IBM Mainframe Discussion List <[email protected]> wrote on 12/09/2008 10:30:32 AM:
> Jim Mulder wrote: > The lesson here is that, if a change has been observed to cause > unexpected "surprise" wrong behaviors in some IBM components during > testing, then similar problems should be expected after deployment. A > documented fall-back "Chicken Switch" should be provided. I think the > proposed, documented DIAG TRAP is a great way to go. None of the wrong behaviors in some IBM components were unexpected or surprising. They were the kinds of things I anticipated. And I expected some similar problems after deployment. That is why there was an undocumented fall-back "Chicken Switch" provided, designed so that a documented TRAPS could be added for 2 lines of code if subsequent experience dictated. So far, the number of problems that I have heard about has been less that I anticipated. However, some of the ESP customers have requested a documented switch and so the APAR will be providing that. I discussed the issue of documenting vs. not documenting the switch with a number of people during development, and there was no strong consensus at that time (although there are some pretty strong opinions now),so I decided to not document initially, with the option to reevaluate after further experience. > And, if IBM, ISV, and customer in-house developers would use > IgvInitGetmain and IgvInitFreemain on their test/development systems--as > we do--nobody would have experienced this issue to begin with. Of > course, it's hard to fault someone for not using an undocumented > feature. These TRAPs have been around since OS/390 V2R6. They work. > Perhaps it's time they were documented, too! I have considered that many times over the years since OS/390 V2R6, and considered it again for z/OS V1R10. That would have been a convenient time, since the TRAPS keyword was being added to the documentation for the first time (with a small subset of the trap names being documented). And then just a few months ago, an ISV using IgvInitGetmain encountered a problem with the CICS's IPCS VERBEXIT. CICS development has estimated that "a complete fix for this in all the dump formatters is probably well over a thousand lines of code given that the DFHPD640 load module comprises circa 200 modules." So the plan is to not fix this in the service stream, and instead try to prioritize it into the development plan. Now, if IgvInitGetmain was formally documented, would CICS had as much flexibilty in deciding how do deal with this? I don't know, but that is an example of the kind of thing that has to be considered when deciding when to document some of the TRAPS. Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY ---------------------------------------------------------------------- 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
