list of letters
This site contains terms and definitions from many IBM software and hardware products as well as general computing terms.
The ITU-T (formerly CCITT) recommendation that defines the link layer of the DSS1 protocol. Q.921 defines an HDLC protocol that ensures a reliable connection between the network and the user. Often used synonymously with LAPD.
An ITU recommendation that defines the network layer protocol for integrated services digital network (ISDN). This layer carries the ISDN messages that control the establishment and clearing of calls.
The CCITT Recommendation that defines the generic procedures applicable for the control of supplementary services at the user-network interface. These procedures expand on the basic call-control functions defined in Q.931. See also supplementary service.
See qualifying data.
See quality assurance.
Q Apply latency
In Q replication, an approximate measurement of the difference between the time that the Q Apply program gets changed data from the receive queue and the time that the data is applied to a target table. This measurement is a subset of the end-to-end latency in a replication scenario. See also Apply latency, Capture latency, end-to-end latency, latency, Q Capture latency, queue latency.
Q Apply server
In Q replication, a database or subsystem on which the control tables for the Q Apply program are located and where the Q Apply program runs. It contains one or more sets of the control tables that store information about target tables and other replication definitions.
See query by example.
See Query by Image Content.
See qualifier bit.
See queue buffer.
Q Capture latency
In Q replication, an approximate measurement of how current a Q Capture program is in reading the DB2 database recovery log. This measurement is the approximate difference between the time that source data was changed and the time that the Capture program made the data available by committing it to WebSphere MQ. This measurement is a subset of the end-to-end latency in a replication scenario. See also Apply latency, Capture latency, end-to-end latency, latency, Q Apply latency, queue latency.
Q Capture program
In Q replication and event publishing, a program that reads the DB2 database recovery log to capture changes made to DB2 database source tables and transmits the changes by using one or more WebSphere MQ queues. See also Capture program, event publishing, Q replication.
Q Capture server
In Q replication and event publishing, a database or subsystem on which the control tables for the Q Capture program are located and where the Q Capture program runs. The Q Capture server contains one or more sets of the control tables that store information about Q subscriptions, publications, and other replication or publishing objects. See also control server.
Q Capture transaction latency
In Q replication, the time between when a Q Capture program reads the commit statement for a transaction in the DB2 database recovery log and when the Q Capture program puts the message that contains the transaction on a send queue.
See query current plan dialog.
See queued direct I/O.
An open source emulator for complete PC systems. In addition to emulating a processor, QEMU permits emulation of all necessary subsystems, such as networking and video hardware, as well as advanced concepts.
See general purpose library.
See Qualified Logical Link Control.
See quality management.
See Query Management Facility.
QMF administrative authority
Authorization for a user to insert or delete rows in a profiles table. Users with this authority can use commands on QMF queries, forms, and procedures that are owned by other users without forcing the owners to share these objects with all users.
An object used by QMF users to query, format, and present data or otherwise manage interaction between QMF and the database. QMF objects include queries and query result data, forms, procedures, reports, charts, and the QMF profile.
See Queue Manager.
See queue name.
See qualified name.
See quality of service.
See qualified Parallel Sysplex.
See queued sequential access method.
See queue sequence number.
In Q replication, an object that identifies a mapping between a source table and target table or procedure and specifies what changes are replicated. See also publication, replication source, subscription.
- The library shipped with the system that contains objects, such as authorization lists and device descriptions created by a user, and the system commands and other system objects required to run the system. The system identifier is QSYS.
- The IBM-supplied user profile that owns most IBM-supplied objects.
A structure that is composed of four quadrants which recursively subdivide themselves by four, to achieve manageable data sets. This permits quick access to information, as the quadtree can confine its search to quadrants covering a particular area of interest.
qualified job name
A job name and its associated user name and a system-assigned job number. See also job name.
Qualified Logical Link Control (QLLC)
An X.25 protocol that allows the transfer of data link control information between two adjoining SNA nodes that are connected through an X.25 packet-switching data network. The QLLC provides the qualifier Q bit in X.25 data packets to identify packets that carry logical link protocol information. See also enhanced logical link control, physical services header.
- The name of the library containing the object and the name of the object. See also object name.
- In C++, a name that is used to qualify a nonclass type name, such as a member, by its class name.
- A data name explicitly accompanied by a specification of the class to which it belongs in a specified classification system.
- A data set name consisting of a string of names separated by periods; for example, TREE.FRUIT.APPLE is a qualified name.
- A name made unique by the addition of one or more qualifiers.
- A name that conforms to the Namespaces in XML specification. A QName consists of an optional prefix, or its associated URI, and a local name. See also expanded QName, in-scope namespace.
qualified 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.
- Each component name in a qualified name other than the right-most name. For example, TREE and FRUIT are qualifiers in TREE.FRUIT.APPLE.
- A term or phrase that is added to the end of a personal name to distinguish that name by specifying a generational standing (such as Junior or Senior, or "fils" in French for Junior), an achievement academic or religious rank that the person has attained (for example, Ph.D.), or a professional qualification of some kind (for example, D.D.S.). For name-matching purposes, a qualifier is considered a peripheral or minor part of a personal name. See also honorific.
- When referring to a QMF object, the part of the name that identifies the owner or the location of an object. When referring to a TSO data set, any part of the name that is separated from the rest of the name by periods. For example, 'TCK', 'XYZ', and 'QUERY' are all qualifiers in the data set name 'TCK.XYZ.QUERY'.
- A simple element that gives another generic compound or simple element a specific meaning. Qualifiers are used in mapping single or multiple occurrences. A qualifier can also be used to denote the namespace used to interpret the second part of the name, typically referred to as the ID.
- A modifier that makes a name unique.
- In data processing, all names in a qualified name other than the name to the far right, which is called the simple name.
- A value that provides additional information about a class, association, indication, method, method parameter, instance, property, or reference.
A key on a keyboard the operation of which has no immediate effect, but which, for as long as it is actuated, modifies the effect of other keys. A qualifier key may be, for example, a level select key or a control key (see ISO/IEC 9995-1).
qualifying data (q_data)
Unique information associated through a condition token with a given instance of a condition. A user-written condition handler uses q_data to identify and react to the condition.
- A measure of system performance and system availability.
- In OSI, a value that specifies certain performance characteristics of a service, session, or link. In OSI Communications Subsystem, quality of service is provided at the network layer.
- Any operation that allows traffic priorities to be designated. Through quality of service, different traffic throughout a network can be classified and administered.
- For an asynchronous transfer mode (ATM) virtual channel or a Networking BroadBand Services (NBBS) network connection, a set of communication characteristics such as end-to-end delay, jitter, and packet loss ratio.
- A set of communication characteristics that an application requires. Quality of Service (QoS) defines a specific transmission priority, level of route reliability, and security level.
Quality of Service policy
A policy that collects performance data for HTTP transactions for one or more web servers, including the entire round-trip time of the transaction, the back-end service time, and the page display time.
A type of analysis that displays the value of the business measures boundaries at the 25th, 50th, or 75th percentiles of a frequency distribution divided into four parts, each containing a quarter of the population.
Pertaining to CICS application programs that run under the CICS quasi-reentrant task control block (QR TCB). See also reenterable.
- In interactive systems, an operation at a workstation that elicits a response from the system.
- A method for filtering and sorting requirements in views by limiting either the values of one or more attributes or traceability and specifying the order in which to display the filtered requirements. See also sorting.
- In a Tivoli environment, a combination of statements that are used to search the configuration repository for systems that meet certain criteria. The query object is created within a query library.
- A reusable request for information about one or more model elements
- In data communications, the process by which a master station asks a slave station to identify itself and to give its status.
- The simple report specifications created and edited by Query Studio.
- A request for information from a database that is based on specific conditions: for example, a request for a list of all customers in a customer table whose balances are greater than USD1000.
- A statement, or combination of statements, that is used to search a rule project (or other scope) and to select rule project elements that meet certain criteria.
- A component of certain SQL or XQuery statements that specifies a result set.
- A specification for a set of data retrieved from a data source.
The part of a query that contains the XQuery expression. See also query prolog.
Query by Image Content (QBIC)
A query technology that enables searches based on visual content, called features, rather than plain text. Using QBIC, you can search for objects based on their visual characteristics, such as color and texture.
The name of an action, and any associated parameters, that can be performed by DB2 for i5/OS query management. The query commands include ERASE, EXIT, EXPORT, GET, IMPORT, PRINT, RUN, SAVE, SET, and START.
query command procedure
In DB2 for i5/OS query management, a type of query procedure that contains a subset of the query commands allowed in a query procedure. The query command procedure can be used for initializing global variables.
query CP parallelism
Parallel execution of a single query, which is accomplished by using multiple tasks. See also sysplex query parallelism.
query current plan dialog (QCP dialog)
A dialog that displays information taken directly from the current plan. The information includes information on operations, workstations, and application occurrences.
A supplement to the user's search string to improve search retrieval results. A search string such as "phone" may be expanded to "phone, phones, telephone, telephones, mobile phone, cellular phone".
A representation of a column of data in a data source. Query items may appear in a model or in a report and contain a reference to a database column, a reference to another query item, or a calculation.
See DB2 Query Manager.
A name string that a user searches for. See also data name.
A component of the SQL and XQuery compiler that chooses an access plan for a data manipulation language statement by modeling the execution cost of many alternative access plans and choosing the one with the minimal estimated cost. See also compensation, data distribution, optimizer hint.
In DB2 XQuery, a series of declarations that defines the processing environment for a query. See also query body.
- An input parameter that specifies the statistical data to be retrieved.
- A character string that specifies the properties and property values for a query. You can create the query string in an application and pass it to the query.
A named collection of query items that are closely functionally related. Query subjects are defined using Framework Manager to represent relational data and form the set of available data for authoring reports in Query Studio and Report Studio. A query subject is similar to a relational view in that it can be treated as a table but does not necessarily reflect the data storage.
A window that specifies a set of rows used in calculations with respect to the current row under examination. The calculation may be for computing a moving set function, a join, or expiring rows from a view.
A set of questions that a Virtual Classroom instructor develops when creating a course that he or she plans to ask at some point during a session. For example, during a session an instructor might want to ask questions to get a sense of whether the students are understanding the course materials.
- A workflow database table that holds work items. See also component queue, system queue, user queue, work queue.
- An object that holds messages for message-queueing applications. A queue is owned and maintained by a queue manager.
- To form or arrange as a list or line.
- 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).
- A line or list of items waiting to be processed, for example, work to be performed or messages to be displayed or transmitted.
queued direct I/O (QDIO)
A hardware channel architecture for direct data exchange with I/O devices, where both the I/O device and the program running on the server reference main storage directly through a set of data queues. The QDIO architecture is used by Open Systems Adapter-Express (OSA-Express), HiperSockets, and Fiber Channel Protocol (FCP) channels.
- The number of input/output (I/O) operations that can be run in parallel on a device.
- In SNADS, the number of distribution items on the distribution queue waiting to be sent.
queued sequential access method (QSAM)
An access method for storing and retrieving logical records in a continuous sequence. Input data blocks awaiting processing or output data blocks awaiting transfer to auxiliary storage are queued on the system to minimize delays in I/O operations.
In VTAM, a requested LU-LU session that cannot be started because one of the logical units (LUs) is not available. If the session-initiation request specifies queuing, the system services control points (SSCPs) record the request and later continue with the session-establishment procedure when both LUs become available.
- A message and its related control information stored in a data record in the MERVA ESA Queue Data Set.
- A block of data or an item in a queue.
In Q replication and event publishing, an approximate measurement of the difference between the time that the Q Capture program commits data to WebSphere MQ and the time that WebSphere MQ makes the data available to the Q Apply program or a receiving application. Queue latency is a subset of the end-to-end latency in a replication scenario or an event publishing scenario. See also end-to-end latency, Q Apply latency, Q Capture latency.
- A component of CICSPlex SM that creates and manages queues of data in a cache that is shared by a CMAS and its local MASs.
- 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.
- A component of a message queuing system that provides queuing services to applications.
- A Java virtual machine (JVM) service that sends and receives documents outside of the product.
queue manager event
An event that indicates one of the following: an error condition has occurred in relation to the resources used by a queue manager. For example, a queue is unavailable, or a significant change has occurred in the queue manager. For example, a queue manager has stopped or started.
In Q replication and event publishing, an object that contains the settings for how Q replication and event publishing programs process transactions and identifies the WebSphere MQ queues that are used in a replication or event publishing scenario. See also publishing queue map, replication queue map.
queue name (Qname)
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 zeroes is supported.
queue sequence number (QSN)
A sequence number that is assigned to the messages stored in a logical queue by MERVA ESA queue management in ascending order. The QSN is always unique in a queue. It is reset to zero when the queue data set is formatted, or when a queue management restart is carried out and the queue is empty.
In WebSphere MQ for z/OS, a group of queue managers in the same sysplex that can access a single set of object definitions stored in the shared repository, and a single set of shared queues stored in the coupling facility. See also shared queue.
In VTAM, a closedown in which any RPL-based communication macroinstruction is terminated (posted complete with an error code), no new sessions can be established, and no new access method control blocks (ACBs) can be opened. See also cancel closedown, orderly closedown.
To copy managed assets from a task group to the production server after the commit of the managed assets from the task group to the production-ready data on the authoring server is successful. See also authoring server, commit, managed asset, production server, production-ready data, task group, workspace.
quick start guide
A standard, two-page document that provides installers with at-a-glance information about the offering, the package contents, the installation process, and the critical resources that are available online. All of IBM's distributed software (DSW) packages must include a quick start guide generated using the template in ID Workbench.
A window containing a variable number of buttons that can be clicked on with a mouse. Each button can be assigned a macroinstruction that issues a predefined sequence of keystrokes or commands.
- To end a process or shut down a system after allowing normal completion of active operations.
- To request that a node stop sending synchronous-flow messages.
quiesced journal backup
A method of journal backup during which all DFSMShsm activity is quiesced while DFSMShsm complete backup of the journal. See also non-intrusive journal backup.
- In WebSphere MQ, a shutdown of a queue manager that allows all connected applications to disconnect. See also immediate shutdown, preemptive shutdown.
- A type of shutdown of the CICS adapter where the adapter disconnects from WebSphere MQ, but only after all the currently active tasks have been completed. See also forced shutdown.
In VTAM, a method of communicating in one direction at a time. Either the primary logical unit (PLU) or the secondary logical unit (SLU) assumes the exclusive right to send normal-flow requests, and the other node does not send such requests. When the sender wants to receive, it releases the other node from its quiesced state.
- In WebSphere MQ, the state of a queue manager before it stops. In this state, programs are allowed to finish processing, but no new programs are allowed to start.
- The process of bringing a device or a system to a halt by rejection of new requests for work.
An LVM facility that determines whether a volume group can be placed online or whether it can remain online after a failure of one or more of the physical volumes in the volume group. With a volume group, quorum is achieved when more than half of the volume group descriptor areas (VGDAs) and volume group status areas (VGSAs) are accessible and identical in content.
- A disk that contains a reserved area that is used exclusively for system management. The quorum disk is accessed when it is necessary to determine which half of the clustered system continues to read and write data. Quorum disks can either be MDisks or drives.
- The disk accessed exclusively by Microsoft Cluster Server to store the cluster recovery log, and to determine whether a server is up or down. Only one server can own the quorum disk at a time. Servers in the cluster can negotiate for the ownership.
The pointer that indicates the order used to resolve a tie. Nodes attempt to lock the first quorum disk (index 0), followed by the next disk (index 1), and finally the last disk (index 2). The tie is broken by the node that locks them first.
- For HSM on AIX, UNIX, or Linux systems, the limit (in megabytes) on the amount of data that can be migrated and premigrated from a file system to server storage.
- For HSM on Windows systems, a user-defined limit to the space that is occupied by recalled files.
- A size limitation, such as the limit on the amount of disk space or size of a file set
- The amount of disk space and number of files and directories assigned as upper limits for a specified user, group of users, or file set.
See delimited identifier.
See queue utility.
A keyboard in which the keys in the second-from-top row (row D) are labeled (from left to right): Q, W, E, R, T and Y. Such keyboards are commonly used in English-speaking countries. See also AZERTY keyboard.