I'm not sure what a "server hall" specifically is. Is that referring to a single data-center or a whole set of data-centers (limited to a geographic area perhap

I'm not sure what a "server hall" specifically is. Is that referring to a single data-center or a whole set of data-centers (limited to a geographic area perhaps)? There is some interesting ideas here but with my limited domain experience I can't really make much sense of what's going on other than simply that we spend a lot of power on servers.