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MAC: (1) See message authentication code.; (2) See Medium Access Control.
machine characteristic: Values defined in the computer.
machine interface (MI): The interface, or boundary, between the operating system and the Licensed Internal Code.
machine language: See computer language. See also computer instruction.
machine object: 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.
machine storage pool: A storage pool used by the machine and certain highly shared programs, whose size is specified in the system value QMCHPOOL.
macro: In REXX, a program that performs certain operations, such as text editor operations, in applications.
macroinstruction: A single instruction that represents a set of instructions.
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 unit.
magnetic tape unit: A device for reading or writing data from or to magnetic tape.
mail: The distribution objects and documents referred to by a mail log.
mailbox: A collection of pointers to message objects that are addressed to a single entity.
mail exchange record (MX record): A record in the Domain Name System (DNS) that indicates which host handles mail for a particular domain.
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.
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 function: In the C language, 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 gets control when a program starts to run.
mainline module: A sequence of instructions called by a program in the main path after it is compiled.
main program: (1) The first program unit to receive control when a program is run.; (2) The highest level program involved in a run unit.
main storage: See memory. See also auxiliary storage.
main storage dump (MSD): (1) 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.; (2) A representation of the contents of main storage that was captured during a suspected i5/OS™ failure. This memory content is used for problem analysis.
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.
maintenance: 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.
main window: 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 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.
make: In VisualAge RPG, the process by which all of the components are compiled and assembled to create a VRPG application.
MAN: See metropolitan area network.
managed object: A resource that is subject to management--such as a layer entity, a connection, or a line--as viewed from a systems management perspective.
managed system: A system that is being controlled by a given system management application; for example, a system managed by an HMC or by iSeries™ Navigator.
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 Central: A suite of systems management functions that is an integrated part of iSeries Navigator. Management Central provides the base for managing multiple systems.
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 domain: 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.
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) A database containing the information pertinent to network management. The database is conceptually organized as a tree.; (2) In the Simple Network Management Protocol (SNMP), units of managed information that specifically describe an aspect of a system, such as the system name, hardware number, or communications configuration. A collection of related MIB objects is defined as a MIB.
management protocols: In OSI, protocols for use in systems management.
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.
manager: (1) The part of a distributed management application that issues requests and receives notifications; that is, uses the services of one or more agents.; (2) See managing process.
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.
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.
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.
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 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.
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.
MAP: See Manufacturing Automation Protocol.
mapped address: A bidirectional mapping of one address to another.
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. See also basic conversation.
mapping: A representation of one thing to another.
mapping object: (1) A function of AFP™ Utilities that maps a database field value to an object name.; (2) 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 e-mail, to add text to the beginning of an e-mail, to specify the path to store the PDF stream file, and more. See also intelligent routing, PDF subsystem, mapping object.
mapping table: 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.
map set: In basic mapping support (BMS), one or more maps combined in a map set. The effects of this combination are to reduce the number of entries in the PPT, and to load simultaneously all maps needed for one application.
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.
marker: In the GDDM® function, a symbol centered on a point. Line charts may use markers to indicate the plotted points.
marking: 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.
mask: A pattern or template that is applied to an Internet Protocol (IP) address to specify which bits are significant and which bits are irrelevant.
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.
master file: A collection of permanent information, such as a file of customer addresses.
master name server: A name server that provides secondary name servers with domain data.
master profile: In iSeries Access family, a file that contains the session profiles and keyboard profiles for a user's workstation function session.
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 licensed program.
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.
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.
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.
matrix: An arrangement in rows and columns.
MAU: See multistation access unit.
maxcon: The number of conversations that can be active at one time. The system asks you to define this number when you set up NAT masquerade rules. The default value is 128. Maxcon only pertains to Masquerade NAT rules.
maximize: A choice that, when selected, enlarges the window to its largest possible size.
maximum transmission unit (MTU): The largest possible unit of data that can be sent on a given physical medium in a single frame. For example, the maximum transmission unit for Ethernet is 1500 bytes.
Mb: See megabit.
MB: See megabyte.
MBCS: See multibyte character set.
MCA: See message channel agent.
MDF: (1) See multiple device file.; (2) See main distribution frame.
MDT: See modified data tag.
mechanism: 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.
media: (1) In Backup Recovery and Media Services, an individual physical tape cartridge or tape reel, or removable storage device available for use by the server. This media is grouped into media classes for management, tracking, and statistical analysis.; (2) Magnetic disks, magnetic tapes, compact discs (CDs), and digital video disks (DVDs).
media access method: The method for determining which device has access to the transmission medium at any time.
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 server.
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.
medialess: 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 origin: One of the four corners of the physical medium (usually paper) where printing begins.
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 set: (1) 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.; (2) 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.
medium: The material on which computer information is stored. Examples of media are diskettes, hard disk drives, CDs, and tape.
Medium Access Control (MAC): In a local area network, the protocol that determines which device has access to the transmission medium at a given time.
medium attachment unit: See transceiver.
megabit (Mb): 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.
megabyte (MB): For processor storage, real and virtual storage, and channel volume, 2 to 50th power or 1,048,576 bytes. For disk storage capacity and communications volume, 1 000 000 bytes.
member: In iSeries, one of several different sets of data, each with the same format, within one database file.
memory: 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 pool: A logical division of memory (storage) that is reserved for processing a job or group of jobs. Synonymous with main storage pool.
menu: A displayed list of items from which a user can make a selection.
menu bar: 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.
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 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.
merge: (1) To insert records throughout a single output file.; (2) 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.
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.
MES: See miscellaneous equipment specification.
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.
message: (1) A communication sent from a person or program to another person or program.; (2) In system programming, information intended for the terminal operator or system administrator.; (3) 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.
message authentication code (MAC): In Cryptographic Support, the first 4 bytes from the last 8-byte block of ciphertext produced when encrypting a message using cipher block chaining, that is added to the end of the plaintext message from which it was created and used to detect whether the message was changed during transmission.
message authentication key: In Cryptographic Support, a data encrypting key used to encrypt data to produce a message authentication code.
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.
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 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 envelope: The information associated with a message aside from attachments and recipients.
message file: (1) In CICS, the file holding the text of all CICS messages.; (2) An object that contains message descriptions. The system-recognized identifier for the object type is *MSGF.
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 help: More information about a message, such as the message type, severity, and date and time sent.
message identifier: A 7-character code that identifies a predefined message, and is used to get the message description from a message file.
message line: An area on the display where messages are displayed.
message object: An abstraction of the data structures or system objects that store mail server framework message information.
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 protocol data unit (MPDU): In OSI, the elements in Protocol 1 (P1) that are used between message transfer agents (MTAs).
message queue: (1) 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.; (2) 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 Interface (MQI): The programming interface provided by WebSphere MQ queue managers. The programming interface allows application programs to access message queuing services. See also message channel agent.
message queuing: A programming technique in which each program within an application communicates with the other programs by putting messages on queues.
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 severity: The measurement of how important or significant a message is. The higher the severity level, the more severe or important the condition.
message store (MS): 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 subfile: A subfile where the records are messages from a program message queue.
message transfer agent (MTA): A program that accepts the mail from user agents, delivers messages to user agents, and forwards messages to other MTAs.
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 type: 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.
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.
messaging: A method for communication between programs. Messaging can be synchronous or independent of time.
metaclass: A class whose instances are classes. Metaclasses are typically used to construct metamodels.
metadata: Data that describes the characteristics of stored data; descriptive data. For example, the metadata for a database table might include the name of the table, the name of the database that contains the table, the names of the columns in the table, and the column descriptions, either in technical terms or business terms. Database catalogs and information catalogs contain metadata.
metafile: 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.
metaphor: 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.
metatable: 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.
metering: 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.
method: In object-oriented programming, an operation that an object can perform. An object can have many methods.
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 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.
metric: A measurement of a particular characteristic of a program's performance.
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 wide area network.
MFIOP: See multifunction IOP.
MFM: See modified frequency modulation.
MHS: See message handling system.
MI: See machine interface.
MIB: See Management Information Base.
microfiche: A photographic negative containing reduced images of pages of a document, arranged in a grid pattern.
microsecond: A measurement of time: one millionth of a second.
Microsoft® Windows®: Pertaining to a Microsoft Corporation program that provides a graphical user interface for DOS.
microswitch: A switch operated by the movement of some part of the machine.
migrate: To move data from one storage location to another.
millisecond: A measurement of time: 1/1000 of a second.
MIME: See Multipurpose Internet Mail Extensions.
minimize: A choice that reduces the window to its smallest possible size and removes all the windows associated with that window from the display.
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.
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.
mirroring: The process of writing the same data to two disk units within the same auxiliary storage pool at the same time. The two disk units become a mirrored pair, allowing the system to continue when one of the mirrored units fails.
miscellaneous equipment specification (MES): A hardware change that is made after the time of the initial order.
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 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 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 data: In DB2® UDB for iSeries, data that is associated with both a single-byte character set and a double-byte character set.
mixed data string: In DB2 UDB for iSeries, a character string that can contain both single-byte and double-byte characters.
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 Object Document Content Architecture™ (MO:DCA™): 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-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.
MLD: See media library device.
MNCS: See multinational character set.
mnemonic: 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.
mnemonic-name: In COBOL, a user-defined word that is associated in the Environment Division with a specific channel-name, switch-name, or unit-name.
MO:DCA: See Mixed Object Document Content Architecture.
mode: (1) A method of operation in which the actions that are available to a user are determined by the state of the system.; (2) The state or setting of a program or device.; (3) In the OSI Communications Subsystem licensed program, a set of parameter values that are proposed for use when an association or connection is being established. The mode specifies the services needed from one or more layers.; (4) The session limits and common characteristics of the sessions associated with advanced-program-to-program communications (APPC) devices managed as a unit with a remote location.
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 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.
model configuration: In iSeries Access, the set of files, created by the iSeries Access administrator, that define a set of common characteristics for a set of iSeries Access users. Model configurations can be used as a base for defining user configurations.
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 output file: A file that contains sample output of a function.
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.
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.
modification level: A distribution of additional function or fixes to a program since the previous release or modification.
modified data tag (MDT): 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.
modified frequency modulation (MFM): (1) Pertains to the number of bytes of storage that can be stored on the recording media. Synonymous with double-density recording.; (2) Variation in the amplitude and frequency of the write signal.
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.
modulator-demodulator: See modem.
module: (1) 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. See also program.; (2) In OSI, one or more instances of the use of the ASN.1 notation for type and value definitions, represented in ASN.1 module notation.; (3) An i5/OS object that can be a collection of one or more procedures and one or more definitions for external or internal variables. This object results from the compiling of source code.; (4) In online education, a unit of instruction that is part of an education course.; (5) An independent unit that is part of a total structure.
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.
modulo check: A calculation performed on values entered into a system by an operator. This calculation is designed to detect most common typing errors.
modulus: 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) A method for verifying data.; (2) Formulas used to calculate the check digit for a self-check field.
monitor mode: In BSC, the mode during which the communications adapter is looking for synchronization characters.
monocase table: A table used to convert lowercase letters to uppercase letters. The actual process of character conversion is called monocasing.
monochrome: Consisting of a single color.
monospace: (1) Referring to a character set that uses one space in a preset width for each character.; (2) One space.
mount: To make a file system accessible.
mounted: 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.
mouse: 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.
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.
MPDU: See message protocol data unit.
MPS: See multiple port sharing.
MPTN: See multiprotocol transport networking.
MQI: See Message Queue Interface.
MQSeries®: A previous name for WebSphere MQ.
MR indicator: See matching record indicator.
MRJE: See multileaving remote job entry.
MS: (1) See message store.; (2) See management services.
MSB: See big endian.
MSD: See main storage dump.
MSF: See mail server framework.
MSG file: In VisualAge RPG, a file containing the application messages. The file is created from the message source file during the make process.
MTA: See message transfer agent.
MTS: See message transfer system.
MTU: See maximum transmission unit.
MUID: See message unit identifier.
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.
multibyte character set (MBCS): A set of characters in which each character is represented by one or more bytes See also double-byte character set, single-byte character set.
multicast: Transmission of the same data to a selected group of destinations. See also broadcast, unicast.
multicast address: (1) See group address. See also individual 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.
multifunction IOP (MFIOP): A server 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.
multihomed host: In the Internet Protocol (IP), a host that is connected to more than one network.
multihoming: 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.
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.
multilingual support: Support that includes more than one national language on a system.
multimedia: Material presented in a combination of text, graphics, video, animation, and sound.
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.
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-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 device file (MDF): (1) A device file in which the maximum number of program devices is greater than one.; (2) 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.
multiple-line entry field: In VisualAge RPG, an entry field that allows the user to enter multiple lines of text.
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-selection field: In iSeries Access, a list from which a user can choose one or more items.
multiple up: The printing of more than one page on a single surface of a sheet of paper.
multiplexed device: 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.
multiplexer: See multiplexed device.
multiplexing: 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.
multipoint: In data communications, pertaining to a network that allows two or more stations to communicate with a single system on one line.
multipoint line: A line or circuit connecting several stations. See also point-to-point line.
multiprocess installation: The process of installing two or more licensed programs at the same time.
multiprocessor: A computer including two or more processors that have common access to a main storage.
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 e-mail without requiring translation into ASCII text.
multistation access unit (MAU): In the IBM Token-Ring Network, a wiring concentrator that can connect up to eight lobes to a ring.
multitasking: A mode of operation that provides for concurrent performance or interleaved execution of two or more tasks.
multithread: A process that has multiple active threads.
multithread capable: See multithread.
multithreaded: In Java™, pertaining to the description of a program that is designed to have parts of its code run concurrently.
multithreading: A general purpose programming technique that reduces the complexity and overhead of concurrent programming. It is a required component to accommodate Java and Lotus® Domino® Server.
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.
multivolume file: A file that occupies more than one diskette or tape.
mutex: See mutual exclusion.
mutual exclusion (mutex): (1) An abstraction that allows two or more threads to cooperate in a mutual exclusion protocol that allows 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.
mutual exclusion lock: In software, a method for preventing two separately running pieces of code from interfering with each other's use of a particular data object. For example, if one thread is running a function that modifies a shared data structure, the application may need to prevent other threads from simultaneously attempting to read the data before the changes are complete.
MX record: See mail exchange record.