🚀 go-pugleaf

In article <Bxw8IL.G95@wang.com>, dbushong@wang.com (Dave Bushong) writes:
|> bdenckla@husc10.harvard.edu (Benjamin Denckla) writes:
|> 
|> >This morning I walked in and out of a number of shops with
|> >anti-shoplifting detectors similar to the security devices they have in
|> >libraries, i.e. two vertical inverted U-shaped bars on either side of the
|> >exit.  Then I found that the disk I had been carrying had some errors on
|> >it which were not there beforehand.  I assume that this is some kind of a
|> >detector for non-demagnetized, i.e. not bought merchandise.  I have heard
|> >that the demagnetizing pads on the check out-counter will erase credit
|> >cards so I try to stay away from them.  But can anyone tell me if my disk
|> >could have been damaged by the detectors?  Also, how far away should I
|> >keep magnetic media like disks, credit cards, and DAT's from the
|> >demagnetizing check out counter pad?  is a foot enough?  If anyone could
|> >help I would really appreciate this as this is a very scary situation,
|> >especially without information as to exactly how scared I should be.

|> Take your tour again, but this time with a pocket compass.  If it
|> doesn't violently react to the devices, the diskette is probably
|> safe.  By the way, the reaction I was talking about is one which,
|> if the compass could talk, it would say boinnnnggggggg!  Normally
|> the disk would have to be close to the magnet to affect it; or the
|> magnet would have to be strong enough where you would feel the pull
|> on your car keys in your pocket.

Unless, of course, the field were alternating (which they probably are
to detect a hysteresis change in the anti-theft material), when the compass
wouldn't do you a bit of good.

Hold a piece of steel or a small magnet up against the detector. On the
chance that the frequency is in the audio range, does it buzz? BTW,
most keys are brass, not steel, so they can be cut easily, and would
not make good detectors.

Being that magnetic fields decline as the cube of distance, I would
doubt that they were at fault in corrupting your disk unless you
rubbed up against a detector.

I saw a demag pad at my local Wal-Mart where the notice, yet
unremoved, said to keep credit cards more than 6" away.

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