ah - after looking at your JCL again, a no DSN= specification won't work in
your example, as you do need the &&SYSEXEC in order to specify the member.

On 11 March 2017 at 01:23, Graham Harris <[email protected]> wrote:

> >>100 records written & read inbetween alloc & free:
> >>
> >>DASD:    5.5 mins elapsed     92 secs CPU
> >>VIO         73 secs elapsed     65 secs CPU
> >>
> >Did I overlook an outer loop?
>
> The 10k iteration remains in place, as per the original figures.  I
> perhaps should have restated that, for clarity.
> Please note this wasn't a terribly scientific approach - i was just
> interested in seeing some ballpark comparative dynamics of VIO versus DASD,
> and thought I'd share.
>
> >When is a temp DS scratched:
> >o When it's FREEd?
> >o End of last step referencing it?
> >o End of job?
> >
>
> In this case, these are ALLOCd  within Rexx with DISP=(NEW,DELETE), so
> they go away when they are freed
> I dont <think> temp dataset disposition behaviour is any different to
> permanant datasets.
>
> >Does "DSN=&&amp;SYSEXEC" count as "no data set name"?  I've used that
> >frequently in such as:
>
> if the DSNAME is a system-generated SYSyyddd.Thhmmss.blah.blah  (which
> should be visible in JESMSG), then its a true temporary dataset.
> Its not really a 'no dataset name', but rather a system-generated one.
> You automatically get a temporary dataset if you do not specify a DSN=
> parameter at all.  Which should work in your particular example i think.
>
>
>
> On 11 March 2017 at 00:18, Paul Gilmartin <0000000433f07816-dmarc-
> [email protected]> wrote:
>
>> On Fri, 10 Mar 2017 23:46:07 +0000, Graham Harris wrote:
>>
>> >100 records written & read inbetween alloc & free:
>> >
>> >DASD:    5.5 mins elapsed     92 secs CPU
>> >VIO         73 secs elapsed     65 secs CPU
>> >
>> Did I overlook an outer loop?
>>
>> When is a temp DS scratched:
>> o When it's FREEd?
>> o End of last step referencing it?
>> o End of job?
>>
>> Does "DSN=&&amp;SYSEXEC" count as "no data set name"?  I've used that
>> frequently in such as:
>>
>> //STEP   EXEC  PGM=IKJEFT01
>> //SYSEXEC   DD  DSN=&&amp;SYSEXEC,UNIT=SYSALLDA,SPACE=(1,(1,,5))
>> //MEMBER   DD  DISP=SHR,DSN=&&amp;SYSEXEC(MEMBER),
>> //  VOL=REF=*.SYSEXEC
>> //SYSIN    DD  *
>>   /* Rexx */ signal on novalue
>>   /* Body of Rexx EXEC ... */
>> //SYSTSIN  DD  *
>>     REPRO INFILE(SYSIN) OUTFILE(MEMBER)
>>     %MEMBER
>>
>> ...  a one-step job with an in-stream Rexx EXEC.
>>
>> -- gil
>>
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