Magic Switch Story
Magic Switch Story
You don't touch an unknown switch on a computer withoutknowing what it does, because you might crash the computer.The switch was labelled in a most unhelpful way. It had twopositions, and scrawled in pencil on the metal switch bodywere the words "magic" and "more magic". The switch was inthe "more magic" position.
I called another hacker over to look at it. He had never seenthe switch before either. Closer examination revealed thatthe switch had only one wire running to it! The other end ofthe wire did disappear into the maze of wires inside thecomputer, but it's a basic fact of electricity that a switchcan't do anything unless there are two wires connected to it.This switch had a wire connected on one side and no wire onits other side.
It was clear that this switch was someone's idea of a sillyjoke. Convinced by our reasoning that the switch wasinoperative, we flipped it. The computer instantly crashed.
Imagine our utter astonishment. We wrote it off ascoincidence, but nevertheless restored the switch to the "moremagic" position before reviving the computer.
A year later, I told this story to yet another hacker, David Moon as I recall. He clearly doubted my sanity, or suspectedme of a supernatural belief in the power of this switch, orperhaps thought I was fooling him with a bogus saga. To proveit to him, I showed him the very switch, still glued to thecabinet frame with only one wire connected to it, still in the"more magic" position. We scrutinized the switch and its loneconnection, and found that the other end of the wire, thoughconnected to the computer wiring, was connected to a groundpin. That clearly made the switch doubly useless: not onlywas it electrically nonoperative, but it was connected to aplace that couldn't affect anything anyway. So we flipped theswitch.
The computer promptly crashed.
This time we ran for Richard Greenblatt, a long-time MIThacker, who was close at hand. He had never noticed theswitch before, either. He inspected it, concluded it wasuseless, got some diagonal cutters and diked it out. Wethen revived the computer and it has run fine ever since.
We still don't know how the switch crashed the machine. Thereis a theory that some circuit near the ground pin wasmarginal, and flipping the switch changed the electricalcapacitance enough to upset the circuit asmillionth-of-a-second pulses went through it. But we'll neverknow for sure; all we can really say is that the switch wasmagic.
I still have that switch in my basement. Maybe I'm silly, butI usually keep it set on "more magic".
GLS