
target event: In VisualAge RPG, an event that a target part receives whenever the state of a source part changes.
target folder: In VisualAge RPG, the folder where the application (composite project) will be created.
target program: In display station pass-through, a program that runs on the remote system.; In VisualAge RPG, the object to be built by the project, such as a Dynamic Link Library (DLL).; In communications, the program that is started on the remote system at the request of the source system. See also source program.
target recovery time: The amount of time estimated by the system that it will need to recover access paths during an initial program load (IPL) after an abnormal system end. Actual performance may range around the target.
target release: In upgrades, the version, release, and modification level of software that is to be installed.; The release of the operating system on which a user intends to use an object being created, or intends to restore or use an existing object. See also source release.
target system: In upgrades, the planned hardware configuration and software level which will exist when the upgrade is completed.; The system that receives a request from another system. See also source system.
tariff: The fee the packet-switching data network charges a user for sending data. The tariff is usually based on the number of packets sent over the network.
taskpad: In System i Navigator, a view of system tasks that lets a user interact with IBM® i operating system functions. A taskpad contains a set of interrelated tasks that either perform a function or launch help that explains how to perform a function.
task swapper: A function, introduced with DOS 5.00, that allows the user to switch from one application to another without ending either application. With the task swapper function, only one application is active at any time. The active program is the application that is currently running; all other applications are suspended until the user switches to that application.
Tb: See terabit.
TB: See terabyte.
TC: See test control.
TCAM: See Telecommunications Access Method.
TCB: See Trusted Computing Base.
TCP: See Transmission Control Protocol. See also Internet Protocol.
TCP ACK storm: A denial-of-service attack on a server in which a hacker or cracker secretly inserts data into a client/server session in an attempt to disrupt the session. The resulting acknowledgements (ACKs) bounce back and forth and a TCP ACK storm ensues after the hacker has hijacked multiple client/server sessions.
TCP/IP: See Transmission Control Protocol/Internet Protocol.
TCP/IP Connectivity Utilities: The IBM licensed program that provides a collective set of industrial communications protocols to support connectivity functions for both local and wide area networks.
TCP/IP stack: The layered suite of protocols that comprise TCP/IP.
TCS: See terminal control system.
TCT: See terminal control table.
TCTUA: See terminal control table user area.
TD: See transient data.
TDDM: See target distributed data manager. See also source distributed data manager.
TDLC: See twinaxial data link control.
TE: See terminal equipment.
TE1: See terminal equipment 1. See also terminal equipment 2.
TE2: See terminal equipment 2. See also terminal equipment 1.
technical information exchange (TIE): A part of the electronic customer support function that allows a user to send files to and receive files from a remote support system, and to search for information on a remote support system. The files are sent and received through a remote support network.
technology-independent machine interface (TIMI): The lowest visible architectural layer of the server. TIMI defines the high-level machine instruction set and application programming interface that is independent of the underlying implementation. This allows the underlying hardware and Licensed Internal Code to evolve over time to take advantage of technology advances without affecting the user-level interface.
TEI: See terminal endpoint identifier.
telecommunication: The transmission of data between computer systems over telecommunication lines and between a computer system and remote devices.
Telecommunications Access Method (TCAM): An access method used to transfer data between main storage and remote or local storage.
Telecommunication Standardization Sector (ITU-T): Formerly known as the International Telegraph and Telephone Consultative Committee (CCITT). As of March 1, 1993, recommendations from this group will be known as ITU-T Recommendations. Recommendations made before March 1, 1993, will continue to be known as CCITT Recommendations.
telephone call state: In telephony, the condition of a telephone call that reflects what the past action on that call has been and what the next set of actions may be.
telephony: The use or operation of systems for the transmission of voice or data communications between separate points.
Telnet: In TCP/IP, a protocol that provides remote-terminal connection service. Telnet enables users of one host to log on to a remote host and interact as if they were directly attached terminal users of that host.
template: In REXX, a guide that allows strings to be parsed by words (delimited by blanks), by explicit matching of strings, or by specifying numeric positions.; An object used to create new objects of the same type. The newly created object has the same characteristics as the template.; A pattern to help the user identify the location of keys on a keyboard, functions assigned to keys on a keyboard, or switches and lights on a control panel.
temporary group: A list of existing calendars used to schedule items for a group of users in one step. The list can be used in the current session only, after which the list is deleted.
temporary library: A library that is automatically created for each job to contain temporary objects that are created by the system for that job. The objects in the temporary library are deleted when the job ends. The system name for temporary library is QTEMP.
temporary object: An object, such as a data path or compiler work area, that is automatically deleted by the system when the operating system is loaded.
temporary storage (TS): The CICS® facility that allows application programs to store data in a temporary storage queue for later retrieval.
temporary-text-delay character (TTD character): The BSC transmission control character that tells the receiving station that there is a temporary delay in sending the data.
terabit (Tb): For processor storage, real and virtual storage, and channel volume, 2 to the power of 40 or 1 099 511 627 776 bits. For disk storage capacity and communications volume, 1 000 000 000 000 bits.
terabyte (TB): For processor storage, real and virtual storage, and channel volume, 2 to the 40th power or 1 099 511 627 776 bytes. For disk storage capacity and communications volume, 1 000 000 000 000 bytes.
teraspace: A one terabyte temporary storage area that provides storage that is private to a process.
term: A string, symbol, or function call contained within a REXX expression.
terminal adapter: A device that connects a computer to an external digital communications line such as an integrated services digital network (ISDN) line.
terminal control: In CICS, a facility that handles addressing, and transmission error detection and correction for terminals (displays and printers) associated with the local CICS system. It also handles the intercommunication data queue used by CICS.
terminal control system (TCS): A table defining the connections between CICS systems.
terminal control table (TCT): A table describing the terminals and logical units within a CICS network.
terminal control table user area (TCTUA): An area used to pass information between application programs, but only if the same terminal is associated with the application programs involved.
terminal endpoint identifier (TEI): A number to identify the endpoint to the ISDN. Normally, assignment of the TEI can be done automatically by the ISDN.
terminal equipment (TE): In an ISDN, data terminal equipment (DTE) that provides the function necessary for the operation of the access protocols by the user.
terminal equipment 1 (TE1): Data terminal equipment (DTE) with integrated ISDN support. In an ISDN, the System i system is a TE1. See also terminal equipment 2.
terminal equipment 2 (TE2): Data terminal equipment (DTE) without an ISDN interface. To communicate with other equipment through an ISDN, this equipment must have the protocol converted to one that can be recognized by the network. For example, a 7820 ISDN terminal adapter may be used. See also terminal equipment 1.
terminating plug: A part that ends the cable path on a computer system. The terminating plug is attached to the last disk, , or tape unit in a series.
test: In communications, a data link command or response used to perform a basic test of the station-to-station link connection.
test condition: A statement that, when taken as a whole, may be either true or false, depending on the circumstances existing at the time the expression is evaluated.
test control (TC): A signal sent by the data terminal equipment (DTE) to the attached data-circuit terminating equipment (DCE) to signal a testing mode.
test library: A user-defined library used for debugging operations that does not contain objects needed for normal processing. See also production library.
test value: A value used to compare for a specified condition.
text attribute: In the GDDM function, characteristics of chart information, such as the color or type style.
text box: A box within a dialog box into which a user can type information. The text box may be empty or may contain default information when the dialog box first appears.
text index entry: An entry for a document in the text search index database. The text index entry is used by the system to locate documents when doing a text search.
text search index database: The database files used by text search services for storing the significant words of documents. These database files are used when a user requests a search of the document library for one or more phrases.
text search services: The system support that lets office users add, delete, and search for documents in the text search index database.
text stream: In the C language, an ordered sequence of characters where each sequence or line is ended with a new line control sequence and consists of zero or more characters.
text transparency: In binary synchronous communication (BSC), a method of sending and receiving data containing any or all of the 256 character combinations in EBCDIC in specific bit patterns, including transmission control characters.
textual data: The collective term for menus, displays, lists, prompts, options, online help information, and messages.
TFTP: See Trivial File Transfer Protocol.
TG: See transmission group.
TGS: See ticket-granting service.
TGT: See ticket-granting ticket.
TH: See transmission header.
Thin Console: An appliance that provides a 5250-based operating system console for the IBM i operating system. This appliance connects directly to the server using one of the HMC Ethernet ports (labeled HMC 1 and HMC 2) on the back of the server.
third-generation language (3GL): A high-level programming language that was designed to run on the third generation of computer processors, built on integrated circuit technology roughly from 1965 to 1970. C, FORTRAN, Basic and Pascal are examples of third-generation languages still in use today.
third party: A company that manufactures and sells applications for use with a major manufacturer's computer or peripherals, usually without any involvement from the major manufacturer.
third-party plug-in: In System i Navigator, the support that allows users to install software from different vendors.
thousands separator: The character (comma in the United States) placed every third number starting left of the decimal point. For example, three thousands separators are used in the number: 641,322,974,821.
thread: A stream of computer instructions that is in control of a process. In some operating systems, a thread is the smallest unit of operation in a process. Several threads can run concurrently, performing different jobs.
thread-capable: Pertaining to the ability to create threads.
thread ID: The unique integral number that can be used to identify a thread. Thread ID is sometimes used to describe the pthread_t data type that represents the abstraction to a thread.
thread local storage (TLS): See thread-specific storage.
thread private storage: See thread-specific storage.
threadsafe: Pertaining to a function, macro, or operating system service that can be called from multiple threads in a process at the same time. See also thread unsafe.
thread-specific storage: Storage that is not shared among threads, but can be accessed by all functions within that thread.
thread unsafe: A thread that cannot be called from multiple threads. See also threadsafe.
threshold: In OSI, a user-specified value that determines the frequency with which events will be reported. For example, if a certain error threshold is set at 10, the error will not be reported until the tenth occurrence of the error.; A level set in the system at which a message is sent or an error-handling program is called. For example, in a user auxiliary storage pool, the user can set the threshold level in the system values, and the system notifies the system operator when that level is reached.
threshold analysis: In Backup, Recovery, and Media Services, the comparison of actual media statistics to standard industry statistics for that media.
threshold event: In OSI, an event that occurs when a counter has reached its user-specified threshold. OSI Communications Subsystem logs threshold events and generates messages to the operator about these events.
threshold value: In the capacity planning tool, a value used as a general guide for optimal resource utilization. If resource utilization is above the threshold value, the resource performance may be unacceptable. Threshold values are also available for the rate of synchronous reads in the machine pool and for the sum of all pools. See also guideline value.
throttle: The act of cutting off or reducing input or output.
throughput: The measure of the amount of work performed by a device, such as a computer or printer, over a period of time, for example, number of jobs per day.; In data communications, the total traffic between stations over a period of time.
throughput class negotiation: In X.25, a packet-switching data network optional facility that allows the data terminal equipment (DTE) to negotiate the speed at which its packets travel through the packet-switching data network.; In OSI, a network layer facility that selects the speed with which data transmission requests are to be handled.
thunking: In System i Access, the process that occurs when a 32-bit application calls a 32-bit application programming interface that is implemented by a 16-bit component of the system.
tick: In Business Graphics Utility, a reference point on either the vertical or horizontal axis of some chart types that represents the location of specified data values.
ticket: A mechanism for securely transmitting the identity of a client to a server.
ticket-granting server: A part of the key distribution center (KDC) that generates service tickets. A principal presents a ticket-granting ticket to the ticket-granting server when the principal requests a service ticket. The ticket-granting server uses the ticket-granting ticket to verify that the principal has authenticated to the authentication server before it grants the request for a service ticket.
ticket-granting service (TGS): A service provided by the key distribution center (KDC) that issues service tickets.
ticket-granting ticket (TGT): A ticket that a principal passes to the ticket-granting server when a service ticket is requested. The ticket-granting service uses the ticket-granting ticket to verify that the principal has authenticated to the authentication server before it grants the request for the service ticket.; A ticket that allows access to the ticket granting service on the key distribution center (KDC). Ticket granting tickets are passed to the principal by the KDC after the principal has completed a successful request. In a Windows 2000 environment, a user logs on to the network and the KDC will verify the principal's name and encrypted password and then send a ticket granting ticket to the user.
TID: See transaction identifier. A unique name that is assigned to a transaction and is used to identify the actions associated with that transaction.
TIE: See technical information exchange.
time: A three-part value that designates a time of day in hours, minutes, and seconds.
time duration: A DECIMAL (6,0) value that represents a number of hours, minutes, and seconds.
time-independent messaging: See also synchronous messaging. See asynchronous messaging.
timemark: A specific period of time that is allowed by the Telnet server to verify that a connection is still active.
timeout: A time interval that is allotted for an event to occur or complete before operation is interrupted.; An event that occurs at the end of a predetermined period of time that began at the occurrence of another specified event.
timer-related event: A CICS interval control function that is used to support events that are delayed, suspended, or restarted after a time interval.
time sharing: Sharing computer time and resources.
time slice: The amount of processor time (specified in milliseconds) allowed for a job before other waiting jobs of equal priority are allowed to process data.
time slicing: A mechanism that preempts running threads at fixed intervals. This ensures that every thread is allowed time to execute.
time stamp: The value of an object that indicates the system time at some critical point in the object's history.
timestamp duration: A DECIMAL (20,6) value that represents a number of years, months, days, hours, minutes, seconds, and microseconds.
time to live: The time interval in seconds that an entry can exist in the cache before the name server discards it.
TIMI: See technology-independent machine interface.
title: In OSI, a permanent identifier for an object.
title bar: The area at the top of each window that can contain the system-menu symbol, the name of the window, and the maximize, minimize, and restore buttons.
TLS: See thread local storage.
toggle: To switch between two modes on a computer or network; for example, to switch between data entry and command entry modes or between stand-alone operation and device emulation.; Pertaining to a switching device, such as a toggle key on a keyboard, that allows a user to switch between two types of operations.
token: A particular message or bit pattern that signifies permission or temporary control to transmit over a network.; In OSI, an attribute of a connection. The token is dynamically assigned to one session-service user at a time to permit certain services to be called. Tokens are a session layer concept.; The basic syntactic unit of a computing language. A token consists of one or more characters, excluding the blank character and excluding characters within a string constant or delimited identifier.
token bucket: A mechanism that controls data flow. As an application requests permission into a network, the token bucket adds characters (or tokens) into a buffer (or bucket). If enough room is available for all the tokens in the bucket, the application is allowed to enter the network.
token highlighting: A function of CoOperative Development Environment/400 that allows a user to view different programming language tokens in different colors or type styles.
token-ring network (TRLAN): A local area network that connects devices in a ring topology and allows unidirectional data transmission between devices by a token-passing procedure. A device must receive a token before it can transmit data.
token type: In CoOperative Development Environment/400, a token or set of tokens having a similar characteristic or function, and assigned the same display attributes by the CoOperative Development Environment/400 program.
toolbar: In a graphical user interface, a horizontal row or a vertical column of buttons used to select desktop or application functions.
topic: In dynamic data exchange (DDE), the data that is to be exchanged within a DDE conversation.
topology: The physical or logical mapping of the location of networking components or nodes within a network. Common network topologies include bus, ring, star, and tree.
topology manager: A function of the Managed System Services program that is responsible for collecting topology information from nodes and clients in the network. The topology manager can reside on any system in the network; however, this system is most likely to be the central site system.
total accumulator: In DFU, a storage area where final totals for a field are kept. See also batch accumulator.
total record: In RPG, an output record written after a group of detail records. Total records generally contain data that is the result of calculations performed on the information in a group of detail records. See also detail record.
total time: The part of the RPG program cycle in which calculation and output operations specified for a group of records are done. See also detail time.
TP: See transaction program.
TPDU: See transport-layer protocol data unit.
TPN: See transaction program name.
trace: A DB2® for z/OS® facility that provides the ability to collect monitoring, auditing, performance, accounting, statistics, and serviceability (global) data.; A record of the processing of a computer program or transaction. The information collected from a trace can be used to assess problems and performance.
trace file: A file that contains a record of the events that occur in the system.
track: A circular path on the surface of a disk or on which information is magnetically recorded and from which recorded information is read.
Traditional Chinese: The Chinese character set expressed in traditional form. Traditional Chinese characters are used in Taiwan, China (Hong Kong S.A.R. of the PRC), and some other parts of the world.
Traditional Chinese double-byte character set: An IBM-defined DBCS for Traditional Chinese, consisting of Traditional Chinese non-Chinese set, primary set, secondary set, and up to 2,632 user-definable characters.
Traditional Chinese non-Chinese character set: A subset of the Traditional Chinese DBCS, consisting of non-Chinese characters, such as Greek, Russian, Roman numeric, alphanumeric and related symbols, Katakana, Hiragana, special symbols and Chinese phonetic symbols. There are 675 characters in this set.
Traditional Chinese primary character set: A subset of the Traditional Chinese DBCS, consisting of commonly used Chinese characters. There are 5,401 characters in this set.
Traditional Chinese secondary character set: A subset of the Traditional Chinese DBCS, consisting of less commonly used Chinese characters. There are 7,652 characters in this set.
traditional file management: The part of the operating system that controls the storing and accessing of traditional file objects (*FILE objects in the QSYS.LIB library) on a System i system. The data may be on internal storage (for example, database objects), on external media (, tape, or printer objects), or on another system.
traffic conditioning: In QoS, control functions that are performed to enforce rules specified in a traffic conditioning agreement. Types of traffic conditioning include metering, marking, shaping, and policing.
traffic profile: In QoS, a description of the temporal properties of a traffic stream such as rate and burst size.
traffic regulation anomaly: A deviation from normal network traffic patterns that is detected by an intrusion detection system. A traffic regulation anomaly could indicate a denial-of-service attack or a hacker who is monitoring connections to a Web server.
traffic shaping: In QoS, a group of techniques that attempt to regulate or meter the flow of packets through the network.
transaction: An atomic series of SQL statements that make up a logical unit of work. All of the data modifications made during a transaction are either committed together as a unit or rolled back as a unit. See also unit of recovery, remote unit of work, transaction.; An exchange between two programs that carries out an action or produces a result. An example is the entry of a customer's deposit and the update of the customer's balance. See also conversation, session.; A unit of processing consisting of one or more application programs, affecting one or more objects, that is initiated by a single request.
transaction code: For the IMS subsystem, the first 1 to 8 characters of the first segment of a message sent to IMS/VS. The transaction code identifies the application program for which the message is intended.
transaction dump: In CICS, a formatted dump for the program active at the time the dump was requested. A transaction dump indicates where the error occurred within the program.
transaction file: A file containing data, such as customer orders, that is usually used only with a master file.; In COBOL, an input-output file used to communicate with display stations and ICF sessions.
transaction ID: See transaction identifier. A number associated with each of several request-parameter lists that define requests belonging to the same data transaction.; See transaction identifier. A unique name that is assigned to a transaction and is used to identify the actions associated with that transaction.
transaction identifier (transaction ID, TID): A unique name that is assigned to a transaction and is used to identify the actions associated with that transaction.
transaction program (TP): A user-supplied application program for processing data received by the system from a finance device.; A program that processes transactions in an SNA network.
transaction program name (TPN): The name by which each program participating in an LU 6.2 conversation is known. Normally, the initiator of a connection identifies the name of the program it connects to at the other LU. When used in conjunction with an LU name, a TPN identifies a specific transaction program in the network.
transaction program network: The hierarchical structure of user or system transaction programs communicating at a synchronization level of none, confirm, or commit. When the synchronization level is commit, the transaction programs communicate over protected conversations using the two-phase commit protocol. In this case, the hierarchy consists of an initiator, optionally one or more cascaded initiators, and agents.
transaction routing: A CICS facility that provides support for inbound and outbound terminal requests from another CICS system connected by an advanced program-to-program communications (APPC) link.
transceiver: In communications, the device that connects the transceiver cable to the Ethernet coaxial cable. The transceiver is used to transmit and receive data.
transceiver cable: In communications, the cable along with its connectors that connects the input/output adapter to the transceiver.
transfer mode: Aspects covering transmission, multiplexing, and switching in a communications network.
transfer request: In System i Access, a description of the file that is to be transferred to a personal computer from IBM i or from a personal computer to IBM i.
transfer syntax: In OSI, a set of rules for the representation of user information while it is in transit between presentation layer entities. The transfer syntax is usually derived from the abstract syntax by use of encoding rules.
transform: In a virtual private network (VPN), a collection of authentication algorithms, Diffie-Hellman groups, and encryption algorithms that are used during both phases of negotiation.; To change the composition of a data stream (AFP) to perform the same functions in a different data stream (ASCII).
transformer: A device that converts power from one circuit to another at the same frequency, but at a changed voltage and current.
transform service: A function of the IBM i operating system that converts PostScript Level 1 spooled files to output. This output can be printed on either IBM Advanced Function printers (IBM i system printers) or Hewlett Packard Printer Control Language printers (commonly used PC printers).
transient data (TD): A CICS facility that provides the ability to read and write data in sequential queues.
transient error: In OSI, an error that occurs once or at unpredictable intervals--for example, network congestion. See also permanent error.
transient event: In OSI, an event that indicates the occurrence of an intermittent error or an error that can be recovered through retry. Transient events are logged but do not result in messages to the operator. See also permanent event.
transit delay processing: In OSI, an X.25 quality-of-service function that keeps track of delays that data encounters on the way to its destination. Any node that receives a call packet can reject it if the transit delay exceeds the maximum specified by the sender.
translator: An IBM i component that performs the final step in a program or module compilation. In the Integrated Language Environment® (ILE) model, this is called the optimizing translator.
transmission control character: In data communications, a special character that can be included in a message to control communications over a data link. For example, the sending station and the receiving station use transmission control characters to exchange information; the receiving station uses transmission control characters to indicate errors in data it receives.
transmission control layer: In SNA, the layer within a half-session that synchronizes and controls the speed of session-level data traffic, checks sequence numbers of requests, and enciphers and deciphers end-user data.
Transmission Control Protocol (TCP): A communication protocol used in the Internet and in any network that follows the Internet Engineering Task Force (IETF) standards for internetwork protocol. TCP provides a reliable host-to-host protocol in packet-switched communication networks and in interconnected systems of such networks. See also Internet Protocol.
Transmission Control Protocol/Internet Protocol (TCP/IP): An industry-standard, nonproprietary set of communication protocols that provides reliable end-to-end connections between applications over interconnected networks of different types.
transmission executive: A part of the DSNX/PC licensed program that runs on the personal computer to control and handle requests and to create responses for DSNX.
transmission group (TG): In SNA, a group of links between directly attached nodes appearing as a single logical link for routing messages. A transmission group may consist of one or more SDLC links (parallel links) or of a single System/370 channel. For type 2.1 nodes in System i networks, a transmission group can only be a single-link connection.
transmission header (TH): In SNA, control information, optionally followed by a basic information unit or a basic information unit segment, that is created and used by path control to route messages within the network.
transmission medium: In communications, the physical path between transmitters and receivers in a communications network, such as an Ethernet bus or a token ring.
transmission queue: A local queue on which prepared messages destined for a remote queue manager are temporarily stored.
transmission services (TS): A switched, nonswitched, or packet-switched communications line provided by a vendor.
transmission services profile (TS profile): In SNA, specified in a request to start a session. Each defined transmission services profile is identified by a number.
transparency: In asynchronous communications, a method of hiding certain ASCII control characters from modems or asynchronous devices.; A picture or text on an acetate sheet designed to be viewed by light shining through it.; See transparent text mode.
transparent data: Data that can contain any hexadecimal value.
transparent text mode: In binary synchronous communications, a method of transmission in which only transmission control characters preceded by the DLE control character are processed as transmission control characters.
transport class 0 (class 0): In OSI, the simplest of five classes of service (0-4) or protocols defined in the transport layer. (I)
transport class 2: In OSI, the transport layer class that provides an intermediate level of service.
transport class 4 (class 4): In OSI, the most complex of five classes of service (0-4) or protocols defined in the transport layer. (I)
transport class negotiation: In OSI, the process by which the peer application entities decide the Transport Layer class to use on an association.
transport layer: In OSI architecture, the layer that provides services for flow control and recovery between open systems with a predictable quality of service.
transport-layer protocol data unit (TPDU): In OSI, a protocol data unit in the transport layer. (I)
transport-layer service access point (TSAP): In OSI, a service access point in the transport layer. (I)
transport-layer service data unit (TSDU): In OSI, a unit of data transferred between the session layer and the transport layer.
transport mode: In the OSI Communications Subsystem licensed program, a set of values that determine the transport layer functions to be used on an association.
transport mode name: In OSI, the name of a transport mode to be used for an association. The network administrator specifies the transport mode name on an application mode.
transport protocol: A specification of the rules that govern the exchange of information between components of a transport network; for example, the User Datagram Protocol (UDP).
trap: In REXX, to recognize that a currently enabled condition occurred and to perform the CALL or SIGNAL instruction specified when the condition trap was enabled.; An unsolicited event generated by an agent and forwarded to a manager. Traps inform the manager of changes that occur in the network.
TRC: See table reference character.
tree view: A view that provides a hierarchical view of an object and the objects that it contains.
T reference point: In Performance Tools, the interface between network termination 2 (NT2) and network termination 1 (NT1).
tributary station: In data communications, a secondary device on a multipoint line.
trigger: In database technology, a program that is automatically called whenever a specified action is performed on a specific table or view. See also read trigger.
trigger action: A set of actions (high-level language statements, SQL statements, or IBM i utilities) that are performed automatically when a specified change operation (trigger event) occurs on a specified table or file.
trigger event: An event, such as a message arriving on a queue, that causes a queue manager to create a trigger message on an initiation queue.; A change operation that calls the trigger action to be run. The trigger event can be an insert, update, or delete operation in any high-level language and in SQL.
triggering: In WebSphere® MQ, a facility that allows a queue manager to start an application automatically when predetermined conditions on a queue are satisfied.
trigger level: The number of records written to an intrapartition transient data destination or queue that will cause CICS to automatically initiate a task to process that queue. See also automatic transaction initiation.
trigger message: A message that contains information about the program that a trigger monitor is to start.
trigger monitor: A continuously running application that serves one or more initiation queues. When a trigger message arrives on an initiation queue, the trigger monitor retrieves the message. It uses the information in the trigger message to start a process that serves the queue on which a trigger event occurred.
trigger point: In REXX, a threshold or boundary limit used in the REXX FORMAT function.
trigger program: A program that contains a set of trigger actions.
trigger time: The time the trigger action runs before or after the trigger event operates.
trigraph: A sequence of three graphic characters that represent another graphic character. For example, in the C programming language, the trigraph ??= is used to denote the # character.
trim: To remove a list entry from the end of a list opposite from the end where the new entry was added.
triplet: A length byte, a type byte, and one or more parameter-value bytes in a Formatted Data Object Content Architecture (FD:OCA) descriptor.
Trivial File Transfer Protocol (TFTP): In Internet communications, a set of conventions that transfers files between hosts using minimal protocol.
TRLAN: See token-ring network.
Trojan horse: A computer program that appears to perform a useful and innocent function. However, it contains hidden functions that use approved authorizations assigned to users when they start the program. For example, it may copy internal authorization information from a computer and send it back to the originator of the Trojan horse.
troubleshooter: An application that assists a user in locating a problem and that provides a possible solution to the problem.
truncate: To shorten a field, value, statement, or string.; To cut off data that cannot be printed or displayed in the line width specified or available. See also fold.
trunk: In telephony, circuits that connect two switching systems, as opposed to connecting a customer line to a switching system.
trunk line: A telecommunications line that links a private telecommunications system to a public switched network.
trusted: Pertaining to the control of a security policy.
Trusted Computing Base (TCB): The combination of hardware and software in a computer system that enforces a unified security policy. This term is used by the U.S. Department of Defense.
trusted root: In the Secure Sockets Layer (SSL), the public key and associated distinguished name of a certificate authority (CA).
trusted system: A system in a network over which you have control of security. A trusted system can directly communicate only with other systems in the network.
truststore: In security, a storage object, either a file or a hardware cryptographic card, where public keys are stored in the form of trusted certificates, for authentication purposes in Web transactions. In some applications, these trusted certificates are moved into the application keystore to reside with the private keys. See also keystore.
TS: See transmission services.; See temporary storage.
TSAP: See transport-layer service access point.
TSAP selector: In OSI, an external identifier for a service access point at the Transport Layer. The TSAP selector is part of a presentation address.
TSDU: See transport-layer service data unit.
TS profile: See transmission services profile.
TTD character: See temporary-text-delay character.
tumble: Pertaining to printing on both sides of a sheet of paper such that the bottom of the printed image on one side of the paper is juxtaposed against the top of the printed image on the other side of the paper. See also simplex.
tunnel: An L2TP access concentrator (LAC)-L2TP network server (LNS) pair. A tunnel carries Point-to-Point Protocol (PPP) datagrams between the LAC and the LNS. There may be many sessions in a single tunnel. A control connection that operates in the tunnel controls the establishment, release, and maintenance of sessions and the tunnel itself.
turnaround: In communications, pertaining to changing a communications line from being able to send to being able to receive, or from being able to receive to being able to send.
turnaround time: In communications, the time required to reverse the direction from sending to receiving or from receiving to sending on a communications line.
Tutorial System Support: An education course, supplied with the operating system licensed program, that provides introductory education for a variety of computer users, including system operators and business and data processing professionals. Tutorial System Support is part of the total IBM curriculum for the System i platform, which consists of classroom training and other methods of self-study.
twinaxial cable: A cable made of two twisted wires inside a shield.
twinaxial console: A 5250-based workstation using a twinaxial cable to connect to the system. The twinaxial console and the Operations Console can be a backup console for each other. See also Operations Console, alternate console, backup console.
twinaxial data link control (TDLC): A communications function that allows personal computers, which are attached to the work station controller by twinaxial cable, to use advanced program-to-program communications (APPC) or Advanced Peer-to-Peer Networking (APPN) support.
twisted-pair: Pertaining to a transmission medium that consists of two insulated conductors twisted together to reduce interference. For example, twisted-pair wiring can be used as an alternative to twinaxial cable.
two-phase commit: A two-step process by which recoverable resources and an external subsystem are committed. During the first step, the database manager subsystems are polled to ensure that they are ready to commit. If all subsystems respond positively, the database manager instructs them to commit.
two-port communications adapter cable: A cable that connects a 50-pin connector on a communications adapter card to two other communications cables that have 25-pin connectors (ports).
type: In Java™ programming, a class or interface.
typed data: In OSI, a data transfer service provided by the session layer that enables an application entity to send data whether or not it has permission to send.
typeface: All characters of a single type family or style, weight class, width class, and posture, regardless of size. An example is Helvetica bold condensed italic, in any point size. See also font.
type of service: In QoS, a 3-bit field within a packet's IP header that signals to routers and other network devices the level of QoS to apply to the packet.