CICS Command Categories

CICS commands are grouped into categories by the kind of service they provide. Knowing the categories helps you guess where any command belongs.

The main categories

• Terminal control — talk to the screen: SEND, RECEIVE, SEND MAP, RECEIVE MAP, CONVERSE.
• File control — VSAM record access: READ, WRITE, REWRITE, DELETE, STARTBR, READNEXT, READPREV, ENDBR, UNLOCK.
• Program control — call and transfer between programs: LINK, XCTL, RETURN, LOAD, RELEASE.
• Interval control — time and delayed work: ASKTIME, FORMATTIME, START, CANCEL, DELAY, RETRIEVE.
• Storage control — working memory: GETMAIN, FREEMAIN.
• Task control — synchronization: SUSPEND, ENQ, DEQ.
• Transient data — queues to destinations: WRITEQ TD, READQ TD, DELETEQ TD.
• Temporary storage — scratchpad queues: WRITEQ TS, READQ TS, DELETEQ TS.

How to remember them

• Terminal = talk to the user’s screen; File = read and write records.
• Program = call another program (LINK) or transfer to it (XCTL); Interval = anything with time.
• Storage = get and free memory inside your task; Task = locks and waiting.
• Transient data queues go somewhere (a destination); Temporary storage queues are just a scratchpad for your programs.
• When you meet a new command, ask “what resource does it touch?” — the answer names its category.
• One example from four different categories:-
  
  *--- One example from four different categories ---* *--- Terminal control: show a screen ---* EXEC CICS SEND MAP('MNTMAP1') MAPSET('MNTSET1') ERASE END-EXEC. *--- File control: read a VSAM record ---* EXEC CICS READ FILE('CUSTMAS') INTO(CUST-REC) RIDFLD(CUST-NO) RESP(WS-RESP) END-EXEC. *--- Program control: call another program ---* EXEC CICS LINK PROGRAM('CALC-TAX') COMMAREA(TAX-AREA) END-EXEC. *--- Temporary storage: keep scratch data ---* EXEC CICS WRITEQ TS QUEUE('SCRATCH') FROM(WS-DATA) LENGTH(100) ITEM(WS-ITEM) END-EXEC.