The Critical 'I'

Read. React. Repeat.

Saturday, May 08, 2004

CD ROT
I noted long ago that the compact discs relied upon to store digital data are anything but long-term solutions. Now, even permanent music and movie CDs and DVDs are showing themselves to be highly susceptible to deterioration over a relatively short period of time.

Yet another illustration of the nature of nomadic data. You can't trust any physical medium, no matter how new and shiny it is. Although considering that paper and other old formats managed to last centuries, it's more than a little disheartening that the solutions from our supposedly advanced era are such duds.

Back to the news article... There's a lot of great technical information about the composition of CDs and DVDs, and why they're failing:
The aluminum layer that reflects the light of the player's laser is separated from the CD label by a thin layer of lacquer. If the manufacturer applied the lacquer improperly, air can penetrate to oxidize the aluminum, eating it up much like iron rusts in air...

Part of the problem is that most people believe that it's the clear underside of the CD that is fragile, when in fact it's the side with the label. Scratches on the underside have to be fairly deep to cause skipping, while scratches on the top can easily penetrate to the aluminum layer. Even the pressure of a pen on the label side can dent the aluminum, rendering the CD unreadable...

DVDs are a bit tougher than CDs in the sense that the data layer (or layers -- some discs have two) is sandwiched in the middle of the disc between two layers of plastic. But this structure causes problems of its own, especially in early DVDs. The glue that holds the layers together can lose its grip, making the disc unreadable at least in parts.
So basically, don't come into any sort of contact with the discs, at all, or else they'll start to dissolve. It's ridiculous. No wonder more and more people are ripping the media off these discs onto hard drives and then storing the original discs for safekeeping.

Here's the part that gets me especially mad:
Users that bend a DVD to remove it from a hard-gripping case are practically begging for this problem, because flexing the disc puts strain on the glue.
We're begging for it?? How the hell else are we supposed to extract the discs out of their cases otherwise? The manufacturers need to come up with better case fixtures for DVDs. I cringe every time I have to pull a disc out of these ridiculous things; "press down on center button" my ass. In fact, I think the DVD cases in general could use massive improvement. They're as bulky and wasteful as the old cardboard "tallboxes" that CDs used to be packaged in back in the 80s; those were eventually abolished thanks to pressure to the record companies. I think the same sort of pressure needs to be applied on DVDs.