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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: comp.misc
Subject: Re: Computer Tape Disposal
Message-ID: <2093@kitty.UUCP>
Date: Fri, 9-Oct-87 13:11:54 EDT
Article-I.D.: kitty.2093
Posted: Fri Oct  9 13:11:54 1987
Date-Received: Sun, 11-Oct-87 15:48:55 EDT
References: <276@cbnscs.UUCP> <2166@sfsup.UUCP>
Distribution: na
Organization: Recognition Research Corp., Clarence, NY
Lines: 40
Summary: Digital tape makes poor audio tape...

In article <2166@sfsup.UUCP>, jeffj@sfsup.UUCP (J.S.Jonas) writes:
> > Our Environmental department asked me if there is anything they need
> > to be concerned with regarding the disposal of a large number of
> > 700' and 2400' reels of magnetic tape.
> 
> If you are concerned about environmental impact, why not erase them
> and sell them to a surplus place (or at least donate them to a college).
> You can bulk erase them if you are concerned about security.
> Hasn't your Environmental department heard of recycling and the 
> surplus market?

	The truth of the matter is that computer tape designed for digital
recording makes a rather unsatisfactory audio tape.  Not that 1/2 inch
computer tape slit to audio size won't work, mind you, but the audio
quality will be poor.  The reason is that digital data recording is a
"saturation" type of recording whereby there are only 0's and 1's written
on the tape, with such binary elements being determined by signals of
proper magnetic polarity.  The magnetic oxide material on digital computer
tapes has a B-H magnetic response curve which is optimized for such
saturation recording.  Not the same type of B-H curve found on audio tape.
	Incidently, there is (or pretty much was) a 1/2 inch tape which
was not that bad when slit for audio use.  This is tape designed for
IRIG-spec analog instrumentation recorders which were extensively used in
military and aerospace applications during the 1950's through 1970's.
These recorders did record signals in analog form, and their tape had decent
B-H curves.  Such analog instrumentation recorders are still used today,
but they are rapidly being replaced by digital signal processing which
uses digital recorders.
	HUGE amounts of surplus analog instrumentation recorder tape
abounded during the 1960's and 1970's, but surplus sources for it have
significantly diminished.  Most of the audio tape that resulted from
sltting surplus tape used analog instrumentation tape.
	So my point is: an honest surplus dealer won't touch surplus
digital tape with a ten-foot pole, so there is effectively no market for
it.  Then again, there are dishonest surplus dealers...

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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