----- Original Message -----
From: "Pete Turnbull" <pete_at_dunnington.u-net.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk_at_classiccmp.org>
Sent: Wednesday, July 28, 2004 2:22 PM
Subject: Re: Article on data rot on CD's
> 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.
>
> I have some CDs that were bought about 8 years ago because they were
> supposedly good quality, and burned in a highly-rated burner. Out of
> the first batch of ten, 4 are now unreadable or give multiple errors.
>
> --
> Pete Peter Turnbull
> Network Manager
> University of York
>
Did the table show any data for what the actual failure mode of the CDs was?
Heat and humidity oxidizing the reflective coating will kill a cd very
quickly, but this assumes moisture can get through the protective coating. I
would also like to know what affect printable adhesive labels have on media
along with permanent markers used for labeling. Having a tested 25yr life on
media doesn't mean much if a felt tipped sharpie marker can ruin a cd in a
year or if the glue on a label can do the same. I have cds burned back in
the mid 90's from a HP4020i 2x burner that was $1200 at the time and only
had 1 failure that I know about and that was a backup OS cd I made that got
beat around and scratched for years.
Received on Wed Jul 28 2004 - 13:51:35 BST