On 7/6/2011 10:33 AM, Edward Jaffe wrote:
On 7/5/2011 1:57 PM, Steve Comstock wrote:
WOW! That's a big deal.
Is this documented somewhere public? Or is this NDA?
Do you what the "certain restrictions" are? Can you tell us? Can
you tell us how it's done?
The Feb 15, 2011 announcement preview is the only public information I'm aware
of. It tells you a lot if you know how to translate the 'announcementese'. It's
been out there four months which proves (I guess) that nobody reads these
announcement previews. Many thanks to Jim Mulder for bringing this to light on
IBM-MAIN!
I read that announcement, and even posted an allusion
to it in one of my posts. I was looking for the next
level of detail. Guess I'll just have to wait.
The previewed enhancement allows 'applications' that need 'virtual storage
constraint relief' (i.e., ordinary, enabled, DAT-ON code) to have some 'programs
running in 64-bit storage'. From that we can infer that the operating system can
now save status over an interrupt for code located above the bar.I agree that is
a 'big deal'!
The part where IBM talks about this enhancement providing VSCR to applications
that 'imbed code in data areas' seems to suggest that applications might have to
manually copy eligible code into data areas above the bar. If so, that seems
like a pretty big 'restriction' to me.
Other possible 'restrictions' immediately come to mind as well. For example,
there are hundreds of callable z/OS services. I imagine the process of
inspecting, updating, testing and documenting required to make them all work for
callers executing above the bar will take years. Enablement and/or approval of
each service will likely need to be individually justified for expenditure of
necessary development, test and tech-writing resources. In z/OS 1.13, probably
only a handful (or possibly none!) of the z/OS services will have been
enabled/approved for use by such code.
Saving status over an interrupt is indeed a 'big deal', but only the tip of the
iceberg...
--
Kind regards,
-Steve Comstock
The Trainer's Friend, Inc.
303-393-8716
http://www.trainersfriend.com
* Special promotion: 15% off on all DB2 training classes
scheduled by September 1, taught by year end 2011
* Check out our entire DB2 curriculum at:
http://www.trainersfriend.com/DB2_and_VSAM_courses/DB2curric.htm
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