EXEC Statement - II

Q. What is the DPRTY Parameter?

The DPRTY Parameter assigns dispatching priority to a particular job-step. It has the following format : DPRTY = (value1,value2) Here, the priority is specified as a hexadecimal value. So, the priority in decimal would be = (16 x value1+ value2).

Q. What is the PERFORM Parameter?

The PERFORM parameter is used to specify the performance group for a job-step. It has the following format : //JOB1 JOB A123,QUASAR,CLASS=A //STEP01 EXEC PGM=PROGRAM1,PERFORMANCE=15 //STEP02 EXEC PGM=PROGRAM2 Performance group : Performance groups are defined when the system programmer guys are installing the MVS OS on the Mainframe Servers. Every performance group has typical characteristics such as storage speed etc. For example, performance group 15 might indicate slow storage speed. Every JOB class is linked to a performance group. If you want to explicitly override the performance group associated with the job class, for your job-step, you use the PERFORMANCE parameter.

Q. What is the RD(Restarting and Checkpointing) Parameter?

Restart Definition(RD) parameter can be used to restart a Batch Job, in case it abends. This is very useful, if we have a Batch(series of jobs), where output of one Job1, is fed as input to the next Job2. The term Checkpoint refers to a point in Job from where the Job can be resumed in case of an abnormal termination. The RD parameter can take any of the following options : RD=R means restart from last checkpoint. Simply means, the Job will restart automatically from the last checkpoint. Checkpoints were saved on the way, while the Job was running previously. RD=NR means no restart. Here, checkpoints are saved, but we don’t want to restart the Job automatically. We will intervene manually, and restart the Job from the desired checkpoint. RD=RNC means the Job will restart automatically, but right from the beginning, since no checkpoints are saved. We say that, CHKPT(Checkpoint macro) is suppressed. RD=NC means no restart, no checkpointing.

Q. What are the common parameters on the JOB and EXEC statement?

REGION Parameter - The REGION parameter specifies an upper bound on the amount of storage space that a Batch Job or a job-step can consume. For example, you know that your Batch Job sometimes occupies 1MB of space, sometimes 2MB, 1.5MB, 3MB, it varies. However, you know that it will always occupy no more that 5 MB at all times. Thus, 5 MB of storage space, is the maximum storage space, the Batch Job could possibly take. You indicate this to the MVS, by specifying the REGION parameter on the JOB statement(if you want to specify a space constraint on the entire Job) or the EXEC statement(if you want to specify space constraint only a particular job-step). //JOB1 JOB A123,QUASAR,CLASS=A,REGION=4K //STEP01 EXEC PGM=PROGRAM1,REGION=2M //STEP02 EXEC PGM=PROGRAM2 If REGION parameter is coded both on JOB and EXEC, REGION on JOB overrides REGION on EXEC. So, in the above example, job-steps STEP01 and STEP02 are allowed to occupy a maximum of 4K bytes. A detailed explanation of COND parameter can be found by clicking on this link. More on COND Parameter COND Parameter – The COND parameter is used for conditional execution. It is useful to control the flow of execution in a Batch Job. Let us first understand, how EXEC statement works, when coded on the EXEC statement. The syntax of the EXEC statement is as follows: COND(,) The comparision code can take any values like 0,4,8,12,16 depending upon the severity of the error. The condition can GT,GE,LT,LE,EQ,NE. Moreover, we can also code EVEN and ONLY options on the COND statement. //JOB1 JOB A123,QUASAR,CLASS=A //STEP01 EXEC PGM=PROGRAM1 //STEP02 EXEC PGM=PROGRAM2,COND(4,GT,STEP01) Here, when the job-step STEP01 is performed, either it is executed successfully, or it may terminate with errors. The result or status of execution is indicated by a unique code, called Return Code(RC). Next, when the job-step STEP02 is to be performed, first the COND clause is to be evaluated. Ask the question, Is 4 greater than the RC of STEP01? If Yes, Bypass job-step STEP01. If No, Perform job-step STEP01. Read more on COND Parameter Here >> Technorati Tags: JOB-step,JOB,EXEC,COND,REGION,COND parameter,REGION parameter,Bypass step,execute step,ABEND,Abnormal termincation,Condition statement,Condition Parameter,JCL,JCL Tutorial,Quasar Chunawalla,DPRTY,Dispatching Priority,PERFORM,RD,Restart,CHKPT,CHKPT Macro,Checkpoint,RNC,Device address