On Tue, 6 Dec 2016 18:27:58 -0600, Kirk Wolf wrote:

>There are two SPFEDIT enqs required to follow the protocol.   The data set
>one (without member) is used to serialize during actual I/O.    You aren't
>seeing that while transferring with FTP, which is why I believe that the
>actual I/O is being deferred.
> 
Now this is interesting.  I have an EXEC using LM services that LMOPENs
several DCBs  on the same DDNAME; writes several lines with LMPUT to
each, interleaved, then does LMMREP (STOW?) on each.

If the data set is a PDSE, each LMMREP creates a directory entry for the
corresponding member and the content of each member is what I apparently
wrote to it.  Excellent exploitation of the ability, new with PDSE to write
seveal members concurrently.

If the data set is a PDS, no error is reported I get the same several
directory entries.  The content of all members is identical, matching
the last member I LMMREPed.  (Is there an easy way (i.e. without
assembler) to see theTTRs?)  Ouch!  WAD?  Caveat emptor, I guess.

LM services requires EXC ENQ on SYSDSN to do this, whether PDS
or PDSE, thereby prohibiting cross-job exploitation of PDSE capability.

So with SPFEDIT ENQ FTP might write directly to PDSE members,
but deferring the I/O would be needed for PDS.

-- gil

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