Mainframe, MVS and zOS Discussion

• we can have 15 Job cards.
  There is no limit.
  It depends on system settings.
  It depends on what is the value edited by system programmer in TIOT.

Can someone please answer, how many JOB statements are allowed in a single JCL?

It depends on what is the value edited by system programmer in TIOT.

I thought go mad and make 1000+ Job statement but my frined said it might hang the mainframe and I did not try it.

Shahid wrote: I thought go mad and make 1000+ Job statement but my frined said it might hang the mainframe and I did not try it.

enrico-sorichetti wrote:

Can someone please answer, how many JOB statements are allowed in a single JCL?

define what You mean by single JCL

anyway a dataset/member can contain as many JOBs as You want (no limit ) !

on the other side there are limits on the number of steps for a JOB and on the number of DDs allowed for a step

Robert Sample wrote:

It depends on what is the value edited by system programmer in TIOT.

No, it does not. The TIOT determines the number of DD statements a single step may have but has nothing to do with the number of JOB statements you may store in a data set (assuming that is what you mean by "single JCL").

I thought go mad and make 1000+ Job statement but my frined said it might hang the mainframe and I did not try it.

Ask your "frined" (sic) what was meant by "hang the mainframe" as I have no idea. If you put 1000+ job statements in a single data set and submit the data set, the jobs will be submitted. It may take them a while to get into the system, depending upon your site's JES set up, and it certainly could take a long time for them to execute (again depending upon your site's JES set up and which job class(es) are used and the JES set up for the job class(es), but they won't "hang the mainframe".

One of the products I install comes as a single data set with over 1 MILLION lines in it. The installation process starts by customizing the job statement and then submitting the job to create the load library and partitioned data sets.

One of the products I install comes as a single data set with over 1 MILLION lines in it.

So as many JOB statements I shall have those many jobs will not get submitted all once? They get submitted one by one?

Anuj Dhawan wrote:

Shahid wrote: I thought go mad and make 1000+ Job statement but my frined said it might hang the mainframe and I did not try it.

Would like to have a calm conversation with your 'frined'(sic)!

Think about the sales happening using plastic-cards on Black Friday, Christmas or on new year - with the theory stated above, these sales could never be a real phenomenon; but you also know that they exist in real and happen every year, don't you? Needless to mention, mainframe is heavily used by banking institutions (plastic card providers).

Robert Sample wrote: JCL is submitted line by line. A single data set with multiple JOB statements is still read into JES line by line.

The million line data set had ONE JOB statement; I was pointing out that really large data sets can still be submitted.

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Robert Sample wrote:

So as many JOB statements I shall have those many jobs will not get submitted all once? They get submitted one by one?

Jobs are not all submitted at one time -- the system will read the data set and each time a JOB statement is found a new job will be submitted to JES. This does not happen in parallel. Although, thinking about your question this morning I realized that there is a hard limit that applies. When your site sets up JES (either JES2 or JES3 -- which doesn't matter), one of the configuration parameters is the number of jobs that can exist in the system. Once you hit that maximum (for JES2 under z/OS 2.2, it is 999999 but the default is 9999), no more jobs can be submitted into the system. Since it is a site-specific parameter, your site may have a different value and your site support group would have to tell you what the limit is.

So if in a batch-cycle, we have, assume, 1000 jobs and we put all those jobs in a single dataset and submit, they wil also get submitted.

Then is it like a smal sechduler in itself?

//verylarge JOB ..
// ... 
// ...
// ...
//onestep JOB 
//STEP EXEC PGM=IEFBR14
//DDNM DD ....