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Originally Posted by wodin
Quote:
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Originally Posted by DMcCunney
In actual fact, I suspect the disk would still work. It tends to take a more powerful magnetic field to scramble one than the sort produced by a refrigerator magnet, especially since the magnet is over the center of the diskette where there won't be any data stored to scramble.
Still a bad idea, but not necessarily deadly...
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Unless of course he used the magnet out of a dead hard drive.  |
Not even then.
The magnets are the read/write heads on the drive. (How many there are will depend on the drive and the number of disk platters.) When the drive is powered up, they are energized and a magnetic field is created. But distance counts: the heads float on a cushion of air a few microns above the spinning disk platter. If the head actually
touches the spinning platter surface, you get a head crash and an unusable drive. It's a reason why drives are assembled in clean rooms and hermetically sealed. The tolerances are so fine a colloidal particle of cigarette smoke might cause a crash. But there is no magnetic field when the drive is powered off, and that head has to be really
close to the platter when it's on to change the pattern of magnetic bits on the surface.
(Back when I worked for the bank, I heard a story from a CDC Field Engineer who provided service on the big removable platter drives used in mainframes and minis.
An operator got a request to mount a disk pack on a drive. He got the appropriate pack from the shelf, powered down a drive, removed the existing pack and put in the new one, then spun up the drive and tried to read the pack. It didn't work.
He powered down the drive, removed that pack, and tried it on another drive. Still didn't work. He called his boss, and between them, they tried it in five other drives.
The result was head crashes on all seven drives, and $33,000 in repair bills to replace the damaged heads.
Given what I knew of the bank, I suspected the operator and his boss still had jobs when the dust settled...
)
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Dennis