In
<[EMAIL PROTECTED]>,
on 07/28/2006
at 10:42 AM, "Hunkeler Peter (KIUB 34)"
<[EMAIL PROTECTED]> said:
>Is is my understanding and experience that the initiator will ENQ on
>all data sets referenced in the JCL (all steps) at job initiation
>time. The job will not start even the first step before all ENQs
>have been granted. So a job might be "WAITING FOR DATASETS" even if
>the one not yet available is only referenced in step nn (nn > 1).
>At step end, the initiator will DEQ any DSNs that are no longer
>needed, i.e. those which are not referenced on a DD in any later
>step.
>It is also my understanding that this is initiator business and
>therefore works the same way in either JES2 or JES3 environments. (I
>don't talk about main device secheduling in JES3, which only handles
>devices, not DSN ENQs).
Correct.
>My colleague claimes that he once was told by an ISV that in a JES2
>environment two jobs can be serialized on a certain step by coding
>a DISP=OLD/MOD DD for a data set in the step to be seriallzed.
It is certainly plausible that an ISV would have a representative who
was not didn't understand how MVS works but also didn't understand
that he didn't understand.
>The jobs would then execute in parallel until they come to that
>specific step. They also said that this will not work in a JES3
>environment because JES3 behaves as I described above. This
>contradicts my understanding (and experience).
You've never experienced an ISV that misinformed its customers, or a
colleague that misquoted an ISV?
>Can anybody enlighten me if this has changed in either JES2 or
>JES3, and if so when this change happended.
The ISV is either wrong or misquoted.
>I seem to remember as far back as MVS/XA that the job-level-ENQ
>behaviour is how it works. Am I wrong?
No, and the behavior goes back, unchanged, to OS/360.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
ISO position; see <http://patriot.net/~shmuel/resume/brief.html>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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