gtpd3m0pLibrary Guide with Master Index and Glossary

M

macro
Synonym for macroinstruction.

macro decoder
The program that interprets SVC requests for control program services.

macro identifier
The byte in an SVC macro instruction used by the TPF system to locate appropriate control program services.

macroinstruction
An instruction that when executed causes the execution of a predefined sequence of instructions in the same source language.

macro invocation
An identifier followed by a parenthesized list of arguments that the preprocessor replaces with the replacement code located in a preprocessor define statement.

main function
A function that has the identifier main. In non-TPF systems, each program must have exactly one function named main, which is the first user function that gets control when program execution begins. TPF does not allow the use of a main function, and will flag it as an error, if defined.

mail
See e-mail and Internet mail.

mail account
In TPF Internet mail server support, a user with a mailbox.

mailbox
A file storage area that holds electronic mail (e-mail).

mail item
A single piece of electronic mail (e-mail).

mail queue
A list used for Internet mail that keeps track of mail items to be delivered.

main I-stream engine
In a CPC with multiple I-stream engines, the I-stream that executes most non-DASD-related I/O commands and the only I-stream engine that can be IPLed. When the MPIF feature is installed and 2 or more I-stream engines exist, MPIF I/O commands are executed on the second I-stream. Contrast with application I-stream engine.

main storage allocations lists
The lists of available block addresses, in each block type, that are used by the control program when programs request or release main storage.

major device number
A number that locates a device driver.

mapping
(1) A data organization procedure that binds application data to a unique hardware address. (2) The programs that permit a user to format and control the data routed between a terminal and an application, or between applications.

MASM
Multiple assembler.

master clock processor
The processor that controls the complex's TOD time and date changes in a loosely coupled system. The master clock processor is usually the first active processor in a loosely coupled system. In 1052 state, the processor where the ZATIM TOD command is entered becomes the master clock processor.

master extra program record
The record used to control the pool of extra program records. Extra program records are the fixed file records within the #XPRGn record type.

master synchronization source
The originator of the oscillator pulses that keep all the TOD clocks in a loosely coupled complex synchronized.

matrix
An array arranged in rows and columns.

MBI
Message block identifier.

MCA
Message channel agent.

MCR
Message control record.

MDBF
Multiple database function.

member
(1) A data object in a structure or a union. (2) A file of object code that is a component of a dynamic load module (DLM), dynamic link library (DLL), or library load module (LLM).

messages
Transactions or entries received by a TPF system for immediate action. TPF system messages (system errors) such as dump messages, and online and offline messages are intended for operators and system programmers responsible for operating and maintaining the TPF system.

message block identifier (MBI)
A field found in the SLC link keypoint that permits chaining of SLC data message blocks.

message channel
In distributed message queuing, a mechanism for moving messages from one queue manager to another. A message channel comprises two message channel agents (a sender at one end and a receiver at the other end) and a communication link. Contrast with MQI channel.

message channel agent (MCA)
A program that transmits prepared messages from a transmission queue to a communication link, or from a communication link to a destination queue. See also Message Queue Interface (MQI).

message collector
The data collection program that records network message traffic data.

message control record (MCR)
A record used to preserve SLC message references until they are acknowledged.

Message Queue Interface (MQI)
The programming interface provided by the MQSeries queue managers. This programming interface allows application programs to access message queuing services.

message recovery
A facility used to retain messages on file until the message is completely processed.

message router
A data communication procedure that directs data messages from or to a host network, to or from a specified terminal, station, application program, or another host network.

message switching (MESW) state
The system state in which message switching entries are the only entries processed. All other entries are queued to be processed when the system reaches NORM state.

MESW state
Message switching state.

method
A procedure contained within a collection object that is made available to other collections for the purpose of requesting the services of that collection. Most communication between collections takes place through methods.

MFST
Module file status table.

minor device number
An optional number that can be passed to a device driver subroutine.

mode
A collection of attributes that specifies a file's type and its access permissions. (POSIX.1)

module file status table (MFST)
The index of online disk assignments for all direct access storage devices (DASD).

module-to-module duplication
A method of allocating duplicate files whereby the duplicate record in a record type (fixed or pool) is assigned to the same relative position on an alternate disk module.

movable virtual IP address
A virtual Internet Protocol address (VIPA) that can be moved from one processor to another in the same loosely coupled TPF complex.

MPIF
Multi-Processor Interconnect Facility.

MPIF complex
Multiple TPF complexes that are channel connected.

MPIF user
One or more programs associated with one or more functions.

MPLF
Multi-path lock facility.

MQI
Message Queue Interface.

MQI channel
Connects an MQI client to a queue manager on a server system, and transfers only MQI calls and responses in a bi-directional manner.

MQI channel directory
The TPF system implementation of an MQSeries channel definition file. The MQI channel directory contains client connection channel type (CLNTCONN) definitions stored in #MQICD fixed file records.

MQ series
Part of an MQSeries product that allows a queue manager to service MQI client systems.

MQI trace table
The TPF system implementation of an MQI function trace facility.

MQSeries
A family of IBM licensed programs that provides message queuing services.

MQSeries client
Part of an MQSeries product that can be installed on a system without installing the full queue manager. The MQSeries client accepts MQI calls from applications and communicates with a queue manager on a server system.

MQSeries server
A queue manager that provides queuing services to one or more clients. All the MQSeries objects (for example, queues) exist only on the queue manager system; that is, on the MQI server machine. A server can support normal local MQI applications as well.

MSRB
Multiple system request block.

multibyte characters
Multibyte characters are a mixture of SBCS and DBCS characters.

multi-path lock facility (MPLF)
A hardware locking facility that can be optionally installed on 3990 Model 3 DASD control units. This facility, or the limited lock facility (LLF), is required in loosely coupled complexes.

Multi-Processor Interconnect Facility (MPIF)
A feature of the TPF system that allows an installation to implement the interconnection of CPCs through the use of channel-to-channel support.

multiple assembler (MASM)
The program that can assemble many programs in partitioned data sets with minimal use of JCL.

multiple assembly print
An offline program that produces one or more printed listings retrieved from the tape or disk data set produced by the multiple assembly program (MASM).

multiple central processing complexes
Several central processing complexes, which can be either uniprocessors or multiprocessors, that are explicitly identified to the channel subsystem by device addresses. See also central processing complex.

multiple database function (MDBF)
A facility in the HPO feature that allows concurrent processing of multiple applications, each with dedicated database support.

multiple images
A facility that allows an installation to define as many as 8 images of the TPF system on a single processor. Maintaining multiple and separate TPF images allows an installation to perform loads while the TPF system is processing messages and to have the ability to fall back immediately to a previous program base without reloading the previous program versions.

multiple inheritance
A design characteristic of an object-oriented database in which a given class can inherit directly from more than one immediate superclass.

multiple release
A pool address that has been released more than once without being dispensed again. See also online multiple release and offline multiple release.

multiple system request block (MSRB)
A data definition describing the format of the request block used to ship each MPIF request type to the appropriate destination. The MSRB contains information defining the sending and receiving MPIF user as well as information describing the specific request type.

multiple TPF image
See image.

multiprocessing
(1) A mode of operation for parallel processing by 2 or more processors of a multiprocessor. (2) Pertaining to the simultaneous processing of 2 or more computer programs or sequences of instructions by a computer.

multiprocessor
(1) A computer including 2 or more processors that have common access to shared main storage. (2) A system of 2 or more processing units, ALUs, or processors that can communicate without manual intervention.