Data center is a specialbuilding orroom built to house a lot of runningcomputerservers. It provides fastnetwork connections between servers to communicate and process a lot ofdata, and some for talking to the outside world. There arecooling machines to deal with heat from each server and controlmoisture to stop computers from breaking too fast. There is often an emergencyelectricity supply from anUPS (ordiesel generator) to make sure that computers still work even when mains power goes out. And there are usually some kind offire extinguishers there to keep fire from computers if there happen to be any.
Data centers are normally built and used bycompanies that need a lot of always-on computer, companies that are hired to docomputing for someone else (for example, ones that doweb hosting), and most moderntelecommunication companies.
