ab0 - A Case of Cd Rot

ab0 - A Case of Cd Rot

Recently, I have experienced first hand cd-rom degradation. Some data cds (homemade), 10 years ago have corrupt files or the entire disc is unreadable by the computer's optical drive. Four or five of my discs have 10-20% files unreadable. One disc was very poor. It refused to be read in 4 different optical drives! This one is a brand-name disc. I'm not going to reveal the brand, but I am very happy with their equipment and their media. Disc rot, I believe happens to any/all brands of media. (It may happen more with generic, no-name discs, but I can't prove this.)

I had read about disc rot in a computer magazine 5+ (?) years ago. The way I understand it: The bits degrade with time and your data becomes corrupt. The computer will be unable to read it &/or give an error message of "cyclic redundancy check error" (or similar). Blank optical discs have a layer of pigment/dye/ink sandwiched in some type of plastic/polymer. The cd-writer laser(s) burn concaves into this dye which is later read as data (ie 1's and 0's). Over time, the dye degrades and so does you data.
One doesn't believe they are susceptible to Cd rot until it happens. It also happened with my commercial discs; but fortunately the corrupt data was only about 5% unreadable. (Perhaps commercial discs are manufactured differently or with different materials.)
Again the moral of the story is to make regular backups of your digital data.
A friend purchased some archival quality cd-r's designed for digital photographs, but they use it for their data. I'm assuming/hoping that these cd-r's would degrade slower than regular quality cd-r's. So far not enough time has passed for an opinion to be made.