On 9/2/2010 5:11 AM, Peter Relson wrote:
If you want an example of a really dumb default that we are powerless to
change (without breaking the world), it is the default of STORAGE (with
LINKAGE=SYSTEM) for a key-specifiable subpool defaulting to key 0 instead
of caller's key. Way back when, the implementor thought that STORAGE
LINKAGE=SYSTEM was most similar to GETMAIN/FREEMAIN LINKAGE=BRANCH. Not.
Anyway, once that was done, it could not be changed in any reasonable way,
so we had to add the CALLRKY=NO|YES keyword.
We've been burned by that unintuitive CALLRKY= default more than once. :-( Also,
we did some benchmarks years ago that found SVC entry to GETMAIN to be
significantly faster than PC entry to STORAGE.
For these reasons we made a conscious decision to avoid use of the STORAGE macro
except where absolutely required--such as in a PC routine.
But then a couple/few years ago we enhanced our privileged code to run in
zIIP-eligible SRB mode. At that point, because of the local lock and strange
input register requirements of branch-entry GETMAIN (R4 and R7 I think?), we
decided to convert *everything* to use to use STORAGE.
I don't think we have any GETMAINs left...
--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
310-338-0400 x318
edja...@phoenixsoftware.com
http://www.phoenixsoftware.com/
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