On 01/19/2012 02:55 PM, Paul Gilmartin wrote:
On Thu, 19 Jan 2012 11:09:27 -0800, Schwarz, Barry A wrote:
IEBCOPY compress generates an error message for a PDSE.
Become familiar with:
Title: z/OS V1R12 DFSMS Using Data Sets
Document Number: SC26-7410-10
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/dgt2d490/3.8.7.1
3.8.7.1 Establishing Connections to Members
Someone might be failing to issue a DISConnect or RELEASE.
(It's not at all clear to me why this problem shouldn't occur similarly
with a classic PDS.)
-- gil
...
How could this be an issue with the classic PDS? Surely the "connection
to members" concept doesn't exist for a traditional PDS, as old member
data can only be eliminated by completely reorganizing, compressing the
PDS. With no re-use of deleted-member space, there is no need for a
special mechanism to prevent over-write of a deleted member while some
other task is still reading the now-deleted version of the member.
The referenced 3.8.7.1 specifically applies to PDSE libraries; but it
also implies that if LLA REFRESH is not sufficient to DISConnect or
RELEASE all the old member connects on a PDSE in the LINKLIST and allow
the deleted PDSE space to be re-used (don't know for sure that this is
the case, but Juergen's experience that started this thread at least
raises that as one possibility), then LLA REFRESH would seem to be
failing to do something it really ought to be doing.
Someone surely is in a position to set up a simple test case, or may
have already tested this: A PDSE library in LINKLIST/LLA which no one
is actually using with but members and minimal free space; delete all
members; check whether there is enough free space to re-create the
members; if not, do an LLA REFRESH on the library; re-check whether
there is now free space for the new members. If the deleted space is
never freed, I would say we have a problem that needs fixing.
I gather from past warnings on ibm-main about forcing dynamic LINKLIST
updates on running address spaces that there are some cases where only a
partial load of a PDSE program object member has been done and a
potential of additional future loading activity still exists. If z/OS
is smart enough to recognize this situation, then one would want it to
preserve a PDSE member connection in such a case and continue to make
the old member version available to the old A/S even across an LLA
REFRESH; but I would also suspect this technique unlikely to be in use
on a typical Installation library added to LINKLIST.
--
Joel C. Ewing, Bentonville, AR [email protected]
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