It's not really new, but it's good to see the fragility of CDs getting some press. One of the ironies of the information age is that information is being lost at a rate unprecedented in human history. A lot of that is pointless BS like my undergrad history papers, but a depressing amount of it is potentially useful technical material and historical primary sources. It'd be nice to have a really good high density long term data archive format. Currently the best we can do with any certainty that it will still be accessible in a hundred years or more is high quality acid-free paper.

I have some problems with that article.

1) Pin-holes. I have a large quanitity of CD'd from the mid-80's. They have been stored in my attic/room at my parents where the temp can hit 110 in the summer when unoccupied. I used to inspect every new CD to the light from the wrap. Some were full of pin-holes from the start and played fine thereafter. The ECC apparently was sufficient to overcome these defects. My CD's were/are absoultely babied in every way.

My question is was these pin-holes in the substrate from the start or did they develop over time? I suspect the former. I have yet to have an older cd fail to play or show audiable defects.

2) This debate would be moot if they simply used Au instead of Al as the substrate material. I have some gold audiophile CD's. Gold will resist oxidation better than Al by orders of magnitude.

To Add:

I would like to see a scientific study done under controlled conditions on some of thse old collections. I would be happy to help out as long as nothing collectable was sacrificed for any 'destructive' testing.

This has been a major issue for cryonicists for years, and they've probably done as much as anyone to come up with long-term data storage techniques, given their high motivation to preserve their memories for an indefinite period of time.

According to the article CDs use aluminum as the reflective layer. If that is true than I wonder how long CDs will truly last. Anyone who is interested in grinding their own telescope mirror and having it coated will hear of stories of pinpricks (or experience it). This is due to microscopic contaminents on the surface of the glass. Depending on the overcoat (SiO or other more exotic materials) these pinpricks will be a source of rapid coating loss. Also, even with perfect coatings a telescope mirror will typically need to be recoated every 10-15 years. I wonder what that will mean to important and irretrivable data on CDs?

The aluminum in a CD is supposed to be sealed under a layer of lacquer, unlike a telescope mirror which is exposed to the air.

Still, gold cd's can take a bit of air without problem and it only takes an infintessimally small amount of Au to make one.

Mike, good point about using gold instead of aluminum. One minor point, tho: gold doesn't oxidize at all; the reaction of gold with oxygen is actually endothermic.

Link: http://matsci.uah.edu/courseware/mts501/reports/sschwitalla.html

I NOTICED THE PROBLEM WITH HOLES YEARS AGO ON SOME OLDER CD'S.I AM VERY ANAL ABOUT THE HANDLING OF CD'S I HAVE NEVER HEARD ANYONE BRING IT UP BEFORE,BUT MAYBE THESE HOLES ARE DUE TO LEAVING CD'S IN YOUR PLAYER AND LEAVING IT ON THE LASER IN YOUR CD PLAYER MAY BE CREATING THE HOLES,I HAVE ALSO NOTICED ON GOLD CD'S THAT THERE SEEMS TO BE A DETERIORATION OF THE GOLD STARTING FROM THE OUTSIDE OF THE DISC AND I HAVE AN UGLY KID JOE CD PRESSED IN THE UK THAT HAS GONE A BRONZE COLOR.