CD-R longevity; alternate backup solutions (Shallow Thoughts)

Akkana's Musings on Open Source, Science, and Nature.

Thu, 25 Nov 2004

CD-R longevity; alternate backup solutions

For years I've been using CD-R for backups, especially of photos. Every now and then I see an article about CD longevity (people are all over the map about how long these things are supposed to last; 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.

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[ 13:40 Nov 25, 2004    More misc | permalink to this entry ]