Protect your data for a million years

Old computer
If you keep all your data backed up, there's no need to keep this kind of thing in a vault

Every now and again, someone on a discussion board will ask "How do I keep my important data safe? Not just safe for a few months or years, but forever. Long enough for someone like Tony Robinson to dig it out of a ditch and reconstruct my life."

Hard disks eventually fail, DVDs rot and devices become obsolete as operating systems change. What time capsule can possibly withstand the slow, crushing grasp of time itself? I'll tell you: