@MathematicalOrchid To add to the other comments, keep in mind that the interconnection wiring, power cables, an in some cases water cooling were all beneath the false floor that you see, and when engineering work was in progress you still had to be able to move around the room when half the floor panels between the boxes had been removed. You didn't shut down the whole mainframe system for a day just because somebody had to remove some floor panels to repair something, or install new kit! – alephzero Jan 25 '19 at 22:40