Ah - OK.  Somewhere back in the mists of time I was once aware that the Edit 
SAVE only enqueued the PDS momentarily, but I failed to recall that fact when 
needed.

So the abend concern is only if the ISPF Edit SAVE occurred at the same 
"instant" as the batch delete.  A small but admittedly not impossible window of 
opportunity and according to Murphy, it would occur at the least convenient 
time.

Thanks for clarifying the issue.

Bill Bass
United Healthcare
Greenville SC

-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf 
Of Joel C. Ewing
Sent: Thursday, October 03, 2013 4:04 PM
To: [email protected]
Subject: Re: Standard TSO/MVS way to delete a PDS(E) member

On 10/03/2013 02:52 PM, Paul Gilmartin wrote:
> On Thu, 3 Oct 2013 12:11:55 -0500, Joel C. Ewing wrote:
>>
>> To test this properly requires either extraordinary timing ability, or
>> getting a program which will OPEN a PDS for output without the
>> appropriate ISPFEDIT enqueue and keep it open for long enough, say 10 to
>> 30 seconds, from a batch job or a 2nd TSO session with DISP=SHR to the
>> PDS, and while  this is running with the dataset open for OUTPUT then
>> trying other activity from batch or ISPF that requires an OPEN for
>> OUTPUT to update the PDS while using SHR access at PDS allocation.  I
>> have done those tests in the past and have also run traces on the
>> ENQ/DEQ requests issued while starting and terminating ISPF edit
>> sessions to be sure I understood what was going on.
>>
> To expose this, you might try in batch Rexx (schematic; untested):
> 
> RC = BPXWDYN( 'alloc rtddn(VAR) shr dsn(DATA.SET(MEMBER)) ...' )
> address MVS 'EXECIO 0 DISKW' VAR '(open'
> address SYSCALL 'sleep 30'  /* or more, to taste.  */
> address MVS 'EXECIO 0 DISKW' VAR '(finis'
> RC = BPXWDYN( 'free dd('VAR') ...' )
> 
> ... and while that runs, try editing a member and saving it, or try your
> DELETE program.
> 
> -- gil
Right.  And it's irrelevant whether the sleeping task and the other task
are attempting to reference the same or different members, it's the 2nd
concurrent open-for-output attempt on the same PDS that causes the problem.


-- 
Joel C. Ewing,    Bentonville, AR       [email protected] 

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