Oftentimes, how something fails can tell you a lot about how it was put together. This holds especially true in software. Legion are the security holes that were found because an innocuous error provided attackers with valuable information about the design.
Sometimes the information exposed is just interesting, but without practical value. In the World of Warcraft, I’ve run into more than a few of these types of errors. The most recent one left me in a sort of limbo state. As part of the new expansion, you take part in an epic battle that includes several ‘phased’ zones that are only enter-able via automation, during cut-scenes. One of these zones is the epic final battle between the Naga and the lord of the water realm they seek to take over. You get zoned into the area after a cut-scene boat-ride, and have a couple of minutes where you can control your character as you follow the automated NPCs around a major battle scene. Hundreds, if not thousands of NPC’s can be seen fighting around you. Eventually another cut-scene starts up, the Naga kill their man and swim into his realm. It looks really nifty. Somehow I ended up stuck in the zone after I should have phased out to the next segment, which is where things got interesting.
All around me, the battle is still raging in the distance, eventually circling around to the point in the timeline where the player gets phased in, but since I wasn’t standing in the magic spot it placed me in, I could control the camera and move around, even during parts that I thought were pre-rendered. What I think this means is that somewhere in the Blizzard datacenter, there are machines (Ok, probably virtual slices of machines) that do nothing but fight this one battle over and over, 24×7, 365 days a year, regardless of if anyone is in them. From a little experimenting with the hostile NPCs, it looks like a practically fully functional zone; the NPCs are unkillable, but suffer and give damage that looks to be properly tracked, up to the 0-point at which some special rule probably kicks in and doesn’t ‘kill’ the mob even when it would hit 0 HP. If I ever get stuck in the zone again (you can get out, FYI, by letting one of those mobs kill you. when you swim back to your body, you get zoned into the post-final-battle version of the zone), I’m going to try attacking one of the talking mobs during what would be a cut-scene for anyone else. Ideally, I’ll do this with a second box running through the zone in normal mode. If only I had an infinite supply of 80’s ready to run through the zone.
During the post-launch rush, I’m sure the zone gets lots of usage, but I have to wonder how well they planned out utilization vs processing-cost a year from now, when visitors could be days or weeks apart. Will they still be spending the same amount of processing power putting on a play to an empty house, or does the zone have enough smarts built in to suspend itself once empty? It makes me wonder how much ‘effort’ is wasted on zones that are practically dead now, like the two racial starting zones from Burning Crusade….