Article on data rot on CD's

From: Doc Shipley <doc_at_mdrconsult.com>
Date: Wed Jul 28 14:22:37 2004

Pete Turnbull wrote:

> On Jul 28, 12:11, Joe R. wrote:
>
>
>> The problem is that AFIK no one has found ANY CD disks that are
>>reliable. Several people that have been interviewed in national
>>publications explictly pointed out that they bought top quality disks
>
> but
>
>>they were still unreliable. In fact, it didn't appear that there was
>
> much
>
>>difference between the cheap ones and the expensive ones.
>
>
> The other day I came across a table from a report showing the relative
> longevity of data on various media (DLT, CD-R, etc) at a variety of
> temperatures and humidities. I'll try and find it again and post some
> of the results. Some of you might be shocked. For example, a CD-R
> with an expected lifetime of something like 25 years (if I'm not
> misremembering the highest figure) under ideal conditions has a
> lifetime of only several *months* at higher temperatures (upper 20s C,
> that would be 80s F) and humidity. DLTs fared much much better.

   Hmm, I can easily check this. I have several hundred CD-Rs that are
obsoleted data backups in my garage. In south central Texas, that means
that they've spent 2-5 years in an uncontrolled climate, with 8 months a
year being over 90F in the garage and near constantly at 50-90%
humidity. If your info is correct, they should pretty much all be useless.

   Umm, no matter whether those CDs in my garage are still good, I vote
for magtape or acid-free paper for any long-term archival. There's no
comparison and no debate in our company. We use CDR for easy retrieval
in the short term, and tape for the real backups.


        Doc
Received on Wed Jul 28 2004 - 14:22:37 BST