CICS Terminology

CICS has its own vocabulary. These terms appear in every manual, error message and interview, so learn them once and the rest of the course becomes much easier.

Core terms

• Transaction - a unit of work in CICS, started by typing a transid. Example: one fund transfer.
• Transid - the 1 to 4 character name that identifies a transaction, for example MNT1 or ORDR.
• Task - one execution (one instance) of a transaction. Ten users running MNT1 means ten tasks.
• Program - the COBOL (or PL/I, Assembler, Java) code that does the work of the transaction.
• Terminal - the device (or emulator session) through which the user talks to CICS.
• Region - the separate z/OS address space in which CICS runs. One region is one CICS system.
• Map / Mapset - the screen layout definition (built with BMS) that programs SEND and RECEIVE.
• COMMAREA - the Communication Area, a block of memory used to pass data between programs or between executions of a program.
• EIB - the Execute Interface Block, a control block CICS fills in for every task (transid, terminal id, response codes).

Resource definition terms

• PCT (Program Control Table) - defines transactions: which transid starts which first program.
• PPT (Processing Program Table) - defines programs known to CICS.
• FCT (File Control Table) - defines files (VSAM datasets) that CICS programs can access.
• TCT (Terminal Control Table) - defines terminals connected to CICS.
• RDO (Resource Definition Online) - the modern way of defining resources with the CEDA transaction instead of assembling tables.
• CSD (CICS System Definition) - the file where RDO definitions are stored.

Command and everyday terms

• EXEC CICS - the prefix of every CICS command in an application program.
• RESP - the option that returns the result of a command so the program can check it.
• Abend - abnormal end of a task, for example ASRA (program check) or AICA (runaway task).
• NEWCOPY - the CEMT command that makes CICS load the fresh copy of a changed program.
• CEMT - the CICS-supplied master terminal transaction used to inquire on and control the system.
• Dump / Trace - diagnostic tools: a dump captures storage at failure time, a trace records the path the task took.