On Fri, 13 May 2022 12:33:20 +0000, Seymour J Metz  wrote:

>IEFBR14 does not allocate anything. The Initiator physically allocates a new 
>DASD dataset before invoking the jobstep program,     ...
>
Is that a valuable clarification (despite having been stated here repeatedly)
or needless pedantry, your specialty.  "allocating datasets via IEFBR14" is
clear enough.  .  "Allocating datasets via DDNAMEs which are never opened"
would be marginally better.

>so it is already there when IEFBR14 gets control. For non-SMS, the VTOC will 
>have been updated but not the catalog; for SMS datasets, the catalog is 
>updated at the same time as the VTOC..
>
>OPEN output for a new non-SMS dataset will allocate an extent for the EOF if 
>the primary extent is zero (cylinders|tracks). 
>
That's an interesting question.  I understand that if WRITE fills an extent, no 
secondary
will be allocated merely to hold the EOF which would be necessary if additional 
extents
existed.  Is this true for OPEN; CLOSE with no intervening WRITE?  Is it true 
even for
a primary extent of zero?

-- 
gil

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