At 21:48 -0500 on 05/22/2007, Scott Fagen wrote about Re: Why is
there JOB scope for DSN ENQ's anyway?:
Why doesn't initiator/terminator downgrade the ENQ from EXC to SHR when the
job has only DISP=SHR interest in the dataset for any of the remaining job
steps. The answer clearly distinguishes where the deficiency lies in the
system (GRS, not Allocation).
If the question is "why isn't there a RET=CHANGE variant for altering EXC to
SHR ownership in ENQ (and/or ISGENQ)?" the answer is, most surely, "because
IBM has never seen sufficient business justification to implement
the function."
Since as I noted, the Support is easy to add (as I documented) and
there is no downlevel exposure if it is initially restricted to use
by the Initiator (just update the Initiator Code to do the EXC->SHR
downlevel ENQ at the point where all subsequent steps are DISP=SHR).
Both the Initiator and ENQ support will be at the same level so you
do not run into the attempt to run the new code against an old ENQ or
the macro parm support that would occur if it were a USER-CODE
supported feature. That Initiator update might actually take a few
man-days (in addition to the man-hour or so to the ENQ code). You can
postpone the availability to USER-CODE via new ENQ/ISGENQ macros
until the problem of handling the accidental attempt to issue the
request on a downlevel system is addressed. I think that a automatic
business case can be made just based on the improved efficiency of
the Initiator.
>
See Robert Rosenberg's recent well-reasoned contribution on this
topic:
Linkname: Re: Why is there JOB scope for DSN ENQ's anyway?
URL: http://bama.ua.edu/cgi-bin/wa?A2=ind0705&L=ibm-main&P=195906
So, I'd have to guess, based on the insulting tones, that you and Mr.
Rosenberg have some resentment about this function not being implemented.
I do not regard my query about why this glaring design flaw in ENQ is
not being addressed (even if the usage of the enhanced support is
restricted to the Initiator initially) as insulting (or do you regard
my characterization of the original/current design of ENQ lacking a
EXC->SHR Downgrade capability as "poor"/"flawed" as insulting?).
I am doing exactly what a SHARE Requirement is supposed to do - Point
out a lack of functionality and provide an suggestion as to one way
to rectify the lack. I do not have access to the SHARE Request List
but I'd be surprised if there has not been one already submitted (or
at least proposed) about this exact issue (the lack of a EXC->SHR
downgrade at the job step boundary between DISP=OLD and DISP=SHR
steps).
IMO, the lack of a fix in progress amounts to a deliberate crippling
of the Initiator since the fix is so easy to make (so long as you
make ENQ part initially an Authorized User facility and restrict its
user-base to the Initiator). If you feel that my estimates of the
ease of writing the needed code understates the effort needed, I
welcome your estimate of the effort and/or pointing out where I am
mistaken about what needs to be done.
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