Glossary
The following terms are used in this book. Other terms used in CICS can be found in the CICS Glossary that is in PDF format on the CD. The IBM Dictionary of Computing at http://www.networking.ibm.com/nsg/nsgmain.htm provides a long list of computer terms, as well.
- abend
Abnormal end of task.
- ACID properties
The term, coined by Haerder and Reuter (1983), and used by Jim Gray and Andreas Reuter to denote the properties of a transaction:
- Atomicity
A transaction’s changes to the state (of resources) are atomic: either all happen or none happen.
- Consistency
A transaction is a correct transformation of the state. The actions taken as a group do not violate any of the integrity constraints associated with the state.
- Durability
After a transaction completes successfully (commits), its changes to the state survives failures.
- Isolation
Even though transactions execute concurrently, they appear to be serialized. In other words, it appears to each transaction that any other transaction executed either before it, or after it.
See Also unit of work (UOW).
- applet
An application program, written in the Java programming language, that can be retrieved from a web server and executed by a web browser. Compare with servlet.
- basic mapping support (BMS)
An interface between CICS and application programs that formats input and output display data and routes multiple-page output messages without regard for control characters used by various terminals.
- BMS
- business application
An application that transacts the business of a company—that is, an application that performs business transactions on behalf of the company.
- business logic
The code that implements a business application.
- business operations application
See business application.
- CAD
Computer-aided design.
- channel
See message channel.
- CICS
- CICS Transaction Gateway (CTG)
This provides a comprehensive set of Java-based web server facilities for access to CICS applications from a web browser.
- CICS-value data area
A CICS value on INQUIRE and SET commands, specifically those that refer to resource status or definitions. See the CICS System Programming Reference for more information.
- CICS Web Interface (CWI)
A collection of CICS resources supporting direct access to CICS transaction processing services from web browsers.
- class
In object-oriented design or programming, a model or template that can be instantiated to create objects with a common definition and, therefore, common properties, operations, and behavior. An object is an instance of a class.
- client
A computer system or process that requests a service of another computer system or process that is typically referred to as a server. Multiple clients may share access to a common server.
- client/server
A distributed application design model in which the frontend transaction (the one that initiates the conversation) is called the client and controls the course of the conversation. The server receives a request from the client, processes it, and returns the results.
- COBOL
Common business-oriented language. An English-like programming language designed for business data processing applications.
- COMMAREA
- Common Object Request Broker Architecture (CORBA)
An architectural standard proposed by the Object Management Group (OMG), an industry standards organization for creating object descriptions that are portable among programming languages and execution platforms.
- communication area (COMMAREA)
A CICS area that is used to pass data between tasks that communicate with a given terminal. The area can also be used to pass data between programs within a task. A CICS program typically populates it with data accessed from files or databases.
- component tracing
Tracing facility provided by CICS to trace transactions through the CICS components, and through user programs.
- constructor
A special class method that has the same name as the class and is used to construct and possibly initialize objects of its class type.
- conversational
(1) Pertaining to a program or a system that carries on a dialog with a terminal user, alternately receiving and transmitting data. (2) Pertaining to an SNA conversation or a dialog between two programs.
- CORBA
- CORBA services
Services that specify the standard interfaces of the OMG object services.
- CRUD
Create, Read, Update, and Delete.
- CTG
- Customer Information Control System (CICS)
A General-purpose data communication system (or online transaction processing system). An online system controller and some batch utilities that are capable of supporting a network of many terminals. The CICS family of products provides a range of application platforms on many operating system platforms, including OS/390, MVS/ESA, MVS/XA, MVS/370, VSE/ESA, DOS/VS, OS/2, System/400, and System/6000.
- CVDA
See CICS-value data area.
- CWI
- Database 2 (DB2)
A relational database management system in which data is presented to the user in the form of tables. It can be accessed by CICS application programs issuing SQL requests.
- DB2
See Database 2 (DB2).
- e-Business
(1) The transaction of business over an electronic medium such as the Internet. (2) Any organization (for example, commercial, industrial, nonprofit, educational, or governmental) that transacts its business over an electronic medium such as the Internet. An e-business combines the resources of traditional information systems with the vast reach of an electronic medium such as the Internet (including the World Wide Web, intranets, and extranets); it connects critical business systems directly to critical business constituencies—customers, employees, and suppliers. The key to becoming an e-business is building a transaction-based web site in which all core business processes (especially all processes that require a dynamic and interactive flow of information) are put online to improve service, cut costs, and sell products.
- e-Commerce
The subset of e-business that involves the exchange of money for goods or services purchased over an electronic medium such as the Internet.
- EBCDIC
Extended binary-coded decimal interchange code.
- ECI
- EDF
- end user
Anyone using CICS to do a job, usually by interacting with an application program (transaction) by means of a terminal.
- Enterprise ToolKit for OS/390 (ET/390)
This is supplied with VisualAge for Java Integrated Development Environment (IDE) to develop Java applications to run in the OS/390 UNIX or CICS for OS/390 environments.
- EXCI
- ET/390
- execution diagnostic facility (EDF)
A facility used for testing application programs interactively online, without making any modifications to the source program or to the program preparation procedure. The facility intercepts execution of the program at various points and displays information about the program at these points. Also displayed are any screens sent by the user program, so that the user of EDF can converse with the application program during testing just as a user would do on the production system.
- external call interface (ECI)
A CICS facility that allows a calling program to call a CICS program as though it had been linked to (using the LINK facility) by another CICS program.
- external CICS interface (EXCI)
A CICS application programming interface that helps to make CICS applications more easily accessible from non-CICS environments. It enables a non-CICS program (a client program) running in OS/390 to call a program (a server program) running in a CICS Transaction Server region and to pass and receive data by means of a communication area. The CICS program is invoked as if linked to by another CICS program. For programming information about EXCI, see the External CICS Interface User’s Guide.
- Extended binary-coded decimal interchange code
A coded character set of 256 8-bit characters.
- FIFO
First in, first out.
- file transfer protocol (FTP)
In the Internet suite of protocols, an application layer protocol that uses TCP and Telnet services to transfer bulk-data files between machines or hosts.
- firewall
A firewall is a software configuration that prevents unauthorized traffic between a trusted network and an untrusted network.
- FTP
- graphical user interface (GUI)
A type of computer interface consisting of a visual metaphor of a real-world scene, often of a desktop. Within that scene are icons, representing actual objects, that the user can access and manipulate with a pointing device.
- GUI
- HTML
- HTTP
- HyperText Markup Language (HTML)
A markup language that is specified by an SGML document type definition (DTD) and is understood by all web servers. It was designed primarily to support the online display of textual and graphical information that includes hypertext links.
- Hypertext Transfer Protocol (HTTP)
In the Internet suite of protocols, the protocol that is used to transfer and display hypertext documents.
- IDE
- IDL
- IIOP
- inheritance
(1) A mechanism by which an object class can use the attributes, relationships, and methods defined in more abstract classes related to it (its base classes). (2) An object-orientated programming technique that allows you to use existing classes as bases for creating other objects.
- initiation queue
A local queue on which the queue manager puts trigger messages.
- Integrated Development Environment (IDE)
In VisualAge for Java, a set of windows that provide the user with access to development tools.
- Interactive System Productivity Facility (ISPF)
An IBM licensed program that serves as a full screen editor and dialog manager. It is used for writing application programs and provides a means of generating standard screen panels and interactive dialogues between the application programmer and terminal user.
- interface
Hardware, software or both, that links systems, programs, or devices.
- interface definition language (IDL)
A contractual, neutral, and declarative language that specifies an object’s boundaries and its interfaces. IDL provides operating system independent and programming language independent interfaces to all services and components that reside on a CORBA bus.
- Internet
A wide area network connecting thousands of disparate networks in industry, education, government, and research. The Internet network uses TCP/IP as the standard for transmitting information.
- Internet Inter-ORB Protocol (IIOP)
An object-oriented protocol that makes it possible for distributed programs written in different programming languages to communicate over the Internet. An industry standard protocol that defines how General Inter-ORB Protocol messages are exchanged over a TCP/IP network.
- interoperable object reference (IOR)
A string that keeps information about the type and key of an object and the communications profiles needed to contact the object server and locate the object. An IOR is represented through a String instance by a process known as stringification.
- intranet
A private network that integrates Internet standards and applications (such as web browsers) with an organization’s existing computer networking infrastructure.
- IOR
- ISPF
- Java
An object-oriented programming language for portable interpretive code that supports interaction among remote objects. Java was developed and specified by Sun Microsystems, Inc.
- JavaBeans
A platform-independent, software component technology for building reusable Java components called beans. Once built, these beans can be made available for use by other software engineers or can be used in Java applications. Also, using JavaBeans, software engineers can manipulate and assemble beans in a graphical drag-and-drop development environment.
- JCL
- Job Control Language (JCL)
Control language used to describe a job and its requirements to an operating system; for example, OS/390.
- KSDS
See Key Sequenced Data Set.
- LAN
- line of business application
See business application.
- local area network (LAN)
A computer network located on a user’s premises within a limited geographical area. Communication within a local area network is not subject to external regulations; however, communication across the LAN boundary may be subject to some form of regulation.
- local queue
A queue that belongs to the local queue manager. A local queue can contain a list of messages waiting to be processed. Contrast with remote queue.
- local queue manager
The queue manager to which a program is connected and that provides message queueing services to the program. Queue managers to which a program is not connected are called remote queue managers, even if they are running on the same system as the program.
- mainframe
A computer, usually in a computer center, with extensive capabilities and resources to which other computers may be connected so that they can share facilities.
- MCI
- message
(1) In message queuing applications, a communication sent between two programs. (2) In system programming, information intended for the terminal operator or system administrator.
- message channel
In distributed message queuing, a mechanism for moving messages from one queue manager to another. A message channel comprises two message channel agents (a sender at one end and a receiver at the other end) and a communication link. Contrast with MQI channel.
- message channel interface (MCI)
The MQSeries interface to which customer- or vendor-written programs that transmit messages between an MQSeries queue manager and another messaging system must conform. A part of the MQSeries Framework.
- message queue interface (MQI)
The programming interface provided by the MQSeries queue managers. This programming interface allows application programs to access message queueing services.
- method
(1) A fragment of Java code within a class that can be invoked and passed a set of parameters to perform a specific class. (2) An implementation of an operation. Code that can be executed to perform a specific request. Methods associated with an object can be structured into one or more programs
- MQI
- MQI channel
Connects an MQSeries client to a queue manager on a server system, and transfers only MQI calls and responses in a bidirectional manner. Contract with message channel.
- MQSeries
The IBM MQSeries family, which provides an open, scalable, industrial-strength messaging and information infrastructure, enabling enterprises and beyond to integrate business processes.
- middleware
A vague term that refers to the software between an application program and the lower-level platform functions.
- network
(1) An interconnected group of nodes. (2) The assembly of equipment through which connections are made between work stations.
- object
(1) A collection of data and methods that operate on that data, which together represent a logical entity in the system. In object-orientated programming, objects are grouped into classes that share common definitions and methods. Each object in the class is said to be an instance of the class. (2) An instance of an object class consisting of attributes, a data structure, and operational methods. It can represent a person, thing, event, or concept. Each instance has the same properties, attributes, and methods as other instances of the object class, although it has unique values assigned to its attributes. (3) In MQSeries, an object in a queue manager, a queue, a process definition, a channel, a namelist, or a storage class (OS/390).
- Object Management Group (OMG)
A consortium of vendors that defines standards pertaining to object-orientated distributed systems. The OMG is responsible for defining CORBA, CORBA services, and CORBA facilities in accordance with the Object Management Architecture.
- object-oriented programming
A programming approach based on the concepts of data abstraction and inheritance. Unlike procedural programming languages, object-orientated programming concentrates on those data objects that constitute the problem and how they are manipulated, and not on how something is accomplished.
- Object Request Broker (ORB)
A CORBA term designating the means by which objects transparently make requests and receive responses from other objects, whether local or remote.
- ORB
- PC
- personal computer (PC)
(1) A microcomputer primarily intended for stand-alone use by an individual. (2) A desk-top, floor-standing, or portable microcomputer that usually consists of a system unit, a display monitor, a keyboard, one or more diskette drives, internal fixed-disk storage, and an optional printer. PCs are designed primarily to give independent computing power to a single user and are inexpensively priced for purchase by individuals or small businesses.
- proxy object
An object on the client side that has the same interface as the server object it represents. Instead of having the actual method implementation, its methods communicate with an ORB.
- pseudo-conversational
A type of CICS application design that appears to the user as a continuous conversation, but that consists internally of multiple tasks—also called transaction-oriented programming.
- queue
An MQSeries object. Message queueing applications can put messages on, and get messages from, a queue. A queue is owned and maintained by the queue manager. Local queues can contain a list of messages waiting to be processed. Queues of other types cannot contain messages; they point to other queues, or can be used as models for dynamic queues.
- local queue manager
See local queue manager.
- remote queue manager
See remote queue manager.
- queue manager
(1) A system program that provides queuing services to applications. It provides an application programming interface so that programs can create and access messages on the queues that the queue manager owns. (2) An MQSeries object that defines the attributes of a particular queue manager.
- receiver channel
In message queueing, a channel that responds to a sender channel, takes messages form communication link, and puts them on a local queue.
- remote queue
A remote queue is a local definition of a queue on a remote queue manager. A program opens a remote queue, the put goes on an XMITQ. Contrast with local queue.
- remote queue manager
To a program, a queue manager that is not the one to which the program is connected.
- reply-to queue
The name of a queue to which the program that issued an MQPUT call wants a reply message or report message sent.
- sender channel
In message queueing, a channel that initiates transfers, removes messages from a transmission queue, and sends them over a communication link to a receiver or requester channel.
- server
(1) A functional unit that provides shared services to clients over a network; for example, a file server, a print server, a mail server. (2) In TCP/IP, a system in a network that handles the requests of a system at another site, called a client-server.
- servlet
An application program, written in the Java programming language, that is executed on a web server.
- SIT
- skeleton
The object-interface-specific ORB component that assists an object adaptor in passing requests to particular methods.
- SNA
- stringification
The process of converting a reference to the CORBA server object to and/or from a string representation of an IOR. Once an object reference has been stringified, it can be used by other applications to obtain a reference to the remote object.
- stub
A local procedure corresponding to a single operation that invokes the operation when called.
- synchronous
(1) Pertaining to an event that happens, exists, or arises at precisely the same time as another event. (2) Pertaining to an operation that occurs regularly or predictably with regard to the occurrence of a specified event in another process; for example, the calling of an input/output routine that receives control at a precoded location in a program. Contrast with asynchronous.
- syncpoint
A logical point in the execution of an application program where the changes made to the databases by the program are consistent and complete and can be committed to the database.
- system initialization table (SIT)
A table containing the parameters used by CICS on start up.
- Systems Network Architecture (SNA)
A description of logical structures, formats, protocols, and operational sequences for transmitting information units through, and controlling the configuration and operation of, networks. The structure of SNA allows the end users to be independent of, and unaffected by, the specific structures used for information exchange.
- task
(1) A unit of work for the processor; therefore the basic multiprogramming unit under the control program. (2) Under CICS, the execution of a transaction for a particular user. Contrast with transaction.
- TCP/IP
See Transmission Control Protocol/Internet Protocol (TCP/IP).
- Transmission Control Protocol/Internet Protocol (TCP/IP)
A set of communication protocols that support peer-to-peer connectivity functions for both local and wide area networks.
- transaction
A transaction can be regarded as a unit of processing (consisting of one or more application programs) initiated by a single request. A transaction may require the initiation of one or more tasks for its execution.
- unit of work (UOW)
A sequence of processing actions (database changes, for example) that must be completed before any of the individual actions performed by a transaction can be regarded as committed. After changes are committed (by successful completion of the UOW and recording of the syncpoint on the system log), they become durable, and are not backed out in the event of a subsequent failure of the task or system.
The beginning and end of the sequence may be marked by:
Start and end of transaction, when there are no intervening syncpoints
Start of task and a syncpoint
A syncpoint and end of task
Two syncpoints
Thus a UOW is completed when a transaction issues an explicit syncpoint request, or when CICS takes an implicit syncpoint at the end of the transaction. In the absence of user syncpoints explicitly taken within the transaction, the entire transaction is one UOW.
- Unix operating system
An operating system developed by Bell Laboratories that features multiprogramming in a multi-user environment. The Unix operating system was originally developed for use on minicomputers but has been adapted for mainframes and microcomputers. (Trademark of AT&T Bell Laboratories.)
- UOW
See unit of work (UOW).
- VSAM
- VTAM
- Virtual Storage Access Method (VSAM)
An access method for direct or sequential processing of fixed and variable-length records on direct access devices. The records in a VSAM data set or file can be organized in logical sequence by a key field (key sequence), in the physical sequence in which they are written on the data set or file (entry-sequence), or by relative-record number.
- Virtual Telecommunications Access Method (VTAM)
IBM software that controls communication and the flow of data in an SNA network by providing the SNA application programming interfaces and SNA networking functions. An SNA network includes subarea networking, Advanced Peer-to-Peer Networking (APPN), and High-Performance Routing (HPR). Beginning with Release 5 of the OS/390 operating system, the VTAM for MVS/ ESA function was included in Communications Server for OS/390; this function is called Communications Server for OS/390 - SNA Services.