Backup Your Backups

Is your data really safer stored digitally? [detnews.com] "I popped the CD-RW into my PC with the same expectation one gets when cracking open a time capsule. And I got -- I got -- nothing but a Windows error message offering to format the unformatted disc in my PC. Everything I had saved, everything I had disposed of because it was supposedly safe, was gone."

This article highlights a fact for which many people have misconceptions: "digital" does not equal "forever." When CDs first came out in the 80s, people said, "Oh, they're digital, they'll last forever. Not like those pesky vinyl albums and magnetic tapes."

What they really meant to say was: "Oh it's stored in a digital format, so it'll be lossless for the life of the medium." Yes, you won't lose any information as long as the storage medium remains intact.

But now we're coming to realize that CDs and DVDs don't last forever, and this is especially the case with recordable CDs and DVDs: CD-R, CD-RW, and the myriad recordable DVD formats. The dyes in CD-Rs will eventually break down, as will the crystalline recording layer of CD-RWs. Recordable DVD have similar physical degradation issues. The optical media industry itself has estimated recordable optical media lifetime of between 20 and 200 years, though there have been reports that some become unreadable after just 5 years.

The current recommendation is to re-copy those backups to newer media every few years or so. Don't just assume that because it's digital, it's forever.

The article also highlights another less publicized issue: that of format obsolescence, as opposed to physical obsolescence. Got any documents in WordStar format? Or pictures in RLE? What can you use to read them now?

In addition to making sure that your physical media isn't degraded, you also need to be sure that your files can be read by existing software. Sure, JPEG seems like it's been around forever, and will always be here. But can you be so sure that it'll be a standard 50 years from now?