Game logic

How the fuck do they code games so that everything moves smoothly and at a consistent rate regardless of the speed of the machine you run it on, and still have tons of shit interacting with each other somehow?
Maybe I need to find a good open-source candidate to have a look at.

Also, I wish I knew the correct terms to describe what I'm talking about.

>>13,33
Does this not succumb to rounding error at some point or other? Or do periodic server corrections account for this? Seems like this would only be good for FPS games, where RTS games for instance have way more entities that can't constantly be corrected so a fixed tickrate would be better.