[comp.sys.mac.hardware] Magnetic storage and X-ray machines.

wilkins@jarthur.Claremont.EDU (Mark Wilkins) (11/18/89)

In article <5850@lindy.Stanford.EDU> romeo@lindy.UUCP (Patrick Goebel) writes:
>
>(2)  Is it true IN THEORY that magnetic storage media are safe from
>these devices?

   A while ago I made the comment in this newsgroup that I thought that disk
drives were safe from soft X-rays because of their RF shielding, which is
required by the FCC.  And yes, I do know that X-rays and radio are not the
same... :-)
   However, you ask about floppies and tapes.  Magnetic media which are
passed through an x-ray machine are definitely at risk.  The reason I made
the comment about hard disks is that they are shielded quite well.
   Unshielded magnetic media definitely should not be passed through the
x-ray detector.  Although I haven't heard of any problems, the chances for
difficulty are at least 100 times greater than with fixed disks.

 -- Mark Wilkins
    wilkins@jarthur.claremont.edu

eacj@batcomputer.tn.cornell.edu (Julian Vrieslander) (11/19/89)

In article <3103@jarthur.Claremont.EDU> wilkins@jarthur.UUCP (Mark Wilkins) writes:
>   However, you ask about floppies and tapes.  Magnetic media which are
>passed through an x-ray machine are definitely at risk.  The reason I made
>the comment about hard disks is that they are shielded quite well.
>   Unshielded magnetic media definitely should not be passed through the
>x-ray detector.  Although I haven't heard of any problems, the chances for
>difficulty are at least 100 times greater than with fixed disks.

I agree with this advice.  I recall seeing a discussion of this subject
elsewhere, where a claim was made that it is not the x-rays themselves that
can damage magnetic media.  But some x-ray machines produce stray magnetic
fields that may be strong enough to do damage.  
-- 
Julian Vrieslander 
Neurobiology & Behavior, W250 Mudd Hall, Cornell University, Ithaca NY 14853    
UUCP: {cmcl2,decvax,rochester,uw-beaver}!cornell!batcomputer!eacj
INTERNET: eacj@tcgould.tn.cornell.edu     BITNET: eacj@CRNLTHRY

pepke@loligo (Eric Pepke) (11/20/89)

It's not the X-rays themselves that you need to worry about; it's the 
thumping great motors that drive the conveyor belt.

Eric Pepke                                     INTERNET: pepke@gw.scri.fsu.edu
Supercomputer Computations Research Institute  MFENET:   pepke@fsu
Florida State University                       SPAN:     scri::pepke
Tallahassee, FL 32306-4052                     BITNET:   pepke@fsu

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