Backup retention

Or: should you keep that tape?

There is an interesting curve of backup retention.

Initially, you should definitely keep them because they’re, well, backups that you might need to restore.

Then there comes a time where you should almost certainly not keep them because they’re too old to be useful as backups.

If they survive that they become, accidentally, archives: perhaps that tape sitting in some box has the only remaining copy of whatever-it-is. So don’t erase it.

At the point where nothing will read the tape any more, well, whatever was on it is effectively gone now, so throw it away.

At some point after that, one or both of two things happen: people become willing and able to do seriously heroic things to read really old media which might have the last remaining copy of something on it and/or the media itself becomes rare enough that it’s now a historical artifact worth preserving. The second thing can’t happen unless enough copies of the media get thrown away in earlier phases of the process: I don’t think minidiscs would be interesting historical artifacts (yet), but if I still had a Fuji Eagle I would definitely not throw it away.

Later still it becomes possible to print, cheaply, replicas accurate at the atomic level of the thing, at which point its value should drop to the cost of making another clone, but in fact people start spending huge amounts of effort authenticating the original copy of the object which is held to be somehow ineffably different to all the perfect clones. At some point, people lose track: no-one now knows which the original is any more, and since there is no physical distinction no-one ever will again. The people who have paid to have their copy authenticated as the original now spend much of their time arranging to have the other people who have done that assassinated.

I forget which film this is.