I remember a *very long* article by Lar about the CPU ccycles which can be used for actions within a game. I have only blurred memories of it in my head, and the text was probably lost.
The thing I found interesting in this text was, that meanwhile the Engine works, *several* things must be done meanwhile - and processors weren't fast enozugh for that some years ago (back to LMK).
I remember a part of it (or a short note) where was said that NPCs might actually sleep - go to bed - but all that must be done meanwhile other things are carried out by the Engine at the same time - animals, sounds, movements, the character him- or herself etc. .
Well, that's all I have in my memory of that.