gtpd3m0oLibrary Guide with Master Index and Glossary

L

label
An identifier followed by a semicolon and is the target of a goto statement.

labeled statement
A C language statement that contains one or more identifiers each followed by a colon and a statement.

LAN
Local area network.

language work area (LWA)
An I-stream unique work area used by C language secondary library routines.

LC
Loosely coupled.

LCB
Link control block.

leap seconds
The adjusted difference between Greenwich mean time (GMT) and the time established as Absolute Time by the National Bureau of Standards.

LEID
In communications, the logical endpoint identifier. In coupling facility (CF) support, the list entry identifier.

LFW
Library function work area.

LGF
Loader general file.

library
A collection of functions, function calls, subroutines, or other data.

library function
A function available to all C application programs that provides the programmer with a generic service, such as determining the length of a string of characters. Library functions are provided so that C application programs can link to generally available service routines to perform their tasks.

library function work area (LFW)
Part of the first stack frame attached to an ECB that is used by C library functions.

library interface scripts
Files that list functions contained in a library and provide an index number for that function. These files are used by the library interface tool (LIBI) to create library stubs.

library members
Files of object code that are components of library load modules (LLMs) or dynamic link libraries (DLLs). For example, CASSART is a library member file of CISO.

library work space
A performance-critical macro area that is used by library functions that need storage to build macro expansions and do not give control to any other real-time segments while macros are running.

LIBVEC
A vector of library function addresses defined by the library interface script and linked into the library load module. It is used in the call linkage to library functions.

limited lock facility (LLF)
A hardware RPQ required for DASD control units shared among multiple CPCs in a loosely coupled multiprocessing environment. It is used to synchronize the modification of the shared database. See also external locking facility (XLF).

limited resource session
An SNA session that traverses a switched link and can be deactivated by the LU when it is no longer being used by a conversation.

line multiplexing
The ability to support multiple terminals on a communication line.

line status table (LSTB)
The system table that contains entries for every non-SNA communication line in the network. The system uses this table to control I/O from non-SNA sources in the network.

link
In the TPF file system, a connection between one or more file names and an associated i-node. Synonym for directory entry. To interconnect items of data or portions of one or more computer programs; for example, the linking of object programs by a linkage editor or linking data items by pointers. (T)

linkage editor
A program that resolves cross-references between separately compiled object modules and then assigns final addresses to create a single load module.

link control block (LCB)
A record used to indicate correct or incorrect reception of an SLC data message block and to provide information regarding the status of an SLC link.

link-edited modules
The files of load module code produced by the linkage editor.

list entry
An entry on a list in a coupling facility (CF) list structure. A list entry consists of list entry controls and can also include a data entry, an adjunct area, or both. See also adjunct area and data entry.

list entry controls
Items that contain control information that is associated with a list in a coupling facility (CF) list structure. See list entry.

list entry identifier (LEID)
An identifier assigned by the coupling facility (CF) to each list entry that is in use in the CF list structure.

list header
A header that anchors the list to the coupling facility (CF) list structure and contains control information (known as list controls) that is associated with the list. See also list controls.

list notification vector
An array of bits that contain an indication of whether a monitor list in a coupling facility (CF) is in an empty state or a nonempty state.

list processing
The cyclic dispatching routine performed by the CPU loop that allocates system resources to entries on a first-in-first-out basis.

lists
Queues of work to be processed by the CPU loop.

list structure
See coupling facility list structure.

listener
A TCP/IP application that monitors information about incoming network connections.

little endian
A method of representing data such that the lower numbered bytes of the data are less significant. Intel-based personal computers (PCs) and IBM RISC System/6000 machines use this format.

live testing
The online testing procedure that uses terminal input rather than simulated batch input.

LLF
Limited lock facility.

LM
Logon manager.

LMA
Long message assembly.

LMT
Long message transmitter.

LNIATA
The line number, interchange address, and terminal address used to address a remote device in an ALC network.

load
The process by which programs are read from an input device by one of the loaders. See auxiliary loader, E-type loader, general file loader, and data loader.

load balancing
The system routine that decides which I-stream engine is to process an entry based on the activity in all I-stream engines in the CPC.

load deck
The control cards or card image input used to create all load media (including loader general files).

loader general file (LGF)
The disk module that contains programs and keypoints required to initialize a system. It is a sequential collection of records created offline under MVS control.

load function
The E-type loader function that reads sets of programs from an input device.

load module
All or part of a computer program in a form suitable for loading into main storage for execution. A load module is usually the output of a linkage editor.

loadset
A group of programs identified by a unique name on which E-type loader functions can be performed.

loadset directory (LSD)
The structure used by the E-type loader that contains information about every loadset in the system.

local area network (LAN)
A computer network located within a limited geographical area.

local cache buffers
Buffers allocated by logical record cache support that contain copies of data that is shared among cache users. Users read data from permanent storage to their local cache buffers and write data from their local cache buffers to permanent storage.

local cache vector
An array of bits that contain an indication of whether data in the local cache buffer is valid. There is one local cache vector for each cache user.

local symbol table
In expression enhancements for the TPF debuggers, a table that contains all symbols included in the assembler program and the data macros (DSECTS) the program invokes except for those symbols that are defined in the common symbol table. The TPFSYM offline program extracts DSECT or symbol definitions from the SYSDATA file that is generated by the assembler and saves the definitions in the ADATA file. The offline loader then loads the ADATA file to the TPF system.

locale
Characteristics of the geographic area, such as time zone, character editing, monetary symbols and formatting, and nonmonetary formatting. The locale definition is built using the EDCLOC assembler macro. The setlocale function is used to select alternate locales.

localedef utility
A utility that processes locale definition files and produces the locale load modules.

locate
A modified REQTAIL logon manager private protocol RU used by the TPF system to solicit a SESINIT session initiation RU. See locate reply.

locate reply
A modified SESINIT logon manager private protocol RU used by the VTAM logon manager to respond to a TPF Locate request. It contains a BIND image for the TPF system to send on the link specified as the last tail in the tail vector.

lock
A serialization mechanism by which a specific resource is restricted for the use of the holder of the lock.

lock holder
A processor or processors that currently hold a lock.

lock table
An array of exclusive locks that you can use to serialize access to coupling facility (CF) list structure resources such as lists or list entries. See coupling facility (CF) list structure.

lock waiter
A processor or processors waiting to obtain a lock.

log A file that contains messages issued from an application or system program.
To record; for example to log all messages to tape.
See also syslog daemon.

log collection
A type of collection with ordered, nonunique elements that are not accessible by a key. Elements are ordered by arrival sequence. The collection cannot be expanded and the elements will wrap when the collection becomes full; that is, the newest element will replace the oldest element in the collection.

log manager
A manager that controls the recovery log and recovery actions.

log processor
In TPF transaction services, the program that allows a user to log on to an application.

LOGI state
The state a terminal is in when it is not connected (logged in) to an application.

logical address
The address found in the instruction address portion of the program status word (PSW). If address translation is off, the logical address is the real address. If address translation is on, the logical address is the virtual address. See also absolute address, physical address, real address, and virtual address.

logical record cache
A cache that provides high-speed access to data, which enables you to develop data sharing programs with improved performance. You can use a logical record cache for data consistency, which ensures the validity of the data that is shared, and to keep track of data that resides in permanent and local storage, but is not stored in the cache itself.

logical DASD subsystem
A subsystem consisting of 2 storage directors, attached to the same DASD strings, together with those DASD strings.

logical endpoint identifier (LEID)
An identifier that is used to give a resource a pseudo line, interchange address, and terminal address.

logical link
A path for data to be transmitted between an adapter on a CLAW workstation and the TPF system.

logical processor
The symbolic identification assigned to a processor in a loosely coupled complex.

logical storage block
Temporary main storage requested by an E-type program, dispensed in fixed sizes of 128, 381, 1055, and 4095 bytes. See also TPF block.

logical unit of work
See unit of work.

logon manager (LM)
A VTAM application that provides logon services for the TPF system. The TPF system communicates with the logon manager regarding the status of its applications on CLU sessions.

long constant
An integer constant followed by the letter l (el) or L.

long message assembly (LMA)
The process by which segmented SNA and non-SNA input messages are assembled into one unit.

long message transmitter (LMT)
A program package that is used to queue and transmit long, non-SNA messages to ALC printer devices. LMT is also known as the SENDL postprocessor.

long-term pool records
Pool records that are maintained for an indefinite period of time, at least longer than the life of a transaction.

longevity
The length of time (seconds, hours, days, weeks, months) during which file pool records are maintained.

lookaside storage buffer
A temporary storage area where a copy of the data is saved to avoid refetching the data on every access. The data is retrieved from the temporary storage area instead of its permanent residence.

loosely coupled complex
Two or more CPCs sharing a common set of DASD and using an external lock facility (XLF) to synchronize multiple CPC access to the DASD records.

loosely coupled (LC) facility
A function in the High Performance Option (HPO) feature that allows multiple CPCs to share a common database.

low address protection
A hardware facility that provides protection against the destruction of main storage information used by the CPU during interrupt processing; accomplished by prohibiting instructions from storing with effective addresses in the 0-511 range.

LSD
Loadset directory.

LSTB
Line status table.

LUWID
Logical unit of work identifier.

lvalue
An expression that represents a data object that can be both examined and altered.

LWA
Language work area.

LWS
Library work space.