More magic

Photo of the infamous magic switch, by Guy L. Steele Jr; licenced under CC BY-NC-SA 3.0. Source.

“You don’t touch an unknown switch on a computer without knowing what it does, because you might crash the computer. The switch was labeled in a most unhelpful way. It had two positions, and scrawled in pencil on the metal switch body were the words ‘magic’ and ‘more magic’. The switch was in the ‘more magic’ position.

“I called another hacker over to look at it. He had never seen the switch before either. Closer examination revealed that the switch had only one wire running to it! The other end of the wire did disappear into the maze of wires inside the computer, but it’s a basic fact of electricity that a switch can’t do anything unless there are two wires connected to it. This switch had a wire connected on one side and no wire on its other side.

“It was clear that this switch was someone’s idea of a silly joke. Convinced by our reasoning that the switch was inoperative, we flipped it. The computer instantly crashed.”

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