JES

 JES read in job and spool it in DASD. The Converter translates the JCL into internal text. An initiator asked for a job to run, JES selects a job based on tge PRIORITY specified in the JCL. The Interpreter allocate the control blocks through which the system will manage the job execution. The Initiator attach the job task. When the job step is running, JES collect the job output and spool it. When the job ends, the Terminator releases the job resources