[net.periphs] diskettes and x-rays

stevens@hsi.UUCP (02/08/84)

Anyone know what happens to diskettes (or mag-tapes) when passed
through an X-ray field ?  I am specifically wondering what happens
to them when passed through the metal detectors at airports or when
sent through the mail.  Are there any recommended precautions (such
as wrapping them in aluminum foil) ?  I notice that the diskettes
sent as products that we buy are never protected in any way, yet we
just had one zapped somewhere during shipment to a client.
Any suggestions or comments would be appreciated.

	Richard Stevens
	Health Systems International, New Haven, CT
	{ decvax | hao | seismo | sdcsvax } ! kpno ! hsi ! stevens
                                             ihnp4 ! hsi ! stevens

henry@utzoo.UUCP (Henry Spencer) (02/11/84)

Neither diskettes nor magtapes should be affected in any way by an
X-ray field.  But note that some airport metal detectors use magnetic
fields rather than X-rays.  This is definitely a consideration.  It
takes a pretty strong field to mangle magnetic media -- the stories
of magtapes being wiped by someone waving a toy magnet six feet from
them are myths -- but I don't know how strong the metal-detector
fields are.  Mmm, I suppose it is just possible, also, that an X-ray
machine would have magnetic fields running around in the vicinity.
There are electric currents inside, after all.

Wrapping them in aluminum foil doesn't seem likely to help.  The foil
is unlikely to stop either a determined X-ray machine or a determined
magnetic field, although it might cut down the intensity of stray
minor fields.  You might check with computer-supplies outfits; they
may well have shielded mailing boxes available.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry

rpw3@fortune.UUCP (02/11/84)

#R:hsi:-11100:fortune:8500002:000:458
fortune!rpw3    Feb 11 03:51:00 1984

Disks and tapes are almost totally immune to X-rays, per se,

	BUT...

there are big womping magnets in most X-ray machines!

Lead foil will not necessarily protect them. Steel cases
will help, aluminum may not (depends on whether the field
is D.C. or A.C., and if A.C., what frequency).

Rob Warnock

UUCP:	{sri-unix,amd70,hpda,harpo,ihnp4,allegra}!fortune!rpw3
DDD:	(415)595-8444
USPS:	Fortune Systems Corp, 101 Twin Dolphins Drive, Redwood City, CA 94065

johnl@haddock.UUCP (02/16/84)

#R:hsi:-11100:haddock:14800001:000:175
haddock!johnl    Feb 15 10:22:00 1984

I always hand my diskettes and tapes around the X-ray machines at
airports.  Otherwise they tend to end up erased, due to the magnets in
the machines.

John Levine, ima!johnl

roger@minn-ua.UUCP (02/17/84)

#R:hsi:-11100:minn-ua:12100001:000:900
minn-ua!roger    Feb 16 18:16:00 1984

>>  ***** minn-ua:net.periphs / orstcs!leed /  7:15 am  Feb 15, 1984
>>  As a quick note, I (for my company) often take 10MByte IMI Discs through
>>  airport customs/inspections.  At first, as a precaution, I used to ask them
>>  to hand inspect them.  Several time, I either did not have time for this,
>>  or the data on the disc was not critical, so I let them X-ray them.  One
>>  time, they couldn't tell what the L was insied, so they put it through again!
>>  And again and again!!! Three times, and all OK.
>>  
>>  But, sometime, sitting on the shelf, they go bad.
>>  
>>  For floppies, I was under the impression that static was your worst enemy?
>>  
>>  Any ideas??? ................................ orstcs!leed
>>  ----------


The problem you have is not the X-rays.  However, these beasties do have
large power supplies with very large transformers...  Just like a bulk
eraser.....

burton@fortune.UUCP (02/18/84)

#R:hsi:-11100:fortune:8500003:000:398
fortune!burton    Feb 17 12:24:00 1984


There are also unshielded electric motors on conveyors, mail and baggage
carts, etc., that handle your package.  Don't assume that Fed Ex - type
shipments are less vulnerable than the PO or UPS.

  Philip Burton      101 Twin Dolphin Drive
  Fortune Systems    Redwood City, CA  94065	   (415) 595-8444 x 526
			- - -
{allegra  decvax!decwrl!amd70 cbosgd harpo hpda ihnp4 sri-unix}!fortune!burton

jones@fortune.UUCP (02/29/84)

#R:hsi:-11100:fortune:8500004:000:844
fortune!jones    Feb 28 18:11:00 1984

I would recommend reading "Erasing Myths About Magnetic Media", by
Sidney B. Geller in the March, 1976, Datamation.  A summary doesn't
do justice to the article, but you can get the drift:

	The study has found that a magnetic field supplies the
	only kind of energy that can cause undetected data
	destruction without any accompanying physical distrorion
	or damage to the magnetic storage media.  It has been
	determined that normally there is no need to shield
	the stored data against x-rays, high voltage fields,
	nuclear radiation, high frequency fields, or light
	energy.  Most important, a spacing of only a few inches
	is sufficient to protect the recorded media against
	magnetic fields which are far more intense than are
	*ever* found in the *normal environment*...(emphasis
	added)

Dan Jones 	Fortune Systems		(408) 595-8444 X440