Multiple members files

Hello,

I have a data PF to which I want to add multiple members on a monthly base, effectively lessening the amount of data to copy to tape daily when running savchgobj. When one record is changed in one huge member, the whole member is saved. With separate „read only“ members, I assume only the changed members since the last full-save (manual save or Save 21) are saved. Is this correct?

I also assumed that new data is added to the alphabetically latest member, which is surprisingly not the case and renders my concept moot. I‘ve observed this on V4R5 without DB2 Multisystem installed.

My RPGLE application just opens the file and uses WRITE to create new records. No overrides, no SQL, or other specialities are used so far. New records end up in neither the first nor the last member, alphabetically as well as order of prior running addpfm. This doesn’t even change when the application is ended and restarted.

How does the system determine which member is used for new records, in a multi-member data-PF?

I wanted to read about files and members to clarify this question myself but I can‘t come up with the right place where this might be documented. I remember to have seen a contemporary „Files“ documentation in PDF format but I can‘t find it. So I guess my memory’s wrong and the name was something else. Pointers to the correct documentation are welcome!

Thanks!

:wq! PoC