I never knew about the 4096 or 8192 rules. I had always been taught that the ONLY time storage is cleared is when RSM assigns a real page to a virtual page that is not already backed by one in aux storage. Otherwise, the page contains whatever residual is in real or aux storage. I have never found this rule to fail.
Bottom line - it is the programmers responsibility initialize storage as needed. Changes in LE have bit us in C++ and PL/I code in this area in the past. Dennis Roach GHG Corporation Lockheed Marten Mission Services FDOC Contract 2100 Space Park Drive LM-15-4BH Houston, Texas 77058 Voice: (281) 336-5027 Cell: (713) 591-1059 Fax: (281) 336-5410 E-Mail: [email protected] All opinions expressed by me are mine and may not agree with my employer or any person, company, or thing, living or dead, on or near this or any other planet, moon, asteroid, or other spatial object, natural or manufactured, since the beginning of time. > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of Edward Jaffe > Sent: Thursday, February 05, 2009 11:06 AM > To: [email protected] > Subject: Re: Interesting APAR OA27291 an undocumented change to GETMAIN > Behavior in z/OS 1.10 > > Knutson, Sam wrote: > > http://www.ibm.com/support/docview.wss?uid=isg1OA27291 > > > > OA27291 is closed with some good information included in the APAR > text. > > > > Hopefully, people understand that this APAR doesn't "fix" the failing > programs. They still make erroneous assumptions about the initial > contents of the storage they acquire and are at risk of failing with > our > without UseZosV1R9Rules(Yes) coded. And, there are also other programs > that make erroneous assumptions about initial storage contents that > still seem to work most of the time, even with the new z/OS 1.10 VSM > behaviors. > > The ONLY way to find all of the programs that make erroneous > assumptions > about the initial contents of acquired storage is to test with the > IgvInitGetmain DIAG trap enabled. I repeat, it's the ONLY way! But, so > far IBM has not documented that facility. IMHO, APAR OA27291 provided > an > appropriate opportunity for them to do so. Unfortunately, that > opportunity was missed. :-( > > So, we're no further along with this than we were before. There are > hundreds, maybe even thousands, of programs making erroneous > assumptions > about the initial contents of acquired storage. These programs are > coded > improperly and are exposed to what might appear to be "spurious" or > "unrepeatable" abends. Those that are APF authorized might even > represent potential exposures to the system! And, yet there is no > DOCUMENTED or SUPPORTED way for IBM's customers to find and fix these > erroneous programs! >:o > > -- > Edward E Jaffe > Phoenix Software International, Inc ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
