You know all those CD’s and DVD’s you have? They could be slowly (or quickly) deteriorating. Especially if they have been poorly taken care of. Nothing lasts forever.
Ah CD’s and DVD’s, touted to be able to save our data for years to come. Except when they don’t. I recently rediscovered this threat to our digital lives as the bonus features stopped working on one of our DVD’s. When I looked at the disk, I saw the signs. Holes eroded through the edge leaving a portion completely dead (and transparent).
So what is Disc Rot? Disc rot/DVD Rot/CD Rot is/are the term(s) used to describe the physical rotting of the media leaving it unusable via complete data destruction. How so? Well a CD or DVD is made of multiple layers. With a top and bottom coating of plastic sandwiching the data layer (shiny layer) a label is then usually printed on top. Disc rot occurs when the material in the disc oxidizes(think how cars rust or copper turns green) This chemical transformation of the data storage medium corrupts and destroys the bits of information that store you movie, game, photos, documents etc. The destruction is 100% and is irrecoverable.
‘Wait, didn’t you just say that it’s sealed in plastic?’ you say. Then this shouldn’t be a problem right? Well, yes actually. So long as the disc isn’t scratched to expose the layer to air and allowing oxidation, the disk should be fine for the decades to hundreds of years that they are touted to last. However, this makes an assumption that the discs were all perfectly manufactured.
After finding one of my discs suffering from this I did some research online and found entire forums dedicated to finding runs of specific movies or publishers who are known to have had poorly constructed DVDs in their history when the technology was new. Essentially most of the discs reported by the forum members all exhibited the same issue. This was because the plastic sandwich started to separate or had other defects allowing the chemical breakdown of the precious data layer. These even included discs that had remained sealed, safe in a case and went unused!
Can it be prevented?
Other than take good care of your discs? No. It’s entirely up to the media itself (manufacturing) to last if you take good care of it. So plan accordingly.
This is just another area where technology attempted to allow us to hold onto things forever, and time again has shown us that this is not true. Nothing lasts forever, so enjoy what you have now and always, always keep your data backed up in multiples. Of course, with media you haven’t authored/created yourself(think movies/music/games), you will want to consult your local laws before making copies to ensure doing so is legal.
For additional information on Disc Rot you can check out the following articles on Wikipedia and MakeUseOf.