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L2TP: See Layer Two Tunneling Protocol.
L2TP access concentrator (LAC): A device that is either attached to the switched network or concurrently located within a Point-to-Point Protocol (PPP) end system that is capable of handling the Layer Two Tunnel Protocol (L2TP). LAC needs to implement only the media over which L2TP operates in order to pass traffic to one or more L2TP network servers. It may tunnel any protocol that is carried within PPP. LAC is the initiator of incoming calls and the receiver of outgoing calls.
L2TP network server (LNS): A server that handles the server side of the Layer Two Tunneling Protocol (L2TP). Because L2TP relies only on the single media over which L2TP tunnels arrive, the L2TP network server (LNS) may have only a single local area network (LAN) or a wide area network (WAN) interface. However, LNS must still be able to end calls that arrive at any L2TP access concentrator (LAC). LNS is the initiator of outgoing calls and the receiver of incoming calls.
label: (1) In REXX, a clause that consists of a single symbol followed by a colon.; (2) In programming languages, a construction naming a statement and including an identifier.; (3) In Backup Recovery and Media Services, an external identifier for media. A label includes information about volume serial identifier, creation date, expiration date, location, and container identifier.; (4) In DB2® UDB for iSeries™ SQL, a way of attaching text to columns, tables, and packages.; (5) An identification record for a tape or disk file.
labeled duration: A number that represents a duration of years, months, days, hours, minutes, seconds, or microseconds.
LABP: See link access procedure-balanced.
LAC: (1) See L2TP access concentrator.; (2) See License Authorization Code.
LADN: See library-assigned document name.
lame delegation: A misconfiguration of the Domain Name System (DNS) files. A lame delegation is the delegation of a domain to any name server that does not have authority for that domain.
LAN: See local area network.
LAN emulation (LE): The transparent use of an ATM network as an Ethernet-type LAN (IEEE 802.3) or a token-ring LAN (IEEE 802.5).
LAN emulation client (LEC): The access point where devices on the emulated LAN use remote applications and data. A single LAN emulation client may serve as the asynchronous transfer mode (ATM) connection point for many devices or sessions. The LAN emulation client imitates the functions of the LAN protocol, either token-ring or Ethernet, over the ATM network. iSeries allows one LAN emulation client on each input/output adapter (IOA). LAN emulation client uses the following LAN emulation services to find another client's ATM address: LAN emulation configuration server, LAN emulation server, and LAN emulation broadcast and unknown server.
LAN emulation configuration server (LECS): A server that provides configuration services to the clients. The LECS provides the clients with the ATM address of an appropriate LAN emulation server to become part of an emulated LAN. The LECS may also provide some measure of security within the emulated LAN by controlling which clients to recognize and configure.
LAN emulation server (LES): A network server that provides asynchronous transfer mode (ATM) address resolution and control-related services to its clients. Each LAN emulation server is associated with one LAN emulation domain. The LAN emulation server recognizes the clients that are either connected to or defined in its domain. The LAN emulation server then translates LAN destinations to ATM addresses at the request of the clients. It also provides control services as part of maintaining the LAN environment.
language attribute: In the Application Development Manager feature of the Application Development ToolSet licensed program, an indicator that further defines a part's type by specifying a high-level language or type of device file.
language ID: See language identifier.
language identifier (language ID): The 3-character representation that identifies the cultural preference for language-related processing and is associated with an object, such as a document. For example, the language identifier is used by text search services to determine how to process the text of a document.
language load ID: See language load identification.
language load identification (language load ID): An IBM® language feature code associated with a language. For example, French is 2928.
language profile: In CoOperative Development Environment/400, a set of rules that define the programming language and environment for editing and compiling programs.
language-sensitive editing: A set of editing functions that are responsive to the programming language, syntax, and environment of source programs as they are being edited. Typical language-sensitive editing features are automatic indenting, token highlighting, syntax checking, and language-sensitive help.
LAN Requester: A product that provides requester function to workstation users.
LAN Server: A product that provides server function to the LAN Requester.
LAN support program: A set of software device drivers used to provide PC applications with an interface to the LAN hardware. LAN device drivers must be loaded on every personal computer that is connected to the server through a local area network (token ring or Ethernet).
LAP: (1) See last agent pending.; (2) See link access procedure.
LAPD: See link access procedure-D-channel.
last agent optimization: An optimization that cuts the number of two-phase commit flows to one agent in half by leaving the last agent out of the first phase of the commit process and giving the last agent the commit decision during the second phase. An initiator or last agent can use this optimization with only one of its subordinates, which is called the optimized last agent (or simply the last agent).
last agent pending (LAP): The last agent pending logical unit of work (LUW) state indicates that the current LUW is in doubt. This system has prepared to commit, but has not received the final vote from the last agent. The LAP state only occurs at the initiator and at a last agent.
last-in first-out (LIFO): A queuing technique in which the next item to be retrieved is the item most recently placed on the queue. See also pushdown list, first-in-first-out.
last record indicator: In RPG, an indicator that signals when the last record (LR) is processed. This indicator can then be used to condition calculation and output operations that are to be done at the end of the program.
latch: An electronic circuit that permanently records (until reset) the status of a signal.
latency: The amount of time between the time when a network device originally receives a packet and the time when the packet is retransmitted.
layer: (1) In a network architecture, a group of services, functions, and protocols that is complete from a conceptual point of view, that is one out of a set of hierarchically arranged groups, and that extends across all systems that conform to the network architecture. (T); (2) In SNA, a grouping of related functions that are logically separate from the functions in other groups; the functions in one layer can be changed without affecting functions in the other layers.
layer entity (LE): In OSI, an active element in a layer.
layer service: In OSI, a service provided by a layer of the OSI reference model.
Layer Two Tunneling Protocol (L2TP): An Internet protocol that permits the tunneling of the link layer of Point-to-Point Protocol (PPP).
lazy write: A function whereby the network server performs a write-to-disk operation rather than caching the data for this storage space. Using lazy write enhances system performance by allowing information to be updated multiple times before being written to disk.
LDAP: See Lightweight Directory Access Protocol.
LDAP Directory Interchange Format (LDIF): A text file format that is used to transfer directory information among LDAP directory servers.
LDIF: See LDAP Directory Interchange Format.
LE: (1) See layer entity.; (2) See LAN emulation.
leader: The blank section of tape at the beginning of a reel.
leaf: An entry that has no children before it in the directory tree.
lease: An agreement that grants permission to use a product or a program.
LEC: See LAN emulation client.
LECS: See LAN emulation configuration server.
legend: An explanatory list of the symbols, lines, and other components of a chart or graphic.
Lempel-Ziv (LZ): A technique for compressing data. This technique replaces some character strings, which occur repeatedly within the data, with codes. The encoded character strings are then kept in a common dictionary, which is created as the data is being sent.
length attribute: A value associated with a string that represents the declared fixed length or maximum length of the string.
LEN node: See low-entry networking node.
LES: See LAN emulation server.
level checking: A function that compares the record level identifiers of a file to be opened with the file description that is part of a compiled program to determine if the record format for the file changed since the program was compiled.
level indicator: (1) In RPG, two characters (L0 through L9 and LR) that control calculation and output processing during total time.; (2) In COBOL, two alphabetic characters (FD or SD) that identify the type of file description entry.
level-number: In COBOL, a numeric character (1 through 9) or a 2-character set (01 through 49, 66, 77, 88) that begins a data description entry and establishes its level in a data hierarchy. Level-numbers 66, 77, and 88 identify special properties of a data description entry.
level-zero entry: In RPG, a calculation specifications entry that indicates the operations to be done during total time for each program cycle when no control break occurs.
LFSID: See local-form session identifier.
library: (1) A repository for demountable recorded media, such as magnetic disks and magnetic tapes.; (2) A system object that serves as a directory to other objects. A library groups related objects, and allows the user to find objects by name.
library-assigned document name (LADN): A unique name, which includes a time stamp and a system name, that is assigned by a system in the office network to a document when it is filed in the document library. On i5/OS™, the time-stamp part of the library-assigned document name is included in a 10-character name that becomes the document object name.
library control sector: The first sector in a library which contains a record of the used and available space in the library.
library descriptions file: A file that lists keywords, document classes, or both, or the access codes associated with different document libraries.
library list: In i5/OS, a list that indicates which libraries are to be searched and the order in which they are to be searched. The system-recognized identifier is *LIBL.
library name: A user-defined word that names a library.
library name space: An attribute that can be set for the current thread. The library name space is the set of objects and libraries that can be accessed in any independent disk pools in a disk pool group plus the libraries in the system disk pool and basic user disk pools (ASPs 2-32) using the regular library-qualified object name syntax.
library routine: In CoOperative Development Environment/400, a routine maintained in a program library.
library user ASP: An auxiliary storage pool that contains libraries and folders. See also nonlibrary user ASP.
license: (1) In license management, a license gives the user authorization to use a user-based priced product.; (2) A permission granted by competent authority to engage in a business or occupation or in an action otherwise unlawful.
License Authorization Code (LAC): Code that is needed to unlock a licensed program.
Licensed Internal Code: For i5/OS, the layered architecture below the machine interface (MI). The Licensed Internal Code is a proprietary system design that carries out many functions. These functions include but are not limited to storage management, pointers and addressing, program management functions, exception and event management, data functions, I/O managers, and security.
Licensed Internal Code fix: A temporary solution to, or bypass of, a defect in a current release of the Licensed Internal Code.
licensed program (LP): A separately priced program and its associated materials that bear a copyright and are offered to customers under the terms and conditions of a licensing agreement.
licensed program offering (LPO): A field-developed program that is not supported on the Licensed Program menu. LPOs have separate instructions for installation.
license term: In i5/OS license management, an indicator of whether the authorized usage limit for a product lasts until the next version, next release, or next modification level of the product.
LID: See local identifier.
LIFO: See last-in first-out.
lightness: The characteristic that allows colors to be put in order from light to dark.
Lightweight Directory Access Protocol (LDAP): An open protocol that uses TCP/IP to provide access to directories that support an X.500 model and that does not incur the resource requirements of the more complex X.500 Directory Access Protocol (DAP). For example, LDAP can be used to locate people, organizations, and other resources in an Internet or intranet directory.
like: Pertaining to two or more similar or identical operating environments. For example, like distribution is distribution between two i5/OS database managers with compatible server attribute levels.
Lilian date: The first date on the Lilian calendar is equivalent to October 15, 1582, on the Gregorian calendar.
limited capability: In CICS®, the use of certain CL commands can be restricted by setting a user's profile to limited capability.
limits file: In RPG, a file that contains the upper and lower values of the record keys used to read from an indexed file.
limits record: In RPG, a record that contains the lowest record key and the highest record key of the records that are to be read (in the keyed file).
LINAGE-COUNTER: In COBOL, a special register whose value points to the current position within the page body.
line: The physical path in data transmission. In COBOL, a division of a page representing one row of horizontal character positions.
line chart: In the GDDM® function, a chart in which the plotted points (each optionally represented by a marker) are joined by straight or curved lines.
line code violation: In Performance Tools, two successive electrical pulses of the same polarity, instead of alternating polarity, on the S/T interface.
line command: An abbreviation used to request a function for a specific line or lines from the command area to the left of the line or lines affected. For example, C for Copy or M for Move.
line configuration: The process of creating configuration descriptions for the lines that make up a data processing system.
line control character: See transmission control character.
line counter specifications: In RPG, a coding sheet on which the programmer indicates or overrides the system defaults for the form length and for the number of lines to print on a page. Line counter specifications can be used for each printer file in a program.
line data: Data prepared for printing on line printers. Line data can contain carriage-control characters and table-reference characters (TRC) for spacing and font selections.
line description: An object that contains information describing a particular communications line that is attached to the system. The system-recognized identifier for the object type is *LIND.
line graph: In Performance Tools, a graph in which plotted points (each optionally represented by a marker) are joined by straight or curved lines.
line number: The number that precedes a line of information in a printout or on a display. This number can be up to 5 digits long, from 00001 through 99999.
line pool: In Point-to-Point Protocol, a list of lines that can be used in a connection profile.
line printer: A device that prints a line of characters as a unit. See also page printer, character printer.
line printer daemon (LPD): The receiving portion, or server portion, of a file transfer that receives the spooled file that was sent and places the file on a local output queue. See also line printer requester.
line printer queue (LPQ): In TCP/IP, a method to display the output queue of spooled files sent to a printer.
line printer removal (LPRM): In TCP/IP, a method of removing spooled files from the queue of a printer.
line printer requester (LPR): The sending portion, or client portion, of a spooled file transfer. The line printer requester allows a spooled file that was sent between remote systems to be sent to a printer queue. See also line printer daemon.
line set: In the OSI Communications Subsystem licensed program, a user-specified group of one or more lines used to establish network connections. When sending an outbound connection request, OSI Communications Subsystem selects a line from a line set. The line characteristics--such as line speed--of each line in a given line set should be similar.
lines per inch (lpi, LPI): The number of characters that can be printed vertically within an inch.
line traffic: The number of transmissions and the amount of data sent and received on a communications line.
line transmission termination (LT): In Performance Tools, the line transmission termination part of the reference model for the integrated services digital network (ISDN).
linguistic conversion: See best-fit conversion. A conversion where a partial mapping is done from the source code page to the target code page. The integrity of characters that are in both the target coded character set identifier (CCSID) and the source CCSID are preserved. Characters that are not in the target CCSID are mapped to the most culturally acceptable alternative for that character.
link: (1) In IDDU, to connect a database file on disk with a file definition in a data dictionary. See also unlink.; (2) A connection that provides the physical transfer of data from one node to another.; (3) In a file system, a connection between a directory and an object. The link is established when the object is created.; (4) In SNA, the combination of the link connection (the transmission medium) and two link stations (one at each end of the link connection). A link connection can be shared among multiple links in a multipoint or token-ring configuration.; (5) In hypertext, an author-defined association between two information nodes.; (6) In TCP/IP, a term for a communications line. A TCP/IP link may share the use of a communications line with SNA.
link access procedure (LAP): A link level element used for data interchange between data circuit-terminating equipment (DCE) and data terminal equipment (DTE) operating in user classes of service 8 to 11, as specified in CCITT Recommendation X.1. LAPB is a duplex, asynchronous, symmetric protocol, used in point-to-point communication. See also link access procedure-balanced.
link access procedure-balanced (LABP): A procedure for gaining access to an X.25 network at the link level. LAPB uses a full-duplex, asynchronous, symmetric (balanced) protocol used in point-to-point communication. LAPB is the link access protocol recommended by the Consultative Committee on International Telegraphy and Telephone (CCITT). It takes the place of the earlier link access protocol (LAP). See also link access procedure.
link access procedure-D-channel (LAPD): A procedure, recommended by the CCITT, for using an integrated services digital network (ISDN) on the data link level. LAPD is a duplex, asynchronous, symmetric procedure used to communicate control instructions, such as setting up and dropping a connection, to the control channel (D-channel) of ISDN.
linkage editor: A computer program for creating load modules from one or more object modules or load modules by resolving cross-references among the modules and, if necessary, adjusting addresses.
Linkage Section: In COBOL, a section of the Data Division that describes data made available from another program.
link level: (1) In SNA, the combination of the transmission connection, protocol, devices, and programming joining network nodes.; (2) A part of Recommendation X.25 that defines the link protocol used to get data into and out of the network across the duplex line connecting the subscriber's equipment to the network.
link pending: A state that indicates a datalink field contains one or more values that cannot be validated due to a system failure, communications failure, or other similar error. The file is still usable when it is in this state, but only for reading data.
Link Problem Determination Aid (LPDA®): A series of procedures used by products to test modem or other data circuit-terminating equipment (DCE) operations, and to provide information about the DCE and the data link. An extended version also provides operational and configuration commands. LPDA commands can be used only with DCEs that support LPDA.
Link Problem Determination Aid-1 (LPDA-1): The first version of the LPDA command set. Although LPDA-1 and LPDA-2 provide several of the same functions, LPDA-1 is not compatible with LPDA-2.
Link Problem Determination Aid-2 (LPDA-2): A second version of the LPDA command set. In addition to most of the functions of LPDA-1, LPDA-2 also supports modem configuration commands, a call out (dial) command, a set transmit speed command, and commands to operate a contact that controls external devices.
link protocol: The rules for sending and receiving data at the link level.
link protocol converter (LPC): A device that changes one type of link-level protocol information to another type of link-level protocol information for processing; for example, 5208 Link Protocol Converter, 5209 Link Protocol Converter, or ROLMbridge 5250 Link Protocol Converter.
list: In Backup Recovery and Media Services, an entry in a control group that contains similar items such as libraries, folders, or objects.
list box: A control that contains a list of objects or settings choices that a user can select from.
list edit mode: In AFP™ Utilities, the mode that allows a user to view and change overlay elements from a list.
list entry handle: A value that uniquely distinguishes an entry in a user interface manager (UIM) list until it is removed from the list. A list entry handle is meaningful only for a particular application, list, and entry combination.
list ID: A two-part name by which a distribution list is known. The two-part name allows distributions to be sent to both local and remote systems.
list ID qualifier: The second part of a two-part name by which a distribution list is known.
list view: In AFP Utilities, the presentation of a display shown while a user is in list edit mode.
literal: In RPG, a character string whose value is defined by the characters themselves. For example, the numeric constant 7 has the value 7, and the character constant 'CHARACTERS' has the value CHARACTERS.
literal pattern: In REXX, a string delimited by apostrophes or quotation marks that is used in a parsing template to specify how a sequence of characters is split.
literal string: In REXX, a sequence including any characters that are delimited by apostrophes or quotation marks.
little endian: An attribute of data representation that reflects how multi-octet data is stored in memory. In little endian representation, the lowest addressed octet of a multi-octet data item is the least significant. See also big endian.
LLC: See Logical Link Control.
LLC protocol: See Logical Link Control protocol.
LMI: See local management interface.
LNS: See L2TP network server.
load: (1) In System Manager, the smallest logical collection of objects that can make an application option. Code and language are the two types of loads. The object type is *PRDLOD.; (2) To move data or programs into storage.
loaded: Pertaining to a status where the optical image associated with the selected image catalog entry is active or loaded in the selected virtual optical device. The installation software will be able to access this image during the installation process.
load font equivalence: The mapping of a descriptive font name to a font member name in a font library.
load identifier: In System Manager, the identification number assigned to a load.
load module: A program in a form suitable for loading into main storage for execution. A load module is the output of the linkage editor.
load object: In System Manager, an object that contains the control information about a load or option.
load-source disk unit: The disk unit that contains the Licensed Internal Code for the system. This unit is always identified as unit number 1 in the disk configuration displays.
lobe: In a star or ring network configuration, two pairs of conductors that provide separate send and receive paths between a wiring concentrator and a network port, such as an electrical outlet.
local: (1) In OSI, pertaining to the node from which one views the rest of the network.; (2) Pertaining to a device, file, or system that is accessed directly from a user's system, without the use of a communication line. See also remote.
local address: In SNA, an address used in a peripheral node in place of a network address and transformed to or from a network address by the boundary function in a subarea node.
local agent: In OSI, an agent process on the local node. See also remote agent.
local application entity: In OSI, an application entity on the local node.
local application process: In OSI, an application process on the local node. See also remote application process.
local area network (LAN): A network that connects several devices into a limited area (such as a single building or campus) and that can be connected to a larger network.
local bus adapter: The bus adapter card in the system unit. The local optical link cards plug into the bus adapter card.
local console: In the iSeries Operations Console, the personal computer that has direct communications with an iSeries server. The local console uses either a dial-up connection or a direct cable. It controls remote access to the iSeries server and grants control of the iSeries server to remote consoles. See also Operations Console, remote console.
local controller: A functional unit within the system that controls the operation of one or more directly attached input/output devices or communications lines. See also remote controller.
local data area: A 1024-byte data area that can be used to pass information between programs in a job. A separate local data area is automatically created for each job.
local definition: In WebSphere® MQ, an MQM object that belongs to a local queue manager.
local device: A device physically attached to the local workstation; that is, the drives in the workstation and any machinery connected to its parts. See also remote device.
local domain name: The primary TCP/IP name associated with the local system. A system can have more than one system name, but only one local domain name. The local domain name consists of two parts, the domain and the host.
locale: A computer setting that defines the user's environment--the conventions for a specific language and culture, including appropriate date and time formatting, character classification, sorting, and text handling. Locales are collections of processing variables used to specify how a process will execute. See also national language support.
local-end code violation: In Performance Tools, an unintended line code violation detected and counted by the terminal equipment (TE) for frames received at the interface for the S/T reference point of the integrated services digital network (ISDN).
local-form session identifier (LFSID): In SNA, a dynamically assigned value used at a type 2.1 node to identify traffic for a particular session using a given transmission group. The LFSID is encoded in the ODAI, OAF', and DAF' fields of the transmission headers that accompany session messages exchanged over the transmission group.
local identifier (LID): In distributed relational database, an identifier or short label that is mapped by the environmental descriptors to a named resource.
localization: The process of modifying or adapting a software product to fit the requirements of a particular locale. This process includes (but is not limited to) translating the user interface, preparing documentation and packaging, changing dialog geometries, customizing features, and testing the translated product to ensure that it still works.
localized: In national language support, pertaining to the support based on a user's national language, country or region, culture, and character encoding. See also national language support, national language version.
local location address: In SNA, the address of the logical unit.
local location name: The name by which your system is known to other systems in an SNA network. Equivalent to an SNA local logical unit name. See also remote location name.
local management interface (LMI): The interface between the frame-relay data terminal equipment (DTE) and the frame handler, which provides the status and configuration information about the permanent virtual circuits (PVCs) available at the frame relay network.
local manager: In OSI, a managing process on the local node. See also remote manager.
local network address: In OSI, a network address that identifies the local node.
local network entity title: In OSI, the network entity title of the local node.
local node: In the OSI Communications Subsystem licensed program, the node from which one views the rest of the OSI network--the node for which resources are defined. See also remote node.
local NSAP: In OSI, an NSAP at the local node.
local NSAP address: In OSI, an NSAP address of the local node.
local optical link card: A smaller card that plugs into the bus adapter in the system unit. The optical bus cables from an expansion unit plug into this card.
local OSI network configuration: In OSI, a general term for the local node and the lines, line sets, and the subnetworks to which it is attached.
local presentation address: In OSI, the presentation address of an application entity at the local node. See also remote presentation address.
local queue: A queue that belongs to the local queue manager. A local queue can contain a list of messages waiting to be processed. See also remote queue.
local queue manager: The queue manager to which the program is connected. and that provides message queuing services to the program. A queue manager to which a program is not connected is called a remote queue manager, even if it is running on the same system as the program. See also remote queue manager.
local service provider: In OSI, a managing process on the local node.
local service requester: In OSI, a service requester process on the local node. See also remote service requester.
local session identification (LSID): In SNA, a field in a format identification 3 (FID3) field transmission header that indicates the type of session and the local address of the directly attached logical unit (LU) or physical unit (PU). See also origin address field.
local space object: An object located in the iSeries system domain storage that is used to maintain and to track CICS storage elements in both system and user storage objects.
local system: For interactive jobs, the system to which the display device is directly attached. For batch jobs, the system on which the job is being processed.
local workstation: A workstation that is connected directly to the system without a need for data transmission functions. See also remote workstation.
location: In Backup Recovery and Media Services, a user-defined storage site where media and containers can be stored awaiting reuse or movement to other locations.
lock: The process by which integrity of data is ensured by preventing more than one user from accessing or changing the same data or object at the same time.
locked: The state of a function in which no programmatic changes can be made. If a function is "locked" it cannot be changed through normal user interfaces.
locked keyboard: A keyboard condition where the display station accepts no input.
locked set: A group of CD-ROMs that contains licensed programs and options that require a license key after 70 days of use.
lock state: A condition defined for an object that determines how it is locked, how it is used (read or write), and whether the object can be shared (used by more than one job).
log: In Backup Recovery and Media Services, a history of backup, archive, recovery, and media management operations. A log can be displayed online or printed.
logarithm: The exponent that indicates the power to which a number is raised to produce a given number.
logarithmic axis: In the GDDM function, an axis on which ascending powers of 10 are equally spaced.
logic: The systematized interconnection of digital switching functions, circuits, or devices.
logical channel: In a packet-switching data network, a path over which data flows between the network and the sending or receiving data terminal equipment.
logical expression: An expression consisting of logical operators, relational operators, or both that can be evaluated to a value of either true or false.
logical file: A description of how data is to be presented to or received from a program. This type of database file contains no data, but it defines record formats for one or more physical files. See also physical file.
logical file member: A named logical grouping of data records from one or more physical file members.
logical interface: An Internet Protocol (IP) address on a given system. Typically, a logical interface has an associated physical interface.
logical I/O: In Performance Tools, the operation used to pass a buffer of data from data management to the data management code of an application program.
Logical Link Control (LLC): A protocol for data-link-level transmission control. The protocol was developed by the IEEE 802 committee, and is common to all LAN standards.
Logical Link Control protocol (LLC protocol): In a local area network, the protocol that governs the assembling of transmission frames and their exchange between data stations independently of the medium access control protocol.
logical operator: (1) In REXX, an operator that performs logical operations on one or two terms. The logical operators include: AND, inclusive OR, exclusive OR, or logical NOT. A value of 1 is returned if the expression is true and 0 if the expression is false.; (2) In COBOL, a reserved word that defines the logical connection between conditions or negates a condition: OR (logical connective, either or both), AND (logical connective, both), and NOT (logical negation).; (3) A word or symbol that defines the logical connection between conditions or that makes opposite a condition.
logical order: In COBOL, the order in which records are sequentially read from a file. For sequential and relative files, the logical order corresponds to the physical order of the records in the file. For indexed files, the logical order is based on the order of the keys in the index of the file.
logical page: In COBOL, a conceptual entity consisting of the top margin, the page body, and the bottom margin.
logical partition (LPAR): A subset of a single system that contains resources (processors, memory, and input/output devices). A logical partition operates as an independent system. If hardware requirements are met, multiple logical partitions can exist within a system.
logical partition firmware: The code that is loaded into an AIX® or Linux® logical partition from the server firmware.
logical partitioning (LPAR): A function of an operating system that enables the creation of logical partitions.
logical record: In COBOL, the most inclusive data item. The level number for a logical record is 01.
logical redundancy check (LRC): A data integrity protection capability on storage devices. A logical redundancy check uses a bit column to create and check parity across bytes of stored data.
logical resource: In OSI, an abstract resource--such as a layer entity. See also physical resource.
logical unit (LU): An access point through which a user or application program accesses the SNA network to communicate with another user or application program. An LU can support at least two sessions--one with an SSCP and one with another LU--and may be capable of supporting many sessions with other LUs.
logical unit 6.2 (LU 6.2): A type of SNA logical unit that supports general communications between programs in a distributed processing environment.
logical unit number (LUN): In the Small Computer System Interface (SCSI) standard, a unique identifier used to differentiate devices, each of which is a logical unit (LU).
logical unit of work (LUW): The work that occurs between the start of a transaction and commit or rollback and between commit and rollback actions after that. LUW defines the set of operations that must be considered part of an integral set.
logical unit of work identifier (LUWID): A name (consisting of a fully qualified LU network name, a logical-unit-of-work (LUW) instance number, and an LUW sequence number) that uniquely identifies a logical unit of work within a network.
logical unit of work state (LUW state): The condition of a logical unit of work (LUW). The LUW state reflects the actions that have been done in that LUW and determines what the next set of actions may be.
logmode table: See logon mode table.
logo: A letter, combination of letters, or symbol that identifies a product or company.
logon mode table: In VTAM® programs, a set of entries for one or more logon modes. Each logon mode is identified by a logon mode name. The entries contain macro-generated constants that associate a logon mode name with a set of session parameters.
log year: The year that a document was filed. Used to identify a printed document number. For example, 88-0001, where 88 is the log year and 0001 is the sequence number. All documents filed in 1988 have a log year of 88.
long comment: Up to a full-screen description of a field, record format, or file. Long comments are typed when the field, record format, or file is created or changed, and displayed either from IDDU or Query.
long format: In binary floating-point storage formats, the 64-bit representation of a binary floating-point number, not-a-number, or infinity.
long-form identifier: A variable-length identifier that includes three parts: An encoding scheme identifier. One or more coded graphic character set global identifiers. Each coded graphic character set global identifier is a concatenation of a graphic character set global identifier and a code page global identifier. Additional coding-related required information.
longitudinal redundancy check: See logical redundancy check.
long string: In DB2 UDB for iSeries, a string whose actual length, or a variable-length string whose maximum length, is greater than 254 bytes or 127 double-byte characters. Any LOB column, LOB host variable, or expression that evaluates to a LOB is considered a long string. See also short string.
lookahead field: In RPG, a field that allows the program to look at information in a field on the next record in an input file.
loop: (1) A sequence of instructions performed repeatedly until an ending condition is reached.; (2) A connectivity topology that connects a series of system units or expansion units together. Signals can travel in either direction for optimized performance. Redundancy is provided to each unit by treating the connection as a string when a failure occurs somewhere in the loop.
loopback address: A specific address that allows testing of communications on a local machine.
Lotus® Domino® for iSeries (Domino for iSeries): The iSeries implementation of the Lotus Domino server. Lotus Domino for iSeries is a full-function Domino server that follows the Domino architecture. The server software includes e-mail, groupware, workflow, calendar and scheduling, and Web server functions.
Lotus NotesPump for iSeries: An IBM licensed program that allows you to transfer data between data sources either on command or on schedule. NotesPump for iSeries provides a number of predetermined activities and a NotesPump extension to LotusScript for additional data customization.
low-entry networking node (LEN node): A node in an APPN network that uses the LU session type 6.2 node type 2.1 architecture without the APPN extension.
LP: See licensed program.
LPAR: (1) See logical partitioning.; (2) See logical partition.
LPC: See link protocol converter.
LPD: See line printer daemon.
LPDA: See Link Problem Determination Aid.
LPDA-1: See Link Problem Determination Aid-1.
LPDA-2: See Link Problem Determination Aid-2.
lpi: See lines per inch.
LPI: See lines per inch.
LPO: See licensed program offering.
LPQ: See line printer queue.
LPR: See line printer requester.
LPRM: See line printer removal.
LRC: See logical redundancy check.
LSID: See local session identification.
LT: See line transmission termination.
LU: See logical unit.
LU 6.2: See logical unit 6.2.
LU-LU session type 0: In SNA, a type of session between two LU half-sessions using SNA-defined protocols for transmission control and data flow control, but using end-user or product-defined protocols to supplement or replace function management data services protocols. The server uses the SNA upline facility support.
LU-LU session type 1: In SNA, a type of session between an application program and single- or multiple-device data processing display stations in an interactive, batch data transfer, or distributed processing environment. The server uses the SNA remote job entry (RJE) support.
LU-LU session type 2: In SNA, a type of session between an application program and a single display station in an interactive environment, using the SNA 3270 data stream. The iSeries system uses the 3270 display emulation support.
LU-LU session type 3: In SNA, a type of session between an application program and a single printer, using the SNA 3270 data stream. The server uses the 3270 printer emulation support.
LU-LU session type 4: In SNA, a type of session between (a) an application program and a single-device or multiple-device data processing or word processing display station in an interactive, batch data transfer, or distributed processing environment; or (b) logical units in peripheral nodes. The server uses the 5250 printer support.
LU-LU session type 6.2: In SNA, a type of session for communications between peer systems.
LU-LU session type 7: In SNA, a type of session between an application program and a single display station in an interactive environment. The server uses the 5250 display station support.
LUN: See logical unit number.
LUSTAT: In SNA, a command used to send logical unit status information.
LUW: See logical unit of work.
LUWID: See logical unit of work identifier.
LUW state: See logical unit of work state.
lvalue: In the C language, an expression that represents a data object that can be viewed, tested, and changed. An lvalue is usually the left operand in an assignment expression.
LZ: See Lempel-Ziv.