> > For private storage (and also for common storage when > >common storage tracking is not turned on), VSM does not > >keep track of the size of the original request. Two > >separate GETMAINs which end up being adjacent are > >indistinguishable from one GETMAIN for the sum of the > >sizes. > > > I hope no programmer counts on that. But I suspect some do > and that was among the motivations for a compatibility option > when the storage management scheme changed radically a few > releases ago. > > --gil
You suspicion would be incorrect. As the designer and implementer or those changes, I would not call them radical. However, even a minor change in storage management has the potential to expose latent bugs, so I included an undocumented DIAGxx TRAP to revert to prior behavior as a bypass if needed. One of the ESP customers for the release hit such a bug in a key 0 program, which had severe consequences. They insisted that we should make the prior behavior the default, with a documented option to request new behavior. Although that was not what we wanted to do, we also did not the risk of an ESP customer giving a Share presentation about a bad migration experience due to IBM's intransigence, so we gave in and did as they requested. Jim Mulder z/OS Diagnosis, Design, Development, Test IBM Corp. Poughkeepsie NY ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
