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