Such rooms were not FULL in the sense of not being able to get any more stuff in them, like a storage locker might be, because you had to be able to get to the various pieces. There was room to walk between the various items, and open panels for servicing, although sometimes not very much. But they were full in the sense that almost all available, useable space was taken up by the machinery. You could not put in any more without blocking access to stuff you needed.