Vernooy, C.P. - SPLXM wrote:
What worries me is the fact that the fix sets default processing to UseZosV1R9Rules(Yes). You don't have to do anything to remain in the safe pre-1.10 mode, so many customers will probably overlook this 1.10 enhancement.
The pre-1.10 mode is not "safe"--just a little different. And, programs that seem to continue to work using the post-1.10 mode are not "safe" either. When programs erroneously expect zeros, in cases where such zeroing is not guaranteed, avoidance of abend depends entirely on luck. Any subtle change in the calling environment's storage allocation can cause them to fail.
The only way to locate these programs is to use the IgvInitGetMain DIAG trap!
I also wish the default had been UseZosV1R9Rules(No). But, when customers get upset, and IBM executives--who fancy themselves experts in risk assessment--get involved, things usually go this way.
There is ample recent precedent at IBM for undocumented options, that become documented options, that default to the old behavior and eventually go the other way. Examples: IosProtCaptUcb which became CaptUcb NO which became CaptUcb YES, IgvNoUserKeyCsa which became Vsm AllowUserKeyCsa YES which became Vsm AllowUserKeyCsa NO. There are some pending ones like AsnReuse which became ReusAsid NO which will hopefully become ReusAsid YES in a future release and CbLoc Virtual24(IHALCCA,IHAPCCA) which will hopefully become CbLoc Virtual31(IHALCCA,IHAPCCA) in a future release.
Arguably, this VSM change should have been handled more like Vsm AllowUserKeyCsa was. Put out the option with default as 'no change' and eventually change the default. That more deliberate approach probably wouldn't have ruffled so many feathers...
-- Edward E Jaffe Phoenix Software International, Inc 5200 W Century Blvd, Suite 800 Los Angeles, CA 90045 310-338-0400 x318 edja...@phoenixsoftware.com http://www.phoenixsoftware.com/ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
