here's one useful article) and wonder if I should worry.
It turns out the answer is yes. Yesterday I was looking for some photos from mid-2001, and discovered that about 80% of the files on the CD wouldn't read in my DVD reader -- "I/O error". Fortunately, my DVD writer could read about 80% of the files (maybe it's a little slower, or something? Or just newer?)
A subsequent flurry of copying my older CD-Rs found read errors on many discs two and three years old. The two worst both had sticky labels on them. In one case (some images I didn't want to lose), I burned two copies of the same disc, printed a pretty label on one and marked the other with a Sharpie. The Sharpie disc read fine; the labelled disc had massive errors and was all but unreadable. The advice saying not to print labels for CDs meant for backup appears to be accurate; but even without labels, they're not reliable.
I'm not sure of a better backup solution, though. I don't trust longevity for anything magnetic (I've seen too many tapes and floppies fail). One solution I'm trying is an IDE disk sitting in an external USB2/firewire enclosure: it can stay powered off most of the time, and copies are fast. But a disk has a lot of failure modes (magnetics, head crash, motor). Safer would be two external drives, kept in sync.
[ 14:40 Nov 25, 2004 More misc | permalink to this entry | ]