On 26 July 2013 00:44, Bernd Oppolzer <[email protected]> wrote:
> Of course you can teach dump reading and debugging; > Steve Comstock does it, I do it, and others do it as well. > At least it gets them beyond the point where they claim it got a protection exception on a LR instruction ;-) I think both MVS and VM use similar linkage conventions (unlike zLinux) so you can walk back the subroutine nesting and understand where you are in there (don't think anyone destroys save area on exit, so you can be tricked in walking it the wrong direction). But experience makes a big difference. That's why you spot odd patterns, recognize a page table in memory, have your own macros to find stuff, or even recognize the program check old PSW from an ancient release. We used to have a set of dumps around for new sysprogs to practice. When you get into this, it's nice to start with problems that can be resolved so you don't get away with "there is nothing useful in the dump" claims. But it may still not be anyone's job to sit down with a dump for a few hours and come up with the exact scenario to reproduce and fix the problem. Rob
