Activation Groups, yesterday and now?

Hello folks,

as far as I understand, activation groups are kind of a shared memory area for multiple programs to be run in. Correct?

Years ago, I stumbled across a file pointer not jumping back to *LOVAL, because the default compile option of ILE RPG (at least with V4) was DFTACTGRP(*YES). Obviously, certain attributes of programs will be retained between runs. That's when I started to always use DFTACTGRP(*NO) ACTGRP(*NEW) when compiling.

I'm very used to the concept in "common" operating systems that if you end a program, used resources are claimed back by the OS and said compiler options force this behaviour.

Now I wonder, what are activation groups actually good for? Or, have been good for 30 years ago? What's the benefit in putting a bunch of programs into the same (named, or default) activation group today? Is it "just" for omitting the overhead for repeated program activation between runs? Even on my ancient 150, programs are starting blazingly fast.

I have a dim idea what "activation" does. AFAIK it's tied to the SLS peculiarities. An unactivated program is just an ordinary object at some address in the vast memory space. An activated program has associated certain resources, so it is actually able to run and do stuff. (At least that's what I understand from reading https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_72/ilec/ileacpa.htm) Correct?

I've been reading through some resources at the internet but there was none which gave clear answers to my above questionary. Most of them also are a bit dated.

Thanks!

:wq! PoC

PGP-Key: DDD3 4ABF 6413 38DE - https://www.pocnet.net/poc-key.asc