PC Hardware in a Nutshell, 3rd Edition

Archival Stability of CD-R(W) Media

So how long can you expect that CD-R disc you just burned to last? There’s been a lot of nonsense written on that topic, but ultimately the answer is that no one knows. Projected lifetimes of 50, 100, and even 200 years are casually tossed around, as though they had any meaning.

Here’s the truth. The only way to know for sure if a disc will last 100 years is to burn one, wait 100 years, and try to read it. Obviously, that’s not a practical solution, so media manufacturers use various testing methods to estimate archival stability. All of those testing methods depend on accelerated aging, achieved by storing the disc at temperatures much higher than normal, often in conjunction with high humidity and high ultraviolet flux intended to simulate bright sunlight.

The rule of thumb in chemistry class says that the rate of most chemical reactions approximately doubles for each 10º C (18º F) increase in temperature. So, in theory, if one assumes that normal storage temperature for a CD-R disc is 20º C, a disc stored at 30º C ages twice as fast as normal, one stored at 40º C ages four times as fast, one stored at 50º C ages eight times as fast, and so on. The trouble is that that rule of thumb is just that—a rule of thumb—and the reaction rate slope is linear over only a limited range of temperatures.

Tip

The well-meaning chemist, being told that his Thanksgiving turkey should be cooked for 8 hours at 325º F, might reasonably conclude that he could decrease ...