+1 Good way of suggesting justification for examples! Best Regards, Doug .
On Nov 12, 2018, at 19:55, Charles Mills <charl...@mcn.org> wrote: The profit comes from the potential for increased utility for the platform. It's hard to connect specific dots "if you show Peter Farley how to do DUCT TRAP somewhere someone will buy another z box" but it is not hard to imagine the ultimate connection. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Farley, Peter x23353 Sent: Monday, November 12, 2018 3:26 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Why are sophisticated system-level coding examples not available? [was: RE: Recommended method for accessing secondary access spaces] Then the not-yet-available examples ought to include all the error recovery infrastructure needed to assure the least system impact possible. Like the brief discussions I had with others on this list a few years back about code to set the DUCT TRAP fields so that TRAP and COMPARE-AND-TRAP instructions would work as architected. IIRC, the conversation went something like this: "Use PC-ss with a server address space that schedules an SRB in your address space to do that, but really, really don't do that because there's no system support for it." "When will there be system support for it?" "What's the business justification for expending those scarce resources?" Etc., etc. An example that showed how to safely set and unset the DUCT TRAP fields with all the attendant recovery infrastructure needed would be a lovely, practical example to have available. Not that I'm holding my breath waiting for it to appear. This set of knowledge isn't unknowable, only obscure and esoteric. IMHO, just hiding it doesn't serve the community or the employers who pay us. Why does there always have to be profit in spreading knowledge? But I have always known that I am a cockeyed optimist about the free availability of knowledge, so I already know the answer to that question even if I don't like it much. Peter -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Binyamin Dissen Sent: Monday, November 12, 2018 5:54 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Why are sophisticated system-level coding examples not available? [was: RE: Recommended method for accessing secondary access spaces] There are a large number of parts to make sure that things are done the right way, and that a fault will not bring the system to a crash. While one might be able to show examples of simple techniques, there is a lot of infrastructure required to handle problems. For example, what happens if you force an SSAR to a swapable address space that happens to be swapped in and the address space gets swapped out in the middle? If I recall correctly, the next page fault that I had in the target address space caused a MEMTERM of the home address space - which meant no ESTAEs got control. On Mon, 12 Nov 2018 22:11:15 +0000 "Farley, Peter x23353" <peter.far...@broadridge.com> wrote: :>And that was my whole point -- Where are the examples for programmers to see how to do it the right way? :> :>If SHARE has some presentations it is good to know that. Not the easiest place to search for stuff, but at least it is accessible. :> :>Yes, of course experience is the best teacher, but without even examples of how to do something it is awfully hard to figure it out on your own. :> :>". . . thoroughly knowledgeable about how the system works" is a whole 'nother can of worms. Back in the day places like universities in some cities offered "adult education" courses on MVS debugging and internals. I took a two-semester course like that back around the time that the MVS lock manager was first introduced, and it was wonderful, complex, interesting material to learn. :> :>Of course, all that is ancient history now. No university or education center offers anything like that anymore. Much more profitable to offer certification courses in Windows. :> :>Peter -- This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. 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