How long do CDs and DVDs last?

So how long do CDs and DVDs last? Sometimes things on the Internet take on a life of their own. That's why I occasionally engage in what is often called "egosurfing" -- that's searching for your own name in Google or other search engines. It can be done by authors to check on illegal use of their material and I've known several fellow writers who have found their words in places where they did not expect them. In my case I have a lot of content that is offered free for non-commercial use provided it includes my byline and a reference to either a specific book of mine or to a more general description of the kind of books I write, (Googling my name will show that a good number of computer user groups have used my articles with correct attribution). It is seven years since I wrote an article for the Melbourne PC User GTroup, the largest computer user group in the world, asking "How long will a CD-R last?" It received widespread republication worldwide and many crosslinks to the original article at http://www.melbpc.org.au/pcupdate/2106/2106article14.htm Then it started to take on a life of its own, and as the article got older I'd still get fairly frequent emails from all over the world with questions on whether the conclusions in the article were still current. I had to reply that while I could not vouch for most, one of those conclusions, that most problems with CDs and therefore most likely with DVDs too occurred while they were being written, rather than in their storage, did seem to be still accurate. Only last month I was given a CD by a relative which was supposed to contain a mass of family photos. It contained nothing. The person who gave it to me was reluctant to go back to the person who had produced the CD but eventually, after getting several people to try it, got another copy -- which again did not work. I suspect that many backup CDs will have the same problem. They will fail when needed a few weeks or months later but not because of any gradual failure in the material. They were not created properly in the first place. However, returning to my theme, my latest find on Google was that the article is referenced as a source in a new book, Robots in Space: Technology, Evolution, and Interplanetary Travel by  Roger D. Launius and Howard E. McCurdy, published this year by Johns Hopkins University Press. You'll find it on Amazon. The real question is, as my article was really just a layman's summary of published research and manufacturers' claims around eight or more years ago, why has no one produced similar advice brought up to date?

Comments

[Dr D Blumbreg]

Hello,
I just started a huge re-backup of my cd's been recorded
in the last 10 years. In awareness talking of a micro-cosmos - of
approx. every burned 100 cd's every fourth
has several unreadable defects and almost every 9th is
entirely gone and for some reason not related to the age.
colour does not make a difference, except all gold layers
(mots 1st generation cd's) seem to be more fault-resilient.

so I went on the web to find out how long these medias
should actually last and found that no company is
commiting itself to a forecast. and there are no real sites
containing serious information thus contemplating this
issue in depth. Your article from 2001 I found by random
is one the most accurate and in my case still a prevailing fact.

I consider the whole predictions up to 50-100 years as a
soother for a second gain. therefore I installed my old scsi
tape streamer, restored for a try 10 year old tapes
without any problems. I still have more faith in tapes
anyway, not only my old video tapes from the late 70ties
are still alive.

with kindest regards

Dr Detlef Blumberg
from Dudley/West Midlands , UK

[Greg]

Hello.

I read somwhere that you shouldn't store CD's horizontally for a long time. Is this true? Should I store my CD's vertically??

[gordonwoolf]

The consensus seems to be that storing vertically may be better, but only because there is less likely to be weight on the surface of the disk. However if they are in a disk case, where the contact is only to the small area around the central hole, this would not be a problem. For this reason, if you are storing them in paper sleeves then horizontal may not be good, and storing them bare would be worse.

I came across a very strange suggestion some time ago that as even windows gradually become thicker at the bottom because glass is a liquid that slowly oozes downwards, that even the plastic substrata of a disk may eventually ooze out of shape if stored vertically. I doubt if that is to be taken seriously as there are many other factors which would come into play first, the most dangerous of which are heat and humidity, maybe decades before they'd ooze out of shape.

So, heat, humidity and pressure seem to be the dangers, and they can be reduced regardless of whether you store horizontally or vertically.

[Greg]

Cheers for the info. I was worrried my cd's would be messed up after a while lol.