24 Jun
2004
24 Jun
'04
12:39 p.m.
Over dinner with a friend the other night the conversation landed on
the subject of reading old magnetic tapes. I learned something which
sounds different from what I've heard in the past, so I figured I
would pass this along.
This was for audio tapes, but it makes sense that it would apply to
digital data tapes too.
The comment was that old tapes absorb moisture into the oxide, which
makes things sticky and causes the oxide to stick to the wrong spots
and flake off the tape. The solution is to set the tape in a fruit
dryer at modest heat (150 F or so) for a while.
Presumably a desiccator, vacuum or otherwise, could serve too.
Apparently this worked well for 20 year old audio tapes.
paul
24 Jun
24 Jun
3:20 p.m.
The comment was that old tapes absorb moisture into
the oxide, which
makes things sticky and causes the oxide to stick to the wrong spots
and flake off the tape. The solution is to set the tape in a fruit
dryer at modest heat (150 F or so) for a while.
Libraries, archives, and other preservation organizations have been
dealing with this for some time. It's called "sticky shed syndrome",
and occurs when the binder layer absorbs water molecules. In some
cases, the tape will cause the tape to stick to the heads, pinch
rollers, etc, and even squeal loudly as it passes through the machine.
The problem doesn't just occur in tapes from the 80s.
Recipes vary quite a bit. Our library purchased a fancy small
convection oven for doing the work on a large collection of old audio
materials, but others use their kitchen appliances. Close temperature
control is important. One should be careful not to let things get
too hot, keeping in mind the hysteresis of the typical home oven.
Sticky shed often returns after a month or two; if you have tapes with
this problem it's best to copy the contents to other media promptly
after baking.
De
7:50 p.m.
From: "Paul Koning" <pkoning(a)equallogic.com>
The comment was that old tapes absorb moisture into
the oxide, which
makes things sticky and causes the oxide to stick to the wrong spots
and flake off the tape. The solution is to set the tape in a fruit
dryer at modest heat (150 F or so) for a while.
"Baking" tapes is a well-known "remedy" in the industry. Afterwards,
the
tapes are not to be used anymore.
Nico
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25 Jun
25 Jun
4:27 p.m.
On Thu, 2004-06-24 at 21:50, Nico de Jong wrote:
"Baking" tapes is a well-known
"remedy" in the industry. Afterwards, the
tapes are not to be used anymore.
I'd like to amplify what Nico points out -- old media like this should
be treated as a one-time shot, prepare it, extract the data, then
(virtually if not actually) abandon in place.
Baking etc won't repair the tape, just give you a temporary window in
which to recover data from a rapidly-failing medium. Act fast, get the
data off and hang the tape on the wall as art.
7404
days inactive
7405
days old
3 comments
4 participants
participants (4)
-
drb＠msu.edu -
nico＠farumdata.dk -
pkoning＠equallogic.com -
tomj＠wps.com