Understanding CICS® terminology
Familiarize yourself with terms that have special meanings in CICS®.
- Transaction
- A unit of processing, consisting of one or more programs.
- Task
- The processing of a transaction for a program user.
- Conversational
- The CICS® term for running a program in nonsegmented mode. A conversational program consists of a sequence of alternating entries and responses between a user and the program. File and database position and locks, and storage resources are held across the terminal I/O operation.
- Pseudoconversational
- The CICS® term for running a program in segmented mode. A pseudoconversational program consists of a series of single CICS® tasks designed to appear to the user as a continuous conversation. File and database position and locks, and storage resources are released across the terminal I/O operation. The program must save conversation status before terminal output and restore it on terminal input.
- Communication area (COMMAREA)
- A data area used to transfer information between two programs within a transaction or between two transactions from the same terminal. When one program transfers to another, the COMMAREA can be any data area the transferring program can access. The transferred-from program can both pass data to that area and receive results in the area. The data area is usually the working storage area of that program.
- Transaction Work Area (TWA)
- A fixed length storage area allocated for each transaction task control area. Generated EGL programs use a 1024 byte section of the TWA. The offset of the EGL section of bytes is controlled by the twaOffset build descriptor option.
- Resource Definitions Online (RDO)
- Definitions of resources used or managed by the CICS® system. Each definition is created by using
resource definition online (RDO). The following list shows the types
of definitions:
- TDQUEUE
- Used to define transient data destinations for the system.
- FILE
- Used to define files used by the system.
- PROGRAM
- Contains information about each program. The Rational® COBOL Runtime for z/Series programs, generated COBOL programs, libraries, and servers, FormGroup online print services programs, FormGroup format modules, and DataTables must be defined. Alternatively, if you use the CICS® autoinstall feature for programs you do not need to create PROGRAM definitions.
- TRANSACTION
- Defines the transaction identifiers that can be entered by program users. For each transaction, it also defines the related program that starts the processing for the transaction.
- DB2CONN, DB2ENTRY, and DB2TRAN
- Describe the interface between the CICS® region and DB2®, including the association of transaction codes with DB2® program plans.
- PROFILE, TYPETERM, and TERMINAL
- Contain descriptions of terminals, their features, and operating information.
- Temporary storage queue
- A CICS® managed file for
storing intermediate results. Records in a temporary storage queue
can be accessed serially or by a relative record number. Descriptions
of the two types of temporary storage follow:
- Auxiliary
- A temporary storage queue that is stored on DASD. It can be recovered and maintained from one CICS® run to the next.
- Main
- A temporary storage queue that exists in the CICS® address space. It is not recoverable and is not maintained from one CICS® run to the next.
- Transient data queue
- A CICS® managed file that
is serially organized. Descriptions of the two types of transient
data queues follow:
- Extrapartition transient data queue
- A CICS® managed serial file in a system sequential data set or tape. The file can be an input file or an output file but not both. Extrapartition queues are not recoverable.
- Intrapartition transient data queue
- A transient data queue that is accessible to transactions running in a CICS® region. The queue can be used for both input and output. On z/OS®, the queue is stored in a VSAM entry sequenced data set. Intrapartition queues can be recovered.