Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!caen.engin.umich.edu!ruddles.sprl.umich.edu!jfm
From: jfm@ruddles.sprl.umich.edu.engin.umich.edu (John F. Mansfield)
Newsgroups: comp.sys.mac
Subject: Re: Hard drives and airport x-rays, bad??
Message-ID: <42378609.a590@mag.engin.umich.edu>
Date: 24 Mar 89 15:50:00 GMT
References: <CMM.0.88.606507161.carter@Portia.stanford.edu> <88494@felix.UUCP>
Sender: netnews@caen.engin.umich.edu
Reply-To: jfm@ruddles.sprl.umich.edu.UUCP (John F. Mansfield)
Organization: University of Michigan, Ann Arbor
Lines: 39

In article <88494@felix.UUCP> kehr@felix.UUCP (Shirley Kehr) writes:
>In article <CMM.0.88.606507161.carter@Portia.stanford.edu> carter@PORTIA.STANFORD.EDU ("Thomas J. Carter") writes:
><I'm planning on taking my hard drive for a ride on a plane.
><I don't plan on letting it go through the x-ray machine, but
><if they insist will it cause a problem?  Thanks in advance.
>

I would have thought that the only danger to a hard disk when passed
through an X-ray machine would be the close proximity of large motors
running the conveyor belt.  The X-radiation is not going to locally
generate a high enough magnetic field to change information on the
disk and the energy of the X-rays is not sufficient to cause
detrimental ionizing effects in the disk medium.  If there were
sufficient energy, then all of the users of the equipment and the
passengers would be getting doses of secondary radiation.  I have
passed hard disks through these machines without even thinking and
also floppies (they are after all not really different) and have not
had a problem.  High speed film IS a problem, but magnetic media, I
think not.

However, I dont want a boatload of flames because people have taken
their disks on a flight and then plugged them in at the end of their
trip to find a "this disk is damaged" or "this disk is unreadable"
dialog.  If that happens, it is more liekly that the disk has been
damaged by a physical shock than by X-rays.  Who knows how firmly
those heads are parked!!









John Mansfield
North Campus Electron Microbeam Analysis Laboratory 2455 Hayward, Ann Arbor,
Michigan 48109-2143. 313-936-3352
Internet: jfm@ruddles.sprl.umich.edu or john_mansfield.um.cc.umich.edu