Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!husc6!spdcc!lexicon!fc
From: fc@lexicon.com (Frank Cunningham)
Newsgroups: comp.sys.amiga
Subject: Re: Floppies vs. Magnetic Fields
Message-ID: <457@lexicon.com>
Date: 20 Jun 89 01:58:48 GMT
References: <7696@hoptoad.uucp>
Distribution: usa
Organization: Lexicon, Inc., Waltham, MA
Lines: 29
In-reply-to: slc@hoptoad.uucp's message of 18 Jun 89 15:51:38 GMT

In article <7696@hoptoad.uucp> slc@hoptoad.uucp (Steve Costa) writes:

> A month or so ago, a floppy that I had left sitting near one of the
> speakers had some problems. I was able to retrieve the files on it
> with DiskSalv. Is it likely that the field from the speaker did this,
> or would magnetic disruption have been so random as to make the data
> irretrievable?

The field to worry about from a loudspeaker is DC, the audio stuff
is noise by comparison (depending on what you listen to :-) ).
It is very likely the speakers did it, and the longer you left the
disk there, the less you would have retrieved.

> In general, it would seem that disks can tolerate mild magnetic
> fields, because, using a compass, I detected a field in the vicinity
> of my hard drive. I'm concerned about whether it's safe to leave a few
> floppies sitting around on top of the desk, near the printer or phone
> (but staying away from those speakers).

I don't think the hard-drive generates a dangerous field, for the
obvious reason. If it has a ferro-magnetic frame, the frame may be
magnetized by the earth's field, or by proximity to those speakers.
Don't leave stuff near the phone; the earpiece is a small dynamic
speaker, and the traditional bell ringer has some big magnets.

-- 
-Frank Cunningham	smart: fc@lexicon.com
			dumb: {husc6,linus,harvard,bbn}!spdcc!lexicon!fc
			phone: (617) 891-6790