A Story About' Magic'
A Story About' Magic'
A Story About’ Magic’ Some years back, I (GLS) was snooping lived through the medicine cabinet which housed the MIT AI Lab’s PDP 10, and also seen a bit of switch glued on the frame of a single box. It was clearly a homebrew job, incorporated by among the lab’s hardware hackers (no one knows who).
You do not touch an unfamiliar switch on a laptop without understanding just what it does, since you may crash the pc. The switch was tagged in a most unhelpful way. It’d 2 positions, and scrawled in pencil on the metal switch body had been the words’ magic’ and’ more magic’. The switch was in the’ more magic’ position.
I known as another hacker over to take a look at it. He’d never noticed the switch before also. Closer examination revealed the switch had just one cable running to it! The opposite end of the cable did disappear into the maze of cables within the computer, though it is a fundamental truth of power that a switch cannot do something unless you will find 2 cables associated with it. This particular switch experienced a wire attached on one side and zero cable on the many other side of its.
It was obvious this switch was someone’s notion of a silly joke. Convinced by the reason of ours which the switch was inoperative, we flipped it. The pc immediately crashed.
Imagine the utter astonishment of ours. We published it all as coincidence, but nonetheless restored the switch to the’ more magic’ position prior to reviving the pc.
A year later on, I told the story to one more hacker, David Moon as I remember. He distinctly doubted the sanity of mine, and suspected me of a supernatural belief in the potential of the switch, or possibly thought I was fooling him with a phony saga. In order to prove it to him, I showed him the really switch, still glued on the box frame with just one cable associated with it, still in the’ more magic’ position. We scrutinized the switch and the lone relationship of its, and also discovered that the opposite end of the wire, although attached to the pc wiring, was linked to a ground pin. Which obviously made the switch doubly useless: not merely was it electrically nonoperative, though it was linked to a put that could not affect anything anyway. So we flipped the switch.
The pc promptly crashed.
This time we ran for Richard Greenblatt, a long time MIT hacker, who was close at hand. He’d never seen the switch ahead of, also. He inspected it, realized it was ineffective, got several diagonal cutters and diked it out. We subsequently revived the pc and it’s run good ever since.
We nonetheless do not understand how the switch crashed the device. There’s an idea that several circuit close to the ground pin was marginal, and flipping the switch altered the power capacitance adequate to trouble the circuit as millionth-of-a-second pulses went through it. Though we will certainly not know for sure; almost all we are able to truly say would be that the switch was secret.
I still need that switch in the basement of mine. Perhaps I am ridiculous, though I typically keep it set on’ more magic’.
1994: Another explanation of this particular story has since been offered. Remember that the switch body was metal. Assume the non connected aspect of the switch was linked to the switch body (usually the body is attached to its own earth lug, but you will find exceptions). The human body is attached to the pc case, presumably, which is, grounded. The circuit ground inside the device is not always at exactly the same opportunity as the situation when ground, therefore flipping the switch connected the circuit ground on the case ground, creating a voltage drop/jump which will reset the device. This was most likely found by somebody that discovered the tough way that we had a possible distinction between the 2, and who next wired in the switch as being a ruse.