Each time electricity goes down, my desktop (without UPS) loses some temporary information.

• Opera can lose settings, history, cache, or mail accounts (Thanks heavens I was wise to use IMAP). Partially or all together.
• a whole file (complete and save) in Geany appeared empty (and I didn't commit it to Git)
• rhythmbox lost all podcasts subscription data

I'm afraid there are other losses I just didn't see.

What's the reason? A memory files cache, a mem-disk? Or non-atomic file writes in xfs? I have Ubuntu 9.10 and XFS on both / and /home partitions.

Is ext4 safer in such circumstances? I've seen ext3 is faster. Is it as safe as *4?

Given that the apartment I rent is connected to a common bus and 1 safety switch for several apartments, and the neighbors - alone or together - overload it at least once every week, the lights go down often enough for this to be an issue.