# When I migrate to SBS I'll copy, not move

> Old systems should be left as static archives.

I'm just [in the process](/blog/0106-creating-dark-mode-images/#i-guess-its-time-to-upgrade-myself-to-the-sbs) of implementing the [SBS](https://sbs.johnnydecimal.com) myself. Our current system has the [identifier](/documentation/multiple-systems-overview) `D85`.

The new system is going to be `D25`: memorable to me as it's the year we released the SBS. [The previous post](/blog/0107-daves-sticker/) made me realise that when I migrate my data across, I should _copy_ it and not _move_ it.

Because these old identifiers will always be useful. I can just leave that data sitting there forever. Maybe move it off to an archive drive so I don't update it by accident. But old systems should never _disappear_: they should just be left, frozen like Han Solo.

Then an email with an old reference can come in years from now and I'll always have the ability to find its related artefacts basically instantly.

Nice.