Using burn-it-yourself CDs for long-term data storage is not safe. After just two to five years the dyes needed for reading the data fade and your data has gone, the bits decayed away. The report in Computerworld quoted an IBM Germany 'physicist and storage expert', Kurt Gerecke, to this effect. He is actually an IBM storage consultant, meaning sales support in fancy language. (He used to be a TotalStorage specialist.) He recommends using magnetic tape or UDO optical disks instead. IBM, of course, sells magnetic tape and also Plasmon UDO kit. Plasmon says UDO disks have a 50-year life.

What about storing data long term on disks. Gerecke advises against it. Hard drives can have the spindle bearings wear out, especially if cheap bearings are used.

He says no media is for ever: "Companies, in particular, need to be constantly looking at new storage technologies and have an archiving strategy that allows them to automatically migrate to new technologies," he said. "Otherwise, they're going to wind up in a dead end. And for those sitting on terabytes of crucial data, that could be a colossal problem." I'd agree with that. It's the same point I've made elsewhere.

A NIST study shows that high-quality optical media can last a long time but there are significant differences in media life between different manufacturers and products. I think I'll believe NIST rather than an IBM product-pusher, even an indirect one.

We might conclude that Gerecke is perhaps over-egging the short life pudding for burnt CDs. Against this the facts for longevity of tape and UDO media are enhanced. Good for Gerecke. He's earned his pay cheque on this one.