Jim,
I definitely would not use update files and AUX files in order to manage DMKSYS for the purposes of a time zone change.? I realize that VM/CE may be more or less set up for that, but it doesn't mean you have to use it.? My stance might irritate some but it is just overkill for the purpose.
Keep in mind that the three user modifiable CP modules DMKSYS, DMKRIO, and DMKSNT are meant to be customized for the specific installation.? There is no need to preserve the "untouched original IBM code" for these three modules.? It is expected that a system programmer will alter these three files.
If you like, you can save a copy of the original IBM versions on another minidisk, but in all seriousness I would directly edit any of those three as changes are needed, and simply reassemble them as usual using VMFASM DMKxxx DMKLCL.?? I wouldn't use any update or AUX files for these three.? The only possible case I could see would be that update files do provide a sort of history of changes; if that is important to you then use them.? In lieu of that, you could also keep track of important changes with comments in these three modules as well, as you see fit.
I'm practicing what I am preaching here still to this day, just as I did on my real VM system on real hardware for years, back in the day.
Regards,
Bob
