See abnormal end of task.

Termination of a task, job, or subsystem because of an error condition that recovery facilities cannot resolve during execution.

See application control block.

See application control block generation.

A control block that contains a description of the current user's security environment, including user ID, current connect group, user attributes, and group authorities. An ACEE is constructed during user identification and verification.

See accessor environment element.

An IMS that performs production work. See also tracker.

The internal resource lock manager (IRLM) that supports the active IMS subsystem in an XRF complex. See also alternate IRLM.

The library from which IMS draws its execution information when online change is used.

In a Remote Site Recovery (RSR) environment, the data-processing center that contains active IMSs.

See active IMS.

See area data set.

An implementation of the SNA LU 6.2 protocol that enables interconnected systems to communicate and share the processing of programs.

A part of IMS Transaction Manager that uses the common programming interface, which enables IMS application programs to communicate with other programs by using LU 6.2.

See application interface block.

A mapping that an application program uses to interpret the application interface block (AIB).

In an Extended Recovery Facility (XRF) environment, the IMS that monitors the active IMS and takes over production work when the active IMS fails.

The internal resource lock manager (IRLM) that supports the alternate IMS subsystem in an Extended Recovery Facility (XRF) complex. See also active IRLM.

See alternate program communication block.

A telecommunication-program program communication block (TP PCB) that is defined by the user and can be used to describe output message destinations other than the terminal that originated the input message. See also alternate response PCB, express alternate PCB, input/output program communication block, modifiable alternate PCB.

A program communication block (PCB) that defines a logical terminal and can be used instead of the I/O PCB when required to direct a response to a terminal in response mode, conversational mode, or exclusive mode. See also alternate program communication block.

See Automated Operator.

See Automated Operator Interface.

See Advanced Program-to-Program Communication.

See Advanced Program-to-Program Communication/IMS.

A control block that is created from the output of DBD and PSB generation and placed in the ACB library for use during online and database batch (DBB) region type execution of IMS.

The process by which application control blocks are generated.

An area in user-defined storage that is passed to IMS for DL/I calls that use the AIBTDLI interface. Application programs can use the AIB to communicate with IMS by using a PCB name instead of a PCB address.

A system definition option that enables users to limit the size and number of output segments that are produced by an application program. This option protects available message queue space from being depleted by a program output loop.

A subset of a data entry database (DEDB) that is defined as a VSAM entry-sequenced data set (ESDS). Each area in a DEDB consists of a root-addressable part, an independent-overflow part, and a sequential-dependent part. Areas contain the entire logical structure for a set of root segments and their dependent segments.

A data set that contains a data entry database (DEDB) area. IMS can maintain up to seven copies of this data set. See also multiple area data set.

See level one data sharing.

A technique for directing application program printout output to a specific printer node name. The destination print queue is specified at logon or signon time, and is created during sign-on of the user who created the input transaction.

A Message Format Service (MFS) option that allows an application program to simulate display (video) attributes such as high intensity on printer devices.

See automatic logon.

An application program that can issue a subset of IMS operator commands and receive status information about the execution of the commands.

An IMS interface that installations can use to monitor and control IMS activities. The interface enables an application program, by using DL/I calls, to issue a subset of IMS operator commands and receive command responses; a user exit routine to monitor activities and take appropriate action; and operator commands, responses, and asynchronous output that is destined for the IMS master terminal to be logged to the secondary master terminal.

A process by which VTAM automatically creates a session-initiation request to establish a session between two logical units (LUs). The session is between a designated primary logical unit (PLU) and a secondary logical unit (SLU) that is not queued for or in session with another PLU.

The component of z/OS that performs XRF processing. Specifically, the availability manager performs I/O prevention during takeover.

See availability manager.

A system in a multisystem environment that accepts transactions from the front-end system, calls application programs for transaction processing, and routes replies to the front-end system for response to the terminal. See also front-end system.

The process of removing all the database updates performed by an application program that has terminated abnormally. See also dynamic backout.

The default logical unit (LU) for an IMS system, when more than one LU is defined.

A common system service base on which many other IMS components are built. BPE provides a common set of system services such as storage management, tracing, and dispatching to various components such as the IMS Common Queue Server (CQS), BPE-based Database Recovery Control (DBRC), IMS Connect, Open Database Manager (ODBM), Operations Manager (OM), Resource Manager (RM), Repository Server (RS), and Structured Call Interface (SCI).

A point in an application program where the work of the application is committed. Unlike with a symbolic checkpoint, an application cannot be restarted from a basic checkpoint.

A facility that performs general editing functions for terminal input and output messages. See also message editing.

A copy of a database or area that reflects the state of the data at a point when no updates were being made. The Database Image Copy utility (DFSUDMP0) creates batch image copies, which IMS utilities can use to recover from failures.

See batch processing program.

An IMS batch processing program that has access to online databases and message queues. BMP programs run online, but like programs in a batch environment, they are started with job control language (JCL). See also batch processing program.

A BMP program that has access to online databases and message queues while performing batch-type processing. A batch-oriented BMP program does not access the IMS message queues for input or output. It can access online databases, GSAM databases, and z/OS files for both input and output. See also transaction-oriented BMP program.

An application program that has access to databases and z/OS data management facilities but does not have access to the IMS control region or its message queues. See also batch message processing program, message processing program.

A method of sharing data among IMS systems so that multiple application programs can access and update data concurrently between multiple IMS subsystems. See also database-level sharing.

See batch message processing program.

See Base Primitive Environment.

An internal component of IMS that maintains buffer pools. When a buffer is needed, the buffer handler selects the buffer at the bottom of the use chain.

A technique for preventing the use of invalid data in an IMS Sysplex data sharing environment. The technique involves marking all copies of data in IMS buffers invalid after a sharing IMS subsystem has updated that data.

For shared VSO DEDB areas, an option that tells IMS to check the private buffer pools for requested data before retrieving data from the coupling facility.

An area of memory into which data pages are read and in which they are modified and held during processing.

See change accumulation.

A coupling facility structure that stores data that can be available to all members of a sysplex. A DB2 data sharing group uses cache structures as group buffer pools.

Services that are provided by IMS for use by IMS exit routines. These services provide clearly defined interfaces that allow exit routines to request various functions, such as acquiring storage or finding an IMS control block.

See IMS catalog.

In a Remote Site Recovery (RSR) environment, the process by which tracked log data is used to make all recoverable resources (for example, shadow databases) current with those resources on the active IMS.

See conversation control block.

See coordinator controller.

The process of creating a compacted version of one or more IMS log data sets by eliminating records not related to recovery, and by merging multiple changes to a single segment into a single change.

A point at which the database manager records internal status information about the log; the recovery process uses this information if the subsystem abnormally terminates.

A local data set that contains Common Queue Server (CQS) system checkpoint information about a group of shared queues.

In a database, any segment that is dependent on another segment above it (its parent) in the hierarchy.

See control interval.

See concurrent image copy.

An attribute that is related to a transaction code and a message region that is used to determine scheduling. See also message class, region class.

A terminal for which the alternate IMS pre-opens backup sessions for the primary sessions that the active IMS opens; VTAM/NCP switches sessions from primary to backup at takeover.

A terminal for which IMS in the alternate reestablishes service at takeover.

A terminal that communicates with XRF IMS but whose sessions are not automatically reestablished at takeover.

A supported non-IMSplex command. A classic command generally requires a leading slash, for example, /DBRECOVERY.

See communication line block.

A group of IMSs in a sysplex that share databases, queues, or both, and have identical resource definitions.

See communication name table.

A Common Queue Server (CQS) private queue type that contains in-doubt data objects for a client that had a cold start or a CQS that had a cold start.

The starting of IMS when it is initialized for the first time or when some error condition prevents a warm or emergency restart. See also emergency restart, normal restart.

A component of the Control Center for IMS that is used to issue IMSplex commands from both a workstation or multiple IMS systems.

The portion of the segment search argument that enables an application program to access a database segment based on some variation in either the call function, the segment qualification, or the setting of parentage.

In an IMSplex, the IMS that Operations Manager (OM) designates to process a command when a command is issued through the OM API. Commands are routed to all IMS systems that are registered for the command and, if the command requires only one IMS to process it, the command master processes the command.

An entity that can process commands or perform other work as directed by an Operations Manager (OM). In an IMSplex, an IMS control region is a command processing client.

A character that permits a z/OS console operator or an IMS subsystem user to route DB2 commands to specific DB2 for z/OS subsystems.

The command status that is associated with a resource, for example, the status of STOP, TRACE, and MFSTEST commands. If a resource structure is defined, the recovery of command significant status is always maintained globally by the Resource Manager (RM) in the resource structure. See also end-user significant status.

To apply all the changes made during the current unit of recovery (UOR) or unit of work (UOW). After the operation is complete, a new UOR or UOW can begin.

A point in time when data is considered to be consistent. See also synchronization point.

The processing that IMS performs at a commit point.

The address space that manages the shared queues for its clients (IMS).

In z/OS, a part of the common area that contains data areas that can be addressed by all address spaces but is protected during its use by the key of the requester.

A collection of IMS manager address spaces that provide the infrastructure that is needed for systems management tasks. The CSL address spaces include Open Database Manager (ODBM), Operations Manager (OM), Resource Manager (RM), and Structured Call Interface (SCI). The CSL is built on the Base Primitive Environment (BPE) layer.

A z/OS address space that uses the services that are provided by the Common Service Layer (CSL). The IMS control region is an example of a CSL client.

An IMS control block that represents a VTAM node or a BTAM line. Each VTAM node or BTAM line has a single CLB.

An IMS control block that represents a logical terminal.

The key that is constructed to access a particular segment. A concatenated key consists of the key fields, including that of the root segment and successive children, down to the accessed segment.

A batch utility program that is used to make a copy of OSAM data sets and VSAM entry-sequenced database data sets (DBDSs), whether or not IMS is running and the database is online.

1. A fixed-length area of direct access storage in which VSAM stores records and creates distributed free space. The control interval is the unit of information that VSAM transmits to or from direct access storage. A control interval always includes an integral number of physical records.

2. In a key-sequenced data set or file, the set of records that an entry in the sequence-set index record points to.

An indicator used in a data-sharing environment to determine which sharing partner last read a control interval (CI). IMS compares the value of the CUSN for each CI to determine whether a CI should be updated during area restart or recovery.

The z/OS main storage region that contains the IMS control program.

A dialog between a terminal and a message processing program using IMS conversational processing facilities. Also, a dialog between an LU 6.2 program and an IMS application program. A conversation between a terminal and a message processing program is significant status that is kept in Resource Manager (RM), if RM is used. Status for a held conversation is not kept in RM. The IMS conversation is represented by a CCB. See also conversational processing.

An IMS control block that represents a conversation between a terminal and an application program.

An optional IMS facility with which an application program can accumulate information acquired through multiple interchanges with a terminal, even if the program stops between interchanges. See also conversation.

See global online change.

A z/OS subsystem that consists of the database resource adapter (DRA) and a transaction management subsystem, such as CICS.

A special logical partition that provides high-speed caching, list processing, and locking functions in a sysplex.

A database or area in a Remote Site Recovery (RSR) environment that is tracked by a tracking subsystem. Recovery information is not maintained by the tracking subsystem for databases or areas that are not covered.

An application program that uses CPI for Communications calls to receive an incoming message and to send a reply.

See Common Queue Server.

See command recognition character.

See common service area.

See Common Service Layer.

See Common Service Layer client.

In an IMS database, the place immediately preceding the segment occurrence that IMS retrieves if the user immediately issues an unqualified retrieval call.

During a HALDB online reorganization, a marker in a database partition that separates the copied database records from the records that have not been copied. The cursor indicates the progress of the reorganization through the HALDB partition.

For high availability large database (HALDB) online reorganization, the status in the recovery control data set (RECON data set) that alerts Database Recovery Control (DBRC) that an online reorganization has started.

See control interval update sequence number.

A collection of interrelated or independent data items that are stored together to serve one or more applications.

An environment that allows full-function databases and data entry databases (DEDBs) to be accessed from one or more transaction management subsystems.

The IMS DB/DC environment without the message handling and queue management capabilities.

Program products that provide a method to separate the designer and programmer from the physical aspects and constraints of data storage and the physical characteristics of the terminal network, so that maximum effort can be placed on the applications.

A data set that contains some or all of the database records that are stored in a full-function database. Other types of data sets that are used in IMS databases include Fast Path area data sets, HALDB indirect list data sets, and HALDB primary index data sets.

The collection of macro parameter statements that define the characteristics of a database, such as the database's organization and access method, the segments and fields in a database record, and the relationship between types of segments.

The process by which a database description (DBD) is created.

The protection of data items in a database while they are available to any application program. This protection includes the isolation of effects of concurrent updates to a database by two or more application programs.

A kind of data sharing that enables application programs in one IMS to read data while another program in another IMS reads from the same database or updates it. See also block-level sharing.

In a Remote Site Recovery (RSR) environment, a tracking subsystem that tracks the active subsystem's databases or areas.

One of two batch regions (the other being a DL/I batch region). DBB is an execution parameter. DBB batch jobs contain JCL DD statements for the ACB library.

See IMS monitor.

A program's place in the database after a DL/I call. IMS tracks the program's position in the database in order to process DL/I calls.

The PCB that describes an application program's interface to a database. One DB PCB is required for each database view that is used by the application program.

In an IMS database, a collection of segments that contains one occurrence of the root segment type and all of its dependents arranged in a hierarchic sequence. A database record can be a physical database record or a logical database record. See also logical database record, physical database record.

The process of restoring data by merging the backup copy with changes accumulated since the backup was made.

A feature of the IMS Database Manager that facilitates easier recovery of IMS databases. DBRC maintains information that is required for database recoveries, generates recovery control statements, verifies recovery input, maintains a separate change log for database data sets, and supports sharing of IMS databases and areas by multiple IMS subsystems.

The process of unloading and reloading a database to optimize physical segment adjacency or to modify the database description (DBD).

An interface to IMS DB full-function databases and DEDBs. The DRA can be used by a coordinator controller (CCTL) or a z/OS application program that uses the ODBA interface.

The unit of access; the smallest amount of data that can be transferred by one IMS operation.

See telecommunication program PCB.

A subsystem that allows IMS TM to act as a stand-alone, full-function transaction manager that can connect to DB2 or other external subsystems.

A control block used by access method routines in storing and retrieving data.

The name of a data definition (DD) statement that corresponds to a data control block that contains the same name.

A unit of storage in a coupling facility list structure that makes up a data entry.

Part of a coupling facility list structure list entry that is used to hold user-specified data.

A direct-access database that consists of one or more areas, with each area containing both root segments and dependent segments. DEDBs use a data structure that allows them to be used for both hierarchic processing and journaling. The database is accessed by using the VSAM Media Manager. See also Fast Path, sequential dependent segment.

The concept of separating the definitions of logical and physical data such that application programs do not depend on where or how physical units of data are stored; the reduction of application program modification in data storage structure and access strategy.

The IMS data manipulation language, which is a common high-level interface between a user application and IMS. DL/I calls are invoked from application programs that are written in languages such as Java, PL/I, COBOL, VS Pascal, C, and Ada. DL/I can also be invoked from assembler language application programs by subroutine calls. IMS lets the user define data structures, relate structures to the application, load structures, and reorganize structures.

An IMS control block in main storage that describes and controls a physical database. A DMB is constructed from information that is obtained from the ACB library or the DBD library.

A piece of client data that is placed on the coupling facility by CQS as a result of a CQSPUT request or a CQSUPD request. From an IMS shared queues point of view, a data object contains one part or all of an IMS message or an entire EMH message. From an IMS Resource Manager point of view, a data object contains information about an IMS resource such as a transaction or a user.

An operating system data set that contains a subset of a database with one or more unique segment types. A database always consists of at least one data set group. See also primary data set group, secondary data set group.

A number, maintained by DBRC in the RECON data set, that counts when an application opens a database for update.

The ability of subsystems or application programs to access data directly and to change it while maintaining data integrity.

A collection of one or more subsystems that directly access and change the same data while maintaining data integrity.

A data attribute that permits the access and handling of the data regardless of location and source.

See database.

See database management batch.

A field that contains both DBCS and EBCDIC data. The DBCS portions must always be enclosed with SO/SI control characters in both inbound and outbound data. For inbound data, the control characters are automatically created by the terminal.

See Database Control.

See database control environment.

See database description.

See database/data communication.

See database description generation.

See database data set.

See database monitor.

See database program communication block.

See Database Recovery Control.

One or more DBRC instances that share a single RECON data set in an IMSplex environment. Each DBRC group has a unique group identifier (GROUP ID). DBRC groups are used by DBRC, regardless of whether parallel RECON access is enabled.

An action (command process, query, and update) that is asked of DBRC by IMS, DBRC application programs, and jobs.

See data control block.

See Data Communications Control.

See data communication program communication block.

See device characteristics table.

See distributed data management (DDM) Architecture.

See data definition name.

See data entry database.

In Message Format Service (MFS), a literal field that MFS inserts into an input message when no data for the field is received from the terminal. See also explicit literal, literal field, system literal.

In Message Format Service (MFS), part of the device output format (DOF) that causes specific terminal functions to be performed if the destination terminal has the required features. See also system control area.

The basic system security that prohibits the entry of certain commands from any terminal other than the master terminal.

An address space, managed by the IMS control region, where IMS application programs run. Dependent region types are MPP, BMP, IFP, JMP, and JBP.

In a database, a segment that relies on a higher-level segment for its full hierarchic meaning. A child is a dependent segment of its parent. See also root segment.

An element of the active IMS system that has a counterpart in the alternate IMS system, but cannot trigger a takeover on its own. z/OS, VTAM, IRLM, and the CPC are DSEs. A DSE depends on IMS to recognize a failure in its processing and request that the alternate take over its operation.

A template from which an IMS control block is built.

In IMS Transaction Manager (TM), an application program, a logical terminal, or an operator command that is associated with the control region.

In a database, the physical or logical parent that is reached by the logical child path.

In an IMS multisystem environment, the system in which the logical destination resides.

A Message Format Service (MFS) table that is generated for IBM 3270 or SLU type 2 devices with symbolic names. An entry is generated for each symbolic name and its associated screen size and physical terminal features. Different combinations of features for the same symbolic name cause separate entries in the table to be created.

In Message Format Service (MFS), the smallest area in a device input format (DIF) or device output format (DOF) whose content and structure are defined by the user.

The Message Format Service (MFS) control block that describes the format of the data that is entered on the device and presented to MFS.

The Message Format Service (MFS) control block that describes the format of the output data that is presented to the device.

In Message Format Service (MFS), a user-defined group of device field definitions that comprise one or more physical pages to be presented to or received from the device.

See device field.

See device input format.

In a data entry database (DEDB), a segment that is chained from a root segment. A direct dependent segment is stored in either the root addressable portion or the overflow portion of a DEDB area.

In an IMS multisystem environment, the routing of response messages to other than the originating terminal as directed by a link receive routing exit routine.

A means of identifying the directory entry of a named object to the coupling facility. The directory, all of its entries, and all of the objects associated with those entries are contained in a single structure.

A data protocol that makes the sharing and accessing of data between computer systems possible by providing a common language and a set of rules that enable different systems to communicate and share data. The DDM architecture enables data interchange among different kinds of systems, increases efficient data exchange among similar systems, and standardizes data management facilities for new systems.

A Message Format Service (MFS) option that allows programs to communicate with device independence by sharing message formatting functions between MFS and a user-written remote program. The user-written remote program performs device-dependent formatting.

Resource recovery in which the resources and participants reside on multiple systems.

The architecture that defines formats and protocols for providing transparent access to remote data. DRDA defines two types of functions: the application requester function and the application server function.

See Data Language/I.

An address space that is used by the online IMS control program to contain most of the DL/I code and control blocks. This option can be selected for the online IMS environment to provide an alternative virtual storage configuration.

See data management block.

See device output format.

See device page.

See distributed presentation management.

See database resource adapter.

See dynamic resource definition.

See Distributed Relational Database Architecture.

See default system control area.

See dependent service element.

See data set sequence number.

An optional facility that produces a duplicate copy of log data.

Assignment of system resources to a program when the program is executed rather than when it is loaded into main storage.

A process that automatically cancels all activities performed by an application program that terminates abnormally. See also backout.

Freeing of system resources during program execution rather than at the end of the job.

See MFS dynamic directory.

A VTAM node created dynamically. See also dynamic terminal.

An IMS function that enables users to create, update, query, and delete the following IMS resources and their descriptors dynamically, without using the batch system definition or online change processes: application programs; databases; Fast Path routing codes; and transactions.

A terminal created through the Extended Terminal Option (ETO). A dynamic terminal has not been defined within the IMS system definition, and no control blocks exist for it at IMS initialization time. See also static terminal, dynamic node.

A user signed on to a dynamic node and for whom a Subpool Queue Block (SPQB) was dynamically created.

See extended address volume.

See extended common service area.

A restart of IMS following an IMS or z/OS failure. See also normal restart, cold start.

See expedited message handler.

See expedited message handler queue.

A type of significant status that relates to the work associated with a resource. IMS defines conversations, set-and-test-sequence numbers terminals, and Fast Path as end-user significant status for nodes and users. See also command significant status.

A terminal where an IMS user can issue transactions, some commands (based upon security authorization), and message switches.

See extended pointer set.

See extended partition specification table.

See error queue element.

A piece of data that is maintained for a Fast Path area data set block that cannot be accessed. Each data set can have up to ten damaged blocks (control intervals).

See External Subsystem Attach Facility.

See extended system contents directory.

See Extended Terminal Option.

A template that contains information about the physical characteristics of terminals, user options and message queue names, and remote LTERMs associated with Multiple Systems Coupling (MSC) links. See also logon descriptor, MFS device descriptor, MSC descriptor, user descriptor.

An access intent that establishes the intent of an application to reserve the exclusive use of the database. If a subsystem requests and DBRC grants exclusive access to a subsystem, then no other subsystem can access the database concurrently, regardless of the share level of the database.

See level zero data sharing.

An optional mode of terminal operation in which a terminal can receive no output other than a response to an input. Any output excluded from being sent is held for transmission until the terminal is removed from exclusive mode.

A program that receives control from another program to perform specific functions.

The expedited message handler shared queue on a coupling facility list structure.

An IMS Fast Path facility that processes single-segment input and output messages. Fast Path messages that use the EMH bypass the normal message queuing and application scheduling and therefore these messages are processed faster than non-Fast Path messages.

In Message Format Service (MFS), a literal field defined by the user for inclusion in an input or output message. See also default literal, literal field, system literal.

An alternate PCB to which output messages are sent before termination of the application program. See also alternate program communication block.

DASD storage that can contain more than 65,521 cylinders per volume.

A major element of z/OS virtual storage above the 16 MB line. This area contains pageable system data areas that are addressable by all active virtual storage address spaces. It duplicates the common system area (CSA), which exists below the 16 MB line.

The facility that allows batch processing programs to establish database positioning and initiate user-specified areas with a DL/I call in place of an OS CHKPT macro.

For Fast Path, an extension of the partition specification table (PST) that contains information for a dependent region that is unique to Fast Path.

In a HALDB, an expanded segment prefix that includes information that allows the use of indirect pointers. An EPS is created for logical child segments and secondary index segments.

A facility that minimizes the effect of failures in z/OS, VTAM, the host processor, or high-availability applications during sessions between high-availability applications and designated terminals. This facility provides an alternative subsystem to take over sessions from the failing subsystem.

A restart, initiated by a DL/I call, that reestablishes database positioning and user-specified areas. See also symbolic checkpoint.

An extension of SCD that is used for Fast Path.

A feature of IMS Transaction Manager that enables users to add or delete ACF/VTAM terminals or message queues (LTERMs) dynamically.

A subsystem that provides a set of resources that is used by IMS, but is not controlled by it

A facility that allows applications running under IMS to obtain data from external subsystems, such as DB2.

A separate IMS control region that monitors IMS, detects failure, and recovers any database resources that are locked by the failed IMS, making them available for other IMS systems.

IMS functions for applications that require good response characteristics and that might have large transaction volumes. Programs have rapid access to main-storage databases (to the field level), and to direct-access data entry databases. Message processing is grouped for load balancing and synchronized for database integrity and recovery. See also data entry database, load balancing group, main storage database.

A type of database that is designed to provide high data availability and fast processing for IMS applications.

See IMS Fast Path region.

A transaction type that runs exclusively in an IMS Fast Path region (IFP). See also Fast Path potential transaction.

A transaction type that can run in either a full-function region such as a Message Processing Program (MPP), or in an IMS Fast Path region (IFP). See also Fast Path exclusive transaction.

A type of image copy that is created by the DFSMS fast replication function.

See Fast Database Recovery region.

In a database, a portion (as defined during the database description generation process DBDGEN) within a segment that is the smallest unit of the data that can be referred to.

The ability of an application program to access data at the field level.

For Fast Path, theI/O area that is constructed by an application program to identify a field within a segment that is to be processed with a FLD call.

In Message Format Service (MFS), a character defined for operator use in separating input fields if the length of the entered data is less than the defined field length, or there is no data for a field.

In Message Format Service (MFS), a character used to pad input message fields or output device fields when the length of the received data is less than the length defined for the field or no data is received for the field.

See Find Destination.

An internal service in IMS used for finding certain IMS resources, most of which represent IMS destinations.

In Message Format Service (MFS), a format definition, all message definitions that refer to the format definition, and any table referred to by the format.

In a hierarchical direct database, the first 8 bytes of an area that is free space. The FSE describes the area of free space in a control interval or block that is 8 or more bytes in length.

In a hierarchical direct database, the first four bytes of a control interval or block. The first 2-byte field contains the offset, in bytes, to the first free space element (FSE) in the control interval or block. The second 2-byte field identifies whether this block or control interval contains a bit map.

An IMS system in a Multiple Systems Coupling (MSC) network in which all terminals are connected, messages are routed to the proper processing IMS, and all replies are routed to the terminals. A front-end system might also perform back-end processing. See also back-end system, pseudo-front-end system, transaction processing system.

See field search argument.

See free space element.

See free space element anchor point.

See field tab.

A hierarchical database that is accessed through Data Language/I (DL/I) call language and can be processed by all six types of application programs. Examples of full-function databases include HDAM, PHDAM, and HIDAM.

An image copy of an online database. The database can be updated while the image copy is being taken and some, all, or none of the updates might appear in the image copy.

Active-site log data that is not available to the tracking IMS. The log data might be missing either because it was not sent or because an I/O error occurred at the tracking site.

A database access method that allows batch application programs to access a sequential data set record that is defined as a database record. This database record is handled as one unit, with no segments, fields, or hierarchical structure. Any records to be added are inserted at the end of the database. GSAM does not allow database records to be updated or deleted.

The PCB that describes an application program's interface to a GSAM data set. One GSAM PCB is required for each GSAM data set view used by the application program.

A set of applications that have the same generic resource name, enabling VTAM to distribute terminal sessions among them.

An IMS system that belongs to a generic resource group.

A name used by VTAM to represent application programs that provide the same function in order to handle session distribution and balancing in a sysplex environment.

An internal resource lock manager (IRLM) lock that interests two IRLMs; both must coordinate to grant it.

Lock management that controls access to resources shared among IMS systems participating in block level sharing.

An IMS function that changes resources online for all IMSs in an IMSplex. See also local online change.

The collection of all IMS subsystems that can access a particular set of databases. A global service group can span several z/OS systems at more than one geographical location.

The name of an entity that joins a z/OS cross-system coupling facility (XCF) group and communicates with IMS by using the OTMA protocol. A member can be either a server (IMS) or a client.

See generalized sequential access method.

See generalized sequential access method program communication block.

See global service group.

See high availability large database.

A named entity of a high availability large database that represents only the structural definition of data and refers to the entire collection of partitions.

See HALDB online reorganization.

A function of IMS that allows non-disruptive, online reorganization of PHDAM and PHIDAM partitions.

A named entity of a high availability large database that represents a partition of an HALDB.

See hierarchical direct access method.

See hierarchic direct organization.

See hierarchical indexed direct access method.

A database access method using algorithmic addressability to records in a hierarchic direct organization. A choice of OSAM or VSAM ESDS is available as a base for HDAM.

A database access method used for indexed access to records in a hierarchic direct organization. This method provides indexed access to the root segments and pointer access to subordinated segments.

A database access method used for indexed access to records in a hierarchic sequential organization.

The physical storage organization in which database segments that represent a physical database record are related by direct address pointers in the segment's prefix.

In a database, the sequence of segment occurrences in a database record defined by traversing the tree top to bottom, front to back, and left to right.

The physical storage organization in which database segments that represent a physical database record are related by adjacency.

The tree-like arrangement of segments in a database, beginning with the root segment and proceeding down to dependent segments.

A partitioned full-function DL/I database. The supported database organizations are PHDAM, PHIDAM, and PSINDEX.

An option, available only to batch message programs, for optimizing the sequential processing of DEDB areas. A simultaneous image copy can also be created.

See hierarchical indexed sequential access method.

See hierarchic sequential organization.

See high-speed sequential processing.

See IMS Fast Path.

See indirect list data set.

See indirect list entry.

See indirect list entry key.

See isolated log sender.

A backup copy of a data set, used to restore the data set if necessary after a failure.

The facility that writes simple checkpoint information without requiring termination of MPPs.

See Information Management System.

A system database managed by IMS that stores metadata about databases and applications and provides a comprehensive view of IMS database metadata.

The IMS program that initiates and controls the major IMS facilities, such as IMS database, telecommunications, and message scheduling.

A database system that processes concurrent database calls and offers high performance for a variety of applications, ranging from those with moderate volumes to high volumes and those with simple data structures to complex data structures.

See IMS Database Manager.

A type of program designed to operate with the expedited message handler in a Fast Path region.

An online environment in which message-driven programs and DEDB online utilities operate.

The 4-byte subsystem identification used by a given IMS job. For the shared-queues and data-sharing environment, each IMSID in the group must be unique; in other cases, each IMSID might not have to be unique.

An active, unique IMS system in an IMSplex.

A driver that provides a connection to the IMS database, which enables users to access and change the database by using SQL queries.

An optional facility that records the activity within the IMS control region and dependent regions.

The IMS request message (IRM) header that is used on input messages from IMS Connect client application programs to communicate protocol options to IMS Connect.

A set of Java class libraries that support database access using the open standard Distributed Relational Database Architecture (DRDA) specification and the distributed data management (DDM) architecture commands.

A set of systems in an Information Management System (IMS) network that work together as a unit. Typically, these systems share resources, run in a Parallel Sysplex environment, and include a Common Service Layer (CSL). See also Multiple Systems Coupling.

An entity (typically running in its own address space) that manages resources, operations, or facilitates communications between other IMS-defined entities. Examples of IMSplex components are IMS subsystems (DB/DC, DBCTL, DCCTL), the Resource Manager, the Operations Manager, and the Structured Call Interface. A DLIBATCH or DBBBATCH region is considered a IMSplex component even though it does not interact with the Common Service Layer managers.

Any IMS-defined entity in an IMSplex that typically runs in its own address space and is managed by the IMS Common Service Layer.

A centralized data storage and retrieval solution that enables multiple IMS systems in an IMSplex to manage, store, share, and retrieve resources, such as resource and descriptor definitions, in common IMS repositories, such as the IMSRSC repository. This function simplifies the dynamic resource definition (DRD) process by eliminating the need to manually coordinate individual resource definition data sets (RDDSs) across an IMSplex. See also IMSRSC repository and dynamic resource definition (DRD).

See IMSRSC repository

A centralized IMS data storage and retrieval facility, managed by the Repository Server (RS), for storing and managing the resource and descriptor definitions that are supported by dynamic resource definition (DRD). A strategic alternative to using resource definition data sets (RDDSs), which require manual coordination. See also IMS repository function and Repository Server (RS).

See IMS system.

The IMS control region and its associated separate address spaces (DL/I and DBRC) and dependent regions.

Logically, a single log made up of online data sets (OLDSs) and write-ahead data sets.

See IMS Transaction Manager.

A data communication system that provides high-volume, high-performance, high-capacity, low-cost transaction processing for both IMS DB and DB2 databases.

A library not currently in use by the online IMS system in a system using online change. This library might be at a different level than the current or active libraries.

In a database, a segment that is located by an index and termed an index target segment.

The segment in an index database that contains a pointer to a segment containing data (the indexed segment), and termed an index pointer segment.

In a secondary index, the segment that contains the data and pointers used to index the index target segments.

In a database, the segment containing the data from which the indexing segment is built. It can be the same as the indexed segment or one of its dependents.

In a database, the segment pointed to by a secondary index entry, that is, from an index pointer segment.

In a HALDB, an IMS system index data set. The ILDS is a repository for the indirect pointers used for PHDAM and PHIDAM databases, which include one ILDS per partition.

In a HALDB, an entry in an indirect list data set.

In a HALDB, a unique token that is assigned to a segment in PHDAM and PHIDAM databases when the segment is created. Eight bytes in length and stored in the prefix of the segment, the ILK uniquely identifies every segment in PHDAM and PHIDAM databases.

In a HALDB, a pointer stored in the indirect list data set and used to eliminate the need to update pointers throughout other database records when a single partition is reorganized.

A transaction or database update that has been prepared for commit, but is not yet committed. If a failure occurs before the in-doubt unit of work is committed, IMS must resolve all the work whose status is in doubt.

See indoubt unit of work.

The state of a resource or unit of recovery that has not yet completed the prepare phase of the commit process.

Any of several system environments available with a database manager and transaction processing that are capable of managing complex databases and terminal networks.

Any valid command, transaction, or message switch.

In Message Format Service (MFS), the way in which input fields from certain devices are defined by the user to be scanned by MFS. See also record mode, stream mode.

An I/O area that is used by the Fast Path DL/I calls that return structural information about DEDBs.

A TP PCB provided automatically by IMS to an application program that executes in a communication system with TM. The I/O PCB is the mechanism by which a program obtains an input message from a terminal and returns a reply to the terminal that originated the input message. See also alternate program communication block.

In a Multiple Systems Coupling (MSC) network, the system to which the input terminal is attached.

In a Multiple Systems Coupling (MSC) network, the terminal from which a primary request originated.

A type of logical terminal that is created automatically by IMS and restricted to non-update transactions. Inquiry logical terminals are created for non-VTAM switched lines.

A program or programs that are run at the end of installation of an IBM licensed program, in order to verify that the program is working correctly.

A condition handled internally by IMS by which processing intent for one segment can propagate to related segments depending on the type of processing and the kind of relationship. It determines the compatibility of scheduling processing applications in parallel or serially.

An enhancement to the IMS offline dump formatter that is used to format IMS dumps through a series of interactive menu-driven panels rather than by creating or editing a DFSFRMAT data set.

In an MSC network, a system through which a message passes on its way from the input system to the destination system, or vice versa, in which no processing other than routing is performed.

A global lock manager that resides in its own address space and provides the option of keeping most of its control blocks in local storage rather than the common storage area.

See level three data sharing.

Any user data in a logical child segment that does not include the logical parent's concatenated key.

An extension of IMS Multiple Systems Coupling (MSC) that, when both subsystems use ISC, permits the connection of IMS to another IMS subsystem, to CICS Transaction Server for z/OS, or to a user-written subsystem.

See level two data sharing.

See input output area input.

See input/output program communication block.

The z/OS process that, during an XRF takeover, ensures that the failing active IMS cannot change the databases during the takeover.

The IMS process that, during a takeover, allows transaction processing after a takeover before I/O prevention has completed.

See IMS request message (IRM).

See internal resource lock manager.

A VTAM session between two internal resource lock managers (IRLMs).

See intersystem communication.

An Intersystem Communication user defined using the SUBPOOL macro in an IMS system definition.

In a Remote Site Recovery (RSR) environment, a component of the Transport Manager Subsystem that sends gap data to the tracking subsystem.

See installation verification program.

A region, dependent on IMS, that has a persistent Java virtual machine (JVM) and supports the scheduling of online, non-message-driven, batch Java applications. A JBP region is similar to a non-message-driven batch message processing (BMP) region.

A Java library that allows JDBC access to IMS databases from JMP or JBP applications, WebSphere Application Server for z/OS Enterprise JavaBeans components, CICS JCICS applications, and DB2 for z/OS stored procedures.

An industry standard for database-independent connectivity between the Java platform and a wide range of databases. The JDBC interface provides a call level interface for SQL-based and XQuery-based database access.

A region, dependent on IMS, that has a persistent Java virtual machine (JVM) and supports the scheduling of message-driven Java applications. A JMP region is like a message processing program (MPP).

See Java batch processing region.

See Java Database Connectivity.

See Java message processing region.

The field in a database segment used to store segment occurrences in sequential ascending order. A key field is also a search field. See also search field, sequence field.

A programming device that provides short-term serialization for IMS tasks running in the online IMS system. Similar in function to a z/OS lock.

See load balancing group.

In a database, the successive vertical dependencies in a hierarchical structure.

For data entry database (DEDB) areas, a method of data sharing in which Database Recovery Control (DBRC) can authorize only one subsystem to update the database and multiple subsystems that are not required to be protected from incomplete changes made by the updater to read it, or it can authorize multiple subsystems to read the database. See also interprocessor block level sharing.

A method of data sharing in which Database Recovery Control (DBRC) and one internal resource lock manager (IRLM) can concurrently authorize and protect multiple subsystems on the same z/OS system for updating or reading the database. See also area-level sharing, intraprocessor block level sharing.

A method of data sharing in which Database Recovery Control (DBRC) and one internal resource lock manager (IRLM) can concurrently authorize and protect multiple subsystems on the same z/OS system for updating or reading the database. See also interprocessor block level sharing.

A method of data sharing in which Database Recovery Control (DBRC) authorizes only one subsystem (for example, one online IMS) to access the database.

The number that determines whether the normal or limit priority value is assigned to a transaction during the scheduling process. See also limit priority, normal priority.

The priority to which a transaction is raised when the number of transactions enqueued and waiting to be processed is equal to or greater than the limit count value. See also limit count, normal priority, scheduling priority.

A variation of response mode where all operations on the communication line are suspended while the application program output message is being generated. See also response mode, terminal response mode.

In an IMS multisystem environment, the connection between two systems. See also physical link and logical link.

An entry on a coupling facility list structure list.

Part of a coupling facility list structure list entry that contains control information associated with the list entry such as the entry key and entry ID.

A header that anchors a list to a coupling list structure and contains control information associated with the list.

The number of the list header, which identifies the particular list. The list header number ranges from 0 to the maximum defined by the first connector to the coupling facility list structure. The list header number must be specified on IXL requests that access the list structure, to identify to which list the request is applicable.

A coupling facility structure that enables multisystem applications in a sysplex to share information organized as a set of lists or queues. A list structure consists of a set of lists and an optional lock table, which can be used for serializing resources in the list structure. Each list consists of a queue of list entries.

In Message Format Service (MFS), a message field or device output field defined to contain specific data. See also default literal, explicit literal, system literal.

The monitoring of application servers and management of the workload on servers. If one server exceeds its workload, requests are forwarded to another server with more capacity. See also transaction load balancing.

A grouping of Fast Path input messages that are ready for balanced processing by one or more copies of a Fast Path program. There is one load balancing group for each unique Fast Path message-driven application program. See also Fast Path.

A user-allocated and user-managed storage area on the local system.

In an IMS multisystem environment, a destination that resides in the local system. See also remote destination.

An internal resource lock manager (IRLM) lock that interests only the IRLM that grants it.

Lock management that controls access to database records used by application programs in the same online IMS system.

Any logical unit (LU), other than the defined base LU, that is used for outbound processing. See also logical unit.

See local logical unit.

An IMS function that performs online change to a local IMS system. To perform local online change in an IMSplex, local online change commands must be made manually on the IMS systems. See also global online change

Resource recovery in which all resources and participants reside on the same system.

In an IMS multisystem environment, a specific system in the multiple configuration.

In a multisystem environment, a transaction that is processed totally by the system in which it is defined. See also remote transaction.

A description of the data that a particular business process requires. It includes a list of the data elements, a conceptual data structure that shows how the data elements are grouped according to the entities they describe, and the relationships among the groups of data elements.

The reservation of a segment by a program. Other programs are kept from using the segment until the program using it is done.

A unique number, issued sequentially, given to a database resource to identify that it is in use (locked) by a requestor. A locked resource cannot be used until the current requestor has finished using it.

In a data-sharing environment, the association IMS makes between a VSO DEDB area and a multi-area structure when an XES connection exists between IMS and the structure.

In a database, a pointer segment that establishes an access path between its physical parent and its logical parent. It is a physical child of its physical parent; it is a logical child of its logical parent.

A database composed of one or more physical databases arranged in a hierarchical structure based on relationships among data segments. The structure of a logical database can be different from the physical structure of the data. See also physical database.

In a database, a set of hierarchically related segments of one or more segment types. As viewed by the application program, the logical database record is always a hierarchic tree structure of segments. All of the segments that exist hierarchically dependent to a given root segment and that root segment. See also database record.

In a database, a hierarchic structure of segments. Application programs written to use IMS deal only with logical data structures.

In a multisystem environment, the means by which a physical link is related to the transactions and terminals that can use that physical link. See also physical link.

In a multisystem environment, the path between any two systems. One or more logical link paths must be defined for each logical link.

The process of moving log records into the log buffers. See also physical logging.

An input or output message that is in a queue associated with a logical rather than a physical terminal. The message queue can be moved, independent of an application, from device to device.

In the IMS Message Format Service (MFS), a user-defined group of related message segment and field definitions. See also physical page.

In the IMS Message Format Service (MFS), the means by which output message segments are grouped for formatting. See also operator logical paging.

In a database, the segment a logical child points to. It can also be a physical parent. The pointer in the logical child to the logical parent can be symbolic or direct.

In a database, a user-defined path between two independent segments.

A message destination logically associated with a physical terminal or user. An LTERM is represented by a CNT control block. See also remote logical terminal.

A user-defined group of logical terminals to be associated with non-VTAM switched communication lines through the /IAM command. Each logical terminal pool consists of one or more logical terminal subpools.

A user-defined group of logical terminals to be associated with non-VTAM switched communication lines through the /IAM command. Each logical terminal pool consists of one or more logical terminal subpools.

In a database, all occurrences of one type of logical child with a common logical parent occurrence. See also physical twins.

An access point through which a user or application program accesses the SNA network to communicate with another user or application program.

The processing that a program performs between synchronization points.

The process of disconnecting from a computer system or network.

The process of connecting to a computer system, network, or terminal session

An Extended Terminal Option (ETO) descriptor that provides information required by IMS to build terminal-related control blocks. See also ETO descriptor.

A sequence number used to identify a log record and to maintain the order of log records for a subsystem.

In a Remote Site Recovery (RSR) environment, the component of the tracking subsystem that receives log data from active subsystems, stores the data in tracked log data sets, and routes the log records to tracking components.

See log record identifier.

A token that identifies a particular log record in the z/OS log stream that is used to locate that log record.

The process of logging records of completed operations to the write-ahead data set before entering them in the online log data set.

The test mode that permits the establishment of an output write loop, whereby continuous attempts are made to transmit a user-entered message to the test terminal.

See logical page.

See log record identifier.

1. See lock sequence number.

2. See log sequence number.

See logical terminal.

See local transaction.

See logical unit.

An LU 6.2 application program defined by an LU (logical unit) name plus a transaction program name.

See logical unit of work.

See log write-ahead.

See multiple area data set.

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

In a Remote Site Recovery (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.

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.

In a Remote Site Recovery (RSR) environment, a database at the active site. If a remote takeover occurs, the shadow database becomes the master database.

The IMS logical terminal that has complete control of IMS resources during online operations.

A Message Format Service (MFS) option that provides a format for a 3270 master terminal.

A communication sent from a person or program to another person or program.

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.

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.

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

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

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.

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.

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.

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.

An editing facility that allows application programs to deal with simple logical messages instead of device-dependent data, thus simplifying the application development process.

In Message Format Service (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.

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

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

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.

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.

An IMS application program that is driven by transactions and has access to online IMS databases and message queues. See also batch processing program.

A set of messages that are waiting to be processed by a program or to be sent to a terminal, display, or workstation.

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

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

The unit of access when referring to a message to or from a terminal.

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

See message field.

See Message Format Service.

See Message Format Service control block.

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

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 Message Format Service (MFS) facility that allows MFS control blocks to be created and tested online without disrupting production activity.

See message input descriptor.

An IMS batch messaging program that has access to Fast Path and full-function databases.

See message output descriptor.

An alternate PCB for which the destination can be changed by the application program during execution. See also alternate program communication block.

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.

See message processing program.

See Multiple Systems Coupling.

Descriptors used by Extended Terminal Option (ETO) to relate LTERMs to statically defined Multiple Systems Coupling (MSC) links. See also ETO descriptor.

See main storage database.

Multiple data sets that contain shadow copies of DEDB areas. See also area data set.

In a data-sharing environment, a coupling facility structure that contains more than one VSO DEDB area. See also single-area structure.

A processing mode in which synchronization points occur only at DL/I CHKP calls or application termination. See also message mode, single message mode.

An IMS facility that permits geographically dispersed IMS systems to communicate with each other. See also IMSplex.

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.

A 1-byte number from 1 to 255 that the client specifies as the first byte of the resource ID. The name type guarantees uniqueness of names for all resources of that name type. This uniqueness prevents clients from putting more than one resource with the same name and name type out on the resource structure. The resources within the name type can have different data resource types.

An IMS resource that represents a physical VTAM terminal. The node is represented by a VTAM terminal control block.

A user signed on to a static terminal. The user is represented by a user ID that is defined to an enhanced security product such as RACF.

An application program that is initiated by the submission of a batch job. This program runs in a batch message processing (BMP) region, a Java batch processing region (JBP region), or an IMS Fast Path (IFP) utility region. See also message-driven program.

Any resource status that cannot be recovered after a terminal logoff, a user signoff, or an IMS restart. Nonrecoverable status only exists while the resource is active and is deleted when that resource becomes inactive.

An inquiry transaction that is not recovered in the event of a failure.

In IMS, a mode of terminal operation that allows asynchronous operations between the terminal operator and the application program. See also response mode.

A type of MSDB characterized by data that is used or updated frequently, and segments that are not owned by specific logical terminals. Direct update of segment fields is allowed but no insertion or deletion of segments is permitted.

The priority assigned to a transaction when the number of transactions enqueued and waiting to be processed is less than the limit count value. See also limit count, limit priority, scheduling priority.

The restart of IMS after a termination initiated by a /CHECKPOINT command. See also emergency restart, cold start.

The period of XRF processing when the active IMS is processing the IMS workload and the alternate IMS is tracking the active IMS.

The message IMS sends to a terminal when no other output is immediately available to satisfy terminal requirements.

See Open Database Access.

See Open Database Manager.

See online forward recovery.

See online log data set.

See online image copy.

See Operations Manager.

An IMS function that supports the adding, changing, or deleting of IMS resources online such as transactions, database directories, program directories, DMBs, PSBs, and Fast Path routing codes without stopping the system to define them. See local online change and global online change.

In a Remote Site Recovery (RSR) environment, the process by which a stopped shadow database or area is brought to currency with the database or area on the active IMS by the tracking IMS.

1. The process of creating an image copy while the database is online.

2. The image copy created by the online image copy process.

A data set on direct access storage that contains the log records written by an online IMS system or Database Control (DBCTL). See also system log data set.

Database reorganization, which is available only for HALDBs and DEDBs, during which the database remains available for updates during the reorganization process.

A callable interface that can be used by a z/OS application program to issue DL/I calls to an IMS DB system. The application program must use the Resource Recovery Services (RRS) of z/OS as a synchronization point manager.

A Common Service Layer (CSL) address space that provides distributed and local access to IMS databases managed by IMS DB systems that are configured for either the DBCTL or the IMS DB/TM environments in an IMSplex.

A component of IMS that implements a transaction-based, connectionless client/server protocol in an MVS sysplex environment. The domain of the protocol is restricted to the domain of the z/OS cross-system coupling facility (XCF). OTMA connects clients to servers so that the client can support a large network (or many sessions) while maintaining high performance.

In an IMSplex, a Common Service Layer (CSL) component that provides an application programming interface (API) for automated operator programs (AOPs). OM receives commands from AOPs, routes the command to IMSplex members, consolidates commands responses, and sends the responses to the AOP, embedded in XML tags.

In Message Format Service (MFS), the means by which a terminal operator controls the display of output messages. Specific operator control functions are provided by IMS, but their use must be defined by the user in an operator control table.

In Message Format Service (MFS), a user-defined table of operator control functions; when a table is used, a specific control function is invoked when the input device data or data length satisfies a predefined condition.

A Message Format Service (MFS) facility that allows the device operator to request a specific logical page of an output message. See also logical paging.

See overflow sequential access method.

See Open Transaction Manager Access.

A function of IMS Open Transaction Manager Access (OTMA) that manages asynchronous IMS output for a group of clients that support the OTMA hold queue, such as IMS Connect. The OTMA super member function allows any client that is a member of the group to retrieve the asynchronous output of the other client members of the group.

A valid response mode message, a conversational mode message, an exclusive mode message, an IMS system message, an application program message, or a message switch.

In an HDAM or PHDAM database, the area in which IMS stores data when the root addressable area does not have enough space for a segment. See also root addressable area.

An IMS data management access method that combines selected characteristics of basic sequential access method (BSAM) and basic direct access method (BDAM) for handling data overflow from indexed sequential access method (ISAM).

A coupling facility list structure that contains shared queues when the primary structure reaches a user-specified overflow threshold. The overflow structure is optional. See also primary structure.

A facility that permits all database calls to be processed in each message processing region or batch message processing region.

In a database, a segment that has one or more dependent segments (its children) hierarchically below it.

1. A subset of a HALDB that has the capacity of a non-HALDB database and that can be administered independently.

2. Part of a display used as the viewport, its associated window, and its display data buffer when in partitioned state.

A data set that stores information about IMS catalog database partitions (when DBRC is not used to manage the database partitions) that is used to create and populate the IMS catalog.

An entry in the partition descriptor block (PDB) for a partition in a partition set

A collection of partition descriptor entries representing a partition set. An intermediate text block (ITB) for the PDB is created by the MFS Language Utility. This PDB ITB is used in creating a part of the device output format (DOF).

A partitioned hierarchical direct access method (HDAM) database organization, which is one type of high availability large database (HALDB).

A partitioned Hierarchical Indexed Direct Access Method database organization, one type of High Availability Large Database.

A partitioned secondary index database organization, one type of High Availability Large Database (HALDB).

All of the partitions which are defined in the partition descriptor block.

An IMS control block that contains information about a dependent region.

In SNA, the remote participant in a session.

In an IMS multisystem environment, two IMS online systems that are connected by an MSC link.

The use of system definition macros and security maintenance utility control statements to restrict the use of IMS resources (databases, application programs, physical and logical terminals, transactions, and commands) to a person or persons who can supply the correct password.

A type of DL/I call that enables a hierarchical path of segments to be inserted or retrieved with one call.

See program communication block.

A data structure in an application program in which IMS puts the status of the application program's DL/I calls. See also status code.

See partition descriptor.

See partition descriptor block.

See partitioned HDAM.

See partitioned HIDAM.

In a database, a segment type that is dependent on a segment type defined at the next higher level in the database hierarchy. All segment types in a database, except the root, are physical children since each is dependent on at least the root.

An ordered set of physical database records. See also logical database.

In databases, a physical set of hierarchically related segments of one or more segment types. See also database record.

An instance of a root segment and the hierarchical arrangement of all its dependent segment occurrences.

A hierarchy representing segment types and the hierarchic arrangement of those segment types in a physical database.

The actual hardware connection between two systems. See also logical link.

The process of writing log records from the log buffers to the system log. See also logical logging.

In Message Format Service (MFS), all or part of a logical page that is defined to be entered (input) or displayed (output) at one time. See also logical page.

A Message Format Service (MFS) facility that permits data from a logical page to be displayed in several physical pages on the device.

In a database, a segment type that has a dependent segment type defined at the next lower level in the physical database hierarchy.

In a database, the description of the relationship that exists between two or more physical segments.

In a database, the smallest unit of accessible data.

A hardware device attached to the computer and supported by the DC feature as a terminal. A physical terminal usually has one or more logical terminals associated with it.

In a database, all occurrences of a single physical child segment type that have the same (single occurrence) physical parent segment type. See also logical twins, twin segments.

See program isolation.

In a Remote Site Recovery (RSR) environment, a remote takeover initiated by the IMS operator as part of shutting down the IMSs at the active site in order to transfer the active IMS workload to the remote site. See also remote takeover.

A time when all of the recoverable data that a program accesses is consistent. The point of consistency occurs when updates, insertions, and deletions are either committed to a physical database or rolled back.

In XRF, a planned shutdown of the active system, and takeover by the alternate system, for maintenance or operational reasons.

The XRF phase, immediately following takeover, when the new active system does not have an alternate system.

To load the root addressable portion and independent overflow portion of a VSO DEDB area into a data space when the area is opened.

To open a DEDB area after the first checkpoint following IMS control region initialization or during /START AREA command processing. If an area is not preopened, it is opened during the first read request for the area.

The display data buffer associated with a partition. The size of the presentation space is defined as equal to, or larger than, the size of the viewport. When the presentation space is equal to the viewport size, all the data in the presentation space is displayed. When the presentation space is larger than the viewport, the user must move the scrolling window within the presentation space to display the data within the viewport. See also scrolling window, viewport.

An optional mode of terminal operation that allows the destination of terminal input to be fixed as a specific transaction code or logical terminal.

In a database, the first or only data set group defined. The root segment type always resides in the primary data set group. See also data set group, secondary data set group.

In an IMS multisystem environment, a message entered into a terminal before it is processed. See also reply, secondary request.

The session between a class 1 terminal and the active IMS.

A coupling facility list structure that contains shared queues or shared resources. See also overflow structure.

An area of local storage, used for VSO DEDB data, that can provide lookaside capability for shared VSO areas.

The attribute defined in the PSB which specifies the program's database access privileges such as insert, delete, and replace.

A transaction attribute that defines how many messages the application program is allowed to process during one program execution.

A control block that contains pointers to Information Management System (IMS) databases. See also program specification block.

A DL/I or IMS facility that separates all the activity of an application program from any other active application program until that application program indicates, via a synchronization point, that the data it has modified or created is consistent and complete.

A facility for local locking in systems for which no internal resource lock manager (IRLM) has been defined. Otherwise, the IRLM is used for all lock management, including local lock management.

In DL/I and IMS, a control block that describes the databases and logical message destinations that are used by an application program. A PSB consists of one or more program communication blocks (PCBs). See also program communication block.

The process by which a PSB is created.

An IMS output message sent by one application program to another application program. See also message switch.

An optional facility for notifying a terminal operator that a current page of output is the last page of a message.

A type of conversation that supports the two-phase commit process for the synchronization of changes.

A resource that is updated in a synchronized manner during resource recovery processing.

See program specification block.

See program specification block generation.

An IMS in a multisystem environment in which all terminals are handled and a few time-consuming transactions are routed to a transaction processing system. See also front-end system, transaction processing system.

See partitioned secondary index.

See partition specification table.

See physical terminal.

See queue buffer.

See Queue Manager.

See queue name.

A DL/I call that contains at least one segment search argument.

A segment search argument (SSA) that contains, in addition to the segment name, one or more qualification statements. A qualified SSA describes the segment type and occurrence that is to be accessed. See also segment search argument.

A data structure for processing work in which the first element added to the queue is the first element processed. This order is referred to as first-in first-out (FIFO).

An IMS queue manager incore buffer that is used to keep the working copy of an IMS message segment.

An IMS component that manages IMS messages and the space the messages occupy. The IMS Queue Manager is part of a DB/DC or DCCTL environment.

The name of a queue on Shared Queues upon which data objects reside. The queue name is 16 bytes long, left justified, padded with blanks. The first byte of the client queue name is the queue type. A client queue name of blanks or zeros is supported.

A structure managed by CQS that contains data in queues.

A grouping of shared queues on the coupling facility list structure whose meaning is client defined or CQS defined.

To end a process or shut down a system after allowing normal completion of active operations.

The normal OSAM buffering method, which reads only one block with each I/O operation.

See Resource Access Control Facility.

See root anchor point.

A function of IMS that automatically reconnects IMS VTAM terminal sessions across outages (IMS, z/OS, or VTAM) and subsequent IMS restarts on the same or different z/OS systems within a sysplex.

See resource access security.

See relative byte address.

See resource definition data set.

See restart data set.

An access intent that establishes the intent of an application to read the database (without making modifications) and to be protected from an updater's incomplete changes. It allows other applications to share the database. See also scheduling intent.

For a Remote Site Recovery (RSR) database-level tracker, the level that determines whether a shadow database is ready to apply database changes as they are received from the active IMS. See also recovery-readiness-level database.

An access level that permits a user or an application to read a document or record but not to update it. See also scheduling intent.

See read access.

See read-only access.

See recovery control data sets.

In Message Format Service (MFS), the default input mode in which fields are defined as occurring within a specific record sent from the device. See also input mode, stream mode.

See protected resource.

A service element (IMS) that is backed up and that can initiate a takeover.

Any resource status that can be recovered after a terminal logoff, a user signoff, or an IMS restart.

An IMS transaction that is recovered in the event of a failure.

A data set in which DBRC stores information about logging activity and events that might affect the recovery of databases.

In a Remote Site Recovery (RSR) environment, a tracking IMS that does not track the databases or areas of the active IMSs, but instead saves all database changes on tracked logs on the tracking IMS until recovery or remote takeover is performed. See also database-level tracking.

A log data set that contains only the log records that are required for database recovery.

In a Remote Site Recovery (RSR) environment, a database or area to which database changes are not applied as they are received from the active subsystem, but instead are saved on tracked logs on the tracking subsystem until recovery or remote takeover is performed, or until the database's (or area's) readiness level is changed to database readiness level. See also readiness level.

The class IMS assigns to a message region that indicates the message classes that can be processed within the region. See also class, message class.

The offset of a data record or control interval from the beginning of the storage space that is allocated to the data set or file to which it belongs.

In an MSC network, a destination that resides in a remote system. See also local destination.

An IMS queue associated with an MSC logical link to allow routing of asynchronous output messages to the local LTERM in another IMS. See also logical terminal.

In a Remote Site Recovery (RSR) environment, the physically remote location of the tracking IMS and shadows databases. If a remote takeover occurs, it becomes the active site.

A feature of IMS that minimizes the impact of active site failures by having a geographically remote IMS track active IMSs. Production work is taken over at the remote site in the event of a disaster or site-wide failure at the active site. See also tracker.

Any other system in the network with which a system can communicate. See also local system.

In a Remote Site Recovery (RSR) environment, an action initiated by an IMS operator to transfer the active IMS workload from the active site to the remote site. See also planned remote takeover, unplanned remote takeover.

A terminal that is not attached to the host system through an I/O channel.

In a multisystem environment, a transaction whose total processing is shared between two or more systems. See also local transaction.

See response.

A VSAM key-sequenced data set (KSDS) that contains the names and keys of all members in an IMS repository. A repository index data set is used by the Repository Server (RS) or a user-defined IMS repository. See also repository member data set and IMS repository function.

A VSAM key-sequenced data set (KSDS) that contains the member data that is indexed by the repository index data set (RID). A repository member data set is used by the Repository Server (RS) or a user-defined IMS repository. See also repository index data set and IMS repository function.

A BPE-based address space for managing the repositories of the IMS repository function, such as the IMSRSC repository. The RS is managed by the Common Service Layer (CSL) Resource Manager (RM), which interacts with the RS to read, write, and delete stored resources, such as resource and descriptor definitions, from an IMS repository. See also IMS repository function and IMSRSC repository.

An IBM licensed program that provides access control by identifying users to the system; verifying users of the system; authorizing access to protected resources; logging unauthorized attempts to enter the system; and logging accesses to protected resources.

The use of RACF security classes to protect resources (PSBs, transactions, and output LTERMs) from unauthorized use by a dependent region.

A category of similar resources that are defined in the RACF class descriptor table (CDT).

A data set that manages IMS resources. IMS systems have options to export resources that are defined by the system definition process and resources that have been created or updated dynamically, into the RDDS. These resources can then be imported from the RDDS into an IMS system during cold start processing or through the use of an IMPORT command.

A member in the IMS.PROCLIB data set that defines the resource definition data set (RDDS) to IMS. See also resource definition data set.

A template in which the attributes for a resource are defined.

The programmable list entry ID that IMS specifies for a resource to ensure name uniqueness. The first byte is the name type, and the remaining 11 bytes are the resource name, padded with blanks.

A Common Service Layer (CSL) component that manages resources and coordinates online change for IMS systems in an IMSplex.

An 11-byte unique name of a client-defined resource. A transaction is an example of an IMS resource name.

A component of z/OS that uses a sync point manager to coordinate changes among participating resource managers.

A coupling facility list structure, used by the Common Service Layer Resource Manager and managed by CQS, that contains uniquely named resources. This structure is typically used to maintain global resource information when multiple Resource Managers exist in an IMSplex.

A resource that is defined by CQS. CQS groups list headers into resource types. The resource types allow CQS and its clients to physically group resources of a particular type on a coupling facility list structure.

A message inserted to a logical terminal destination specified by an I/O PCB or an alternate response PCB. When VTAM is used, the term reply is substituted for response because response has a separate meaning in VTAM communications. See also primary request, secondary request.

See alternate response PCB.

A mode of terminal operation that synchronizes operations between the terminal operator and the application program. See also line response mode, terminal response mode, nonresponse mode.

The direct-access data set used to contain the information necessary to restart IMS.

See repository index data set.

See recovery log data set.

See Resource Manager.

When RM and a resource structure are used, an association between an IMS and a user or node with LOCAL status recovery mode. If RM indicates that the user or node has RM affinity to an IMS, the user or node cannot log or sign on to another IMS. This affinity occurs because end-user significant status (conversation, STSN, or Fast Path) is being recovered on an IMS.

See repository member data set.

See Rapid Network Reconnect.

In an HDAM or PHDAM database, the primary storage area in HDAM and PHDAM databases. IMS always attempts to put new and updated segments in the root addressable area, and if there is not enough room, IMS puts the segment into the overflow area instead. See also overflow area.

In an HDAM or DE database, a pointer at the beginning of each physical block that points to a root segment that belongs in that block.

In a hierarchical database, the highest segment in the tree structure. It remains in main storage when other overlay segments are run. See also dependent segment.

For EMH, a user-defined code that allows transactions to be routed to programs within a load balancing group.

In an MSC network, the route through which IMS passes a message from its origination through processing. One or more systems may be included in a routing path.

See Resource Recovery Services.

See Repository Server.

A reserved repository used to maintain the definitions of the user-defined IMS repositories that are managed by the RS, such as the IMSRSC repository. The RS catalog repository manages the association of repository names with repository data sets. See also Repository Server (RS).

Two pairs of VSAM key-sequenced data sets (KSDSs) used by the Repository Server to maintain the definitions of the user-defined IMS repositories that are managed by the RS. RS catalog repository data sets consist of a primary pair and a secondary pair of repository index data sets (RIDs) and repository member data sets (RMDs). See also IMS repository function, IMSRSC repository, and Repository Server (RS).

See recoverable service element.

The name that an installation gives to the two IMS subsystems that form a recoverable service element (RSE).

See Remote Site Recovery.

The runtime template (in an internal format of control blocks) that can be used as a model when creating runtime resource definitions. See also runtime resource definition.

The resource information such as attributes, status, and relationships to other resources that IMS maintains at run time in an internal format called control blocks. The runtime resource definitions include, but are not limited to, database directories (DDIRs), program directories (PDIRs), data management blocks (DMBs), program specification blocks (PSBs), Fast Path routing codes (RCTEs), and scheduler message blocks (SMBs) or transactions.

See sequential buffering.

See system control area.

See system contents directory.

An IMS control block that represents a transaction.

An application program attribute that is defined in the program specification block (PSB) and that specifies how the program is scheduled if multiple programs are contending for scheduling. See also read access, read-only access.

A transaction attribute that is used in calculating which transaction is selected for scheduling. See also limit priority, normal priority.

See Structured Call Interface.

A work area used in conversational processing to retain information from an application program across executions of the program.

The portion of the presentation space that is mapped to the viewport at any given time. The window can be moved vertically within the presentation space by scrolling. See also presentation space.

See SNA character string.

See sequential dependent segment.

See system diagnostic work area.

In a DL/I call, a field that is referred to by one or more segment search arguments (SSAs). See also key field.

In databases, a data set group or groups defined in addition to the primary data set that can improve auxiliary storage use. See also data set group, primary data set group.

An index that is used to establish accessibility to a physical or logical database by a path that is different from the one provided by the database definition. A secondary index contains an index pointer segment type that is defined in a secondary index database.

A nonhost port through which the user gains access to the services of the network.

In a database, the hierarchical order of segment types in a physical or logical database that results automatically when a database is accessed through a secondary index.

In a multisystem environment, a message inserted into a transaction code destination by an application program. See also primary request, reply.

In IMS, the unit of access to a database; for the database system, the smallest amount of data that can be transferred by one IMS operation.

In a database, an instance of a segment type. See also segment type.

The portion of a DL/I call that identifies a segment or group of segments to be processed. Each SSA contains a segment name and, optionally, one or more command codes, and one or more qualification statements. Multiple SSAs may be required to identify the wanted segment. See also qualified segment search argument, unqualified segment search argument.

In a database, a user-defined category of data. See also segment occurrence.

See scheduling priority.

A segment type in a database to which an application program is sensitive.

An IMS capability that ensures that only data segments or fields predefined as sensitive are available for use in a particular application. The sensitivity concept also provides a degree of control over data security, inasmuch as users can be prevented from accessing particular segments or fields by omission of those segments or fields from the logical database. Sensitivity is implemented through the database program communication block (DB PCB).

The field in a database segment that used to store segment occurrences in sequential ascending order.

Efficient sequential input buffering techniques that reduce the elapsed time required to sequentially process large IMS OSAM databases.

A segment of a data entry database that is chained off the root segment and inserted (last-in first-out) into the last part of a DEDB area. After being inserted by an online program, the SDEP cannot be modified. See also data entry database.

A set of several consecutive blocks that are read with a single read I/O operation. Sequential reads are issued by the sequential buffering (SB) component of IMS in order to reduce the elapsed time required to sequentially process large IMS overflow sequential access method (OSAM) databases.

One of the discrete hardware and software products that provide a terminal user with processing ability.

In a Remote Site Recovery (RSR) environment, a collection of all IMSs that access RSR-covered databases at an active or at a remote site, including the recovery control data set (RECON data set). A service group usually includes one or more IMSs at a single site, with the databases and RECON data set shared between the IMSs.

A control block that represents a routine that performs a particular function or service in a specified address space.

The XRF process that switches primary sessions on class 1 terminals to backup sessions or reestablishes service on class 2 terminals during takeover.

See service group.

In a Remote Site Recovery (RSR) environment, a database maintained at the tracking site as a remote copy of a database at the active site. If a remote takeover occurs, the shadow database becomes the master database.

A secondary index database containing more than one secondary index in the same physical operating system data set.

A collection of data objects with the same name that reside on a coupling facility queue structure. Data objects on a shared queue are available to all CQS clients that have access to the structure.

A group of subsystems using IMS and DBRC that share the same RECON data sets.

See simple HISAM.

See simple hierarchical sequential access method.

Two or more occurrences of different sibling segment types having a common parent segment occurrence. See also twin segments.

Two or more segment types having a common parent segment type.

State data that keeps a resource from being deleted in Resource Manager (RM) when the resource is no longer active on any IMS. See also state data.

A resource status classified as significant. In addition to being recoverable, if the resource status is specified as significant, the resource cannot be deleted after a terminal logoff, a user signoff, or an IMS restart.

The act a terminal user performs in order to end an identification of a user to IMS. When the terminal is an ETO terminal, the signoff process usually disconnects the user structure from the terminal structure and deletes the user structure.

A request made by an application process or terminal user to verify authorization to use resources.

The verification of a user ID that takes place at sign-on. Sign-on verification is required before a user can access protected IMS resources.

The periodic recording of control information and system status on the system log at user-specified intervals.

A type of HSAM database that contains only root segments, which have no prefixes.

The support for a HISAM database that contains only one segment type.

In a data-sharing environment, a coupling facility structure that contains only one VSO DEDB area. See also multiple-area structure.

A concept where locks for database resources shared between programs or subsystems are handled by one control point. Either an IRLM or a Program Isolation locking function can be invoked for the subsystem.

A processing mode in which synchronization points occur as each message is read from the queue, as well as at application termination. See also message mode, multiple message mode.

In a sysplex, a method for managing multiple subsystems as if they were one system. For example, instead of entering commands on each subsystem, a user can enter commands from one SPOC and the commands will run on each subsystem in the sysplex.

See system log data set.

See scheduler message block.

In SNA, a string of EBCDIC control characters carried within a request/response unit (RU); the string can also contain user data.

A database segment containing the data used to construct the secondary index pointer segment.

See scratchpad area.

See single point of control.

See Subpool Queue Block.

A structure that provides an application program with information about the execution of its SQL statements. An SQLIMSCA is updated after each SQL statement executes.

See SQL communication area.

See service request block.

See structure recovery data set.

See segment search argument.

The first part of the process of defining an IMS system. Stage 1 checks input specifications and generates a series of job steps that are the input to stage 2.

The second part of the process of defining an IMS system. Stage 2 builds IMS system libraries, execution procedures, and the IMS online control program tailored to support the wanted set of IMS functions. Stage 2 then stores these in an IMS library.

Those libraries that are modified by offline functions in a system using online change. Changes are first applied to the staging libraries, which are then copied to the inactive libraries.

An application program that uses the existing DL/I call interface. It does not issue any CPI communications calls, nor does it allocate any LU 6.2 conversations.

Information that must be kept in Resource Manager (RM) so that users can sign onto another IMS and resume their states. See also significant data.

A VTAM node defined by the IMS system definition.

A terminal created through the system definition process. See also dynamic terminal.

Non-ISC user or ISC user defined statically through the IMS system definition process.

A two-character code in the program communication block (PCB) mask that indicates the results of a DL/I call. See also PCB mask.

The scope of recovery for a resource, it determines where the resource status can be recovered from. GLOBAL indicates the status is managed by RM, LOCAL indicates the status is managed by IMS in local control blocks and log records, and NONE indicates the status is not recovered.

The information from which IMS builds a runtime descriptor definition. See also runtime descriptor definition.

The resource information that is stored offline, from which IMS builds runtime resource definitions. Stored resource definitions can reside in system data sets, such as IMS.MODBLKS, IMS.ACBLIB, IMS.FORMAT, and a resource definition data set (RDDS). See also resource definition data set.

In Message Format Service (MFS), the input mode in which fields are defined as a stream of data without record boundaries. See also input mode, record mode.

A CSL component that manages communications between the IMSplex members.

A primary queue structure and its associated overflow structure.

Shared data sets that contain structure checkpoint information for shared queues on a structure pair. There are two SRDS data sets per structure pair.

A collection of logical terminals (LTERMs) that can be allocated to an ISC node and can be used with parallel sessions.

An IMS control block that represents a user.

In a secondary index, a field added to the index segment key data to make the pointer segment key unique.

A checkpoint in a batch, BMP, or JBP application that indicates to IMS that the program has reached a commit point and that establishes a place in the program from which the application can be restarted. See also extended restart.

The concatenation of the keys in the sequence fields of all segments that must be retrieved to reach the wanted segment including the sequence field key of the wanted segment.

The XRF phase, immediately after initialization, when the alternate builds the IMS control blocks to mirror those in the active.

A point in time from which IMS or an application program can start over if a failure makes recovery necessary. The two types of synchronization points are system checkpoints done by IMS itself, and application program synchronization points (also known as commit points) done on behalf of individual application programs. See also commit point, system checkpoint.

See synchronization point.

See system generation.

A set of z/OS systems that communicate with each other through certain multisystem hardware components and software services.

The ability of multiple IMS subsystems to share data across multiple MVS images. Sysplex data sharing differs from two-way data sharing in that the latter allows sharing across only two z/OS images.

A point at which IMS records its internal status-control information, plus a unique checkpoint ID, and writes the checkpoint table to the restart data set (RDS). This information allows IMS to reconstruct its condition if recovery is later necessary. System checkpointing is done automatically each time a user-selected number of records is written to the log. See also synchronization point.

A data area whose primary function is to contain major entry pointers for all IMS facilities. Its secondary function is to contain system data and the status of the log functions and commands.

In Message Format Service (MFS), a message field that allows an application program to control specific terminal features when the features apply to the terminal for which the message is destined. See also default system control area.

An IMS process that describes databases, application programs, terminals, and other resources to IMS.

An optional step in the system definition process that performs resource name checking, thus bypassing that procedure in stage 1.

In a z/OS environment, the data that is recorded in a SYS1.LOGREC entry that describes a program or hardware error.

See system definition.

In an IMS multisystem environment, the means by which a system that is part of a logical link path is identified.

In Message Format Service (MFS), a literal field provided by MFS and defined by the user for inclusion in an output message. See also default literal, explicit literal, literal field.

A data set on which IMS archives a full online log data set (OLDS). An SLDS can be on DASD or tape. The contents are used as input to the database recovery process. See also online log data set, write-ahead data set.

In Message Format Service (MFS), an output device field on 3270 display devices that can be defined to receive system messages, thereby preventing unsolicited IMS messages from destroying a screen format.

In an XRF environment, the process by which the failing active IMS is released from its XRF sessions with terminal users and replaced by an alternate IMS.

An event in the active that causes IMS in the alternate to request a takeover.

The replacement of the failing active IMS by the alternate IMS.

The name of a client that connects to an OTMA group.

In secondary indexing, the segment to be retrieved.

A z/OS control block that is used to communicate information about tasks within an address space that is connected to a subsystem.

See task control block.

An industry-standard, nonproprietary set of communication protocols that provides reliable end-to-end connections between applications over interconnected networks of different types.

The program communication block (PCB) that supports communication between an application program and a terminal or other application program. There are two types of TP PCBs: I/O PCB and alternate PCB.

A type of main storage database (MSDB) in which each segment is assigned to and owned by one logical terminal (LTERM), the owner with terminal security may alter or update that segment, and a segment may be referenced by someone other than the owner. Terminal-related MSDBs are either fixed ((permitting changes) or dynamic (permitting segment insertion and deletion).

The type of response mode that suspends all input operations from the terminal until the application program has generated the output message. See also line response mode, response mode.

The use of system definition macros and security maintenance utility control statements to authorize a particular logical or physical terminal to issue some or all of the operator commands and to send or receive some or all of the currently defined transactions.

The extended recovery facility (XRF) phase in which the XRF complex returns to two separate and independent environments and all XRF activity in the alternate system stops.

The mode that causes any input message entered into a terminal under test to be returned to the test terminal, with error analysis procedures bypassed.

An IBM-supplied application from which a user can manage operations of all IMS systems within an IMSplex.

See target member.

See Transport Manager Subsystem.

See transaction pipe.

See telecommunication program PCB.

In a Remote Site Recovery (RSR) environment, the system log data set on the tracking IMS to which the log records received from the active IMS are written.

See tracking IMS.

In a Remote Site Recovery (RSR) environment, the online log data set for the log of the tracking IMS.

In a Remote Site Recovery (RSR) environment, an IMS that tracks the activities of active IMSs to provide disaster recovery support. A tracking IMS is usually geographically remote from the active IMSs. See also active IMS, Remote Site Recovery.

The XRF phase during which the active processes the IMS workload and the alternate maintains IMS control blocks to duplicate those in the active and uses surveillance to check the active for signs of failure.

See tracking IMS.

An option for recovery from permanent read/write errors on VSAM data sets. Track recovery permits database reconstruction at the track level rather than the data set level.

A specific set of input data that triggers a specific process or job. A transaction also can refer to a message destined for an application program.

A DFSMS function that provides record-level sharing and transactional recovery for VSAM data sets. Transactional VSAM provides a data set access mode that is used by DBRC to provide parallel RECON data set access.

A 1- to 8-character alphanumeric code that calls an IMS message processing program.

The use of system definition macros and security maintenance utility control statements to permit specific application programs to issue some of the IMS operator commands.

An optional facility that enables a transaction to be scheduled into more than one message or batch message region at the same time.

A batch message processing program (BMP program) that performs transaction-type processing in a batch environment. A transaction-oriented BMP program obtains its input from the IMS message queues and can also use the message queues for output. See also batch-oriented BMP program.

A named IMS process management resource. An OTMA client must specify this resource when submitting a transaction to IMS. A tpipe is analogous to an LTERM.

An IMS in a multisystem environment that accepts transactions from the front-end system, calls application programs for transaction processing, and routes all replies to the front-end system for response to the terminal. See also front-end system, pseudo-front-end system.

In a Remote Site Recovery (RSR) environment, the subsystem that provides communication services to IMS components.

See Time Sharing Option single point of control.

In a database, all child segments of the same segment type that have an instance of the same parent segment type. Root segments are also considered twins to each other. See also physical twins, sibling segments.

A two-step process by which recoverable resources and an external subsystem are committed. During the first step, the database manager subsystems are polled to ensure that they are ready to commit. If all subsystems respond positively, the database manager instructs them to commit.

An application program that can issue a subset of IMS commands by using the CMD call in DB/DC and DCCTL environments.

A command, generally preceded by a leading slash character, that can be entered from any valid IMS command source. See also type-2 command.

An application program that can issue a subset of IMS commands using the ICMD call in DB/DC, DBCTL, and DCCTL environments.

A command that is entered only through the OM API. Type-2 commands are more flexible and can have a broader scope than type-1 commands. See also type-1 command.

See unit control block.

See utility control facility.

A control block in common storage that describes the characteristics of a particular I/O device on the operating system.

A sequence of operations within a unit of work between synchronization points.

For HALDB online reorganization (HALDB OLR), the database records that are reorganized within one commit boundary

A recoverable sequence of operations within an application process. At any time, an application process is a single UOW, but the life of an application process can involve many UOWs as a result of commit or rollback operations. In a multisite update operation, a single UOW can include several units of recovery. See also unit of recovery, transaction.

In a Remote Site Recovery (RSR) environment, a remote takeover initiated by the tracking IMS to transfer the workload from the active IMS to the tracking IMS at the remote site without waiting for an orderly shutdown of the active IMS. See also remote takeover.

In IMS, a Data Language/I (DL/I) call that does not contain a segment search argument.

A segment search argument that contains only a segment name that specifies the segment type to be accessed. See also segment search argument.

See nonrecoverable transaction.

An output message that is not generated as a response to an input command. For example, a system informational message is an unsolicited output message.

See unit of recovery.

See unit of work.

An access intent that establishes the intent of an application to modify the database. Other applications may read the database if they do not need to be protected from the updater's incomplete changes.

A facility that allows the user to define inquiry transactions as unrecoverable.

A transaction in the data chaining (DC) feature system with capabilities to update a database. Update transactions are recoverable.

A descriptor that is generated by a system or a process, for example, installation-created and node. See also ETO descriptor.

A table of messages generated by the user and used by certain user written edit routines.

A set of control blocks, including a user block and one or more LTERM blocks. The message queues are associated with the dynamic user, as opposed to the physical terminal, and they are queued to the user ID.

An optional facility that provides a method of performing most database utility and maintenance operations in preparation for recovery and reorganization.

See VTAM Generic Resources.

For VTAM Generic Resources, an association, managed by VTAM or IMS, that a VTAM logical unit has with a specific IMS in a generic resource group.

That portion of a partition or usable area defined for display of data to the operator. The viewport has a predefined size and position on the screen and is related to a presentation space through a specified window. See also presentation space.

An option for data entry database (DEDB) areas that maps an area into a data space or a coupling facility structure when the area is opened. The share level of the database determines which is used. Any VSO area control interval (CI) or coupling facility structure that has been loaded into a data space is subsequently read from the data space or coupling facility structure rather than from DASD.

See Virtual Storage Option.

The name an installation gives to a subsystem to identify it to VTAM.

IMS VGR, together with VTAM V4R2, enables VTAM to automatically distribute terminal sessions among a cooperative set of IMS systems known as a generic resource group.

An IMS control block that represents a VTAM terminal, both static and dynamic. The VTCB contains the following IMS control blocks and data areas: CLB, CTB, CRB, CIB, device-dependent module (DDM) work area, and CTT.

See VTAM Terminal Control Block.

See write-ahead data set.

See normal restart.

A data set containing log records that reflect completed operations and are not yet written to an online log data set. See also system log data set.

An expression that searches through an XML document and extracts information from the nodes (any part of the document, such as an element or attribute) in that document.

See extended recovery facility.

The central processor complexes (CPCs) and the licensed programs in the active and the alternate that provide the extended recovery facility (XRF) for IMS users.

See takeover.

See extended restart.