So every five or ten years, you should move it onto a different format, like from VHS tape to DVD. And that's fine, but then DVD is already obsolete, there's Blu-ray, and so what's going to happen in another 10 years?

Making lots of backups is good advice, and on different formats, different places; consider paper as an archival medium. Some paper we have has lasted thousands of years. If Moses had gotten the Ten Commandments on a floppy disk, it would never have made it to today.

DP: What about Internet backup services?

DS: Oh, the Internet--is that still around? [CHUCKLES]

Keeping it on the Web is also not a really great strategy. A very large photo site just went out of business, and they gave people, I think, a month's notice to say, "We've run out of money, get your photos off the site and put them somewhere." Web sites are fine for sharing, but in terms of preserving your data, I wouldn't recommend it.

DP: So let's say people don't do this 10-year migration. What's the worst case?

DS: The damage depends on the importance of the information in the first place. Personally, I find family stuff to be the single most important stuff that I care about. It is your memory. And when you lose your memory, you lose your personality, you lose who you are. And that's why it's very troublesome that we're taking all these wonderful pictures and movies, but not thinking about how long they're going to last.

DP: Well, who should be? I mean, should this be a government project? Should there be some company stockpiling machines in the salt mines? Whose job is this?

DS: It's really nobody's job, sadly. Technology is often just thrown over the wall, and the long-term consequences are not thought through. The computer industry is one of planned obsolescence. And if you don't upgrade, you start to fall behind the envelope. You know, your kids send you a video and you can't watch it, because you don't have an upgraded operating system, or your computer is too slow. There are all these pressures to get you to replace your computer every three to five years.

DP: Can you give me a couple examples of some of the offbeat technologies that people at one point embraced and thought was the latest and greatest?