//STEP4  EXEC PGM=DREC,PARM='3018,NO'

The EXEC statement named STEP4 invokes a program named DREC and passes the value in the PARM parameter to DREC.

//       EXEC PGM=ENTRY,TIME=(2,30)

This EXEC statement, which does not have a stepname, invokes a program named ENTRY and specifies the maximum processor time for execution of the step.

//FOR    EXEC PROC=PROC489,ACCT=DB1528,RD.PSTEP2=RNC,DEV=3390

The EXEC statement named FOR invokes a cataloged or in-stream procedure named PROC489. The ACCT parameter applies to all steps in the procedure. The RD parameter applies to only the step named PSTEP2. The DEV parameter assigns the value 3350 to the symbolic parameter Device Support Bucket in a procedure statement.