If a tree falls in the grey forest...

[Morgenes]

Actually, from my 20 years of experience with the Diku engine, I have yet to see one that doesn't hold all the areas, rooms, items and npcs in memory and iterates over all of them all of the time. I know that other MUD engines do as you suggest X-D, but without experience I can't say specifically which do. But Diku is a memory abuser, it loads everything at boot time and it stays there till the game is shut down.

[Twilight]

At some point during this thread, I was sort of like...seriously folks?

l w
watch w

That will definitively answer your question about whether rooms/mobs/objects stay in memory when a PC is not in the same room as them.  Watch scripts (where you can see into another room like the Arena in Nak) will definitively answer the question of whether or not scripts are being ran in rooms that PCs are in.  It also (if you have encountered the right rooms) will answer the "But maybe its coded to only load NPCs/Objs/Rooms into memory within three rooms of a PC" potential rebuttal.

[lordcooper]

But maybe watching a room causes it to 'need to exist', and thus it does.

[X-D]

Besides, watch does not see emotes and many other types of echos outside the same room...wonder if that could be fixed.

I'll bow to morg on this point at least for arm, as my diku experiance is as old as his is long.

[Fredd]

But maybe watching a room causes it to 'need to exist', and thus it does.

Exactly this  goes to Heisenberg uncertainty principle. Which states that the very act of observing an action, changes the outcome.

And further expanded upon this is Schrödinger's cat.

For those that don't know:

A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter, there is a tiny bit of radioactive substance, so small that perhaps in the course of the hour, one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges, and through a relay releases a hammer that shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. Therefore, until the resault is seen the cat is considered both living, and dead.

Therefore, undead cat.

In other words, You never know for certain unless you observe somethig. But if you observe it, you have changed it.

[lordcooper]

It also proves once and for all that Schrödinger was more of a dog person.

[brytta.leofa]

watch w

That will definitively answer your question about whether rooms/mobs/objects stay in memory when a PC is not in the same room as them.

On Diku/circle, and, I assume, on Arm, rooms are grouped into zones of, I think, less than 1000 rooms each?  If things did go inactive (which, per Morg, they don't), I would expect it to be per zone, not strictly per room.  The test would be something like:
- Find an NPC that chases but doesn't wander. (Are there any? Don't answer.)
- Lead it to the edge of a zone, then escape.
- Walk across the zone boundary and circle around so you can see your critter from afar.
- Back away from him, past "very far."
- Wait 30-60 minutes.
- Practice your spells so it's IC and stuff, I mean we're not twinks here.
- Go back and verify that the NPC is gone--gone past where it could have wandered.

But Morgenes says it doesn't work this way and hasn't worked this way in living memory so...no.

[Twilight]

Except that isn't the purpose of zones in Diku.  You can actually infer a lot about how Diku works just by observation.  I spent six years as an Overlord on a different Gamma Diku based MUD, so I know all that stuff stays in memory anyways, all the scripts keep going off, etc.  So perhaps my perspective is warped, but it seems to me that is one of the easy things to guess at correctly.

[BleakOne]

Lots of the game world would be needed to remain in existance anyway, so NPCs and critters can wander around.