A B C D E F G H I J K L M N O P Q R S T U V W X Y and Z Special characters and Numerics

This site contains terms and definitions from many IBM software and hardware products as well as general computing terms.


See measuring and test equipment.

See machine to machine.


  1. See mandatory access control.
  2. See message authentication code.
  3. See Media Access Control.

MAC address
See Media Access Control address.

Macao S.A.R. of China
See Macao S.A.R. of the PRC.

Macao S.A.R. of the PRC

MAC frame
A transmission frame that controls the operation of the IBM Token-Ring Network and any ring station operations that affect the ring.

machine characteristic
Values defined in the computer.

machine check handler (MCH)
A feature that analyzes errors and attempts recovery by retrying the failing instruction. If retry is unsuccessful, it attempts to correct the malfunction or to isolate the affected task.

machine check interruption
An interruption that occurs as a result of an equipment malfunction or error.

machine data
Any information that is automatically created from a computer process, application or other machine without the intervention of a human.

machine-generated data structure (MGDS)

  1. An IBM structured data format protocol for passing character data among the various Content Manager ImagePlus for OS/390 programs.
  2. Data extracted from an image and put into general data stream (GDS) format.

machine instruction

  1. A binary number that directs the operation of a processor. Compilers and assemblers convert source instructions to machine instructions.
  2. See computer instruction.

machine interface (MI)
The interface, or boundary, between the operating system and the Licensed Internal Code.

machine language
See computer language.

machine learning model
The application of past experience, such as training data, to determine or predict the correct outcome of future experiences based on characteristics of the data. These past experiences are captured in the form of a model by calculating feature scores for each candidate answer or evidence and combining that with known outcomes.

machine level control (MLC)
A database that contains the engineering change (EC) level and configuration of products in the field.

machine object

  1. An entry in the Network Installation Management database that represents a machine configuration.
  2. A program object that has no defined storage form; the object is defined internally to the machine. The machine aspect is not available to the user. See also data object.

Pertaining to data a machine can acquire or read from a storage device, a data medium, or other source.

machine-readable information (MRI)
All textual information contained in a program such as a system control program, an application program, or microcode. MRI includes all information that is presented to or received from a user interacting with a system. This includes messages, dialog boxes, online manuals, audio output, animations, windows, help text, tutorials, diagnostics, clip art, icons, and any presentation control that is necessary to convey information to users. See also machine readable material, presentation control information.

machine readable material (MRM)
Machine readable information (MRI), executable code, and constants. See also machine-readable information.

machine-reported product data (MRPD)
Product data gathered by a machine and sent to a destination such as an IBM support server or RETAIN. This data includes information about the configuration and connections of this particular machine.

machine state
A state that identifies the machine execution state and control state for each machine.

machine storage pool
A storage pool used by the machine and certain highly shared programs, whose size is specified in the system value QMCHPOOL.

machine to machine (M2M)
Pertaining to an Internet of Things technology that supports the communication of both wireless and wired systems with devices of the same type.

machine word
See fullword.

See macrolibrary.

MACLIB library
A library that contains macros, copy files, or source program statements for use under CMS.

MAC protocol

  1. See medium access control protocol.
  2. See Media Access Control protocol.


  1. An instruction that causes the execution of a predefined sequence of instructions. See also function.
  2. An XML script that defines a set of screens. Each screen includes a description of the screen, the actions to perform for that screen, and the screen or screens that can be presented after the actions are performed. A macro can be specified as one of the actions to be taken when a host screen matches the screen recognition criteria of a screen customization.
  3. In REXX, a program that performs certain operations, such as text editor operations, in applications.
  4. A program that performs a series of automated tasks on behalf of the user. A macro consists of three components: the trigger (when it acts), the search (what documents it acts on), and the action (what it does).
  5. In Analyst, a set of commands that have been recorded and grouped together as a single command, which is used to automatically complete a list of instructions in one step.
  6. A single object defined by an administrator to automate a series of administration tasks in Contributor.
  7. A label that is declared at the start of a program or file. The label can then be used to represent the values assigned to the label in the declaration.
  8. A fragment of code that can be inserted in a number of locations in models and reports, such as calculation and filter expressions and SQL statements. Macros can include references to session parameters, parameter maps, parameter map entries, and use functions to dynamically customize applications. With macros, a single report can address different business scenarios.

macro call
See macro.

macro definition
A named sequence of statements that can be called with a macro instruction.

macro file
A file that contains one or more storage manager administrative commands, which can be run only from an administrative client using the MACRO command. See also Tivoli Storage Manager command script.

See long-running process.

See macro.


  1. The form the library takes varies by environment, being a MACLIB in CMS, a PDS in TSO, and so on.
  2. A library of macrodefinitions used during macroexpansion.

macro processor
A program that converts macro instructions into specified values.

See macro.

During formatting, the substitution of control words, symbols, and text for a macro.

MAC sublayer

  1. See Media Access Control sublayer.
  2. See medium access control sublayer.

made-to-customer (MTC)
Pertaining to an order that is created based on the requirements of the buyer. It assumes that the buyer places multiple orders for this particular item.

made-to-order (MTO)
Pertaining to an order that has items that are produced uniquely for the order. The item is made from unfinished materials specifically for the order.

See multiple area data set.

A closed-source mobile Linux operating system that was created by Nokia for smart devices. See also MeeGo, mobile operating system.

magazine view
A format for document lists in which properties appear in a phrase, such as created by [property] on [date].

magic number
A numeric or string constant in a file that indicates the file type.

An internal component that analyzes network traffic and security events against defined custom rules.

magnetic drum
A right circular cylinder with a magnetizable layer on which data can be stored. (T) (A)

magnetic ink
An ink that contains particles of a magnetic substance whose presence can be detected by magnetic sensors.

magnetic ink character recognition
The identification of characters through the use of magnetic ink. See also optical character recognition.

magnetic storage device controller
The I/O controller card in the card enclosure that controls the operation of the disk, diskette, and tape devices.

magnetic stripe reader
A device, attached to a display station, that reads data from a magnetic stripe on a badge before allowing an operator to sign on.

magnetic tape drive
A technique for moving and controlling magnetic tape.

magnetic tape subsystem
A tape unit that includes the logic interface hardware necessary to operate with a system.

magnetic tape unit
A device for reading or writing data from or to magnetic tape.

magnetic toner
Toner used with specific printers to print magnetic ink character recognition (MICR) fonts.

A device that measures the direction and strength of magnetic fields. In mobile computing, magnetometers can be used to asses the position of the device relative to the earth. For example, in an augmented reality app, if a user points the camera north, then points the camera at the ground, the app redraws the 3D compass to show north relative to the phone's current positioning (in this case, now pointing to the top of the phone). See also accelerometer.

magneto-optic recording (MO recording)
A method of storing information on magneto-optic media using a laser and magnetic read/write heads. A laser is used to heat a small spot on the media that the write head alters magnetically. The ability to focus the laser tightly increases the data density over standard magnetic media. MO disks are erasable and rewritable.

A measure of the relative importance of a particular offense. Magnitude is a weighted value calculated from relevance, severity, and credibility.

The distribution objects and documents referred to by a mail log.

mailbag envelope
An EDI envelope that is created by a header and trailer for the purpose of tracking interconnected data.


  1. A folder or set of folders used to store messages that are being transferred between mail recipients. There are two types of Gentran Server for Windows mailboxes: non-gateway and gateway.
  2. A collection of pointers to message objects that are addressed to a single entity.
  3. A storage location in a network to which messages for a user are sent.

mailbox restore
A function that restores Microsoft Exchange Server data (from IBM Data Protection for Microsoft Exchange backups) at the mailbox level or mailbox-item level.

mail drop
The file into which messages are first received.

The program that does the actual delivery of mail.

mail exchange record (MX record)
A record in the Domain Name System (DNS) that indicates which host handles mail for a particular domain.

mail file
A Notes application that stores user mail messages, calendar entries, and to-do information.

mail file delegation
See delegation.

mail file quota
The maximum size allowed for a Notes mail file.

mail file template
A Notes template database that controls the design of the mail file.

mail gateway
A machine that connects two or more electronic mail systems (often, mail systems on different networks) and transfers messages between them.

mail hub server
An on-premises Domino mail server that routes mail to and from SmartCloud Notes servers.

mail hygiene server
A server that scans email for viruses and malware.

mail journal file
A record of SmartCloud Notes email messages that are sent.

mail rule
A rule that is created to act on emails that meet specified criteria.

mail server

  1. A software program or computer that provides mailing services to other software programs and computers.
  2. A server that manages mail routing.

mail server framework (MSF)
A set of user exit points and application program interfaces (APIs) that embody an abstract design for solutions to a number of related communications problems.

mail session
A resource collection of protocol providers that authenticate users and control user access to messaging systems.

A subdivision of a mailbox that contains electronic data in different formats, and that is used to separate different types of documents or data from specific trading partners.


  1. A processor, named by an initialization statement, on which jobs can execute. A main represents a single instance of MVS. The two types of mains are global main and local main.
  2. In FORTRAN, the default name given to a main program if one was not supplied by the programmer.

main branch
The starting branch of a version tree of an element. The default name for this branch is main.

main composite operator
A composite operator that encapsulates the data flow graph, that is the root of that graph, that has no input or output ports, and that when compiled represents a streams processing application. See also composite operator, data flow graph, streams processing application.

main device scheduler (MDS)
A device management facility that controls the setup of input/output (I/O) devices associated with job execution.

main distribution frame (MDF)
In the CallPath licensed program, a series of quick-connection blocks, supported on a frame, that allows trunk lines and telephones to be connected to the 9722 Redwood system.

main DSP
A dynamic support program (DSP) that chooses jobs and supplies them to the MVS initiators.

main entry
A first-level or primary index entry in an index. Main entries are the key access points to the information, representing the main concepts in the information. They use both the product and the users' terminology.

A computer, usually in a computer center, with extensive capabilities and resources to which other computers may be connected so that they can share facilities.

mainframe interactive (MFI)
In SAA usage, pertaining to systems in which nonprogrammable terminals are connected to a mainframe.

main function
A function that has the identifier main. Each program must have exactly one function named main. The main function is the first user function that receives control when a program starts to run.

main index build
In enterprise search, the process of building the entire index. See also delta index build.

mainline module
A sequence of instructions called by a program in the main path after it is compiled.

mainline program
A program that performs primary functions, passing control to routines and subroutines for the performance of more specific functions.

mainline routine
The first subroutine encountered when link-editing.

main network address
In VTAM, the logical unit (LU) network address that is used for the SSCP-LU session and certain LU-LU sessions with the LU. See also auxiliary network address.

main program

  1. The highest level program involved in a run unit.
  2. The first routine in an enclave to gain control from the invoker. See also subprogram.
  3. The first program unit to receive control when a program is run.

main service
A dynamic support program (DSP) that provides operator control over jobs.

main storage

  1. The part of internal storage into which instructions and other data must be loaded for running or processing.
  2. See memory.
  3. Program-addressable storage from which instructions and other data can be loaded directly into registers for subsequent execution or processing.

main storage database (MSDB)
A root-segment database that can be accessed at the segment level and resides in main storage during execution. See also Fast Path.

main storage dump (MSD)
A process of collecting data from the system's main storage. It can be done automatically by the service processor as a result of a system failure, or it can be performed manually by the operator when there appears to be a system failure.

main storage dump space
A section of storage reserved on the disk unit that is used as a place to save main storage for recovery and debugging.

main storage pool
A division of main storage, which allows the user to reserve main storage for processing a job or group of jobs, or to use the pools defined by the system. See also auxiliary storage pool.

main storage - TS queue
A dynamic storage area managed by CICS under the temporary storage facility. Data in main storage is not kept from one CICS run to the next. See also auxiliary storage - TS queue.

main system
The system on a multisystem RACF remote sharing facility (RRSF) node that is designated to receive most of the RRSF communications sent to the node.

maintain system history program (MSHP)
A program used for automating and controlling various installation, tailoring, and service activities for a VSE system.

In Backup, Recovery, and Media Services, the tasks that must be performed on a routine basis to perform cleanup activities and other Backup, Recovery, and Media Services functions. Examples of maintenance are tape expiration, recovery analysis reports, and media movement.

maintenance analysis procedure (MAP)
In hardware maintenance, a step-by-step procedure that assists an IBM service representative to trace a symptom to the cause of the failure.

maintenance and operator subsystem (MOSS)
A subsystem of an IBM communication controller, such as the 3725 or the 3720, that contains a processor and operates independently of the rest of the controller. It loads and supervises the controller, runs problem determination procedures, and assists in maintaining both hardware and software.

maintenance and operator subsystem extended (MOSS-E)
A subsystem of the IBM 3745 Communication Controller that operates independently of the rest of the controller. It loads and supervises the controller, runs problem determination procedures, and assists in maintaining both hardware and software.

maintenance catalog
A feature in Sterling Business Center that can be used to define master catalog details, create a category, add an asset to a category, modify asset details in a category, delete an asset from a category, and localize the fields.

maintenance-level keyword
In diagnosing program failures, a keyword that identifies the maintenance level of DFSMSdss.

maintenance level update
The service updates (fixes and enhancements) that are necessary to upgrade the Base Operating System (BOS) or an optional software product to the current release level.

maintenance location record
A record that contains detailed information about vendors, manufacturers, and other maintenance locations

maintenance mode

  1. A state of a node or server that an administrator can use to diagnose, maintain, or tune the node or server without disrupting incoming traffic in a production environment.
  2. The state in which a product or system can be serviced.

maintenance network
The network that Heartbeat uses to communicate between the two Netezza nodes.

maintenance point
A CICSPlex SM address space (CMAS) that is responsible for maintaining CICSPlex SM definitions in its data repository and distributing them to other CMASs involved in the management of a CICSplex.

maintenance service
In SNA, a network service in system services control points (SSCPs) and physical units (PUs). Maintenance service provides facilities for testing links and nodes and for collecting and recording error information. See also session services.

maintenance significant item (MSI)
A component or part whose failure might have serious consequences for the safety and operation of the aircraft, such as engine stage checks, that require regular or reoccurring maintenance

maintenance window

  1. A user-defined time period for running only required automatic maintenance activities. See also automatic maintenance.
  2. A time period during which system maintenance is performed and network processing is unavailable for customers.

main window

  1. In certain printers, the window on the operator console in which the main dialog between users and the printer takes place. The main window always appears on the operator console.
  2. In VisualAge RPG, a window that is an immediate child of the desktop.

major/activity token
In OSI, the session-layer token that controls activities and major synchronize operations.

major device number
A system identification number for each device or type of device. The major device, minor device, and channel numbers uniquely identify a hardware device.

major node
In VTAM, a set of resources that can be activated and deactivated as a group. See also minor node, NCP major node, packet major node.

major object descriptor block (MODB)
In CICSPlex SM, a control structure built by Kernel Linkage during initialization of a CICSPlex SM component that contains a directory of all methods that make up that component. The structure of the MODB is the same for all components.

major object environment block (MOEB)
In CICSPlex SM, a control structure built by Kernel Linkage during initialization of a CICSPlex SM component and pointed to by the MODB. MOEB stores information critical to a CICSPlex SM component and anchors data used by the component. The structure of the MOEB is unique to the component it supports.

major synchronization point
In OSI, a session-layer synchronization point that usually represents a logically significant piece of work. Major synchronization points are a confirmed service. See also minor synchronization point.

major synchronize
In OSI, a confirmed service provided by the session layer that enables peer application entities to synchronize the exchange of data. For example, an application entity can send data followed by a major synchronize request; its peer sends back a major synchronize response, which indicates that it has received all of the data that was sent up to the major synchronize request. The major synchronization function also marks a recovery point in the data stream. See also minor synchronize.

major tick
In Business Graphics Utility, a mark on an axis that denotes character grid units on a chart. See also minor tick.

major version

  1. A document that has been released. The security of a major version makes the document available to a wide range of users. A major version is typically an approved document of record.
  2. A version of the metadata in which the structure of the case data has changed. For example, the structure can change with the addition or deletion of questions or categories, or the changing of a variable's data type, minimum or maximum value, or name.


  1. The manufacturer of an automobile.
  2. In VisualAge RPG, the process by which all of the components are compiled and assembled to create a VRPG application.

make command
A statement that can be used to build an application.


  1. In UNIX, a text file containing a list of an application's parts. The make utility uses makefiles to maintain application parts and dependencies.
  2. A text file that contains commands, which may include commands to do backups, set up build environments, or start execution of a program. Traditionally, makefiles specify the dependencies of target files on source files.

The total duration of a schedule, between the start of the first activity and the end of the last activity.

make utility
A utility that maintains all of the parts and dependencies for an application. The make utility uses a makefile to keep the parts of a program synchronized. If one part of an application changes, the make utility updates all other files that depend on the changed part.

malformed packet
A packet that does not conform to TCP/IP standards for size, destination, checksum, or flags in the TCP header.

malicious file execution attack
An attack that uses SMB file wrappers in PHP scripting language to run code, install a root kit, or compromise an entire system on a web server remotely.

Software that is designed to disrupt or gain unauthorized access to a system, gather information that compromises a person's privacy or assets, or other behavior that is harmful to the user.

See metropolitan area network.

The ability to manage a resource, or the ability of a resource to be managed. (OASIS)

manageability capability
A capability associated with one or more management domains. (OASIS)

manageability capability interface
A web service interface representing one manageability capability. (OASIS)

manageability consumer
A user of manageability capabilities associated with one or more manageable resources. (OASIS)

manageability endpoint
A web service endpoint associated with and providing access to a manageable resource. (OASIS)

manageability interface

  1. A service of a managed resource that includes the sensor and effector that are available to an autonomic manager. The autonomic manager uses the manageability interface to monitor and control the managed resource and any of its managed resources. See also autonomic manager, effector, management topic, sensor, touchpoint.
  2. The composition of one or more manageability capability interfaces. (OASIS)

manageable resource
A resource capable of supporting one or more standard manageability capabilities. (OASIS)

managed application
An instrumented version of an application that has been added to a project in the test workbench.

managed application system (MAS)
A running CICS Transaction Server for z/OS region that is being managed by CICSPlex SM. A MAS contains CICSPlex SM agent code that implements CICSPlex SM functions, such as data collection.

managed asset
A component or resource that is enabled for workspaces and allows content to be written to separate workspace database schemas. See also quick publish.

Managed Bean (MBean)
In the Java Management Extensions (JMX) specification, the Java objects that implement resources and their instrumentation.

managed deployment environment
A set of server components that are used to test and deploy applications in a controlled environment.

managed destination
A queue that is provided by the queue manager, as the destination to which published messages are to be sent, for an application that elects to use a managed subscription. See also managed subscription.

managed device
A non-node device for which Cluster Systems Management supports power control and remote console access.

managed disk (MDisk)
A Small Computer System Interface (SCSI) logical unit (LU) that a Redundant Array of Independent Disks (RAID) controller provides and a clustered system manages. The MDisk is not visible to host systems on the storage area network (SAN).

managed disk group
See storage pool.

managed environment
An environment where services, such as transaction demarcation, security, and connections to Enterprise Information Systems (EISs), are managed on behalf of the running application. Examples of managed environments are the web and Enterprise JavaBeans (EJB) containers.

managed file
A library item that is created outside of IBM Process Designer and that is part of a process application, such as an image or Cascading Style Sheet (CSS). Creating managed files ensures that all required files are available and installed when a project is ready for testing or production.

managed group
A group of systems or objects managed by IBM Director.

managed handle
An identifier that is returned by the MQSUB call when a queue manager is specified to manage the storage of messages that are sent to the subscription.

managed mail replica
A replica of a Notes mail file that is configured through a Domino policy and that is created and managed automatically on a user's local computer.

managed manual mode
The mode of operation that allows the user to locate and move cartridges to and from drives and cells under the direction of the library manager. The library robot implements this mode. See also manual mode.

managed mode

  1. An access mode that enables virtualization functions to be performed. See also access mode, image mode, unconfigured mode.
  2. An environment in which connections are obtained from connection factories that the Java EE server has set up. Such connections are owned by the Java EE server.

managed node

  1. A node that is federated to a deployment manager and contains a node agent and can contain managed servers. See also node.
  2. In Internet communications, a workstation, server, or router that contains a network management agent. In the Internet Protocol (IP), the managed node usually contains a Simple Network Management Protocol (SNMP) agent.
  3. In a Tivoli environment, a computer system on which Tivoli Management Framework is installed.
  4. A node that is controlled by a management server in a management domain. Managed nodes do not have knowledge about the other nodes that are being managed. Managed nodes only know about the servers managing them. See also management domain.

managed object

  1. A resource that is subject to management as viewed from a systems management perspective. Examples of such resources are a connection, a scalable system, or a line.
  2. A definition in the database of a managed server that was distributed to the managed server by a configuration manager. When a managed server subscribes to a profile, all objects that are associated with that profile become managed objects in the database of the managed server.

managed object class
An identified set of managed objects sharing (a) the same identified sets of attributes, notifications, and management operations (packages) and (b) the same conditions for presence of those packages.

Managed Object Format (MOF)
A language for defining Common Information Model (CIM) schemas.

managed object ID
A unique identifier for each managed object.

managed private cloud
A cloud computing environment that is enterprise owned and operated by another company. The customer owns and pays for infrastructure and has unlimited exclusive access.

managed resource

  1. In a Tivoli environment, a database object that represents a resource and is governed by policies. See also resource.
  2. An entity that exists in the runtime environment of an IT system and that can be managed. See also effector, monitor component, resource, sensor.

managed resource ID
The globally unique identifier (GUID) for an instance of a managed resource that can be used to compare the managed resource with another managed resource and find an endpoint reference (EPR) for the managed resource. See also endpoint reference.

managed resource interface
See manageability interface.

managed resource prototype
An XML document that describes a resource type and extends the manageability interface of the managed resource such that it can be easily and readily located within a system. Whereas a manageability interface can be used by many managed resources of the same resource type, the managed resource prototype describes the resource properties and any restrictions on the possible values for those properties. See also resource type.

managed server

  1. A server within a managed node, to which SCA modules and applications can be deployed.
  2. A server that receives configuration information from a configuration manager using a subscription to one or more profiles. Configuration information can include definitions of objects such as policy and schedules. See also configuration manager, enterprise configuration, profile, subscription.

Managed Service Provider (MSP)
A role that includes the practice of transferring day-to-day related management responsibility as a strategic method for improved effective and efficient operations.

managed software system (MSS)
An installed management system product that implements the managed operations that are targets for logical operations. An MSS contains information about configuration items, and this information is discovered by a sensor or discovery library adapter. Its functions might be invoked by a system integration module.

managed subscription
A subscription for which the queue manager creates a subscriber queue to receive publications because the application does not require a specific queue to be used. See also managed destination.

managed synchronization
The use of mapping files to synchronize a local z/OS project with a remote system.

managed system

  1. A particular operating system, subsystem, or application in an enterprise where a monitoring agent is installed and running.
  2. A system that is being controlled by a given system management application. See also dynamic LPAR, Hardware Management Console.

Managed System Services
An IBM licensed program that enables a system to be managed by a central site ES/9000 system running the IBM NetView Distribution Manager program. Managed System Services enables objects and program temporary fixes (PTFs) to be sent or retrieved, PTFs to be applied, programs to be run, and the central site system to control an initial program load (IPL) of the system.

management agent
An agent that is installed on a monitored computer and that communicates information to a management server. The management agent provides the following functions: discovery, listening and playback, ARM engine for data collection, policy management, threshold setting, event support, and Store and Forward.

management application
A software product or solution that uses the components of the Tivoli common agent services to manage a resource. A management application might provide one or more resource managers. See also resource manager.

management bundle
A set of XML files that is parsed to define and install platforms and applications. A management bundle describes one artifact such as a platform, an application, or an application binding, and references bundles that contain resources relating to the artifact. An example of a management bundle is an application bundle. See also bundle, CICS bundle.

management by subscription
In a Tivoli environment, the concept of managing network resources by creating sets of profiles and distributing the profiles (through profile managers) to physical entities (Tivoli resources), called subscribers.

Management Center
In WebSphere Commerce, a suite of tools that support store management, merchandising and marketing tasks for business users.

Management Central
A suite of systems management functions that is an integrated part of System i Navigator. Management Central provides the base for managing multiple systems.

management class
A policy object that users can bind to each file to specify how the server manages the file. The management class can contain a backup copy group, an archive copy group, and space management attributes. See also bind, copy group, hierarchical storage management client, policy set, rebind.

management collection
An object within the i5/OS operating system that includes the data for a number of collections. The collections begin when the collector is started and continue until the collection is either ended or cycled. The system-recognized identifier for the object type is *MGTCOL.

management console

  1. The main user interface for the system. The console is used to define and assign security policies, to configure and monitor agents, to define, monitor and analyze security events, to schedule system scans, and to create, generate and view reports.
  2. A system (server, desktop computer, workstation, or mobile computer) on which IBM Director Console is installed.
  3. A component of the system that is installed on a single machine to coordinate the system. The user logs in to the management console to start or schedule project runs and to view results and reports. The management console issues instructions to agents to complete jobs.

management control point
See management server.

management domain

  1. An area of knowledge relative to providing control over, and information about the behavior, health and lifecycle of manageable resources.
  2. In OSI X.400, a set of one or more message transfer agents and zero or more user agents that make up a system capable of handling messages and is managed by either an administration or private company.
  3. A set of nodes that are configured for management from a single point of control. See also managed node, management server.
  4. A set of nodes that are configured for management by Cluster Systems Management. Such a domain has a management server that is used to administer a number of managed nodes. Only management servers have knowledge of the domain. Managed nodes only know about the servers managing them. See also peer domain.

management host
The logical partition that hosts management software.

management information
In OSI, information--associated with a managed object--that is operated on by management protocols to control and monitor that object.

Management Information Base (MIB)

  1. In the Simple Network Management Protocol (SNMP), a database of objects that can be queried or set by a network management system. See also Simple Network Management Protocol.
  2. A definition for management information that specifies the information available from a host or gateway and the operations allowed.

Management Information Base variable (MIB variable)
A managed object that contains pertinent management information, which is accessible as defined by the access mode. The MIB variable is defined by a textual name and the corresponding object identifier, syntax, access mode, and status, as well as a description of the semantics of the managed object. See also MIB module.

management module
The BladeCenter component that handles system-management functions. It configures the chassis and switch modules, communicates with the blade servers and all I/O modules, multiplexes the keyboard/video/mouse (KVM), and monitors critical information about the chassis and blade servers.

management node

  1. A node that is used for configuring, administering, and monitoring a system.
  2. A node that is used for deploying, configuring, administering, and monitoring a cluster.

management plan
A set of tasks that modify a service deployment instance.

management protocols
In OSI, protocols for use in systems management.

management region
The set of managed objects on a particular map that defines the extent of the network that is being actively managed. The management region may vary across Tivoli NetView maps.

management rights
The limitation of console operators to a specified group of computers. Only a site administrator or a master operator can assign management rights.

management server

  1. A distributed process that controls runtime processing. All data management service requests are sent through the management server, which then sends requests to agents configured for the server.
  2. A system that provides a central point of control for managing data replication.
  3. The hardware component of Tivoli Service Automation Manager on which the product and its prerequisite middleware reside.
  4. A node that acts as a control point for the rest of the management domain. Only the management server has knowledge about the domain. A domain can have more than one management server, which is defined for high availability purposes, but only one node can be in control at a specific time. See also management domain.
  5. The control center of the Tivoli Monitoring for Transaction Performance software. The management server collects information from and provides services to the deployed management agents. The management server provides the services and user interface needed for centralized management.
  6. The server and logical partition (LPAR) that are configured to manage Cluster Systems Management nodes.
  7. A server on which the systems management software runs.
  8. The server on which IBM Director Server is installed.

management server domain
A type of cluster domain that consists of one or more management nodes that are used to administer one or more redundancy nodes. See also cluster domain node.

management server relationship
A connection between two replication servers, where one server acts as the active server and replicates the data that is necessary for the standby server to take control of the replication environment.

management services (MS)
In SNA, one of the types of network services in control points and physical units. Management services is the service provided to assist in the management of SNA networks, such as problem management, performance and accounting management, configuration management, and change management. See also session services.

management services focal point (MSFP)
For any given management services discipline (for example, problem determination or response time monitoring), the control point that is responsible for that type of network management data for a sphere of control. This responsibility may include collecting, storing, or displaying the data, or all of these. (For example, a problem determination focal point is a control point that collects, and that may store or display, problem determination data.) See also focal point.

management services unit (MSU)
A collection of major-vector encoded management services data. The management services unit may be carried by multiple transports, including the network management vector transport (NMVT), the control point management services unit (CP-MSU), or the multiple-domain support message unit (MDS-MU). See also control point management services unit.

management station
In Internet communications, the system responsible for managing all, or a portion of, a network. The management station communicates with network management agents that reside in the managed node by means of a network management protocol, such as the Simple Network Management Protocol (SNMP).

management topic
A set of operations and data elements that define a manageability interface for a managed resource. See also manageability interface.

management TOR switch
A top-of-rack switch that provides a private network connection between an IBM System z 196 (z196) Support Element (SE) and a IBM System z BladeCenter Extension (zBX). See also top-of-rack switch.

management VLAN
See service network.


  1. In DCE Remote Procedure Call (RPC), a set of remote procedures that implement the operations of an RPC interface and that can be dedicated to a given type of object.
  2. See managing process.
  3. The part of a distributed management application that issues requests and receives notifications; that is, uses the services of one or more agents.

manager access
The highest access level that can be assigned in a Notes database access control list.

Manager class
In AIXwindows, a metaclass that provides the resources and functionality to implement certain features, such as a keyboard interface and traversal mechanism. It is built from the Core, Composite, and Constraint classes.

manager entry point vector
In the Distributed Computing Environment Remote Procedure Call (RPC), the entry point vector used by the runtime code on the server side to dispatch incoming RPCs.

manager list
In OSI, a list that an agent maintains of the managing processes that are--or are eligible to become--managers of that agent.

manager node
In OSI, a node that provides a managing process.

manager role
In systems management, a role assumed by a user where the user is capable of issuing management operations and of receiving notifications.

managing process
In OSI, the part of a systems management application that monitors and controls the resources of an agent process. In OSI Communications Subsystem, the managing process can send operator commands to--and receive event reports from--its agent processes.

managing system
In systems management, an open system containing a user that can assume the manager role.

man command
In UNIX-based operating systems, a command that displays the specified man page.

mandatory access control (MAC)
A means of restricting access to objects on the basis of the sensitivity (as represented by a label) of the information contained in the objects and the formal authorization (clearance) of subjects to access information of such sensitivity. See also discretionary access control.

mandatory cryptographic session
See required cryptographic session.

mandatory entry field
A field in which an operator must enter at least one character.

mandatory-fill field
A field that a user must leave blank, or must fill in completely.

mandatory fill field
A field that a user must leave blank, or must fill in completely.

mandatory mode
A mode of remote mirroring in which I/O operations stop when the communication between the master and secondary volumes is broken. See also best effort mode.

mandatory print labeling (MPL)
A class, defined to the Resource Access Control Facility (RACF), that causes PSF to automatically label separator pages and data pages and to enforce the user-printable area.

mandatory support level
See base support level.

mandatory value profile
A user profile in zSecure Command Verifier that specifies and enforces the specific owner and default group of a new ID that is added to the RACF group hierarchy.

mangled name
An external name, such as a function or variable name, which has been encoded during compilation to include type and scope information.

The encoding, during compilation, of C++ identifiers such as function and variable names to include type and scoping information. The linker uses these mangled names for type-safe linkage. See also demangling.


  1. A shipment confirmation that may contain tracking identification information.
  2. A special file that can contain information about the files packaged in a JAR file. (Sun)
  3. A component of the service header that provides information (in the form of a structured listing) about the payload. It describes certain characteristics of the service content and also lists the number of attachments included in the payload.
  4. A file that describes the resources, the location of supporting artifacts, application prerequisites, and services that are included in a bundle to deploy part or all of an application.
  5. An XML file that describes the content of an entire migration package and that facilitates the deployment of the package in a target Maximo environment.
  6. A list of packages, cartons, cases, or pallets on a transportation vehicle.
  7. A list of data about a server that has been gathered by a collector. Manifest data is used by selectors to choose servers. Manifests for servers can be updated automatically or manually.

manifest file

  1. In Informix, an ASCII file, which must not be customized, that is automatically created during installation of a database server instance. The file contains a history of installation activity. See also response file.
  2. A file that contains information, such as settings, instructions, or metadata, about other files or artifacts.
  3. With Android apps, the manifest file specifies permissions and data collection parameters so that mobile devices can report required information from testers and customers. Different manifests are required for internal testers and customers.

manifest station
An area in a warehouse where parcel shipment containers are processed, so that each container is associated with the appropriate carrier's manifest.

man-in-the-middle attack
An intrusion in which an attacker intercepts messages between a user and a website in order to observe and record transactions.

A modification by an attacker of a data element, group of elements, action, or group of actions based on one or more properties. For example, modification of input by removing a required argument, or performing steps out of order.

A value that can be inserted into streams or extracted from streams to affect or query the behavior of the stream.

man page
In UNIX systems, one page of online documentation. Each UNIX command, utility, and library function has an associated man page.

manual adjustment
A one-time change to a value that is applied in specific scenarios. Administrators can add manual adjustments to any payee for any open period.

manual alert
An alert that a user enters for a specific shipment or order. For example, a shipper might add an alert to tell the carrier about a construction detour. See also tracer.

manual answer
In data communications, a line type that requires operator actions to receive a call over a switched line. See also automatic answer.

manual call
In data communications, a line type requiring operator actions to place a call over a switched line. See also automatic calling.

manual cartridge-entry processing
The process by which a volume is added to the tape configuration database (TCDB) when it is added to a manual tape library (MTL). DFSMSrmm can initiate this process.

manual connection
A virtual private network (VPN) connection in which all of the parameters of a manual connection must be set up manually. Manual connections do not automatically refresh the keys that maintain data security. See also dynamic connection.

manual discount percentage
The discount percentage that is calculated when a manual price adjustment is applied to the line items in an order or an order total.

manual emulator
An emulator that requires users to specify response values for an emulated component or reference at run time. See also emulator, programmatic emulator.

manual explore
The process of manually crawling a web application to access and test parts of the site that are dependent on input from a real user.

manual forms feed
The ability to manually feed a medium into a printing device rather than having the device automatically feed the medium.

manual IPL
See attended mode IPL.

manual load
In Q replication, a load process in which the user loads data into a target table and then notifies the replication program. See also automatic load.

manual mode

  1. The mode of operation in which DFSMSrmm runs without recording volume usage or validating volumes. The DFSMSrmm Time Sharing Option (TSO) commands, Interactive System Productivity Facility (ISPF) dialog, and inventory management functions are all available in manual mode. See also record-only mode, warning mode.
  2. An operating mode in which an administrator must manually initiate deployment requests on applications or application tiers.
  3. The mode of operation of an Automated Tape Library Dataserver (ATLDS) that allows the operator to locate and move the cartridges to and from drives and cells under the direction of the library manager. In manual mode, the robot is not operating. See also managed manual mode.

manual price adjustment rule
A pricing rule that enables a field sales representative to offer special discounts in the form of coupons or promotions to certain customers.

manual pricing rule
A rule that is used by a customer sales representative to perform pricing adjustments to a quote if certain conditions are met.

manual reporting
Workstation reporting in which events that have taken place are manually reported to Tivoli Workload Scheduler for z/OS. This type of reporting requires that some action be taken by a workstation operator. Manual reporting is usually performed from a list of ready operations.

manual tape library (MTL)
A set of tape drives defined as a logical unit (LU) by the installation, along with the set of system-managed volumes that can be mounted on those drives. See also Automated Tape Library Dataserver, tape library.

manual task
A release related task that users must manually complete. See also automated task.

manual tender
A tendering method in which the shipper submits the tender to a single carrier. Sterling TMS provides a list of eligible carriers, based on the criteria the shipper defined in the Route Guide. See also direct tender.

Manufacturing Automation Protocol (MAP)
In OSI, a specification developed by industrial users to provide a common set of protocols to allow communications between computers and factory floor equipment in the manufacturing environment. It is based on a subset of the open systems interconnection (OSI) standard.

manufacturing execution system (MES)
A system that provides an intelligent process control through an electronic system designed to execute instructions to control manufacturing operations.

manufacturing refresh
An update of an existing product release in which the product media are completely replaced. A manufacturing refresh contains the base product plus new function and cumulative fixes. See also interim fix, refresh pack, test fix.


  1. To establish a set of values having a defined correspondence with the quantities or values of another set; for example, to evaluate a mathematical function, that is, to establish the values of the dependent variable for values of the independent variable or variables of immediate concern. (I) (A)
  2. In BMS, a format established for a page or a portion of a page, or a set of screen format descriptions. A map relates program variables to the positions in which their values appear on a display device. A map contains other formatting information such as field attributes. A map describes constant fields and their position on the display, the format of input and output fields, the attributes of constant and variable fields, and the symbolic names of variable fields.
  3. A set of related submaps that provides a graphical and hierarchical presentation of a network and its systems.
  4. A collection of attribute-to-attribute mappings. See also mapping.
  5. In the EJB development environment, the specification of how the container-managed persistent fields of an enterprise bean correspond to columns in a relational database table or other persistent storage.
  6. A set of instructions that are defined in the Gentran Server for Windows Application Integration subsystem and that indicate the corresponding relationship between an application file and the EDI standards (including the Japanese Center for the Information of Industry (CII) standard), and defines how the system should translate data.
  7. An entity that contains the Java code to specify how to transform attributes from one or more source business objects to one or more destination business objects. A map either converts from an application-specific business object to a generic business object (outbound map) or from a generic business object to an application-specific business object (inbound map).
  8. A file that defines the transformation between sources and targets.
  9. A data structure that correlates keys to values.


  1. See maintenance analysis procedure.
  2. See message addressing property.
  3. See Manufacturing Automation Protocol.
  4. See mobile application part.

map component
An Integration Flow Designer object that encapsulates a reference to an executable map, along with its execution settings. There are three types of map components: source, compiled, and pseudo.

map definition
Definition of the size, shape, position, potential content, and properties of BMS map sets, maps, and fields within maps, by means of macros. See also field definition macro, map definition macro, map set definition macro.

map definition macro (DFHMDI)
In BMS, a macro that defines a map within the map set defined by the previous DFHMSD macro. See also map definition.

See Message Application Programming Interface.

MAPI gateway
An optional gateway that links the Mailbox Server mailboxes with predefined MAPI message stores.

MAPI profile
A profile that is used to store configuration information about a particular user of the MAPI service. These profiles keep track of the proper message storage areas, address book, and transport protocols for the user.

map object
An object used in the TX Programming Interface that represents an instance of a map in the program memory.

Map Page Segment structured field (MPS)
The Map Page Segment structured field identifies the page segments to be preloaded into the printer and that may remain in the printer while the entire print file is printed.

mapped address
A bidirectional mapping of one address to another.

mapped category value
A numeric value that the Metadata Model (MDM) assigns to each unique category full name in the metadata.

mapped condition
A mapped expression that specifies a mapping between the columns in a table and the fields of a business object, and an SQL WHERE clause that determines the data that is retrieved from the database. See also mapped expression, mapped key, mapped query.

mapped conversation
In advanced program-to-program communications (APPC), a temporary connection between an application program and an APPC session in which the system provides all the information on how the data is formatted.

mapped expression
A relationship between the data in a database and the fields of a business object, and an associated statement that determines the data that is retrieved from the database. See also mapped condition, mapped key, mapped query.

mapped file
A file that can be accessed through direct memory operations instead of being read from disk each time it is accessed.

mapped key
A mapped expression that specifies a mapping between the columns in a table and the fields of a business object, and that specifies which of these fields are used to determine the data that is retrieved from the database. See also mapped condition, mapped expression, mapped query.

mapped query
A mapped expression that specifies an SQL SELECT query or a stored procedure call that determines the data that is retrieved from a database, and a mapping between the columns in the query result set and the fields of a business object. See also mapped condition, mapped expression, mapped key.

mapped user name
An operating system identity for users who do not have operating system user accounts. The mapped user name is either mapped to an operating system account or to a default set of properties.

A function that records errors from resources attached to a communication controller or from certain channel-attached devices.


  1. In Enterprise Service Tools, the act of the user who models data transformation between an output message (represented by output terminal on one node) and an input message (represented by an input terminal on another node).
  2. A list, usually in a profile, that establishes a correspondence between items in two groups. For example, a keyboard mapping can establish what character is displayed when a certain key is pressed.
  3. The correlation of attributes between specifications. For imports, mappings relate the attributes of the file specification to the attributes of the primary specification of the catalog or hierarchy. For exports, mappings relate the attributes for the primary specification to the attributes of the destination specification. See also map.
  4. The act of developing and maintaining a map.
  5. A representation of one thing to another.
  6. In BMS, the process of transforming field data to and from its displayable form.
  7. The process of transforming data from one format to another.
  8. The relationship between fields in different abstractions of event and action objects.
  9. A set of expressions that define how to create data in the target database using data from a source. See also data source, integration adapter, target database.
  10. The process of defining the relationship between components to enable the flow of data from a data source to fact build or reference structure.

mapping cardinality
The granularity of the way that message elements are mapped from message source to message target. For example, one source element to one target element, or many source elements to one target element.

mapping expression
An expression that determines how Integration Composer transforms data instances in the original data source to a data instance in the target data source.

mapping file
A file that provides predefined mapping expressions to use to transform data instances in the original data source to data instances in of the target data source.

mapping link
A visual line that connects the fields on the input side of a map to mapped fields on the output side of a map.

mapping object

  1. A function of AFP Utilities that maps a database field value to an object name.
  2. The main object of the specified application from which the mapping is configured.
  3. An object that passes values to the IBM-supplied mapping program. It is used to customize the PDF subsystem without writing a mapping program. See also mapping program, PDF subsystem.

mapping program
An exit program used to interpret routing tags, to specify the subject of an email, to add text to the beginning of an email, to specify the path to store the PDF stream file, and more. See also intelligent routing, mapping object, PDF subsystem.

mapping repository
A mechanism to create or upload mapping rules for specific invoice formats.

mapping scheme
A set of rules that determines how information is displayed on a map.

mapping service
A service that intercepts requests that are sent from a client to a provider so that the requests can be transformed or rerouted to a different provider.

mapping specification
A set of mappings that describe how data is extracted, transformed, or loaded from one data source to another.

mapping table

  1. A table that the REORG utility uses to map the associations of the RIDs of data records in the original copy and in the shadow copy. This table is created by the user.
  2. An object that contains a set of hexadecimal characters used to map data from one character set and code page to another. For example, unprintable characters can be mapped to blanks, and lowercase alphabetic characters can be mapped to uppercase characters.
  3. A table for entering default jobs.

map record
The record that maps the tracks dumped by DFSMSdss.

map rule
An expression that evaluates to data and produces the required output. A map rule is entered on an output card in the Map Designer and cannot be longer than 32KB.

map service provider
A business or organization that offers software or products that provide access to maps and related services.

map set
In basic mapping support (BMS), one or more maps combined in a map set. Using a map set means that you can load simultaneously all maps needed for one application.

map set definition macro (DFHMSD)
A macro that is used to define a set of BMS maps. See also map definition.

map set suffix
In BMS, a suffix relating different versions of a map set to different terminal models or partitions. This allows you to format the same data differently on different screen types, in response to the same programming request.

The left and right borders of text on a screen or hardcopy page.

margin A
The margin between the 7th and 8th character positions of a reference format for a COBOL source program line.

margin B
The margin between the 11th and 12th character positions of a reference format for a COBOL source program line.

margin C
The margin between the 6th and 7th character positions of a reference format for a COBOL source program line.

margin L
The margin immediately to the left of the leftmost character position of a reference format for a COBOL source program line.

margin R
The margin immediately to the right of the rightmost character position of a reference format for a COBOL source program line.

margin text
Notes written in the margins on the top, bottom, left, or right of a document.

A symbol or symbols that indicate the beginning or the end of a field, a word, an item of data or a set of data such as a file, record, or block.


  1. In the GDDM function, a symbol centered on a point. Line charts may use markers to indicate the plotted points.
  2. In computer graphics, a glyph with a specified appearance that is used to identify a particular location.
  3. A visual symbol within a non-interactive pane indicating the location of the cursor when the pane was last interactive.

marker attribute
In architecture, a characteristic that controls the appearances of a marker; for example, size and color.

marker bar
The gray border at the left of the editor area of the workbench, where bookmarks and breakpoints are shown.

marker cell
In architecture, a conceptual rectangular box that can include a marker symbol and the space surrounding that symbol.

marker precision
In architecture, a method used to specify the degree of influence that marker attributes have on the appearance of a marker.

marker record
The name of a class used for physical records in records manager.

marker set
In GOCA, an attribute used to access a coded font. See also symbol set.

marker symbol
In architecture, a symbol that is used for a marker.

market basket analysis
A data mining process for analyzing sales transaction data that determines which products customers purchase together. Retail organizations can use market basket analysis to optimize the placement of products on websites or on shelves.

market data
Quote and trade-related data that is associated with financial instruments.

market depth
The number of bid levels or ask levels in an order book.

The process of planning and executing the conception, pricing, promotion and distribution of an offering and/or solution to create exchanges with target groups that satisfy customer and organizational objectives.

marketing channel
The highest level of marketing source categorization. By default, there are four channels: Direct Load, Natural Search, Referring Sites, and Other MMC Sources.

marketing event
In WebSphere Commerce, any event within the system that is considered to be significant for the purposes of marketing. Examples include catalog browsing, navigation, and shopping cart activity.

marketing experiment
A type of experiment that enables Marketing Managers to run alternative paths within existing web activities to determine whether small changes might improve the effectiveness of a web activity.

marketing manager
A defined role in WebSphere Commerce that monitors, analyzes, and understands customer behavior. The marketing manager also creates and modifies customer segments for targeted selling and creates and manages campaigns.

Marketing tool
A feature in Management Center to create and manage activities that support a site's marketing campaigns. Marketing Managers can use the tool's extensive features to deliver targeted marketing messages to customers on store pages, or using email or mobile text messages.


  1. An online intermediary that connects buyers and sellers. Marketplaces eliminate inefficiencies by aggregating offerings from many sellers or by matching buyers and sellers in an exchange or auction.
  2. A business-to-business e-commerce website in which those organizations granted access to the site are presented with a unified view of the products and services being traded on that site. They are also provided with a variety of trading mechanisms to facilitate trade among themselves.

mark field
A letter, number, symbol, character, or group of characters that is marked to indicate a respondent's answer to a categorical or grid question.

mark form sequence
In printing, a function that prints identifying marks on the perforations between jobs to make it easy to see the end of a job run. The sequence is controlled by the printer when it detects a mark form command.


  1. A method of updating certain structured fields to identify a resource as printer-resident.
  2. In QoS, the process of setting the bits in the Internet Protocol (IP) type-of-service byte. This is primarily a mechanism that is used in differentiated services. As an example, in-profile packets could be marked with one differentiated services code point, while out-of-profile packets are marked with another code point.

Markowitz threshold
A value that is associated with the Markowitz criterion for pivoting, which can be of use in a sparse matrix. The threshold condition requires that a selected pivot be a given multiple of the maximum value within its row. This condition is a guard against numerical instability which can result from choosing an extremely small pivot.

mark up
To insert markup into a source document.

Characters or other symbols that are inserted in a text or word processing file to indicate how the file should look when it is printed or displayed or to describe the document's logical structure.

markup card
A document that contains additional charges levied by the supplier apart from the contractor pay rate.

markup component
An additional charge levied by the supplier other than the fixed contractor pay rate.

markup-content separator (MCS)
In DCF, a delimiter used in GML markup that indicates the end of the markup and the beginning of the text. The default markup content separator for GML is a period (.).

markup language
A notation for identifying the components of a document to enable each component to be appropriately formatted, displayed, or used. XML is a markup language.

mark weight (MW)
A weight that is used in Arabic sorting to accommodate special needs of the Arabic script. See also alphanumeric weight, case weight, diacritical weight, indifferent weight, special weight.

marooned log data
In an RSR environment, active subsystem log data at the tracking subsystem that follows a gap. Marooned log data cannot be processed by the tracking subsystem until the log data that fills the gap has been received.


  1. To convert an object into a data stream for transmission over a network.
  2. To copy data into a remote procedure call (RPC) packet by using a stub. See also unmarshal.

See serialization.

See managed application system.

MAS configuration
See multi-access spool configuration.

A graphical interface that features two or more reusable web applications (widgets) presenting seemingly disparate data in an understandable combination for a specific purpose.


  1. To use a pattern of characters to control retention or elimination of portions of another pattern of characters.
  2. A pattern of bits or characters that controls the keeping, deleting, or testing of portions of another pattern of bits or characters.
  3. To redact sensitive information from view in order to protect it.
  4. A tool used to provide protection against casual viewing of a password that has been defined or altered, when an encryption function is not available.
  5. Data that is used to extract information that is stored in another location.
  6. A guide to recording answers to open-ended and numeric questions in a specific way. For example, a mask for a numeric question can specify the number of digits before and after the decimal symbol. A mask for open-ended questions can specify the maximum number of characters and other alphanumeric formatting.
  7. A pattern or template that is applied to an Internet Protocol (IP) address to specify which bits are significant and which bits are irrelevant.

masking character
A character used to represent optional characters at the front, middle, or end of a search term. Masking characters are normally used for finding variations of a term in a precise index.

To operate as another user, with all the permissions granted to that user.

masquerade NAT
A TCP/IP function that allows a user to translate multiple Internet Protocol (IP) addresses to another single IP address. Masquerade NAT is used to hide one or more IP addresses on an internal network behind an IP address that will be made public. Traffic can initiate from the private internal addresses only.

mass delete
The deletion of all rows of a table.

massively parallel processing (MPP)
The coordinated execution of a single request by multiple single-processor computers in a shared-nothing environment (in which each computer has its own memory and disks). See also database partitioning, interpartition parallelism.

mass update
The process of taking the same action for multiple individuals at once. For example, once a suitable candidate is identified for a single vacancy, a recruiter may mass reject all other candidates that applied to that position. For another example, a manager may mass approve/reject multiple employees' goals.

mass updating
A function of the Application Description dialog in which a large update to the application database can be requested.


  1. In a multi-MVS configuration, a region that issues commands to dependent regions at takeover time. See also coordinator.
  2. A slide view or page on which formatting for all slides or pages in a presentation is defined.

master account
The main account that is created by a service provider to which all the charges for a specific user group are allocated directly or indirectly. One or more sub-accounts can be assigned to a master account.

master address space
The virtual storage used by the master scheduler task.

master agreement
A framework agreement between a buying organization and a supplier that is used to define rates for future orders.

master bill of lading (master BOL)
A reference number that is used to track a shipment.

master BOL
See master bill of lading.

master build descriptor
In EGL, a build descriptor part whose options cannot be overridden.

master carton
Standard shipping carton of a size to hold smaller cartons being collected for shipment to a common customer or order. The master carton allows consolidation of a group of smaller cartons into one, reducing transportation cost.

master catalog

  1. A comprehensive list of items belonging to an organization.
  2. A key-sequenced data set (KSDS) or file with an index containing extensive data set and volume information that the Virtual Storage Access Method (VSAM) requires to locate data sets or files, allocate and deallocate storage space, verify the authorization of a program or operator to gain access to a data set or file, and accumulate usage statistics for data sets or files.
  3. The main catalog containing all products, SKUs, descriptions, and standard pricing for each product. See also online catalog, sales catalog.
  4. A hierarchy of items that is organized into groups for easy maintenance of items. It is created by default for each catalog organization when that catalog organization is defined.

master configuration
The configuration data held in a set of files that form the master repository for either a deployment manager profile or a stand-alone profile. For a deployment manager profile, the master configuration stores the configuration data for all the nodes in the network deployment cell.

master CQS
The Common Queue Server (CQS) that coordinates a sysplex-wide task. The other CQSs that share in the task are participants. If the master CQS fails for any reason, another CQS takes over the role of master and either continues or ends the task.

master cryptography key
In SNA products, a key that is used to encipher operational keys that are to be used at a node.

master data
Data about customers, suppliers, partners, products, materials, accounts and other critical entities, that is commonly stored and replicated across IT systems.

master database
In an RSR environment, a database at the active site. If a remote takeover occurs, the shadow database becomes the master database.

master data shard
In a sharded deployment, the data that exists in one master data shard per colony.

master data upload
A feature that allows the Enterprise Administrator to upload certain system data for their organization in a bulk or batch mode format.

master distribution schedule (MDS)
The primary plan that a company follows to distribute products to buyers.

master domain manager (MDM)
An installed component that performs the role of management hub of the top-level domain in the Tivoli Workload Scheduler network. It maintains the database of all scheduling objects in the domain and the central configuration files, as well logs and reports for the network. The master domain manager generates the plan and creates and distributes the Symphony file. See also backup master domain manager, command-line client, domain.

master dump table
A structure containing dump table entries generated by kernel components. The dump program uses this table to locate data structures that should be included in a dump.

master encryption key (MEK)
A key used to encrypt other keys. See also encryption key.

master file

  1. A collection of permanent information, such as a file of customer addresses.
  2. A file that is used as an authority in a given job and that is relatively permanent, even though its contents may change.

master index
An index made up of entries from two or more components or deliverables. Examples are master indexes for a product information center, a solution containing more than one product, or a PDF library.

master license plate (MLP)
A bar coded identifier that identifies a specific pallet and the contents of that pallet. A License Plate Number (LPN) identifies a collection of SKUs on a pallet or case. A Master License Plate (MLP) identifies a collection of LPNs on a pallet.

master location
A single identifier that is used to link multiple location records together that are in the same facility.

master metadata server
The metadata server in a cluster that is responsible for load balancing and physical-space allocation.

master model
One of two models used in model decomposition as applied in column generation techniques. See also model decomposition, submodel.

master name server
A name server that provides secondary name servers with domain data.

master node
See management node.

master operator
A console operator with administrative rights. A master operator can do almost everything a site administrator can do, with the exception of creating new operators.

master order
A type of order that enables users to specify a series of orders and the time intervals at which these orders will be shipped and charged to customers.

master port
In Fibre Channel trunking, the port that determines the routing paths for all traffic flowing through the trunking group. One of the ports in the first inter-switch link (ISL) in the trunking group is designated as the master port for that group. See also ISL Trunking.

master preventative maintenance record
A template that creates a schedule to generate work orders for required maintenance.

master price list
A price list that has one or more dependent price lists inheriting the price information from it.

master primary data set
The first data set activated in the primary RACF database. See also primary data set.

master production schedule (MPS)
A plan for manufacturing that a company follows that takes various demands into account.

master profile
In System i Access family, a file that contains the session profiles and keyboard profiles for a user's workstation function session.

master record
During one-source matching, the record that is considered to be the primary record of a set of related records. Each group of two or more matched records has one master record. See also duplicate record, one-source matching.

master release calendar
A view that displays timelines for all of the releases that are defined in the environment. The view provides general release information as well.

master replica

  1. In the DCE Cell Directory Service (CDS), the first instance of a specific directory in the namespace. After copies of the directory have been made, a different replica can be designated as the master, but only one master replica of a directory can exist at a time. CDS can create, update, and delete object entries and soft links in a master replica.
  2. In ClearCase MultiSite, the replica at which a mastered object can be modified or instances of the object can be created.

master replicate
An Enterprise Replication replicate that guarantees data integrity by verifying that replicated tables on different servers have consistent column attributes. See also replicate, shadow replicate.

master schema definition
A physical model of the inferred properties that are generated out of the selected data. It reflects the inferences of the data instead of the original definitions of the metadata.

master server
In a network installation environment, the server that has permissions to execute commands on all other machines in the environment. The master server is designed to manage the network, client, and resource objects in the network installation database.

The ability to modify an object or to create instances of an object in a replica.

master shipper
A group of shippers that have inventory allocated to them for picking.

master sort table
A system-supplied table that contains sort information required for sorting double-byte characters. This table is maintained by the character generator utility function of the Application Development ToolSet feature.

master style
A style that defines the layout and common elements for a master.

master supplier
A record of a supplier in the Emptoris Strategic Supply Management platform that has a unique ID and can be reused in other applications for transactions.

master system

  1. In z/VM Center, an operating system instance that has been set up to serve Virtual Server Deployment as a model for creating operating system templates.
  2. The MVS system on which the master DFSMSrmm control data set (CDS) resides.

master table

  1. A table that exists to define the range of an entity in a relational database. For example, a product master table would provide information about all the products of a company.
  2. In SQL replication, specifically in update-anywhere replication, the original source table for data in the replica table. If replication conflict detection is enabled, changes made to the master table are retained, whereas changes made to the replica table are rejected. See also conflict detection, replica table, update-anywhere replication.

master task card
A record that is associated with a configuration-managed part and is used to describe a maintenance task, including the interval at which it occurs, and is also used to create task cards for specific aircraft and components.

master terminal

  1. In CICS, the terminal at which a designated operator is signed on.
  2. The IMS logical terminal that has complete control of IMS resources during online operations.

master terminal formatting option
An MFS option that provides a format for a 3270 master terminal.

master terminal function
A function that allows a user to dynamically control and alter the operation of a CICS system.

master terminal operator (MTO)
Any CICS operator authorized to use the master terminal functions transaction.

master volume

  1. A volume that has snapshots.
  2. A private volume that contains data that is available for write processing.
  3. The first volume assigned to the system storage pool that stores the most critical system metadata.
  4. In most cases, the volume that contains a production copy of the data and that an application accesses. See also auxiliary volume, relationship.

master workbook
The initial collection of data that is created from an output results file. The data in a master workbook is read-only. See also workbook.

A collection of files that contain the parameters of the IBM Endpoint Manager process, including URLs that point to where trusted Fixlet content is available. The IBM Endpoint Manager Client brings content into the enterprise based on subscribed mastheads.

The part of a result that met a condition during a search operation. A search can yield a perfect match or a partial match.

match comparison
An algorithm that analyzes the values in columns and then calculates a score that contributes to the composite weight, which is used to determine the strength of the match. See also score, score.

match criteria
Parameters that shippers and carriers define to govern visibility to shipments and capacity. For example, a carrier can specify how far it is willing to travel to pick up a shipment.

match description
A description used to automatically match source and target dimension items with the same name. In addition, match descriptions can be used to perform an allocation by date.

Match Designer database
A database that stores the results of match test passes that are generated by InfoSphere QualityStage.

matched record
A data record that is identified to be the same as a reference record by a two-source matching process. See also clerical record, nonmatched record, two-source matching.

matched signature
A signature that is defined by multiple instances of a software signature.

match engine
A program that identifies groups of load modules or executable files in the Inquisitor tables as belonging to certain products.

match fields
In RPG primary or secondary multifile processing, fields within a record type that are to be used for checking the order of a single file, or for matching records of one file with those of another file.

match ID
See match identifier.

match identifier (match ID)
A string that identifies a dedicated fleet truck, continuous move, or round trip. Each shipment on a dedicated fleet, continuous move, or round trip route uses the same match ID.


  1. In MPTN architecture, pertaining to the relationship between peer transport users or peer transport providers that use the same user protocols or the same transport protocols.
  2. A probabilistic or deterministic record linkage process that automates either the identification of records that are likely to represent the same entity or the identification of a relationship among records. See also data deduplication, deduplication, one-source matching, score, two-source matching.

matching record indicator (MR indicator)
An indicator used in calculation or output specifications to indicate operations that are to be performed only when records match in primary and secondary files.

matching rule

  1. A rule that describes how to perform a comparison.
  2. The portion of a policy rule in a processing policy that defines the criteria to determine whether the message is processed by its processing rule.

match level
In RPG, the value (M1 through M9) assigned to the match field. The match level identifies fields by which records are matched during primary or secondary multifile processing.

match merge rule
See resolution rule.

match pay
A freight payment process that compares the carrier charges to the calculated shipment charges and automatically generates a voucher if the charges are within defined tolerances and thresholds. If the charges are not within tolerances and thresholds, the shipper must manually reconcile the charges. See also auto-pay.

match unknown
A query modifier option that when selected the query will display objects with unknown attributes.

material handling equipment (MHE)
Automated equipment, usually a conveyor, used for moving material from one point to another. It can have the capability for moving, scanning, weighing, putaway, retrieving, and sorting.


  1. To place an LOB value into contiguous storage. Because LOB values can be very large, DB2 for z/OS avoids materializing LOB data until doing so becomes absolutely necessary.
  2. To put rows from a view or nested table expression into a work file for additional processing by a query.

materialized query table (MQT)
A base table whose definition is based on the result of a query and whose data is in the form of precomputed results that are taken from the table or tables on which the MQT definition is based. See also summary table.

materialized view
A representation of table data that can contain columns from one or more tables.

material requirements planning (MRP)
A method of ensuring that materials and products are available to customers while maintaining the lowest possible inventory to keep costs down.

mathematical programming (MP)
A set of optimization techniques that were developed in operations research to solve intractable problems. See also constraint programming.

mathematic operator
A built-in function that performs a mathematic operation on two values. The mathematic operators are +, -, *, / and %. See also operator.


  1. In computers, a logic network in the form of an array of input and output leads with logic elements joined at some of their intersections.
  2. A data structure used to represent the coefficients of the variables in a set of linear functions that serve as the constraints in a problem. There is no limit on the number of dimensions of a matrix, but in practice most matrices are only two-dimensional. That is, they consist of one array, the elements of which are arrays themselves. See also array.
  3. A rectangular array of elements arranged in rows and columns that can be manipulated based on matrix algebra rules.

matrix code
A 2D barcode used for tagging. See also Quick Response code, tag, tagging.

matrix printer
See dot matrix printer.

matrix stack
In GL, a stack of matrices with hardware and software support.

A name element that is derived from the name of a person's mother or other female ancestor.

mature project
An existing project that has a work breakdown structure (WBS) and assigned resources.

See multistation access unit.

The number of conversations that can be active at one time.

max connects
The maximum number of foreground and background users and Time Sharing Option (TSO) connections allowed to a DB2 subsystem.

maximal character set
The largest registered character set that is assigned to a registered code page following a particular encoding scheme. See also full character set.

Maximo Anywhere project
A MobileFirst project that includes the content for building and deploying the Maximo Anywhere applications. The project is generated from the Maximo Anywhere directory.

Maximo business object (MBO)
A standardized data entity within Maximo.

In constraint programming, the greatest value in the domain of a variable.

maximum ascender height
The maximum of the individual graphic character ascender heights within a font character set.

maximum baseline extent
The sum of the positive maximum-ascender height and positive maximum-descender height.

maximum bid quantity
The maximum quantity of an item that a supplier can bid for.

maximum burst size (MBS)
The maximum number of cells that an asynchronous transfer mode (ATM) endsystem can transmit at the peak cell rate. See also peak cell rate, sustainable cell rate.

maximum descender depth
The maximum of the individual graphic character descender depths within a font character set.

maximum desired quantity
The maximum number of items that the buyer wants to procure.

maximum high key
The high key that has the maximum value.

maximum instructions per transaction
The number of system instructions per transaction that the instruction sheet interpreter (ISI) process will execute before temporarily storing the work item in the ISI queue.

maximum operations per transaction
The number of database operations per transaction that the instruction sheet interpreter (ISI) process will execute before temporarily storing the work item in the queue.

maximum possible score
A score that describes the maximum of the maximum scores of all individual scorecards. The maximum possible score is a complex scorecard property, its value should be the same in all the scorecards used in a complex scorecard.

maximum score
The upper limit in a given interval for an attribute that is used in determining reason code assignment. Typically used for linear and logistic models where variable interaction is controlled.

maximum speed
The rated speed of the printer with an optimal amount of data per page. Speed is measured in 8.5-by-11-inch pages in characters per second (cps), impressions per minute (ipm), lines per minute (lpm), or pages per minute (ppm),

maximum SSCP rerouting count
The maximum number of times that a session initiation request will be rerouted to intermediate system services control points (SSCPs) before the request reaches the destination SSCP. This count is used to prevent endless rerouting of session initiation requests.

maximum transfer unit (MTU)
The maximum number of bytes that an Internet Protocol (IP) datagram can contain.

maximum transmission unit (MTU)
The largest block that can be sent on a given physical medium in a single frame. For example, the maximum transmission unit for Ethernet is 1500 bytes.

maximum workspace
The amount of memory reserved for Analyst. The maximum workspace may be changed to allow larger models to run more effectively.

See megabyte.

See megabit.

See mobile backend as a service.

See multibyte character set.

See Managed Bean.

MBean command
A command entered into a wsadmin command session that is associated with, and can control, an IBM Connections application that runs on the server. MBean commands are grouped into services that perform related tasks, such as managing application membership.

MBean provider
A library containing an implementation of a Java Management Extensions (JMX) MBean and its MBean Extensible Markup Language (XML) descriptor file.

See more-data bit.

See Maximo business object.

See megabits per second.

See megabytes per second.

See maximum burst size.

A small (256-byte) buffer provided by the mbuf management facility to the various layers of communication software in AIX.


  1. See message channel agent.
  2. See Micro Channel architecture.

A proprietary transfer protocol of Tivoli Provisioning Manager for OS Deployment that delivers the same file to several target computers using multicast. See also PCAST, unicast.

See migration control data set.

See machine check handler.


  1. See message channel interface.
  2. See media control interface.

See multiple chip module.


  1. See markup-content separator.
  2. See multiple console support.
  3. See message control system.

MCS console
A device that can be physically attached to a global or local processor.

See multipoint control unit.

A type of message algorithm that converts a message of arbitrary length into a 128-bit message digest. This algorithm is used for digital signature applications where a large message must be compressed in a secure manner.

See message-driven bean.


  1. See metadata controller.
  2. See modify current plan.

MDC table
See multidimensional clustering table.

MD driver
See multiple device driver.


  1. See multiple device file.
  2. See main distribution frame.

See migration data host.

See managed disk.

See Model Definition Language.


  1. See master domain manager.
  2. See Metadata Model.

See Message Disposition Notification.

See miscellaneous data record.


  1. See main device scheduler.
  2. See multiple-domain support.
  3. See master distribution schedule.

See metadata source component.

MDS message unit
See multiple-domain support message unit.

See multiple-domain support message unit.

See modified data tag.

See Multidimensional Expression Language.

In architecture, a table heading for architecture syntax. The entries under this heading convey the meaning or purpose of a construct. A meaning entry can be a long name, a description, or a brief statement of function.

mean time between failures (MTBF)

  1. The average time in seconds between the recovery of one incident and the occurrence of the next one.
  2. A number representing the hours between initial use and failure of an average unit in a specific population of units under specified conditions. MTBF is obtained by dividing the total number of failures into the total number of operating hours of all units.

mean time to recovery (MTTR)

  1. The average time it takes to make a system operational after a failure.
  2. The average number of seconds between an incident and service recovery.

mean time to repair (MTTR)

  1. A measure of serviceability indicating the expected time required to repair a unit after failure.
  2. See mean time to recovery.


  1. A value that can be analyzed, such as the number of defects.
  2. Measurable information in a dimension row. Common measures are spend and count.
  3. A performance indicator that is quantifiable and used to determine how well a business is operating. For example, measures can be Revenue, Revenue/Employee, and Profit Margin percent.
  4. A component that is used to define a unit in XBRL. For example, the unit km/s (kilometers per second) contains two measures: kilometers and seconds. See also fact.
  5. A metric combined with an aggregation type such as average, count, maximum, minimum, sum, or average. See also aggregate metric.
  6. Metrics such as count, maximum, minimum, sum, or average that are used in a fact table. Measures can be calculated with an SQL expression or mapped directly to a numeric value in a column.

measure element
An element in the transformation model that represents a business measure.

measure folder
A folder that groups measures from a model into logical groupings. A measure folder can contain measures, and it can be a measure and have a value.

measurement base
In architecture, a base unit of measure from which other units of measure are derived.

measurement point
A record that defines the acceptable upper and lower conditions and performance limits for a point or place on a piece of equipment.

measurement set
A component of the configurable service for a MedicalDeviceInput node that contains one or more measurements and specifies the device type that can be used.

measurement source
The source application where a measurement originates.

measuring and test equipment (M&TE)
A calibrating tool that has a higher degree of accuracy than the asset being calibrated.

A specific algorithm or operation (such as a queueing discipline) that is implemented in a node to realize a set of one or more per-hop behaviors.


  1. Magnetic disks, magnetic tapes, compact discs (CDs), and digital video disks (DVDs).
  2. In Backup, Recovery, and Media Services, physical tape cartridges, tape reels, or removable storage devices available for use by the system. This media is grouped into media classes for management, tracking, and statistical analysis.

Media Access Control (MAC)
In networking, the lower of two sublayers of the Open Systems Interconnection model data link layer. The MAC sublayer handles access to shared media, such as whether token passing or contention will be used.

Media Access Control address (MAC address)
A hardware address that uniquely identifies each node of a network. On a local area network (LAN), the MAC address is the unique hardware number of a computer's network adapter card.

Media Access Control protocol (MAC protocol)
In a local area network, the protocol that determines which device has access to the transmission medium at a given time.

Media Access Control sublayer (MAC sublayer)

  1. One of two sublayers of the ISO Open Systems Interconnection data link layer proposed for local area networks by the IEEE Project 802 Committee on Local Area Networks and the European Computer Manufacturers Association (ECMA). It provides functions that depend on the topology of the network and uses services of the physical layer to provide services to the logical link control (LLC) sublayer. The OSI data link layer corresponds to the SNA data link control layer.
  2. In a local area network, the part of the data link layer that applies a medium access method. The MAC sublayer supports topology-dependent functions and uses the services of the physical layer to provide services to the logical link control sublayer.

media access method
The method for determining which device has access to the transmission medium at any time.

media access port
A hardware component (such as a communication adapter) of a node, which can be addressed, that gives the node access to a transmission medium and enables data to pass into and out of the node.

media archiver
A physical device that is used for storing audio and video stream data. The VideoCharger is a type of media archiver. See also storage system.

media class
In Backup, Recovery, and Media Services, a user-defined name used to identify the type and characteristics of the physical media to be managed as a group for backup, archive, or recovery operations. Each media class is distinguished by attributes, such as format or capacity, that are used by the system.

media control interface (MCI)
An interface that is used to control multimedia devices. Each device must have an MCI driver that implements a standard set of MCI functions. Also, each MCI driver can implement functions that are specific to a particular device.

media destination
The destination to which sheets are sent as the last step in the print process. See also media source.

media format
The type of volume, recording format, and techniques used to create the data on the volume.

media gallery
A community widget that displays photos and videos.

media image
In WebSphere MQ on UNIX and Linux systems and WebSphere MQ for Windows, the sequence of log records that contain an image of an object. The object can be re-created from this image.

media inventory
In Backup, Recovery, and Media Services, a library that contains information about media that has been enrolled in Backup, Recovery, and Media Services. The media inventory contains information such as volume serial identifier, expiration date, creation date, and location. Media in the media inventory is used for backup, archive, and recovery operations.

Pertaining to a personal computer or workstation that does not have a diskette or tape drive or a hard disk.

medialess programmable workstation
A programmable workstation that does not contain a diskette or tape drive or a hard disk. Cooperative processing is done through a shared folder on the server.

media library device (MLD)
A tape storage device that contains one or more tape drives, tape cartridges, and a part (carriage and picker assembly) for moving tape media between the cartridge storage slots and the tape drives.

media management
In Backup, Recovery, and Media Services, the overall control, cataloging, and tracking of removable media by status, storage location, container placement, and contents by volume from creation to expiration. Backup, Recovery, and Media Services tracks only enrolled volumes. Tapes and other media are managed by media class and individual volumes within the class. Both active and expired media are tracked by volume serial number.

media management system
A program that assists in managing removable media. DFSMSrmm is an example of a media management system.

media origin

  1. One of the four corners of the physical medium (usually paper) where printing begins.
  2. The reference point from which the logical page origin is positioned by the medium map. This point is represented by Xm=0, Ym=0 in the Xm, Ym coordinate system. The media origin is defined relative to the top-left corner of the form. See also logical page origin, paper origin.
  3. The first hardware addressable point on the physical sheet.

media policy
In Backup, Recovery, and Media Services, a policy that defines the default values used for management of a media class. A user can have multiple media policies (one for each media class) to define such things as the move policy used for this media class, the type of retention, the use of save files, and the number of copies to be made. Values for a media policy are inherited from the system policy and can be overridden by the media policy or by the user at the control group level.

media pool
In Backup, Recovery, and Media Services, a grouping of media by similar characteristics such as by tape density or tape capacity. A media pool is used to help track media and protect the active data on the media. Synonymous with media class.

media server

  1. An AIX-based component of the Content Manager system that is used for storing and accessing video files.
  2. In a z/OS environment, a program that provides access to z/OS disk and tape storage for Tivoli Storage Manager servers that run on operating systems other than z/OS.

media set

  1. In software distribution and installation, a multivolume CD-ROM, CD-R, or tape group created for the purpose of distributing a selection of software to customers for installation on to the system. Some media sets, for example, a system software release upgrade media set, may consist of a collection of smaller media sets, each containing a specialized selection of the Licensed Internal Code, licensed programs, the operating system, and program temporary fixes needed to operate the system and use it to do business.
  2. In Backup, Recovery, and Media Services, a multivolume tape group created as a result of a backup operation or archive operation. Media sets are managed as a group to provide consistent management of single and multivolume output and to provide integrity in cases where an individual volume in a media set is expired in advance of the remaining volumes.

media source
The source from which sheets are obtained for printing. Some printers support several media sources so that media with different characteristics (such as size, color, and type) can be selected when desired. See also media destination.

An application of service interaction logic to messages flowing between service requesters and providers.

mediation flow
A sequence of processing steps, or mediation primitives, that run to produce the mediation when a message is received. See also message flow.

mediation flow component
A component that contains one or more mediation primitives arranged into request and response flows. Rather than performing business functions, mediation flow components are concerned with the flow of messages.

mediation framework
A mechanism that supports creation of mediation flows through the composition of mediation primitives.

mediation module
An SCA module that includes a mediation flow component and primarily enables communication between applications by changing the format, content, or target of service requests.

mediation period
A process to achieve a resolution within a predefined time period after a noncompliance event occurs.

mediation policy
A policy that is held in a registry and is applied to a Service Component Architecture (SCA) module. The mediation policy enables mediation flows, which are in the module, to be configured at run time by using dynamic properties.

mediation policy attachment
An attachment that is a prerequisite for using the mediation policy and gate conditions on the mediation policy.

mediation primitive
The building blocks of mediation flow components.

mediation service
A service that intercepts and modifies messages that are passed between client services (requesters) and provider services.

mediation subflow
A preconfigured set of mediation primitives that are wired together to create a common pattern or use case. Mediation subflows run in the context of a parent flow, and can be reused in mediation flows or in subflows.

mediator DSA
A type of data source adaptor that allows data provided by third-party systems, devices, and applications to be accessed.

Medical Subject Headings (MeSH)
The U.S. National Library of Medicine's controlled vocabulary thesaurus. It consists of sets of terms naming descriptors in a hierarchical structure that permits searching at various levels of specificity.


  1. The material on which computer information is stored. Examples of media are diskettes, CDs, and tape.
  2. A physical carrier of information.

Medium Access Control
See Media Access Control.

medium access control protocol (MAC protocol)
In a local area network, the protocol that governs access to the transmission medium, taking into account the topological aspects of the network, in order to enable the exchange of data between data stations.

medium access control sublayer (MAC sublayer)
In a local area network, the part of the data link layer that applies a medium access method. The MAC sublayer supports topology-dependent functions and uses the services of the physical layer to provide services to the logical link control sublayer.

medium attachment unit
See transceiver.

medium map
An internal object in a form definition or a print data set that controls such items as modifications to a form, page placement, and overlays.

medium name
In DFSMSrmm, a value of up to eight characters that describes the type and shape of removable media located in a storage site.

medium origin
See media origin.

medium overlay
An electronic overlay that is invoked by the medium map of a form definition for printing at a fixed position on the form. See also page overlay.

medium presentation space
In architecture, a two-dimensional conceptual space with a base coordinate system from which all other coordinate systems are either directly or indirectly derived. A medium presentation space is mapped onto a physical medium in a device-dependent manner. See also physical medium.

An open-source mobile Linux operating system. MeeGo is usually used for entry-level devices. MeeGo was based on a combination of Moblin and Maemo. See also Maemo, mobile operating system, Moblin, Tizen.

meeting room center
A feature that provides information about stored meeting rooms, such as owners, managers, room settings, and usage statistics.

meet-in-the-middle mapping
An approach for mapping enterprise beans to database tables in which enterprise beans and database schema are created simultaneously but independently.

megabit (Mb)

  1. For processor storage, real and virtual storage, and channel volume, 2 to the power of 20 or 1 048 576 bits. For disk storage capacity and communications volume, 1 000 000 bits.
  2. In data communications and data transfer, 10 to the 6th power or 1 million binary pulses.

megabits per second (Mbps)
A measure of bandwidth on a data transmission medium, where 1 Mbps = 1,000,000 bits per second. See also kilobits per second.

megabyte (MB)
For processor storage, real and virtual storage, and channel volume, 2 to the 20th power or 1,048,576 bytes. For disk storage capacity and communications volume, 1,000,000 bytes.

megabytes per second (MBps)
A unit of data transfer rate equal to 1024 * 1024 bytes.

megahertz (MHz)
A unit of measure of frequency. One megahertz equals 1 000 000 hertz.

See master encryption key.


  1. A person, group, or organization known to the system. A member can be a user, an organization, an organization unit, or a member group.
  2. A portion of the system that contains the software and processing for specific tasks. There are four member types in the system: catalog, container, informational, and operational.
  3. A user who has no administrative rights and has access to one or several workspaces.
  4. A specific function of a multisystem application that is defined to the cross-system coupling facility (XCF) and assigned to a group by the multisystem application. A member residing on one system in a sysplex can use XCF services to communicate with other members of the sysplex.
  5. In SQL, a component of an opaque data type that can be accessed by an SQL statement by using a user-defined accessor function.
  6. A C++ data object or function in a structure, union or class. Members can also be classes, enumerations, bit fields and type names.
  7. In the Type Designer, a single occurrence of a component in a group in a type tree. If a component has a range, each occurrence of that component might be referred to as a member of a series.
  8. A field or method of a class.(Sun)
  9. A node in a dimension or reference structure.
  10. In IBM i, one of several different sets of data, each with the same format, within one database file.
  11. Someone who belongs to an IBM Connections community.
  12. A data object in a structure, a union, or a library.
  13. In multidimensional clustering, the element of a dimension. See also dimension.
  14. A unique item within a hierarchy. For example, Camping Equipment and 4 Man tent are members of the Products hierarchy. See also category, dimension item, member unique name.
  15. A single database manager process that runs DB2 server software on a physical or logical host. See also guest member, resident member.
  16. A partition of a partitioned data set (PDS) or partitioned data set extended (PDSE).

member combination
See cell.

member crash recovery
In a DB2 pureScale instance, the process of recovering the database transactions after a member failure. Recovery is done using the log stream of a single member and ensures consistency of the transactions in the log stream. See also group crash recovery.

member function
A C++ operator or function that is declared as a member of a class. A member function has access to the private and protected data members and member functions of an object of its class.

member group
A group that is used to implement role-based control in WebSphere Commerce. A customer group is for general use, while an access group is for access control purposes.

member ID
The member name of a resource object minus the 2-character prefix. For example, BITR is the member ID of the font whose member name is X1BITR.

member manager
See virtual member manager.

member name

  1. The z/OS XCF identifier for a particular DB2 for z/OS subsystem in a data sharing group.
  2. In AFP, the name under which a file is stored in a library. For example X1S0BITR is the member name of a font in the font library.

member profile
A profile that defines a member and security level for that member.

member restart
The act of restarting a member after a member failure and performing member crash recovery on each database in the DB2 pureScale instance. See also group restart.

The state of being a portal user and a place member. Membership in the portal is controlled by the administrator during the installation and set up of portal servers. Membership in places is controlled by a place manager, who determines the level of access for each place member: participant, place designer, or place manager.

membership level
A customer attribute that shows the level of membership that a customer is at. Examples include gold, silver, platinum, and so on.

membership policy
A subexpression that is evaluated against the nodes in a cell to determine which nodes host dynamic cluster instances.

membership protocol
A mechanism whereby all cluster managers running in a cluster determine which nodes are members of the cluster and handle membership transactions.

member system
Any one of the z/OS system images in a multisystem RRSF node.

member unique name (MUN)
A path of member names, one from each level in a hierarchy, defining the exact location of the member from either an OLAP data source or a dimensionally modeled relational source. For example, Geography.Europe.France.Paris uniquely identifies Paris, France, distinguishing it from other instances of Paris in the City level. See also category code, member.

memorandum macro (mm)
A macro for manuscript preparation and printing that supports the eqn and troff commands or the neqn and nroff commands and features annotation, footnoting, indexing, and tables.


  1. All of the addressable storage space in a processing unit and other internal storages that is used to execute instructions.
  2. Program-addressable storage from which instructions and other data can be loaded directly into registers for subsequent running or processing. See also auxiliary storage.

memory affinity
A feature available in AIX to allocate memory attached to the same multiple chip module (MCM) on which the process runs. Memory affinity improves the performance of applications on some IBM Power Systems servers.

memory dump

  1. The means by which the computer system records its state at the time of a failure.
  2. See dump.

Memory Grant Manager (MGM)
A database server component that coordinates the use of memory and I/O bandwidth for decision-support queries.

memory image
The logical layout of the parts of a process in memory.

memory leak
The effect of a program that maintains references to objects that are no longer required and therefore need to be reclaimed.

memory load control
A Virtual Memory Manager (VMM) facility that detects memory over-commitment and temporarily reduces the number of running processes, thus avoiding thrashing.

memory mapped I/O (MMIO)
A method of accessing an input or output port as if it were a memory location.

memory pool
A logical division of memory (storage) that is reserved for processing a job or group of jobs. Synonymous with main storage pool.

memory set
A group of one or more memory allocations from the operating system that are managed by the database manager. Memory in a specific memory set shares common attributes, such as the general purpose for which the memory is used, the expected volatility of the memory, and any constraints on its growth.

memory weight
A relative value that is one of the factors in determining the allocation of physical memory to the shared memory partitions. A higher value relative to the values set for other shared memory partitions increases the probability of the hypervisor allocating more physical memory to the shared memory partition.

In social media, a reference to another user that provides a link to that user's profile as well as sending them a notification of the mention. For example, in Twitter, members can use the "@" sign in conjunction with someone's user name to mention them.

A displayed list of items from which a user can make a selection.

menu bar

  1. The area near the top of a window, below the title bar and above the rest of the window, that contains choices that provide access to other menus.
  2. In the AIX operating system, a rectangular area at the top of the client area of a window that contains the titles of the standard pull-down menus for that application.

menu bar field
In DDS, a panel element that contains a numeric field containing one or more menu-bar choice keywords.

menu bar separator
In DDS, a panel element that contains a horizontal line that appears directly below a menu bar.

menu bar switch key
A key that alternates the cursor between the menu bar and that application display.

menu file
A text file that contains specific syntax to add menu items to any menu.

menu pane
The physical window containing a pop-up menu listing a group of options to be chosen by the user.

menu security
A function of the operating system that controls which system resources are available to users. Menu security restricts a user to a single menu or a sequence of menus that are defined in the user profile.

menu system
An interactive interface that lists related software options in a manner that expedites review and selection by the user.

See message exchange pattern.

The variety, display, and promotion of products for purchase and the management of quantity, price, and placement.

merchandising association
An association between two catalog items for the purpose of a sales activity. For example, a camera might have a "requires" merchandising association with a set of batteries, and a dictionary might have a "goes with" merchandising association with a thesaurus. See also accessory.


  1. The commit that results after bringing content from another branch into the current branch.
  2. To insert records throughout a single output file.
  3. A point in the process where two or more alternative sequence flow paths are combined into one sequence flow path. No synchronization is required because no parallel activity runs at the join point. BPMN uses multiple incoming sequence flow paths for an activity or an exclusive gateway to perform a merge.
  4. A process element that recombines multiple processing paths, typically after a decision. A merge brings several alternative paths together.
  5. To consolidate source data in the transformation model using a specified merge method. Data can be merged for measure elements or attributes.
  6. To combine one stream or baseline into another stream.
  7. A process in which duplicate records are removed and a unique ID is assigned to each record.
  8. To combine overrides for a file from the first call level up to and including a greater call level, producing the override to be applied when the file is used.
  9. To fetch content from one branch and apply it to another branch.

MERGE disk
The virtual disk in the VM operating system that contains program temporary fixes (PTFs) after the VMFMERGE EXEC is invoked. See also DELTA disk.

merged item
An item that is created by merging the information held in two or more items. See also item.

merge file
In COBOL, the temporary file that contains all the records to be merged by a MERGE statement. The merge file is created and can be used only by the merge function.

merge method
The type of calculation to perform when merging data.

merge node
A node used for zone skipping in order to minimize shipping costs.

A sorting algorithm that merges sorted lists into larger sorted lists; in Netezza, DBOS on the host performs a merge-sort of sorted data received from multiple SPUs.


  1. See miscellaneous equipment specification.
  2. See manufacturing execution system.

A network topology in which devices are connected with many redundant interconnections between network nodes. Every node has a connection to every other node in the network.

See Medical Subject Headings.

mesh-connected session network
A configuration where every network node has a control point-to-control point session to every other network node. As the number of network nodes increases, the number of CP-to-CP sessions increases dramatically.

mesh network
A network in which there are at least two nodes with two or more paths between them.


  1. Status information that the engine returns about a build or JobStream execution.
  2. One or more linked blocks of data or information, with associated STREAMS control structures containing a message type. Messages are the only means of communicating within a stream.
  3. In Web Services Description Language (WSDL), a single piece of information moving between the invoker and the service that describes which operations the service provides. A message consists of logical parts, each of which is associated with a definition within some type of system.
  4. An informational event that does not require user action. See also event.
  5. A unit of information made up of a header consisting of meta-information and a body consisting of the message data.
  6. In system programming, information intended for the terminal operator or system administrator.
  7. A set of data that is passed from one application to another. Messages must have a structure and format that is agreed by the sending and receiving applications. See also category.
  8. A communication sent from a person or program to another person or program.
  9. In UML modeling, a model element that defines a specific kind of communication between participants (roles or objects) in an interaction.
  10. In OSI Message Services, a piece of electronic mail in the format of the X.400 CCITT standard. An X.400 message can be a document, note, message, or file.
  11. To send an instant message.
  12. An object that depicts the contents of a communication between two participants. A message is transmitted through a message flow and has an identity that can be used for alternative branching of a process through the event-based exclusive gateway.
  13. A string of bytes that is passed from one application to another. Messages typically comprise a message header (used for message routing and identification) and a payload (containing the application data being sent). The data has a format that is compatible with both the sending and receiving application.
  14. In EDIFACT and TRADOCOM, a business document, such as a purchase order or invoice, that can be represented in any supported format. For example, an XML purchase order and an EDI purchase order are both documents, but each uses a different format. See also document.
  15. An assembly of characters and sometimes control codes that is transferred as an entity from an originator to one or more recipients. A message consists of two parts: envelope and content.

message addressing property (MAP)
An XML element that conveys addressing information for a web service message, such as a unique message ID, the destination of the message, and the endpoint references of the message.

message affinity
The relationship between conversational messages that are exchanged between two applications, where the messages must be processed by a particular queue manager or in a particular sequence.

Message Application Programming Interface (MAPI)
A layered messaging subsystem that is built into Microsoft Windows. This subsystem acts as a broker between a client (such as Mailbox Server) requesting services, and the messaging system (such as Microsoft Exchange Server) providing those services.

message area
In BMS, the area of a screen used to send instruction messages to assist the operator in processing a transaction. This area should be separate from the application data area to allow communication with the operator, without disturbing the application data. The message area is normally the bottom one or two lines of the screen.

message authentication
A process that verifies the identity of the sender and the integrity of the data. PowerHA SystemMirror can take advantage of the encryption services provided by base AIX for encrypting messages before sending and decrypting them after being received.

message authentication code (MAC)
In computer security, a value that is a part of a message or accompanies a message and is used to determine that the contents, origin, author, or other attributes of all or part of the message are as they appear to be.

message authentication key
In Cryptographic Support, a data encrypting key used to encrypt data to produce a message authentication code.

message-based schedule
A schedule that is used to trigger job execution by an event signaled by a Java Messaging Service (JMS) message. For example, when a job relies on the input from a third-party application, the application must send a JMS message when the input file is ready for processing.

message body
The part of the message that contains the message payload. See also message header.

message box
A secondary window that displays a message about a particular situation or condition.

message cache
A temporary storage queue with the name DFHMxxxx, where xxxx is the identification of a logical unit, into which CICS reads messages (for message-protected tasks only) during emergency restart. A user-written inquiry program run after emergency restart can read the contents of message caches. CICS does not read or purge message caches.

message catalog
An indexed table of messages. Two or more catalogs can contain the same index values. The index value in each table refers to a different language version of the same message.

message category
A group of messages that are logically related, such as message that are all used by one application.

Message Center
An IBM product that uses DirectTalk's voice processing capabilities to provide a wide range of voice mail, fax, and email functions.

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. See also 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.

message channel interface (MCI)
The WebSphere MQ interface to which customer-written or vendor-written programs that transmit messages between a WebSphere MQ queue manager and another messaging system must conform. See also Message Queue Interface.

message choreography
The exchange of business actions and business signals required to complete a business activity specified by a particular standard process.

message class
A class, assigned to a transaction code, that determines within which message region an application program is to process that transaction. See also class, region class, transaction class.

message component
A message summary that contains information about the message such as the sender, receiver, subject, protocol type, and any attachments included with the message.

message consumer

  1. A program, function, or organization that gets and processes messages. See also consumer, event handler.
  2. In JMS, an object that is created within a session to receive messages from a destination.

message context
Information about the originator of a message that is held in fields in the message descriptor. There are two categories of context information: identity context and origin context.

message control block
In the X.25 API, the structure used to indicate what type of packet has arrived and to point to the structure that contains the packet information.

Message Control Information
The part of the Open Transaction Manager Access (OTMA) message prefix that contains such information as the transaction pipe name and the message type. It is not contiguous with the rest of the message prefix and it must be specified for every OTMA message.

message control system (MCS)

message data set

  1. In PSF, a virtual data set built by the library access system interface (LASI) subcomponent in memory to store error messages for printing at the end of the document.
  2. The message data set is used principally to pass messages about the current state of specific resources from the active system to the alternate system. It is also used for the secondary surveillance signals of the active, alternate, or both CICS systems, when the control data set is unavailable for this purpose, either because the last write has not completed yet or because of I/O errors.
  3. A data set on disk storage that contains queues of messages awaiting transmission to particular terminal operators or to the host system.

message definition
Information that describes the structure of the messages of a particular type, the elements that each message of that type can or must contain, how a message of that type is represented in various network formats, and the validation rules that apply to a message of that type.

message definition file
A file that contains the messages, elements, types, and groups that make up a message set.

message delete option
An option that may be defined to prevent nonessential messages from being sent to a specific terminal.

message delivery preference
The subscriber's choice of whether voice mail is stored as voice mail only, as email only, or as both voice mail and email.

message delivery type
The format in which a voice message is delivered.

message descriptor
Control information describing the message format and presentation that is carried as part of a WebSphere MQ message. The format of the message descriptor is defined by the MQMD structure.

message destination
A destination that is a transaction, an LTERM, an MSNAME, or a command.

message digest

  1. A fixed-size, numeric representation of the content of a message, which provides assurance that the message has not been modified. The message digest is sent with the message itself. The receiver can generate a digest for the message and compare it with the sender's digest. If the two digests are the same, this verifies the integrity of the message.
  2. A hash value or a string of bits resulting from the conversion of processing data to a number.

Message Disposition Notification (MDN)
A receipt document that contains the message ID and status information from the original message. See also receipt.

message domain

  1. A group of all the message definitions that are required to satisfy a particular business need (for example, transferring SWIFTNet FIN messages, transferring SWIFTNet Funds messages, or transferring SWIFTNet system messages).
  2. A repository for CICS messages that handles the sending of messages to transient data destinations or to the console. It also provides an interface for returning the text of a message to the caller.

message-driven bean (MDB)
An enterprise bean that provides asynchronous message support and clearly separates message and business processing.

message-driven program
An application program that is initiated by the scheduling of an input message. The types of message-driven programs are MPP, IFP, and JMP. See also non-message-driven program.

message-driven rule bean
An enterprise bean that allows Java EE applications to process messages asynchronously. The bean invokes the execution unit (XU) when a JMS message arrives and posts the results of the rule engine processing to a JMS destination.

message editing
The process by which messages are formatted for presentation to an application program or terminal. Additional message editing routines may be written by the user. See also basic edit.

message end event
An end event that also sends a message. See also end event.

message envelope
The information associated with a message aside from attachments and recipients.

message event
An event that arrives from a participant and triggers another event. If the message event is attached to the boundary of the activity, it changes the normal flow into an exception flow upon being triggered. See also event.

message exchange
The transfer of a message from one organization to another organization.

message exchange pattern (MEP)
A list of interaction patterns to define the interaction type, schema, and bindings of an operation.

message exit
A type of channel exit program that is used to modify the contents of a message. Message exits usually work in pairs, one at each end of a channel. At the sending end of a channel, a message exit is called after the message channel agent (MCA) has got a message from the transmission queue. At the receiving end of a channel, a message exit is called before the message channel agent (MCA) puts a message on its destination queue.

message fabric
The message service handler that is used to send and receive messages between organizations or components.

message field (MFLD)
In Message Format Service (MFS),the smallest area in a message input or output descriptor with content and structure that is defined by the user.

message file

  1. In CICS, the file holding the text of all CICS messages.
  2. A file containing messages sent in bulk through a message bulking service.
  3. An object that contains message descriptions. The system-recognized identifier for the object type is *MSGF.

message flood condition
A condition in which the number of incoming messages that are waiting to be processed by OTMA threatens IMS performance or rises above acceptable limits. A message flood condition occurs when too many transactions are waiting to be processed by OTMA, and can deplete all available local system queue area (LSQA) storage and result in a z/OS abend.

message flow

  1. A sequence of processing steps that execute in the broker when an input message is received. Message flows are defined in the workbench by including a number of message flow nodes, each of which represents a set of actions that define a processing step. The connections in the flow determine which processing steps are carried out, in which order, and under which conditions. See also broker, execution group, mediation flow, subflow.
  2. A connecting object that shows the flow of messages between two collaborating participants. A message flow is represented by a dashed line.

message flow control
A distributed queue management task that involves setting up and maintaining message routes between queue managers.

message format
The definition of the internal structure of a message, in terms of the fields and the order of those fields. When a message format is self-defining, the message is interpreted dynamically when it is read.

Message Format Service (MFS)
An IMS editing facility that allows application programs to deal with simple logical messages instead of device-dependent data, thus simplifying the application development process.

Message Format Service control block (MFS control block)
In MFS, the representation of a message or format that is stored in the IMS.FORMAT library and called into the MFS buffer pool as needed for online execution.

message frequency
The rate at which messages are generated as a build is executed.

message group
A logical group of related messages. The relationship is defined by the application putting the messages, and ensures that the messages are retrieved in the sequence put if both the producer and consumer honor the grouping.

message guideline
A part of a published RosettaNet specification that provides information that supports, but cannot be specified in, a particular declarative schema. Both the message guideline and the declarative schema (presently an XML DTD) are used to validate that a particular message or service content is properly formatted and uses expected values.

message handle
A reference to a message. The handle can be used to obtain access to the message properties of the message.

message handling service (MHS)
An application service element that provides a generalized facility for exchanging electronic messages between systems.

message handling system (MHS)
In OSI X.400, a collection of message transfer agents and user agents that provide support for sending and receiving messages.

message header
The part of a message that contains control information such as a unique message ID, the sender and receiver of the message, the message priority, and the type of message. See also message body.

message help
More information about a message, such as the message type, severity, and date and time sent.

message ID
See message identifier.

message identifier

  1. A 7-character code that identifies a predefined message, and is used to get the message description from a message file.
  2. A number ranging between 1-65535 that indicates a specific error for a component.

message input descriptor (MID)
The Message Format Service (MFS) control block that describes the format of the data presented to the application program. See also message output descriptor.

message integrity
The assurance that the data that a recipient receives was not altered during transit. Message integrity is ensured with digital certificates and message authentication.

message integrity check (MIC)
A cryptographic hash of the EDI data contained in a message.

message intermediate event
An intermediate event that can be used to either receive or send a message. See also intermediate event.

message line
An area on the display where messages are displayed.

message listener
An object that acts as an asynchronous message consumer.

message mode
A transaction attribute that describes how the transaction is handled by the application program. See also multiple message mode, single message mode.

message object
An abstraction of the data structures or system objects that store mail server framework message information.

message output descriptor (MOD)
The Message Format Service (MFS) control block that describes the format of the output data produced by the application program. See also message input descriptor.

message passing
The process by which parallel tasks explicitly exchange program data.

Message Passing Interface (MPI)
A library specification for message passing. MPI is a standard application programming interface (API) that can be used with parallel applications and that uses the best features of a number of existing message-passing systems.

message prefix
A structured set of areas that define information needed for processing each message in IMS. Some parts of the message prefix always exist, while others are included only if the IMS system is defined with a particular function.

message priority
In WebSphere MQ, an attribute of a message that can affect the order in which messages on a queue are retrieved, and whether a trigger event is generated.

message processing facility (MPF)
An MVS facility that controls message display and message processing.

message processing node
A node in a message flow that represents a processing step. A message processing node can be either a primitive or a subflow node.

message processing program (MPP)

  1. A program that processes or otherwise responds to messages received from terminals.
  2. An IMS application program that is driven by transactions and has access to online IMS databases and message queues. See also batch processing program.

message processing unit (MPU)
A message processing unit is used to correlate information within a message, for example reason or completion information, and a message text.

message producer
In JMS, an object that is created by a session and that is used to send messages to a destination. See also producer.

message property
Data associated with a message, in name-value pair format. Message properties can be used as message selectors to filter publications or to selectively get messages from queues. Message properties can be used to include business data or state information about processing without having to alter the message body.

message protection
A recovery and restart function provided by CICS. It logs input and output messages for SNA LUs and enables the messages to be recovered following a system failure.

message protection policy
A set of conditions that define whether a message can be sent or received between web services.

message protocol data unit (MPDU)
In OSI, the elements in Protocol 1 (P1) that are used between message transfer agents (MTAs).

message queue

  1. A named destination to which messages can be sent until they are retrieved by programs that service the queue.
  2. A list on which messages are placed when they are sent to a user ID or device description. The system-recognized identifier for the object type is *MSGQ.
  3. A set of messages that are waiting to be processed by a program or to be sent to a terminal, display, or workstation.
  4. In interprocess communications, a mechanism that allows a process to communicate with other processes by sending messages to a process, receiving messages from a process, or performing control operations on a process.

message queue definition
The configuration information for a messaging service provider message queue that is defined in the system. Queue definitions are associated with messaging receivers and destinations for the transfer of messages in the system.

message queue ID (msqid)
An identifier assigned to a message queue for use within a particular process. It is similar in use to a file descriptor of a file.

Message Queue Interface (MQI)
The programming interface provided by WebSphere MQ queue managers. The programming interface allows application programs to access message queuing services. See also Java Message Service, message channel agent, message channel interface.

message queue management (MQM)
In WebSphere MQ for HP NonStop Server, a facility that provides access to PCF command formats and control commands to manage queue managers, queues, and channels.

message queuing
A programming technique in which each program within an application communicates with the other programs by putting messages on queues.

message reception registry (MRR)
The registry where SWIFT stores the central routing rules. Each receiver defines its own rules and submits them to SWIFT. SWIFT uses these rules to determine the destination of message traffic, that is, to which store and forward queue or to which SWIFTNet Link it is to route each message.

message recovery point
The last inbound message for which IMS returned a definite response or the last outbound message for which IMS requested a definite response.

message reference key
A key assigned to every message on a message waiting line. This key is used to remove a message from a message waiting line, to receive a message, and to reply to a message.

message reference number (MRN)
A unique 16-digit number assigned to each message for identification purposes. The message reference number consists of an 8-digit domain identifier that is followed by an 8-digit sequence number.

message resynchronization
A facility that detects and corrects a lost message condition if a network failure occurs.

An option available to an MCA that is unable to put a message. The MCA can wait for a predefined amount of time and then try to put the message again.

message routing
A method used for building a logical message and routing it to one or more terminals. The message is scheduled, for each designated terminal, to be delivered as soon as the terminal is available to receive messages, or at a specified time. Terminal operators who receive the message use terminal operator paging commands to view it. A variety of operands on the ROUTE command allow you flexibility when specifying the message destinations.

message segment

  1. One of a number of segments of a message that is too large either for the application or for the queue manager to handle.
  2. The unit of access when referring to a message to or from a terminal.

message selector
In application programming, a variable-length string that is used by an application to register its interest in only those messages whose properties satisfy the Structured Query Language (SQL) query that the selection string represents. The syntax of a message selector is based on a subset of the SQL92 conditional expression syntax.

message sequence number (MSN)
A sequence number for messages.

message sequence numbering
A programming technique in which messages are given unique numbers during transmission over a communication link. This number enables the receiving process to check whether all messages are received, to place them in a queue in the original order, and to discard duplicate messages.

message service handler
A system that sends and receives messages.

message set
A container for a logical grouping of messages and associated message resources (elements, types, and groups). It provides a business context for a set of messages.

message severity
The measurement of how important or significant a message is. The higher the severity level, the more severe or important the condition.

message signal unit (MSU)
An MTP packet containing data.

message standard
A standard that describes a family of message definitions.

message start event
A start event that is triggered when a specific message is received. See also start event.

message store

  1. A hierarchical structure in which the storage area is divided into a collection of folders and the messages are subdivided into a set of properties which the client software can access. These folders are created and controlled by the MAPI messaging software.
  2. A component that is usually associated with the local delivery exit. The message store provides application program interfaces (APIs) for maintaining mailboxes, and it provides pointers to message objects.

message style
In Tivoli Distributed Monitoring, the amount and format of information presented by certain monitors.

message subfile
A subfile where the records are messages from a program message queue.

message switch
A terminal input message directed to another terminal without being processed by a message processing program. See also program-to-program message switch.

message switching
The process of receiving a message, storing it, and forwarding it to its destination unaltered. See also circuit switching.

message token
A unique identifier of a message within an active queue manager.

message transfer agent (MTA)
A program that accepts mail from user agents, delivers messages to user agents, and forwards messages to other MTAs.

message transfer part (MTP)
Part of the SS7 protocol normally used to provide a connectionless service roughly equivalent to levels one to three of the OSI reference model.

message transfer state
In BSC, a condition in which a bid exchange was completed and data can be transmitted.

message transfer system (MTS)
In OSI X.400, a collection of message transfer agents. A message transfer system provides the means by which user agents can exchange messages.

message transformation
The process of changing the structure and values of a message (possibly an XML-based message) from one form to another. This facilitates the ability to integrate disparate systems with different data forms by enabling a transformation of the message from one form to the other.

Message Transmission Optimization Mechanism (MTOM)
The implementation to optimize the transmission and format of SOAP messages.

message type

  1. A defined set of values identifying the contents of a message.
  2. A value used to define the type of data sent for a distribution to a recipient. The message types supported on a system are defined when the mail server framework is configured. The value associated with the message type must be a unique type value.
  3. The logical structure of the data within a message. For example, the number and location of character strings.

message unit (MU)
In SNA, the unit of data processed by any layer; for example, a basic information unit (BIU), a path information unit (PIU), or a request/response unit (RU).

message unit identifier (MUID)
In SNA, a number that uniquely identifies a distribution message unit throughout its existence. A message unit exists for only one hop, from one system to the adjacent system.

message waiting indicator (MWI)
A visible or audible indication (such as a light or a stutter tone) that a voice message is waiting to be retrieved.

message warehouse table
A database table in which the message warehouse service stores index and status information about each message processed by services.


  1. A formatted electronic data exchange over a secure network.
  2. A method for communication between programs. Messaging can be synchronous or independent of time.

messaging adapter
An adapter that enables Sterling B2B Integrator to send messages to and from remote messaging queues.

messaging API
A programming interface that enables an application to send and receive messages and attached files over a messaging system.

messaging destination
The message queue where the system sends message requests and responses.

messaging engine

  1. The messaging and connection point to which applications connect to the bus.
  2. A server component that provides the core messaging functionality of a service integration bus.

messaging middleware
Software that provides an interface between applications, allowing them to send data back and forth to each other asynchronously. Data sent by one program can be stored and then forwarded to the receiving program when it becomes available to process it.

messaging receiver
The named destination for a messaging service provider message queue that receives messages. A message exchange is triggered when a message is received on the queue identified by the messaging receiver.

messaging system
Software used to deliver electronic messages.


  1. In UNIX, a character that has special meaning to the shell.
  2. ASCII character with special meaning during pattern processing. Such characters are used to represent single-byte or multibyte character patterns that can be matched during processing.


  1. In AIXwindows and Enhanced X-Windows, an object class that does not instantiate widgets or gadgets but is capable of passing a unique set of inheritable resources to the subclasses beneath it in the class hierarchy.
  2. A class whose instances are classes. Metaclasses are typically used to construct metamodels.

Data that describes the characteristics of data; descriptive data. See also application-specific information.

metadata collection
A metadata component that groups together all the metadata star models to be included in a metadata export. A metadata collection can contain an entire data warehouse model, or a subset of a model, such as a single subject area.

metadata controller (MDC)
A central metadata management facility for data stored on shared disks.

metadata dimension
A metadata component that contains the description of a conformed dimension to include in a metadata export.

metadata export
A utility that allows the user to export descriptions of the target conformed model in a data mart or data warehouse to an XML file. This file can then be used to produce a model of the target data mart or data warehouse in Framework Manager, without the need to recreate the complete model.

Metadata Model (MDM)
The part of the Data Model that defines access to metadata that is stored in a repository, XML file, or proprietary format. An important part of the model is the MDM document, which is populated by using the metadata source component (MDSC) to expose the metadata to the Provider, or by reading the metadata from a repository or XML file.

metadata model
A set of related dimensions, query subjects, and other objects that represent data for reporting applications.

metadata relational map
A map that displays related metadata from case documents.

metadata repository
A shared component that stores design-time, runtime, glossary, and other metadata for product modules in the InfoSphere Information Server suite. See also operations database.

metadata repository tier
The metadata repository and, if installed, the InfoSphere Information Analyzer database (analysis database) and the computer or computers where these components are installed.

metadata schema
A set of database tables that holds information about the dimensions of a model. In particular, it holds the members of each dimension, and information about how the members relate to each other. See also optimal snowflake schema, optimal star schema, parent-child schema, snowflake schema, star schema.

metadata server
A server that off-loads the metadata processing from the data-storage environment to improve SAN performance. An instance of the metadata server runs on each engine; together, the metadata servers form a cluster. See also asymmetric virtualization, system pool.

metadata server log
A log that maintains a history of routine activities and error conditions that are generated by a metadata server.

metadata service
A shared set of components that provide common functions (such as import and export) to other product modules in the InfoSphere Information Server suite.

metadata shard
A shard for a database that contains information about colonies and their connection pools.

metadata source component (MDSC)
A data source component (DSC) that exposes metadata to the Provider.

metadata star
A catalog object containing the description of the fact table to include in a metadata export, with reference to the metadata dimensions that have been set up.

metadata tree

  1. A list in a tree structure, which is prepared and displayed by the external service wizard, that presents all of the objects discovered from the enterprise information system (EIS).
  2. Within a studio, a structure that contains objects such as query subjects, query items, dimensions, levels, and members. A metadata tree is used as a palette of the available data that can be inserted into calculations, filters, display areas, and other authoring gestures.


  1. An XML file that contains document-related metadata, such as a service class association and retention period. A metafile is automatically created for each archived document.
  2. A file containing a series of attributes that set color, shape, and size, usually of a picture or a drawing. Using a program that can interpret these attributes, a user can view the assembled image.

A language that is used to create other specialized languages.

A model that defines the language for expressing a model.

The one node per open file that is responsible for maintaining file metadata integrity. In most cases, the node that has had the file open for the longest period of continuous time is the metanode.

An instance of an XMI class as defined in the metamodel.

meta-object facility (MOF)
A generalized facility and repository for storing abstract information about concrete object systems; dealing mostly with construction, standardized by the Object Management Group (OMG).

Meta Object Facility (MOF)
An abstract language and a framework for specifying, constructing, and managing technology neutral metamodels. Examples include the metamodels for UML, CWM, and the MOF itself, as well as those in various OMG specifications in progress.

A phonetic algorithm that is used for indexing similar or identical names or words with variant spellings based on their English pronunciation. Metaphone uses variable-length keys. See also Double Metaphone, Metaphone 3, Soundex.

Metaphone 3
A phonetic algorithm that is used for indexing similar or identical names or words with variant spellings based on their English pronunciation. Metaphone 3 is the third generation of Metaphone and includes a more complex set of rules that improves accuracy of up to 99% for English words and familiar non-English words. See also Double Metaphone, Metaphone, Soundex.

Metaphone match


  1. In WebSphere Commerce, a usage paradigm that customers can use to navigate product catalogs. Metaphors are provided as part of the Product Advisor component.
  2. A word, phrase, or visual representation that denotes or depicts one object or idea but suggests a likeness or analogy with another object or idea.

In the OSI Communications Subsystem licensed program, the machine-readable form of an abstract syntax. The metatable is generated by the Abstract Syntax Checker and used by the OSI Communications Subsystem presentation layer to encode and decode data being exchanged.

A device that measures the consumption of electricity, gas, or water, and charges standard rates according to use.

In QoS, the process of measuring the temporal properties (such as rate) of a traffic stream that is selected by a classifier. The instantaneous state of this process can be used to affect the operation of a marker, shaper, or dropper; and can be used for accounting and measurement purposes.

meter sampling group
Meter assets that are grouped by similar attributes, such as vendor, meter type, and age. Meter assets are sampled according to a meter sampling template.

meter sampling template
A template that defines the percentage or sample size of meters that must be tested.

meter sampling work order
A work order that identifies the meter assets that are to be tested. The work orders trigger the work to replace the meter and the return of the meter to the meter test shop so that it can be properly tested.


  1. In object-oriented design or programming, the software that implements the behavior specified by an operation.
  2. In Enhanced X-Windows, the functions or procedures that a widget itself implements.
  3. In object-oriented programming, an operation that an object can perform. An object can have many methods. See also operation.
  4. In Java programming, a function that is defined in a class. (Sun)
  5. See member function.
  6. A database object that encapsulates procedural logic to provide behavior for a structured type. A method can be implemented as an SQL method or an external method. See also external method, routine, SQL method.
  7. A way to implement a function on a class.
  8. In ODM, executable code associated with an object and defined as the value of a method descriptor for the object. The method can be a command, program, or shell script.

method authoring
The process of creating a template for an entire project to be used as a collection of best practices.

method binding signature
A hexadecimal value that contains the method signature (obtained from the signature bank), inheritance level, slot, and signature of the method's class. The method binding signature is added to the Interface Definition Language (IDL) source file by the signature emitter.

method body
The implementation of the logic of a method. See also routine body.

method descriptor
In ODM, a named variable of type method used to define a method or operation to associate with an object. The method can be any executable code such as a command, program, or shell script.

method extension
An IBM extension to the standard deployment descriptors for enterprise beans that define transaction isolation methods and control the delegation of credentials.

method file

  1. A file that allows users to indicate to the localedef utility where to look for user-provided methods for processing user-designed codepages.
  2. For ASCII locales, a file that defines the method functions to be used by C runtime locale-sensitive interfaces. A method file also identifies where the method functions can be found. IBM supplies several method files used to create its standard set of ASCII locales. Other method files can be created to support customized or user-created codepages. Such customized method files replace IBM-supplied charmap method functions with user-written functions.

method permission
A mapping between one or more security roles and one or more methods that a member of a role can call.

method pointer
A special i5/OS pointer type. A method pointer on a single class. Method pointers are not guaranteed to be persistent between multiple jobs.

method procedure
A function or procedure, written in an arbitrary programming language, that implements a method of a class.

method signature
A hexadecimal value obtained from a server and placed in a signature bank on the workstation. The signature bank uniquely identifies a method. Method signatures are added to the Interface Definition Language (IDL) source file by the signature emitter. Method signatures are added in the form of a binding signature.

method statistics
Information about a method that includes the package (and class) to which the method belongs, the number of calls made to the method, the CPU time spent in the method, and the cumulative time spent in that method.


  1. A measurement summary of global and community behavior and activity that is collected by the IBM Connections Metrics application.
  2. A measurement type. Each resource that can be monitored for performance, availability, reliability, and other attributes has one or more metrics about which data can be collected. Sample metrics include the amount of RAM on a PC, the number of help desk calls made by a customer, and the mean time to failure for a hardware device. See also service level objective.
  3. A holder for information, typically a business performance measurement, in a monitoring context. See also aggregate metric, instance metric.
  4. In information analysis, a mathematical calculation that is performed on statistical results from data rules, rule sets, and other metrics themselves. A metric consolidates measurements from various data analysis steps to reduce hundreds of detailed analytical results into a few meaningful measurements that effectively convey the overall quality of the data.
  5. A measurement that assesses a key area of a business.
  6. In Internet communications, a value that is associated with a route, which is used to discriminate between multiple exit or entry points to the same autonomous system. The route with the lowest metric is preferred.

metric extract
A set of mappings between an existing Cognos data source and a Metric Studio object or value. For example, a cube measure named Revenue is mapped to a Metric Studio metric named Revenue Actual Value.

metric-only font (MOF)

metric package
In Cognos Connection, a representation of a Metric Studio application. A metric package contains connection information, reports, and metric management tasks for that application. See also package.

metric report
An aggregation of data points for a single metric. A metric report uses the dimensions and fact fields that are defined in fact tables to represent a specific metric calculation.

metrics aggregation
A process that is used by the Transaction Collector to summarize tracking data by using vertical linking and stitching to associate items for a particular transaction instance. Metrics aggregation ensures that all appropriate tracking data is aggregated.

metric store
A database that contains content for metric packages. A metric store also contains Metric Studio settings, such as user preferences.

metric type
A category of metrics that defines the business rules such as performance pattern, units, and meaning of a group of metrics. For example, Revenue can be a metric type, and European Revenue and North American Revenue would be metrics of this type.

Metro Global Mirror

  1. A three-site, high availability, disaster recovery solution. Metro Global Mirror uses synchronous replication to mirror data between a local site and an intermediate site, and asynchronous replication to mirror data from an intermediate site to a remote site.
  2. A cascaded solution where Metro Mirror synchronously copies data to the target site. This Metro Mirror target is the source volume for Global Mirror that asynchronously copies data to a third site. This solution has the potential to provide a disaster recovery with no data loss at Global Mirror distances when the intermediate site does not participate in the disaster that occurs at the production site.

Metro Mirror

  1. A method of synchronous replication that maintains data consistency across multiple volumes within the system. Metro Mirror is generally used when the write latency caused by the distance between the source site and target site is acceptable to application performance.
  2. A function of the remote mirror and copy feature that constantly updates a secondary copy of a volume to match changes made to a source volume. See also capacity licensing, Global Copy, Global Mirror, remote mirror and copy.

An application that takes a snapshot of the Tivoli Workload Scheduler configuration and generates an HTML report. It is used in problem determination to provide information to IBM Software Support.

metropolitan area network (MAN)
A network formed by the interconnection of two or more networks which may operate at higher speed than those networks, may cross administrative boundaries, and may use multiple access methods. See also local area network, wide area network.

See mainframe interactive.

See multifunction IOP.

See message field.


  1. See multifunction monitor.
  2. See modified frequency modulation.

An in-band address signaling system using six tone frequencies, two at a time. MFR1 is used principally in North America and is described in ITU-T recommendations Q.310 through Q.332.

See Message Format Service.

MFS control block
See Message Format Service control block.

MFS device descriptor
A descriptor used by ETO to update screen size in the DCT and generate new MFS default formats without system generation. See also ETO descriptor.

MFS dynamic directory
A technique that is used by the online IMS control program when operating under z/OS to manage message format control blocks that are stored in extended private storage.

An optional MFS facility that allows MFS control blocks to be created and tested online without disrupting production activity.

See mostly global address space.

See millions of gallons per day.

See machine-generated data structure.

See Memory Grant Manager.

See material handling equipment.


  1. See message handling system.
  2. See message handling service.

See megahertz.

See machine interface.

See Management Information Base.

MIB application program
A systems management application program used to monitor network devices.

MIB module
In the Simple Network Management Protocol (SNMP), a collection of objects relating to a common management area. See also Management Information Base variable.

MIB object
See Management Information Base variable.

MIB tree
In the Simple Network Management Protocol (SNMP), the structure of the Management Information Base (MIB).

MIB variable
See Management Information Base variable.

MIB view
In the Simple Network Management Protocol (SNMP), the collection of managed objects, known to the agent, that is visible to a particular community.

MIB walking
In the Simple Network Management Protocol (SNMP), a technique of looking for Management Information Base (MIB) tree information when it is presented in a hierarchical format.


  1. See middle-in-chain.
  2. See message integrity check.

A service for posting short, public messages. A microblog message is usually one or two sentences long. It is useful for many purposes such as sharing links, asking questions, and making statements.

A method of blogging that limits bloggers to a fixed number of characters. Forms of microblogging include tweets and text messages.

A web browser designed for small display screens on smart phones and other handheld wireless devices.

Micro Channel architecture (MCA)

  1. The rules that define how subsystems and adapters use the Micro Channel bus in a computer. MCA defines the services that each subsystem can or must provide.
  2. The I/O channel used on the POWERstation and POWERserver system units.


  1. To design, write, and test one or more microinstructions.
  2. Stored microinstructions, not available to users, that perform certain functions.
  3. A code, representing the instructions of an instruction set, that is implemented in a part of storage that is not program-addressable.

Microcom Network Protocol (MNP)
An error correction protocol used between modems to transfer data over asynchronous communications.

microfiche (fiche)
A sheet of microfilm containing a photographic record on a reduced scale of printed matter.

A film containing a photographic record of printed matter, on a reduced scale.

microfilm device
Non-IBM output device that presents a hardcopy on microfilm.

microfilm setup resource
A setup file that contains information used to present AFP data on microfilm.

microfilm utility
A non-IBM utility that builds an object container for microfilm setup data and places it in the AFP library.

A short-running process that runs in one transaction. A microflow, which is an IBM extension to the BPEL programming language, runs automatically from start to finish and cannot be interrupted.

A medium that contains microimages; for example, microfiche, microfilm. (T) (A)

The branch of science and technology concerned with techniques for converting any form of information to or from microform. (A)

A logical partition that uses a partial processor. With Micro-Partitioning technology, a partition can be as small as 1/20th of a processor or can consist of full plus partial processors.

A pattern that creates a reusable subprocess from a main process. See also pattern.

Extremely small perforations. After forms are separated, those with microperforations typically have smoother edges than those with regular perforations.

A measurement of time: one millionth of a second.

Microsoft Cluster Server (MSCS)
A technology that provides high availability by grouping computers running Windows into MSCS clusters. If one of the computers in the cluster hits any one of a range of problems, MSCS shuts down the disrupted application in an orderly manner, transfers its state data to another computer in the cluster, and re-initiates the application there.

Microsoft Transaction Server (MTS)
A facility that helps Windows users run business logic applications in a middle tier server. MTS divides work up into activities, which are short independent chunks of business logic.

A switch operated by the movement of some part of the machine.

MICR printing
The ability of a printer either to print with magnetic toner or to allow magnetic character ink recognition through a post-processing device.

See message input descriptor.

middle-in-chain (MIC)
A request unit (RU) whose request header (RH) begin chain indicator and RH end chain indicator are both off. See also RU chain.

middle name
The second given name in Anglo names. See also given name.

Software that acts as an intermediate layer between applications or between client and server. It is used most often to support complex, distributed applications in heterogeneous environments.

middleware agent
An agent that enables the administrative domain to manage servers that run middleware software.

middleware descriptor
An XML file that contains information about different middleware platform types, including discovery sensor intervals and installation information.

middleware installer
The installer that is used for installation and configuration of middleware, including database server, application server, and directory server applications.

middleware node
A node that is federated to the deployment manager. These nodes must include nodes that run the node agent or middleware agent.

See Musical Instrument Digital Interface.

Mid-Level Manager (MLM)
A Systems Monitor function that performs a subset of systems and network management tasks (for example, polling, status monitoring, and node discovering) for a defined set of Simple Network Management Protocol (SNMP) devices in the network, thereby offloading these tasks from the top-level manager.

midrange workload license charge (MWLC)

See multiple image facility.


  1. To move data from one location to another. See also migration level 1, migration level 2.
  2. To install a new version or release of a program to replace an earlier version or release.
  3. To move data to another location, or an application to another computer system.

migrated file
A file that has been copied from a local file system to storage. For HSM clients on UNIX or Linux systems, the file is replaced with a stub file on the local file system. On Windows systems, creation of the stub file is optional. See also file state, premigrated file, stub file.

The process of moving data from one computer system to another, or an application to another computer system.

migration control data set (MCDS)
One of the control data sets (CDSs) in DFSMShsm. The MCDS is a Virtual Storage Access Method (VSAM) key-sequenced data set (KSDS) that contains statistics records, control records, user records, records for data sets that have migrated, and records for volumes under the migration control of DFSMShsm. See also control data set.

migration data host (MDH)
A node that acts as both an APPN end node and a type 5 subarea node. See also interchange node.

migration installation
An installation method for upgrading AIX Version 3.2 or later to the current release while preserving the existing root volume group. This method preserves the /usr, /tmp, /var, and / (root) file systems, as well as the root volume group, logical volumes, and system configuration files. Migration is the default installation method for, and can only be used on, an AIX Version 3.2 or later machine.

migration job
A specification of files to migrate, and actions to perform on the original files after migration. See also job file, threshold migration.

migration level 1 (ML1)
DFSMShsm-owned direct access storage device (DASD) volumes that contain data sets migrated from primary storage volumes. The data can be compressed. See also migrate, migration level 2, primary storage, storage hierarchy.

migration level 2 (ML2)
DFSMShsm-owned tape or direct access storage device (DASD) volumes that contain data sets migrated from primary storage volumes or from migration-level-1 volumes. The data can be compressed. See also migrate, migration level 1, primary storage, storage hierarchy.

migration policy
A user-defined schedule for moving objects from one storage class to the next. It describes the retention and class transition characteristics for a group of objects in a storage hierarchy.

migration threshold
High and low capacities for storage pools or file systems, expressed as percentages, at which migration is set to start and stop.

A function of the resource manager that checks migration policies and moves objects to the next storage class when they are scheduled to move.

See missing-interrupt handler.

A measurement of thickness: 1/1000 inch.

mile marker
Indicators that are placed along a highway to mark the distance from a known reference point.


  1. A significant event in a project or process that is used to determine progress toward goals.
  2. A transition step required to be completed during the service order lifecycle.
  3. A significant event in the supply chain that indicates a point in the order lifecycle.

milestone-transfer approach
A migration approach in which users transfer the process instance state midstream, let the existing process instances in the old system run to a designated set of business milestones, and then start new instances in the new system from those milestones. See also drain approach.

In British, German, and French, 10 to the power of 9. Equivalent to billion in American English.

millions of gallons per day (mgd)
A unit of flow commonly used for waste water discharges. One mgd is equivalent to 1.547 cubic feet per second.

millions of service units (MSU)
A measure of the amount of processing a computer can perform in one hour.

The military network that was originally part of ARPANET. It was partitioned from ARPANET in 1984. MILNET provides a reliable network service for military installations.

See multiple instruction stream, multiple data stream.

See Multipurpose Internet Mail Extensions.

MIME type
An Internet standard for identifying the type of object being transferred across the Internet.

mined data
Data that is pulled from a business process and written to an internal database.

The name of the code that runs in segment 1 of the coprocessor.

A direct access storage device (DASD) or a logical subdivision of a DASD that has its own virtual device number.

See preview map.

minimally managed node
A node with no Cluster Systems Management or Reliable Scalable Cluster Technology code installed.

In a large diagram, a view that shows a smaller version of the entire diagram to orient users to their current location in the diagram.

minimize crossed links layout
A layout in which entities are arranged in a configuration where the fewest number of links overlap. See also layout.

In constraint programming, the least value in the domain of a variable. See also lower bound.

minimum bid change
A configuration that is set by buyers and used by suppliers to make their current bid better by a certain percentage or amount.

minimum bid quantity
The minimum number of items that the supplier has to bid for.

minimum desired quantity
The minimum number of items that the buyer wants to procure.

minimum notification time
The minimum number of business hours it takes to ship an order once it has been scheduled to the node.

mining base
A repository where all the information about the mining run settings and the corresponding results is stored.

mining model
The output of a data mining function that describes patterns and relationships that are discovered in historical data. A data mining model can be applied to new data for predicting likely new outcomes.

In a z/OS system running on z/VM, a z/OS-formatted z/VM minidisk whose size is equal to or less than that of the physical volume. DFSMSdss uses the device size specified in the volume table of contents (VTOC). Minivolumes are supported only by the system version of DFSMSdss.

A strategy of replenishment that monitors the inventory level of a location and triggers a replenishment task when that level goes below the minimum quantity defined. The replenishment moves a quantity of the item to satisfy existing customer demand plus enough to bring the location's inventory level up to the maximum quantity defined. See also top-off replenishment.

minor device number
A number that specifies various types of information about a particular device. For example, a number that distinguishes between several printers of same type.

minor node
In VTAM, a uniquely defined resource within a major node. See also major node.

minor synchronization point
In OSI, a session-layer synchronization point that represents a less significant piece of work than a major synchronization point. Minor synchronization points are an unconfirmed service. See also major synchronization point.

minor synchronize
In OSI, a service provided by the session layer that enables peer application entities to mark recovery points in the flow of data being exchanged in case they need to resynchronize the data stream. See also major synchronize.

minor tick
In Business Graphics Utility, one of the marks located between major ticks on an axis of a chart. See also major tick.

minor version

  1. A version of the metadata in which the changes affect only the metadata and not the case data. For example, change to custom properties or question and category texts.
  2. A document version that has not been released. The security of a minor version makes the document available only to the authors and reviewers.

An ordered set of arrays representing the same image at progressively lower resolutions.

mirror copy
In cross-site mirroring, an independent disk pool that is being geographically mirrored so that it is a replica of the production copy of the independent disk pool. If a switchover or failover causes the system that owns the mirror copy to become the current primary node, the mirror copy becomes the production copy of the independent disk pool. The mirror copy has current data only when geographic mirroring is active.

mirror copy data state
In cross-site mirroring, the current status of the data that is being geographically mirrored; for example, insynch, usable, and unusable.

mirror copy state
In cross-site mirroring, the geographic mirroring state of the mirror copy; for example, active, resume pending, resuming, and suspended.

mirrored pair
Two units that contain the same data and are referred to by the system as one logical unit.

mirrored protection
A function that protects data by duplicating all disk data in an auxiliary storage pool (ASP) to another disk unit (mirrored unit) in the same ASP. If a disk failure occurs, the system keeps running, using the operational mirrored unit of the mirrored pair until the disk unit is repaired or replaced. See also checksum protection, device parity protection.

mirrored unit
One half (one of the units) of a mirrored pair of units.

mirrored volume
A volume with two volume copies.

mirror function
A function such as Tab and Carriage Return that should work in a mirror-image manner, depending on the current orientation in a bidirectional environment.

mirror group
A single entity that is equivalent to a consistency group, which consists of a group of disks that use storage-based replication.


  1. See remote mirroring.
  2. The process of writing the same data to multiple disks at the same time. The mirroring of data protects it against data loss within the database or within the recovery log.
  3. The creation of a mirror image of a primitive.

mirror partition
A disk partition that is used for storing tables that are a copy of another disk’s primary data.

mirror pool
A collection or pool of one or more physical volumes that are used to mirror the data associated with a volume group. By grouping the mirrors of a volume group according to their physical location within a site, data can be mirrored across sites such that there will always be enough mirrors available at either site to make the volume group available. Such a configuration can help ensure that a volume group can fallover between sites without loss of data. A physical volume can belong to only one mirror pool at a time.

mirror server
A server required in the IBM Endpoint Manager system if the enterprise does not allow direct web access but instead uses a proxy server that requires password-level authentication.

mirror task
A CICS task that services incoming requests that specify a CICS mirror transaction (CSMI, CSM1, CSM2, CSM3, CSM5, CPMI, CVMI, or a user-defined mirror transaction identifier).

mirror transaction
CICS transaction that recreates a request that is function shipped from one system to another, issues the request on the second system, and passes the acquired data back to the first system.

mirror volume
A volume which contains a backup copy of the original volume.

miscellaneous data record (MDR)
A record of a network hardware error that is recorded by the NCP and sent to the VTAM host that owns the failing component. Then VTAM writes the error on the operating system error data set.

miscellaneous equipment specification (MES)
A hardware change that is made after the time of the initial order.

misclassification cost
A specification of the relative importance of different kinds of classification errors, such as classifying a high-risk credit applicant as low risk. Costs are specified in the form of weights applied to specific incorrect predictions.

mismatched disk
A replacement disk that cannot be activated because it already has valid data from another Netezza system

missing data
A special data item that indicates that the data in a given cell does not exist. This may be because the member combination is not meaningful (for example, a given company does not sell toboggans in Miami) or has never been entered. Missing data is similar to a null value or N/A, but is not the same as a zero value.

missing-interrupt handler (MIH)
An MVS and MVS/XA facility that tracks I/O interrupts. MIH informs the operator and creates a record whenever an expected interrupt fails to occur before a specified elapsed time is exceeded.

mitigation cost
The financial impact of lessening risk by lowering its chances of occurring or by reducing its effect if it does occur.


  1. In architecture, a method used to determine how the color of a graphics primitive is combined with the existing color of a graphics presentation space.
  2. In multimedia applications, the combination of audio or video sources during postproduction.

mixed-byte character set
A set of characters that contain both single-byte characters and double-byte characters. For example, a file might contain characters from a single-byte coded character set (such as code page 00290) and characters from a double-byte coded character set (such as code page 00300).

mixed case
A case containing a mix of different SKUs.

mixed CCSID
A mixed-byte (single byte and double byte) encoding scheme. CCSID 05026 is an example of a mixed CCSID. CCSID 05026 contains both single-byte code page 00290 and double-byte code page 00300.

mixed character string
A string containing a mixture of single-byte and multibyte characters.

mixed chart
In the GDDM function, the combination of more than one type of chart in a business chart. For example, the overlaying of a line chart on a bar chart.

mixed cluster
A cluster with both AIX and Linux nodes managed by a single management server.

mixed code page
A CCSID specially defined to refer to a combination of SBCS and DBCS coded character sets (MBCS) that may be used in data streams or files. For example, Japanese files may use a Latin character set (1172) and code page (1027), and in the same string uses a Kanji character set (370) and code page (300), with the CCSID 5035 for convenient reference. 5035 would be the mixed code page. This is not a real code page.

mixed complex
A global-resource-serialization complex in which one or more of the systems in the global resource serialization complex are not part of a multisystem sysplex.

mixed data
In DB2 or i5/OS, data that is associated with both a single-byte character set and a double-byte character set.

mixed-data file
A file that consists of composed and uncomposed portions. Only the uncomposed portions require a page definition for formatting.

mixed data string
A character string that contains both single-byte and double-byte characters.

mixed-format print data set
A data set that consists of line-data pages and composed-text pages.

mixed list
A list of unlike values for a parameter that accepts a set of separately defined values. An example of a mixed list is a list of user names that embeds another list. See also simple list.

mixed-mode application
An application that includes mixed-mode code, both Perl code and SPL code. The Perl code augments the existing SPL code. See also streams processing application.

mixed-mode BMP
An IMS batch messaging program that has access to Fast Path and full-function databases.

Mixed Object Document Content Architecture (MO:DCA)

  1. An IBM-architected, device-independent data stream for interchanging documents.
  2. The architecture that provides a single interface definition allowing objects from different products to be interchanged so that the data can be edited, presented, or manipulated by processes of varying characteristics and intent.

Mixed Object Document Content Architecture-Presentation (MO:DCA-P)
A subset of MO:DCA that defines presentation documents.

mixed pallet
A pallet containing a mix of different SKUs.

mixed-pitch font
A font that simulates a proportionally spaced or typographic font. The characters are in a limited set of pitches (for example, 10 pitch, 12 pitch, and 15 pitch).

mixed-release support
An approach to managing software delivery that makes it possible for IBM-supplied distribution media to deliver entire (or parts of) licensed programs at existing releases with or without a new release of i5/OS. Existing licensed programs that are enabled for mixed releases but that have no new function are not rebuilt. They are not renewed with a new release of the operating system. Similarly, optionally installable parts of licensed programs that are enabled for mixed releases are not rebuilt or are not renewed with each new release of its base licensed program. Enabled licensed programs that remain at earlier releases are compatible and function with the new release of the operating system.

mixed string
A character string that consists of both single-byte character set (SBCS) data and bracketed double-byte character set (DBCS) data.

mixed traffic
A function of the z/OS Communications Server class of service facility. Different kinds of traffic can be assigned to the same virtual route, and, by selecting appropriate transmission priorities, undue session interference can be prevented.

See multipoint control unit.


  1. The combining of audio or video sources, or both.
  2. Combining foreground and background of multiple intersecting object data elements in the object presentation space.
  3. Combining foreground and background of one presentation space with foreground and background of another presentation space in areas where the presentation spaces intersect.

mixing rule
In architecture, a method for specifying the color attributes of the resulting foreground and background in areas where two presentation spaces intersect.

See Motion JPEG.

See migration level 1.

See migration level 2.

MLA facility
See multilevel alias facility.

See machine level control.

See media library device.

See Mid-Level Manager.

See multinode load balancing.


  1. See master license plate.
  2. See multilingual code page.

See modified link pack area.

See modified least-recently used.

See memorandum macro.

See memory mapped I/O.

M-Motion Video Adapter/A
An IBM adapter for PS/2 system units with Micro Channel architecture that puts an analog signal on a video graphics adapter (VGA) video stream. With this adapter, full-motion video and VGA graphics and text can be displayed on a standard PS/2 color display.

See Multimedia Messaging Service.

MMS message
See Multimedia Messaging Service message.

See multinational character set.


  1. The field of an assembler instruction that contains the acronym or abbreviation for a machine instruction.
  2. A symbol or abbreviation chosen to help the user remember the significance or meaning of the symbol. For example, CRTUSRPRF is a mnemonic for the Create User Profile command.
  3. See accelerator.

In COBOL, a user-defined word that is associated in the Environment Division with a specific channel-name, switch-name, or unit-name.

mnemonic symbol
A symbol chosen to assist the human memory. For example, the abbreviation X for multiply.

See multinode load balancing.

See Microcom Network Protocol.

See modus operandi.

See Mixed Object Document Content Architecture.

See MO:DCA Resource Interchange Set.

See Mixed Object Document Content Architecture-Presentation.

MO:DCA-P data
Print data that has been composed into pages. Text-formatting programs (such as DCF) can produce composed text data consisting entirely of structured fields.

MO:DCA-P data definition
A resource containing a set of formatting controls for printing logical pages of data. Includes controls for the number of lines per printed sheet, font selection, and print direction, and for mapping individual fields in the data to position on the printed sheets.

MO:DCA-P data stream
A data stream that enables a printer to format a complete page at one time, including text, images, and page segments.

MO:DCA-P document
Data composed entirely of structured fields and containing a Begin Document structured field and an End Document structured field.

See MO:DCA Presentation Interchange Set 1.

See MO:DCA Presentation Interchange Set 2.

MO:DCA Presentation Interchange Set 1 (MO:DCA-P IS/1)
A subset of MO:DCA-P that defines an interchange format for presentation documents. See also MO:DCA Resource Interchange Set.

MO:DCA Presentation Interchange Set 2 (MO:DCA-P IS/2)
A subset of MO:DCA Presentation that defines an interchange format for presentation documents and is a superset of MO:DCA-P IS/1. See also MO:DCA Resource Interchange Set.

MO:DCA Resource Interchange Set (MO:DCA-L)
A subset of MO:DCA that defines an interchange format for resource documents. See also MO:DCA Presentation Interchange Set 1, MO:DCA Presentation Interchange Set 2.

See mobile device.

mobile app
See mobile application.

mobile application (mobile app)
An application that has been designed for a mobile platform. Similar to web applications, mobile apps provide some function beyond static display of information, for example, allowing the user to filter news in near real-time. See also app.

mobile application part (MAP)
Optional layer 7 application for SS7 that runs on top of TCAP for use with mobile network applications.

mobile authentication
An authentication factor which allows mobile users to sign-on securely to corporate resources from anywhere on the network.

mobile backend as a service (MBaaS)
A computing model that connects mobile applications to cloud computing services and provides features such as user management, push notifications, and integration with social networks through a unified API and SDK.

mobile browser simulator
A web application in MobileFirst Studio that simulates different types of mobile browsers for previewing and testing.

mobile client
See Application Center installer.

mobile cloud
An infrastructure in which the storage and processing of data for applications is offloaded from a mobile device into the cloud. With mobile cloud computing, applications are not limited to a specific carrier, but are accessed through the Web.

mobile device (mobile)

  1. A telephone, tablet, or personal digital assistant that operates on a radio network. See also Android, BlackBerry OS, mobile phone, satellite phone, tablet.
  2. A portable computing device such as a smartphone or tablet computer.

mobile directory catalog
A condensed Directory Catalog set up on a Notes client.

MobileFirst adapter
See adapter.

MobileFirst application package
The server component of a MobileFirst Server application. MobileFirst application packages are deployed to MobileFirst Server and have an extension of .wlapp.

MobileFirst Data Proxy
A server-side component to the IMFData SDK that can be used to secure mobile application calls to Cloudant by using MobileFirst Platform OAuth security capabilities. The MobileFirst Data Proxy requires an authentication through the trust association interceptor.

MobileFirst Operations Console
A web-based interface that is used to control and manage MobileFirst runtime environments that are deployed in MobileFirst Server, and to collect and analyze user statistics.

MobileFirst runtime environment
A mobile-optimized server-side component that runs the server side of your mobile applications (back-end integration, version management, security, unified push notification). Each runtime environment is packaged as a web application (WAR file).

MobileFirst Server
A MobileFirst component that handles security, back-end connections, push notifications, mobile application management, and analytics. The MobileFirst Server is a collection of apps that run on an application server and acts as a runtime container for MobileFirst runtime environments.

MobileFirst Studio
A MobileFirst component that is an integrated development environment (IDE) that can be used to develop and test mobile applications.

mobile native application
A client application that is specifically designed to work on the hosting mobile platform. For example, an Android native application only works on Android-based mobile devices. Tealeaf CX Mobile supports the capture of sessions from mobile native applications.

mobile operating system (mobile OS)
An operating system for mobile devices. See also Android, BlackBerry OS, HP webOS, iOS, Maemo, MeeGo, Moblin, QNX, Symbian OS, Tizen, Windows Mobile, Windows Phone.

mobile OS
See mobile operating system.

mobile partition
A logical partition that can be moved from the source server to the destination server.

mobile phone
A portable telephone that operates on a radio network. See also cell phone, mobile device, satellite phone.

mobile solutions terminal (MoST)
The mobile terminal used by service personnel.

mobile web browser
A browser that is specifically designed to work with a mobile device.

Mobile WiMAX
See Mobile Worldwide Interoperability for Microwave Access.

Mobile Worldwide Interoperability for Microwave Access (Mobile WiMAX)
A flexible, long-range, high-speed wireless network that is considered a potential replacement for the current predominant wireless networks. WiMAX is compatible with 2G, 3G, and 4G networks. See also 4G.

An open-source Linux mobile operating system created by Intel. See also MeeGo, mobile operating system.

See message output descriptor.

The state in which a secondary window receives keyboard or pointer input that it does not pass on to its associated window.

modal dialog
In AIXwindows, a Dialog widget that interrupts the work session to solicit input from the user.

modal statement
A conditional statement that is used to alter the sequence of Sterling Connect:Direct Process execution based on completion of a previous step in the process.

modal window
A child window, usually a dialog box, which has to be addressed before the user can continue to operate the parent application.

See major object descriptor block.


  1. A method of operation in which the actions that are available to a user are determined by the state or setting of the system, program, or device.
  2. A copy group attribute that specifies whether to back up a file that has not been modified since the last time the file was backed up. See also absolute mode, modified mode.
  3. A collection of attributes that specifies a file's type and its access permissions.
  4. A transportation service, such as a truckload, LTL, intermodal, or parcel.
  5. In CICS BTS, the processing state of an activity. An activity can be in an initial, active, dormant (that is, waiting for an event), cancelling, or complete mode.
  6. In data communications, the set of rules and protocols to be used for a session.

mode-2 character
In the GDDM function, a graphics character (symbol), characterized by an unchanging size, constructed from picture elements. See also mode-3 character.

mode-3 character
In the GDDM function, a graphics character (symbol), characterized by a variable size and shape, constructed from lines and curves. See also mode-2 character.

mode conditioning patch
A cable that converts a single-mode signal generated by a longwave adapter into a light signal that is appropriate for multimode fiber. A second mode-conditioning-patch cable is required at the terminating end of the multimode fiber to return the light signal to a single-mode signal for a longwave adapter.

mode description
A system object created for advanced-program-to-program communications (APPC) devices that describes the session limits and the characteristics of the session, such as the maximum number of sessions allowed, maximum number of conversations allowed, the pacing value for incoming and outgoing request or response units, and other controlling information for the session. The system-recognized identifier for the object type is *MODD.

A z/OS Communications Server LOGMODE entry, which can specify (among other things) the class of service required for a group of APPC sessions.


  1. The allowable configuration of an asset that is used to validate assets
  2. A container that holds an ordered set of builder calls. See also builder.
  3. A representation of the product options of a configurable product.
  4. A representation of a process, system, or subject area, typically developed for understanding, analyzing, improving, and replacing the item being represented. A model can include a representation of information, activities, relationships, and constraints.
  5. In Cognos Planning, a group of D-cubes, D-lists, D-links, and other objects stored in a library. A model may reside in one or more libraries, with a maximum of two for Contributor.
  6. A system, consisting of fact data and metadata, that represents the aspects of a business.
  7. A physical or business representation of the structure of the data from one or more data sources. A model describes data objects, structure, and grouping, as well as relationships and security. In Cognos BI, a model is created and maintained in Framework Manager. The model or a subset of the model must be published to the Cognos server as a package for users to create and run reports.
  8. A group of data items and decision variables that are subject to constraints. A model can contain an objective function to minimize or maximize and a search procedure to guide the algorithm solving the problem.

model access control list (model ACL)
See default access control list.

model ACL
See model access control list.

model application program definition
In VTAM, an application program definition that contains a wildcard character, and that has characteristics that VTAM application programs can use when opening application control blocks (ACBs), to dynamically create application program definitions.

model building
The process of creating data models by using algorithms. Model building typically consists of several stages: training, testing and (optionally) validation. See also testing, training, validation.

model configuration
In System i Access, the set of files, created by the System i Access administrator, that define a set of common characteristics for a set of System i Access users. Model configurations can be used as a base for defining user configurations.

model decomposition
The process of breaking down one complex model into several models and defining a sequence to solve those other models so as to lead to a solution that is also a solution to the original model. See also master model, multimodel architecture, submodel.

Model Definition Language (MDL)
A proprietary language that can express the Transformer model definition. MDL is compatible with different versions of Transformer. Transformer model files that are formatted for export use the .mdl extension.

modeled fault
A fault message that is returned from a service that has been modeled on the Web Services Description Language (WSDL) port type.

model element
An element that is an abstraction drawn from the system being modeled. In the MOF specification, model elements are considered to be meta-objects.

model file
In performance, a complete representation of a system. It includes both the system configuration and the set of workloads running on the configuration.

model group
A collection of models, option class groups, option item groups, or even other model groups.

modeling coordinates
In GL, the coordinate system in which all drawing primitives do their drawing. The user can select the position and orientation of the modeling space with regard to the world space by means of translations, rotations, scales, or generalized transformations.

modeling node
A node that can build a model by using an algorithm. The model that is built is represented graphically by a model nugget. See also model nugget.

modeling transformation
In GL, a type of transformation that maps modeling coordinates into world coordinates. All drawing primitives specify positions that are presumed to be positions in modeling coordinates. Modeling transformation can be used to move an image.

model LU
An LU definition that specifies the characteristics to be used for a dynamically-defined LU. See also LU group.

model nugget
The graphical representation of the model that is produced by a modeling node. See also modeling node.

model number
In Ada language, an exactly representable value of a real type. Operations of a real type are defined in terms of operations on the model numbers of the type. The properties of the model numbers and of their operations are the minimal properties preserved by all implementations of the real type.

model output file
A file that contains sample output of a function.

model queue object
A set of queue attributes that act as a template when a program creates a dynamic queue.

model segment
A part of a Framework Manager project, such as a parameter map, a data source, a namespace, or a folder, that is a shortcut to a second project. Segments are used to simplify model maintenance or to facilitate multi-user modeling.

model space
See graphics model space.

model store
A store that has a set of operational processes that are also followed by many other stores.

model system
A system that manages the fix (PTF) levels for each of the systems in a network by comparing what fixes are available on the model system with a specific endpoint system.

model transform
In architecture, a transform that is applied to drawing-order coordinates. See also viewing transform.

model view controller (MVC)
A software architecture that separates the components of the application: the model represents the business logic or data; the view represents the user interface; and the controller manages user input or, in some cases, the application flow.

modem (modulator-demodulator)
A device that converts digital data from a computer to an analog signal that can be transmitted on a telecommunication line, and converts the analog signal received to data for the computer.

modem eliminator
A device that connects a workstation directly to a computer port through a wired connector with a specific pin arrangement. When two devices both function as DTEs (data terminal equipment), the cable that connects them must transmit send and receive signals using a modem eliminator.

mode name
A name for the collection of physical and logical characteristics and attributes of a session.

mode-name entry
An entry in an LU-mode pair that contains information about the mode that is associated with the partner logical unit.

moderated community
A community where anyone in the organization can see community content but must request to join.

A method of overseeing and managing IBM Connections content in Blogs, Communities, and Forums.

The person who sets up the meeting and/or leads it. The moderator can lead the meeting as a presenter or they can give a participant the role as presenter or moderator.

Pertaining to left-to-right, top-to-bottom writing or printing for kanji fonts.

mode selection threshold
A set of conditions that are specified to automatically assign a transportation mode to orders and shipments, based on weight, volume, or quantity.

In CICS, a group of APPC sessions. A modeset is linked by its mode name to a mode group (z/OS Communications Server LOGMODE entry) that defines the class of service for the modeset.

mode word
An inode field that describes the type and state of the inode.

modifiable alternate PCB
An alternate PCB for which the destination can be changed by the application program during execution. See also alternate program communication block.

A change to the fit, form, or function of an asset, such as an aircraft or its components, that is a critical element to manage engineering and maintenance tasks that are related to an aircraft throughout its service life.

modification level
A distribution of additional function or fixes to a program since the previous release or modification. See also release, variation.

modification number
The modification level of a program, which is an indicator of changes that do not affect the external interface of the program. See also release number.

modification reason
A reason code that defines why a modification was made by a user.

modified data tag (MDT)

  1. An indicator, associated with each input or output field in a displayed record, that is automatically set on when data is typed into the field. The modified data tag is maintained by the display file and can be used by the program using the file.
  2. In the attribute byte of each field in a BMS map, a bit that determines whether the field should be transmitted on a READ MODIFIED command (the command used by CICS for all except copy operations).

modified-default form definition
A form definition that was the default specified in the PRINTDEV statement of the PSF startup procedure, and that has been modified by the groupvalue parameter of the COPIES parameter or by the FLASH parameter in the JCL statement.

modified-default page definition
A page definition that was the default specified in the PRINTDEV statement of the PSF startup procedure, and that has been modified by a font list specified in any of the following: the CHARS parameter from the user JCL or the PRINTDEV statement, the UCS parameter from the user JCL, and the JES default font in the current printer setup.

modified frequency modulation (MFM)

  1. Variation in the amplitude and frequency of the write signal.
  2. Pertains to the number of bytes of storage that can be stored on the recording media. Synonymous with double-density recording.

modified least-recently used (MLRU)
A list that tracks modified pages in a queue.

modified link pack area (MLPA)
An area of virtual storage containing reenterable routines from system data sets that are to be part of the pageable extension of the link pack area (LPA) during the current initial program load (IPL). See also pageable link pack area.

modified mode
In storage management, a backup copy-group mode that specifies that a file or directory is considered for incremental backup only if it has changed since the last backup. A file or directory is considered changed if the date, size, owner, or permissions have changed. See also absolute mode, mode.

modified standard DL/I application program
An application program that uses CPI-C calls to allocate additional LU 6.2 conversations to the same or different LU 6.2 devices, and sends and receives data.

modified state
A snapshot state that indicates that the snapshot can never be used for restoring its master volume.

A word or quantifier that is used to change an instruction, thereby causing the execution of a different instruction. Consequently, the original instruction, successively changed by a modifier, can be used repetitively to carry out a different operation each time it is used.

modifier key

  1. In CDE, a key that when pressed and held along with another key or mouse button changes the meaning of the second key or mouse click. Control, Alt, and Shift are examples.
  2. In Enhanced X-Windows, keys such as Shift, Shift Lock, Control, Alt, Caps Lock, and Meta.

To make a change to the installed package, for example adding and removing features or languages.

modify current plan (MDC)
A dialog function used to dynamically change the contents of the current plan to respond to changes in the operation environment. Examples of special events that would cause alteration of the current plan are a rerun, a deadline change, or the arrival of an unplanned application.

modify lock
An L-lock or a P-lock with a MODIFY attribute. A list of these active locks is kept at all times in the coupling facility lock structure. If the requesting subsystem fails, that subsystem's modify locks are converted to retained locks.

modular program design
A design in which multiple programs do a function (normally one program per function). Modular program design applies to both batch and interactive processing.

modular water unit (MWU)
A unit that circulates water, chilled by the heat exchanger, and distributes it to the nodes.


  1. The process by which a message signal is impressed upon a carrier signal so that the carrier is altered to represent the message signal.
  2. The process of changing the frequency or size of one signal by using the frequency or size of another signal.
  3. The process by which a characteristic of a carrier is varied in accordance with a characteristic of an information-bearing signal.

See modem.


  1. A program unit that is discrete and identifiable with respect to compiling, combining with other units, and loading.
  2. A collection of objects that is stored and shared in a repository. A module corresponds with a project in a workspace.
  3. In bar code symbologies, the nominal width of the smallest element of a bar or space. Actual bars and spaces can be a single module wide or some multiple of the module width.
  4. See program unit.
  5. An object that represents a logical grouping of various functional areas in the application and provides more immediate access to those functions. Within the application programming interfaces, a module is called a manager. See also console.
  6. A software artifact that is used for developing, managing versions, organizing resources, and deploying to the runtime environment.
  7. A database object that is a collection of other database objects, including conditions, data types, functions, procedures, and variables. See also module body, module object, package, routine prototype.
  8. A new node or additional server in an application.
  9. In Java EE programming, a software unit that consists of one or more components of the same container type and one deployment descriptor of that type. Examples include EJB, web, and application client modules. (Sun) See also project.
  10. A packaged functional hardware unit designed for use with other components.
  11. A piece of software that is provided to enable the viewing of a particular document type or to provide a specific piece of functionality; for example, redaction.
  12. A collection of elements describing a set of entities with a common set of attributes.
  13. In programming languages, a language construct that consists of procedures or data declarations and that interact with other such constructs.
  14. A structured document that is composed of multiple requirement artifacts. Structure can be created in a module by modifying the order and hierarchy of the artifacts.
  15. In ESQL, a named container of code. In the service flow project tools, this name is associated with a particular condition expression in a particular node (Switch or While) and returns a Boolean value.
  16. In the Integrated Language Environment (ILE) model, the object that results from compiling source code. A module cannot be run. To be run, a module must be bound into a program.
  17. In networking, a pair of queues that perform functions on messages traveling between stream head and driver.

module body
For a given module, the unpublished module objects and the routine bodies of published module routines. See also module.

module initialization procedure
A procedure that is automatically called when any module routine or variable is first referenced in a session.

module map
A listing of a program module showing the length and module offset of each section.

module object
A database object defined in a module. See also condition, module, published module object.

module width
In AFP Utilities, the basic element width used in a bar code. The actual code element may be a module width or a multiple of a module width.

Pertaining to a modulus; for example, 9 is equivalent to 4 modulo 5.

modulo check
A calculation performed on values entered into a system by an operator. This calculation is designed to detect most common typing errors.

modulo level
The maximum number of path information units (PIUs) that a device can send before stopping to wait for a response.

modulo-n check
A check in which a value is divided by a number n to generate a remainder that is compared with the remainder previously calculated. (T)

In communications, a number, such as a positive integer, in a relationship that divides the difference between two related numbers without leaving a remainder. For example, 9 and 4 have a modulus of 5 (9 - 4 = 5; 4 - 9 = -5; and 5 divides both 5 and -5 without leaving a remainder).

modulus 10 checking/modulus 11 checking

  1. Formulas used to calculate the check digit for a self-check field.
  2. A method for verifying data.

modus operandi (MO)
A Latin phrase that means a method of doing something.

See major object environment block.


  1. See metric-only font.
  2. See Meta Object Facility.
  3. See meta-object facility.
  4. See Managed Object Format.

See monitor mode.


  1. An entity that performs measurements to collect data pertaining to the performance, availability, reliability, or other attributes of applications or the systems on which the applications rely. These measurements can be compared to predefined thresholds. If a threshold is exceeded, administrators can be notified, or predefined automated responses can be performed.
  2. A product feature that monitors a changing quantity and sends notification when the quantity reaches a specific level. For example, the availability monitor raises a global alert when inventory falls below a configured level.
  3. In enterprise search, a user who has the authority to observe collection-level processes.
  4. In performance profiling, to collect data about an application from the running agents that are associated with that application.
  5. A user role defined in the Presence Zones environment. The monitor is responsible for system status monitoring and has read-only access in the Presence Zones system. For example, the monitor is able to view tools such as the Live Sensor Map, or any reports.
  6. A facility of the integration test client that listens for requests and responses that flow over the component wires or exports in the modules of a test configuration.

monitor component
The autonomic manager component that collects, aggregates, filters, manages and reports details (metric properties, topologies, and so on) that were collected from managed resources. See also autonomic manager, managed resource.

monitor configuration server
The application server installation that owns the overall application server configuration for a cell.

Monitor control server
In replication, a database that contains the Monitor control tables, which store information about alert conditions that the Replication Alert Monitor monitors. See also control server.

monitor details model
A container for monitoring contexts and their associated metrics, keys, counters, stopwatches, triggers, and inbound and outbound events. The monitor details model holds most of the monitor model information.

monitored directory
The directory where the rapid deployment tools detect added or changed parts and produce an application that can run on the application server. See also automatic application installation project, free-form project.

monitor element
A data structure that is used by the system monitor to store information about a particular aspect of the database system status. Monitor elements collect data for one or more logical data groups. Each monitor element collects one of the following specific types of data: counter, gauge, watermark, textual information, or timestamp. See also logical data group.


  1. Running a hardware or software tool to measure the performance characteristics of a system.
  2. The capture, analysis, and reporting of project performance, usually as compared to plan.
  3. The regular assessment of an ongoing production system against defined thresholds to check that the system is operating correctly. See also monitoring domain.

monitoring agent
See agent.

monitoring application
An application that observes and records the activity of specific applications or systems. It typically monitors information such as available disk space or application errors and compares the information to defined thresholds. When thresholds are exceeded, the monitoring application can either notify an administrator or respond automatically based on predefined rules.

monitoring collection
A collection of predefined monitors. Administrators can also use custom-developed or third-party monitoring collections.

monitoring configuration
A set of monitoring options for a particular monitoring application. These options are defined in the monitoring application, and are referenced by Tivoli Intelligent Orchestrator to configure monitoring for devices.

monitoring context
A definition that corresponds to an object to be monitored, such as a process execution, an ATM, a purchase order, or the stock level in a warehouse. At run time, monitoring contexts process the events for a particular object.

monitoring context instance
Information in IBM Business Monitor that is collected at a specific point in time within a monitoring context.

monitoring domain
In CICS, the domain responsible for producing performance information about each task. See also monitoring.

monitoring record
Any of three types of task-related activity record (performance, event, and exception) built by the CICS monitoring domain. Monitoring records are available to the user for accounting, tuning, and capacity planning purposes. See also exception class data, performance class data.

monitoring schedule
A schedule that determines the days and times on which monitors collect data.

monitor interval
A specified time, scalable to seconds, minutes, hours, or days, for how often the monitoring server checks to see if a situation has become true. The minimum monitor interval is 30 seconds; the default value is 15 minutes.

monitor mode

  1. In BSC, the mode during which the communications adapter is looking for synchronization characters.
  2. A mode in which an application program can directly access the display adapter.

monitor model
A model that describes the business performance management aspects of a business model, including events, business metrics, and key performance indicators (KPIs) that are required for real-time business monitoring.

monitor model CEI configuration owner
The server installation that owns the overall server configuration that contains the monitor model Common Event Infrastructure (CEI) server target.

monitor qualifier
A case-sensitive character string that identifies an instance of a Replication Alert Monitor process.

monitor switch
A database manager parameter that is manipulated by the user to control the type and quantity of information that is returned in performance snapshots.

To change alphabetic characters from one case (usually lowercase) to another case (usually uppercase). One should use monocased data only for presentation or parsing, never for replacement of original data. See also folding.

monocase table
A table used to convert lowercase letters to uppercase letters. The actual process of character conversion is called monocasing.

The translation of alphabetic characters from one case (usually the lowercase) to their equivalents in another case (usually the uppercase). See also folding.


  1. A special case of static gray in which there are only two color map entries. Some monochrome adapters can display shades of gray in the Gray Scale Adapter.
  2. Consisting of a single color.

mono-indexed chart
A chart that provides a view of a one-dimensional array view.

A sysplex consisting of one system that uses a sysplex couple data set (CDS).


  1. One space.
  2. Referring to a character set that uses one space in a preset width for each character.

monospaced font

  1. See uniformly spaced font.
  2. A font in which the spacing of the characters does not vary.

The spacing of characters according to a single predetermined width. See also proportional spacing.

Pertaining to an expression or function whose set of all possible results preserves the order of the set of inputs. An expression or function that is used to derive a generated column and that is monotonically decreasing, increasing, nondecreasing, or nonincreasing can increase functionality on tables organized by dimensions.

MO recording
See magneto-optic recording.

more-data bit (M-bit)
In X.25 communications, the bit in a data packet that indicates that there is more data to follow in another data packet, when a message is too large for one packet.

The smallest unit of meaning in a language. A word must consist of one or more morphemes. In English, the word 'desks' has two morphemes: the root word 'desk' and the suffix 's', which indicates plurality.

The branch of linguistics that studies the patterns of word formation.

Pertaining to the part of morphology that covers the relationship between syntax and morphology.

The study of the characteristic arrangement of morphemes in a sequence.

A method of prioritizing requirements developed within DSDM. MoSCoW stands for Must, Could, Should, and Won't.

See maintenance and operator subsystem.

See maintenance and operator subsystem extended.

See mobile solutions terminal.

most accurate date
The data calculation process that is used to determine the departure and arrival schedule for a shipment.

most critical application occurrences
Unfinished applications in which latest start time is earlier than or equal to the current time.

mostly global address space (MGAS)
A flexible virtual address space model, used in systems such as HP-UX, that preserves most of the address space for shared applications. This model can enhance performance for processes that share a lot of data. See also mostly private address space.

mostly private address space (MPAS)
A flexible virtual address space model, used in systems such as HP-UX, that can allocate larger address space blocks to processes. This model can enhance performance for processes that require a lot of data space. See also mostly global address space.

most significant byte (MSB)
See big endian.


  1. See OSF/Motif.
  2. User interface software, from Open Systems Foundation, for use with the X Window System.

Motion JPEG (M-JPEG)
A JPEG that is used for animation.

motor pool
The group of vehicles that are available or potentially available to be assigned to vehicle requests.


  1. To place a data medium in a position to operate.
  2. To make a file system accessible.
  3. To make recording media accessible.

Pertaining to a status where the optical image associated with the selected image catalog entry is active or loaded in the active virtual optical device. The mounted image is the currently available optical image that can be seen by using the Work with Optical Volumes (WRKOPTVOL) command. One optical image can be in mounted status at a time. The installation software will start with this image during the installation process.

mount handle data set
In z/OS, a data set used to store the file handles of Network File System (NFS) mount points.

mount limit
The maximum number of volumes that can be simultaneously accessed from the same device class. The mount limit determines the maximum number of mount points. See also mount point.

mount point

  1. A directory established in a workstation or a server local directory that is used during the transparent accessing of a remote file.
  2. In Linux operating systems and in UNIX operating systems such as the AIX operating system, the directory at which a file system is mounted and under which other file systems can be mounted.
  3. A directory at which a file system is mounted and under which other file systems can be mounted.
  4. A logical drive through which volumes are accessed in a sequential access device class. For removable media device types, such as tape, a mount point is a logical drive associated with a physical drive. For the file device type, a mount point is a logical drive associated with an I/O stream. See also mount limit.

mount retention period
The maximum number of minutes that the server retains a mounted sequential-access media volume that is not being used before it dismounts the sequential-access media volume.

mount wait period
The maximum number of minutes that the server waits for a sequential-access volume mount request to be satisfied before canceling the request.

A device with one or more buttons used to position a pointer on the display without using the keyboard. It allows a user to select a choice or function to be performed or to perform operations on the display, such as dragging or drawing lines from one position to another.

mouse button
A mechanism on a mouse that a user presses to select choices or start actions.

mouse event
The act of a mouse interacting with items on an interface. For example a click, hold, or drag from the mouse are all interpreted as different mouse events.

mouse pointer
A symbol on the screen (such as an arrow or hand) that follows the movement of the mouse as the user moves it.

mouse threshold
An operating system parameter that determines the amount of horizontal or vertical mouse movements required to move the cursor on the screen.

movement account
An account generated from a base account, or a manually defined account that reflects movement of equity or fixed assets between opening and closing balances.

movement extension
A suffix which together with a base account form a movement account.

movement type
The direction for a shipment route, such as outbound, inbound, or interplant transfer.

move mode
A transmittal mode in which the record to be processed is copied to or from a user work area. See also locate mode.

move order
In architecture, a drawing order that specifies or implies movement from the current position to a given position.

move policy
In Backup, Recovery, and Media Services, a policy that defines the movement of media between or among storage locations, and the length of time the media is to remain at each location. After the move is specified in the move policy, the media is returned to the user-specified home location. A move policy can be used with any media policy.

moving-in volume
A volume for which a move into a bin has been started, but not yet confirmed.

moving-out volume
A volume for which a move out of a bin has been started, but not yet confirmed.

Moving Pictures Experts Group

  1. The standard developed by the Moving Pictures Experts Group.
  2. A group that is working to establish a standard for compressing and storing motion video and animation in digital form.

moving set function
A function that performs calculations on a set of the latest rows in a view. The set of rows to include is determined only when a new data stream arrives.

See mathematical programming.

See mostly private address space.

See multipath channel.

See message protocol data unit.

See Moving Pictures Experts Group.

See message processing facility.

See Message Passing Interface.

A portable implementation of the Message Passing Interface (MPI).

See mandatory print labeling.

See multiple program, multiple data.

See multiprocess multithread.


  1. See message processing program.
  2. See massively parallel processing.


  1. See Map Page Segment structured field.
  2. See master production schedule.
  3. See multiple port sharing.

See multiprotocol transport networking.

MPTN access node
A node that has MPTN components installed, allowing transport users to use nonnative transport providers.

MPTN connection
An end-to-end connection through the MPTN network that may traverse multiple networks running different protocols. If the network consists of multiple MPTN segments, the MPTN connection is formed by having MPTN transport gateways concatenate the MPTN segments into one logical connection.

MPTN datagram
A datagram that carries an MPTN header as part of the data.

MPTN network
A network consisting of a mixture of native nodes, MPTN access nodes, MPTN address-mapper nodes, and MPTN transport-gateway nodes. The resulting network has the appearance to the user of one logical network. An MPTN network that consists of just a single transport network does not contain an MPTN transport gateway.

MPTN-qualified transport address
A transport address that is qualified by its corresponding address type. The address conforms to the syntax and meaning of the specified address type. An example of an MPTN-qualified transport address is the pair (type=SNA, transport address=network-qualified LU name).

MPTN segment
A connection across a single-protocol transport network between an MPTN node (either an MPTN access node or gateway node) and another node that may or may not be an MPTN node.

MPTN transport gateway
An MPTN component that concatenates two or more single-protocol networks to form an integrated heterogeneous network.

See message processing unit.

See WebSphere MQ Administration Interface.

MQ Gateway
A message that uses the MQ protocol to support application integration by enabling the transfer of data across multiple platforms using queues, sending and receiving data as messages.

See Message Queue Interface.

MQI channel
A connection between a WebSphere MQ client and a queue manager on a server system. An MQI channel transfers only MQI calls and responses in a bidirectional manner. See also channel.

See message queue management.

See WebSphere MQ script commands.

MQSeries Interface
A message queue using the MQ protocol that allows applications to exchange data through a common interface.

See materialized query table.

MQ Telemetry Transport (MQTT)
An open, lightweight publish/subscribe messaging protocol flowing over TCP/IP to connect large numbers of devices such as servos, actuators, smart phones, vehicles, homes, health, remote sensors, and control devices. MQTT is designed for constrained devices and low-bandwidth, high-latency or unreliable networks. The protocol minimizes network bandwidth and device resource requirements, while ensuring some degree of reliability and assured delivery. It is used increasingly in the “machine-to-machine” (M2M) or “Internet of Things” world of connected devices, and for mobile applications where bandwidth and battery power are at a premium.

See MQ Telemetry Transport.

MQTT client
A client application that connects to MQTT capable servers such as WebSphere MQ Telemetry channels. Users can write their clients to use the published protocol, or download the free Mobile Messaging & M2M Client Pack from IBM. A typical client is responsible for collecting information from a telemetry device and publishing the information to the server. It can also subscribe to topics, receive messages, and use this information to control the telemetry device.

MQTT daemon for devices
An advanced MQTT V3 client. It is a very small footprint MQTT server designed for embedded systems. Its primary use is to store and forward messages from telemetry devices and other MQTT clients, including other MQTT daemons for devices.

MQTT server
A messaging server that supports the MQ Telemetry Transport protocol. It enables mobile apps and devices, supported by MQTT clients, to exchange messages. It typically allows many MQTT clients to connect to it at the same time, and provides a hub for messages distribution to the MQTT clients. MQTT servers are available from IBM and others. IBM MessageSight, WebSphere MQ Telemetry, and the MQTT daemon for devices are MQTT servers from IBM.

See machine-readable information.

MR indicator
See matching record indicator.

See multileaving remote job entry.

See machine readable material.

MRM domain
The message domain that includes all messages that are modeled in the workbench. Message models can be created to represent a wide range of message types, with one or more optional physical formats. Messages in this domain are processed by the MRM parser. See also JMS domain, XML domain.

MRM parser
A program that interprets a bit stream or tree that represents a message that belongs to the MRM domain, and generates the corresponding tree from the bit stream on input, or bit stream from the tree on output. Its interpretation depends on the physical format that you have associated with the input or output message.

See message reference number.

See multiregion operation.

See material requirements planning.

See machine-reported product data.

See message reception registry.


  1. See management server.
  2. See message store.
  3. See management services.

See multiport serial adapter.

See most significant byte.

See Multiple Systems Coupling.

MSC descriptor
Descriptors used by Extended Terminal Option (ETO) to relate LTERMs to statically defined Multiple Systems Coupling (MSC) links. See also ETO descriptor.

See Microsoft Cluster Server.

See main storage dump.

See main storage database.

See mail server framework.

See management services focal point.

MSG file
In VisualAge RPG, a file containing the application messages. The file is created from the message source file during the make process.

See maintain system history program.

See maintenance significant item.

See message sequence number.

See Managed Service Provider.

See message queue ID.

See managed software system.


  1. See millions of service units.
  2. See message signal unit.
  3. See management services unit.

MSU day
The measurement of the capacity of mainframe software based on the number of millions of service units (MSUs) that are activated on a server during a contiguous 24-hour period.

See message transfer agent.

See mean time between failures.

See made-to-customer.

See Multitasking Facility.

See manual tape library.


  1. See master terminal operator.
  2. See made-to-order.

See Message Transmission Optimization Mechanism.

See message transfer part.


  1. See message transfer system.
  2. See Microsoft Transaction Server.


  1. See mean time to recovery.
  2. See mean time to repair.


  1. See maximum transmission unit.
  2. See maximum transfer unit.

See message unit.

mug book
A file containing mug shots of criminals used for eyewitness testimony.

mug shot
A two-part photograph of an individual that shows the profile and face-forward view. Mug shots are often taken at the time of arrest and used for eyewitness identification.

See message unit identifier.

The compressing and expanding algorithm used primarily in North America and Japan when converting from analog to digital speech data. See also A-law.

multi-access network
A network in which multiple devices can connect and communicate simultaneously.

multi-access spool complex
See multi-access spool configuration.

multi-access spool configuration (MAS configuration)
A multiple-processor complex that consists of two or more processors at the same physical location, which share the same spool and checkpoint data sets.

multi-adapter bridge
A PCI bridge resource in the I/O hardware which provides for the connection of PCI adapters to the system PCI I/O bus. Each PCI adapter connected under a multi-adapter bridge is controlled individually by the multi-adapter bridge. The multi-adapter bridge number identifies a multi-adapter bridge on a given system PCI I/O bus and is part of the Direct Select Address for a PCI I/O adapter. The bus number and the multi-adapter bridge number together identify a unique multi-adapter bridge in the system.

multi-adapter bridge function
A function that identifies a single PCI adapter card location under a multi-adapter bridge. The multi-adapter bridge function number is part of the Direct Select Address for a PCI I/O adapter. The multi-adapter bridge number and the multi-adapter bridge function number together indicate a unique card location connected to a given system PCI bus. The bus number and the multi-adapter bridge number and the multi-adapter bridge function number together identify a unique PCI I/O resource in the system.

multi bid
A feature that enables a supplier to enter bids on many items on the same bidding form.

multibyte character
A mixture of single-byte characters from a single-byte character set and double-byte characters from a double-byte character set. See also single-byte character.

multibyte character set (MBCS)
A character set that represents single characters with more than a single byte. See also double-byte character set, single-byte character set, Unicode.

multibyte control
See escape sequence.


  1. A protocol that is used to deliver data simultaneously to multiple recipients. For example, sending out a live video transmission.
  2. Transmission of the same data to a selected group of destinations. See also broadcast, unicast.

multicast address

  1. See group address.
  2. A type of IP address that identifies a group of interfaces and permits all of the systems that are in that group to receive the same packet of information.

A method of transmitting data in which a single copy of data is sent to multiple users. The primary purpose of multicasting is to reduce network bandwidth usage.

multicast routing
The process by which network devices determine how multicast packets are delivered to intended recipients of the multicast traffic.

multicharacter collating element
A sequence of two or more characters that collate as an entity. For example, in some coded character sets, an accented character is represented by a non-spacing accent, followed by the letter. Other examples are the Spanish elements ch and ll. X/Open.

multiconnection server
See concurrent server.

Referring to a system that integrates multiple processors into one virtual processor. See also core, dual-core.

multicultural support
In computing, the ability of a single software solution to be translatable and to support the cultural conventions of multiple languages and geographic regions. Cultural conventions include the use of various writing systems, sort orders, different formats for date, time, numbers, and currency, different keyboard layouts, and so on. See also globalization.

multi-developer support
A concept that allows developers to share information in a catalog. Multi-developer support can be achieved in and across catalogs using source code control, component packages, and backing up and restoring catalogs. See also component package, source code control.


  1. In the DB2 OLAP Server, pertaining to a method of referencing data through three or more dimensions. An individual data value in a fact table is the intersection of one member from each dimension. See also business dimension.
  2. Pertaining to any system for which the dimension is the fundamental basis of data organization.

multidimensional aggregation
The process of reading data across one level of a hierarchy or auto-level hierarchy, and simultaneously summarizing it across a number of dimensions. See also aggregate rule, aggregation, multilevel aggregation, regular aggregate.

multidimensional analysis
The process of assessing and evaluating an enterprise on more than one level. See also business dimension.

multidimensional array
A group of data cells arranged by the hierarchy of the data. Multidimensional arrays organize data according to how it is used in an enterprise.

multidimensional clustering table (MDC table)
A table whose data is physically organized into blocks along one or more dimensions, or clustering keys, specified in the ORGANIZE BY DIMENSIONS clause.

multidimensional data source
See dimensional data source.

multidimensional data structure
See multidimensional array.

Multidimensional Expression Language (MDX)
A query language for dimensional sources.

multidimensional query language
A computer language that allows users to specify which data to retrieve out of a multidimensional database.

multidimensional server
A high-capacity, multi-user database server that locates and accesses data values based on their intersection of dimension members.

multidirectional replication
In Q replication, a replication configuration that includes peer-to-peer or bidirectional replication.

multi-divisional corporation
A corporation or business whose primary focus is managing purchasing and sales activities. It typically is a buyer, a seller, or both. However, it could also be a retailer, a manufacturer, or both.

multidomain network
A network that consists of two or more interconnected domains.

A network configuration in which there are one or more intermediate nodes on the path between a central node and an endpoint node.

multidrop line
See multipoint line.

multifunction IOP (MFIOP)
A system processor that as a unit contains more than one processor function such as a diskette controller, a storage device controller, and a communications controller. See also combined function IOP.

multifunction monitor (MFM)
The master dispatcher. The MFM scans the function control table (FCT) for dynamic support programs (DSPs) that are ready to be started and runs them.

multi-homed computer
A computer that has more than one network adapter card and, therefore, capable of having more than one IP address.

multihomed host
In the Internet Protocol (IP), a host that is connected to more than one network.

For TCP/IP, the ability to specify multiple interfaces per line description. The system can have multiple hosts on the same network over the same communications line or multiple hosts on different networks over the same communications line.

To pass through one or more intermediate queue managers when there is no direct communication link between a source queue manager and the target queue manager.

multi-instance queue manager
A queue manager that is configured to share the use of queue manager data with other queue manager instances. One instance of a running multi-instance queue manager is active, other instances are on standby ready to take over from the active instance. See also queue manager, single instance queue manager.

A variation of binary synchronous communication (BSC) that enables several devices to communicate concurrently over a link without using station addresses.

multileaving remote job entry (MRJE)
The fully synchronized, two-directional transmission of a variable number of data streams between two computers using binary synchronous communications.

multilevel aggregation
The process of reading data across one level of a hierarchy or auto-level hierarchy, and summarizing it to lower levels. See also aggregate rule, aggregation, multidimensional aggregation, regular aggregate.

multilevel alias facility (MLA facility)
A function that allows catalog specification based on one to four data-set name qualifiers.

multilevel security
A security policy that allows the classification of data and users based on a system of hierarchical security levels combined with a system of non-hierarchical security categories. The system imposes mandatory access controls restricting which users can access data based on a comparison of the classification of the users and the data.

Referring to many languages. A multilingual program strives to handle data in a way that is not dependent on a particular language or writing system. Multilingual documents combine text which is written in different languages. Multilingual may refer to many languages which all use the same script (such as English, French, and German), or to many languages which use distinct scripts (such as German, Hebrew, and Korean). The latter case is also referred to as multiscript. See also multiscript.

multilingual code page (MLP)
A code page supporting more than one language.

multilingual computing
The ability for software to handle multilingual content, including different scripts within the same computing session. See also globalization.

multilingual support
Support that includes more than one national language on a system.

multilink transmission group
A transmission group that consists of a group of links. The links are viewed as a single logical link.

Material presented in a combination of text, graphics, video, animation, and sound.

multimedia file system
A file system that is optimized for the storage and delivery of video and audio.

Multimedia Messaging Service (MMS)
An extension of the SMS standard, a message service that can include a multimedia file with a 160-character message. MMSs have become particularly relevant with the advent of smart devices that have cameras. See also Short Message Service.

Multimedia Messaging Service message (MMS message)
An evolution of SMS messaging that allows for messages that include pictures, video, or audio content to be sent to another device.

Pertaining to one or more data collection methods that are to be employed simultaneously for a specific project, survey, routing, or all three.

multimodal carrier selection
A process that is used to select the best mode and service for a single shipment. The mode is selected based on the service that has the lowest rate and can deliver the shipment on time.

multimodel architecture
An approach to big problems whereby a large model is decomposed into a main model and submodels. The results of each solved submodel are aggregated and returned to the main model to produce a global result. See also model decomposition.

multimode optical fiber
A type of optical fiber that incorporates shortwave lasers and that is used with gigabaud link modules. Typically, multimode fiber is used for links of up to 500 m (1640.42 ft). See also single-mode optical fiber.

multi-MVS environment
A physical processing system that is capable of operating more than one MVS image. See also MVS image.

multinational character set (MNCS)
A set of graphic characters that support the languages within a specific language group. On i5/OS, character set 697 and code page 500 are implied when speaking about the MNCS.

multinational enterprise
Enterprise operating in more than one country.

multinode installation
A system installation that has more than one server or node.

multinode load balancing (MLNB, MNLB)
A workload balancing function which distributes TCP/IP traffic through Cisco routers across multiple destination TCP/IP stacks.

multinode persistent session
An LU-LU session that is retained after the failure of VTAM, the operating system, or the hardware. See also persistent session.

multinomial logistic regression
A logistic regression that is used for targets with more than two categories. See also binomial logistic regression, target.

A storage configuration that supports multiple paths from servers to disks.

multipath channel (MPC)
A channel protocol that uses multiple unidirectional subchannels for VTAM-to-VTAM bidirectional communication.

multipayment framework
In WebSphere Commerce, the structure that allows for different merchant servers using different payment systems to issue the same generic commands and use the same generic data. Now replaced by the Payments subsystem.

multiphase scan
A scan that consists of two or more phases. See also phase.

multiple allegiance
An ESS hardware function, independent of software support, that enables multiple system images to concurrently access the same logical volume (LVOL) on the ESS as long as the system images are accessing different extents. See also extent, I/O Priority Queuing, parallel access volume.

multiple area data set (MADS)
Multiple data sets that contain shadow copies of DEDB areas. See also area data set.

multiple-area structure
In a data-sharing environment, a coupling facility structure that contains more than one VSO DEDB area. See also single-area structure.

multiple-authority requirement
An authorization condition for the CKGRACF USER and CKGRACF CMD commands that requires one, two, or three authorizations before the command can be processed.

multiple axis chart
In the GDDM function, a chart in which more than one horizontal or vertical axis, or both, are used.

multiple bar chart
In the GDDM function, a form of bar chart in which the bars at a given horizontal axis value are placed side by side. See also composite bar chart, floating bar chart.

multiple chart
In the GDDM function, two or more charts appearing together on the work station or page. Multiple charts can be of the same type or different types and can be constructed from one or more sets of data.

multiple chip module (MCM)
The fundamental processor building block of some IBM Power Systems servers.

multiple-choice selection field
A field that contains a fixed number of choices arranged in a list in which one or more selections can be made.

multiple-choice selection list
A field that contains a potentially scrollable list of choices in which one or more selections can be made.

multiple configuration instances
More than one instance of a product running in the same machine at the same time.

multiple console support (MCS)
The operations interface to z/OS systems and sysplexes.

multiple-context device
A single appliance that is partitioned into multiple virtual devices. Each virtual device is an independent device, with its own security policy.

multiple device driver (MD driver)
A RAID driver that employs a RAID-1 algorithm in order to carry out mirroring.

multiple device file (MDF)

  1. In RPG, any work station (WORKSTN) file with one of the keywords ID, IND, NUM, or SAVDS. Such a file can access more than one device, and devices of various types.
  2. A device file in which the maximum number of program devices is greater than one.

Multiple Digital Trunk Processor
The IBM 9295 Multiple Digital Trunk Processor. The combination of a number of digital signal processing cards and supporting equipment that provides high-level voice compression, high voice quality, and digital telephone signaling functions (transmit and receive) via an external shielded cable to an attached IBM RS/6000 computer. See also Single Digital Trunk Processor.

multiple-domain support (MDS)
A technique for transporting management services data between management services function sets over LU-LU and CP-CP sessions. See also multiple-domain support message unit.

multiple-domain support message unit (MDS message unit, MDS-MU)
The message unit that contains management services data and flows between management services function sets over the LU-LU and CP-CP sessions used by multiple-domain support. This message unit, as well as the actual management services data that it contains, is in general data stream (GDS) format. See also control point management services unit, multiple-domain support, network management vector transport.

multiple-entry font
A font with multiple entries in the Map Coded Font (MCF) structured field. The only fonts that have multiple entries are double-byte fonts that are defined dynamically. (The MCF points directly to a set of code page and font character set pairs.) See also single-entry font.

multiple extended remote copy (MXRC)
An enhancement to extended remote copy (XRC) that allows up to five XRC sessions to run within a single logical partition (LPAR).

multiple-file format
In DFSMShsm, a tape format that requires a unique, standard-label data set for each user data set written. When DFSMShsm writes in multiple-file format, it writes one, tape data set for every user data set to all tape migration and backup volumes.

multiple gateways
More than one gateway that serves to connect the same two SNA networks for cross-network sessions.

multiple image facility (MIF)
A facility that allows channels to be shared among Processor Resource/Systems Manager (PR/SM) logical partitions in an ESCON environment.

multiple inheritance
An object-oriented programming technique implemented in C++ through derivation, in which the derived class inherits members from more than one base class.

multiple instruction stream, multiple data stream (MIMD)
Pertaining to a parallel programming model in which different processors perform different instructions on different sets of data.

multiple-line entry field
In VisualAge RPG, an entry field that allows the user to enter multiple lines of text.

multiple logical partitions
A partitioned database environment with multiple database partition servers installed on one computer.

multiple message mode
A processing mode in which synchronization points occur only at DL/I CHKP calls or application termination. See also message mode, single message mode.

multiple occurrence data structure
In RPG, a data structure that appears more than once in a program.

multiple port sharing (MPS)
An arrangement for short-hold mode operation in which both the first call and a reconnection call (recall) for a population of DTEs are directed to any available port within a port group.

multiple program, multiple data (MPMD)
Pertaining to a parallel programming model in which different, but related, programs are run on different sets of data.

multiple response
Pertaining to a question characteristic that allows for one or more entries within an entry field.

multiple response category
A category that can be chosen with other categories in a category list in answer to a question.

multiple response variable
A categorical variable that can have more than one value for each case, such as a variable that is based on a question to which the respondent can choose several answers from a predefined set of answers.

multiple-selection field
In System i Access, a list from which a user can choose one or more items.

multiple-subsystem scope
A RACF classification model used in conjunction with the DB2 access control module, or RACF external security module, to construct DB2 resource names with the subsystem ID as part of the class name. See also single-subsystem scope.

Multiple Systems Coupling (MSC)
An IMS facility that permits geographically dispersed IMS systems to communicate with each other. See also IMSplex.

multiple up
The printing of more than one page on a single surface of a sheet of paper.

multiple value list
A set of descriptive values from which a user can select more than one.

Multiple Virtual Storage (MVS)
An IBM operating system that accesses multiple address spaces in virtual storage. See also Base Control Program.

Multiple Virtual Storage/Enterprise Systems Architecture (MVS/ESA)
See z/OS.

Multiple Virtual Storage/Operator Communication Control Facility (MVS/OCCF)
A facility that intercepts messages from the MVS supervisor. The NetView program and MVS/OCCF help a network operator control multiple MVS systems from a central site.

To simultaneously transmit two or more messages on a single channel.

multiplexed connection
A single network connection between a database server and a client application that handles multiple database connections from the client.

multiplexed device

  1. A device capable of interleaving events of two or more activities or capable of distributing events of an interleaved sequence to the respective activities.
  2. A device that takes several input signals and combines them into a single output signal so that each of the input signals can be recovered.


  1. See multiplexed device.
  2. A device that takes several input signals and combines them into a single output signal in such a manner that each of the input signals can be recovered.

multiplexer channel
A channel designed to operate with a number of I/O devices simultaneously. Several I/O devices can transfer records at the same time by interleaving items of data.


  1. In data transmission, a function that permits two or more data sources to share a common transmission medium so that each data source has its own channel.
  2. In OSI, the technique of using a single network connection by multiple Transport Layer connections so that multiple associations can share the same line. Multiplexing is available only for transport classes 2 and 4.

See connection multiplicity.

multiplier variable
A helper variable that is used to store numeric data associated with a category.

In data communications, pertaining to a network that allows two or more stations to communicate with a single system on one line.

multipoint connection
A connection that is established for data transmission between more than two data stations.

multipoint control unit (MCU)
A device that connects callers to an audio or video conference.

multipoint line
A line or circuit that connects several stations. See also point-to-point line, point-to-point network.

multipoint network

  1. A network in which there are precisely two endpoint nodes, any number of intermediate nodes, and only one path between any two nodes.
  2. In data communication, a configuration in which more than two terminal installations are connected. The network may include switching facilities.
  3. More than two devices sharing the same transmission line at the same time. See also point-to-point network.

multiport serial adapter (MSA)
An adapter on the ESS Master Console that has multiple ports to which ESSs can be attached.

An enterprise server of the S/390 family.

Simultaneous processing by multiple central-processing units.

multiprocess installation
The process of installing two or more licensed programs at the same time.

multiprocess multithread (MPMT)
A process architecture of the IBM HTTP Server that supports multiple processes as well as multiple threads per process.

A processor complex that has more than one central processor.

The concurrent execution of two or more computer programs by a computer.

multiprotocol node
An implementation of MPTN architecture that supports more than one transport protocol.

multiprotocol transport network
A collection of single-protocol transport networks, each using a different transport protocol.

multiprotocol transport networking (MPTN)
A networking architecture that allows application programs using common upper-layer protocols and expecting the same transport services to communicate over transport networks that may use protocols different from the transport network the programs were designed to use. For example, socket application programs that were originally designed to communicate over a TCP/IP transport network can, using MPTN support, communicate over an SNA transport network.

Multipurpose Internet Mail Extensions (MIME)
An Internet standard that allows different forms of data, including video, audio, or binary data, to be attached to email without requiring translation into ASCII text.

multiregion operation (MRO)
Communication between CICS systems in the same processor without the use of SNA network facilities. This allows several CICS systems in different regions to communicate with each other, and to share resources such as files, terminals, temporary storage, and so on. See also CICSplex.

Referring to multiple languages that differ in script, for example: German, Hebrew, and Korean. See also multilingual.

MULTISET constructor
A type constructor used to create a MULTISET data type.

MULTISET data type
A collection data type created with the MULTISET constructor in which elements are not ordered and duplicates are allowed.

multisite update
Distributed relational database processing in which data is updated in more than one location within a single unit of work. See also unit of work.

multistation access unit (MAU)
In the IBM Token-Ring Network, a wiring concentrator that can connect up to eight lobes to a ring.

Pertaining to a shipment that is picked up at multiple origins or delivered to multiple destinations.

multi-stream backup
In Netezza, the ability to output backup data simultaneously to multiple backup locations to reduce the time to complete the backup.

multisystem application
An application program that has various functions distributed across MVS systems in a multisystem environment.

multisystem cascaded transaction
A sequence of transactions across multiple systems in a sysplex that are coordinated by Resource Recovery Services (RRS).

multisystem environment
An environment in which two or more systems reside on one or more processors, and one or more processors can communicate with programs on the other systems.

multisystem RRSF node
An RRSF node consisting of multiple z/OS system images that share the same RACF database. One of the systems is designated to be the main system, and it receives the unsolicited RRSF communications sent to the node.

multisystem sysplex
A sysplex in which two or more MVS images can be initialized as part of the sysplex.

multitail connection
Multiple simultaneous connections to the subarea network through one or more boundary nodes using independent LU protocols.


  1. Describing a disk that is connected to multiple nodes.
  2. Pertaining to a communication controller with an NCP attached to more than one host processor.
  3. Pertaining to a communication controller with an NCP attached to more than one host processor.
  4. Pertaining to a communication controller with an NCP attached to more than one host processor.

The act of tapping a key multiple times to get a different character. For example, on a standard telephone keypad, one can tap "2" twice for the letter "b." See also predictive text.

A mode of operation in which two or more tasks can be performed at the same time.

Multitasking Facility (MTF)
A facility provided separately by C and by Fortran to improve turnaround time on multiprocessor configurations. MTF is provided by C library functions or by Fortran callable services.

multitask node
A navigation node in which multiple page instances can be opened in the work area per session.

The ability to deliver software to multiple client organizations from a single, shared instance of the software.

multitenant deployment
A deployment that consists of multiple enterprises having unique business requirements, such as different process flows, enterprise specific extensions, and rules.

multithread application program
A VTAM application program that processes requests for more than one session concurrently.

multithread capable
See multithread.


  1. Pertaining to concurrent operation of more than one path of execution within a computer.
  2. Pertaining to a process that has multiple active threads.
  3. Pertaining to the description of a program that is designed to have parts of its code run concurrently.

multithreaded application
An application written using threads. See also threadsafe.

A mode of operation in which the operating system can run different parts of a program, called threads, simultaneously.

multithread test
In CICS, this type of test involves several concurrently active transactions. Whether the new function can coexist with other related functions is tested. See also single-thread test.

multitiered application
An application that is deployed on more than one physical machine. A client/server application is a common multitiered application in which there are two tiers: the client tier (for example, the presentation and the graphical user interface) and the server tier (for example, the service and the database). See also application, dependent resource groups, location dependency.

multitier replication
In replication, a replication configuration in which changes are replicated from a replication source in one database to a replication target in another database, and changes from this replication target are replicated again to a replication target in another database. See also peer-to-peer replication, update-anywhere replication.

An input method with two or more inputs. For example, a pinch requires two fingers and is considered a multi-touch gesture. See also gesture, pinch.

multiuser mode
A mode of operation that enables two or more users to use the services of a processor within a given period of time. The usage is usually serial unless otherwise specified.

multiuse rule
A rule that defines the conditions under which multiple invocations of a product require only a single license. These rules are applicable only to concurrent licenses. The vendor of the product defines multiuse rules.

multiversion file system (MVFS)
A file system that supports dynamic views.

multivolume file
A file that occupies more than one diskette or tape.

multiword expression (MWE)
A semantically or syntactically significant expression that consists of multiple words that expresses a single concept. Multiword expressions can be phrasal in nature, comprising several sentence elements, for example: 'kick the bucket'. When compared to a regular sequence of words, multiword expressions does not decompose the meaning of each lexical unit in the phrase. For example, 'pass the buck' is a multiword expression with a single concept, whereas 'pass the salt' is a regular occurrence of three single lexical units. See also compound word, solid compound.

multiword format dictionary
A dictionary that permits the use of support dictionaries to convert each word that is encountered in a text into its lemma. The lemma form is then looked up in the multiword format dictionary, which is useful for defining inflected terms.

multiword unit (MWU)
A group of words, usually found in sequence, that are mechanically recognized in text without regard to sentence structure, and annotated. A multiword unit may or may not constitute a multiword expression (MWE), and may consist of one word for the uniformity of data development. LanguageWare provides separate domain term dictionaries containing multiword units.

Non-speech noise that a user interjects while speaking.

See member unique name.

Musical Instrument Digital Interface (MIDI)
A protocol that allows a synthesizer to send signals to another synthesizer or to a computer, or a computer to a musical instrument, or a computer to another computer.

music channel
A channel on which sounds can be broadcast to one or more telephony (voice) channels.

music title
The name by which WebSphere Voice Response knows a tune.

The capability of modifying tuples on a port. Both input ports and output ports can be defined as mutating or non-mutating.

mutator method
A method that an object provides to define the interface to its instance variables. See also accessor method, getter method, setter method.

See mutual exclusion.

mutex attribute object
A type of attribute object with which a user can manage mutual exclusion (mutex) characteristics by defining a set of variables to be used during its creation. A mutex attribute object eliminates the need to redefine the same set of characteristics for each mutex object created. See also mutual exclusion.

mutex object

  1. A means of coordinating access to a shared resource so that it cannot be used by more than one thread or process at a time. Mutex is short for mutually exclusive.
  2. An identifier for a mutual exclusion (mutex).

mutual exclusion

  1. An abstraction that enables two or more threads to cooperate in a mutual exclusion protocol providing safe access to shared resources.
  2. A synchronization function that is used to allow multiple jobs or processes to serialize their access to shared data.
  3. See semaphore.
  4. A flag used by a semaphore to protect shared resources. The mutex is locked and unlocked by threads in a program. See also mutex attribute object.

mutual exclusion lock
A lock that excludes all threads other than the lock holder from any access to the locked resource.

mutual exclusivity
In Sterling Order Management, a pricing rule strategy that prevents multiple pricing rules from being duplicated or contradictory.

See model view controller.

See multiversion file system.

See Multiple Virtual Storage.

MVS configuration program (MVSCP)
See hardware configuration definition.

See MVS configuration program.

MVS/Data Facility Product (MVS/DFP)
A major element of MVS, including data access methods and data administration utilities.

See MVS/Data Facility Product.

See Multiple Virtual Storage/Enterprise Systems Architecture.

MVS/Extended Architecture (MVS/XA)

MVS extended nucleus
A major element of MVS virtual storage. This area duplicates the MVS nucleus above the 16 MB line. See also MVS nucleus.

MVS image
A single occurrence of the MVS operating system that has the ability to process work. See also multi-MVS environment, single-MVS environment.

MVS nucleus
A major element of MVS virtual storage. This static storage area contains control programs and key control blocks. The area includes the nucleus load module and is of variable size, depending on the installation's configuration. The nucleus is duplicated above the 16 MB line as the MVS extended nucleus. See also MVS extended nucleus.

See Multiple Virtual Storage/Operator Communication Control Facility.

MVS router
A system service that provides a focal point and a common system interface for all products providing resource control. The MVS router is always present, regardless of whether RACF is present.

MVS subproject
A subproject that is subordinate to a z/OS project and contains development resources that reside on an MVS system. See also z/OS project.

MVS system symbol
In a sysplex where a customer runs a copy of a given program (such as CICS or the NetView program) on more than one MVS image, a symbol that the customer can use to write generic JCL for use by each instance of the given program. An MVS system symbol behaves like a program variable that the sysplex resolves at execution time with the value that is appropriate to the MVS image on which the program instance is running.

A type of operating system used on a System/370 computer.

See MVS/Extended Architecture.

See mark weight.

See multiword expression.

See message waiting indicator.

See midrange workload license charge.


  1. See modular water unit.
  2. See multiword unit.

MXQR service
See telemetry service.

See multiple extended remote copy.

MX record
See mail exchange record.