[yjftsjthsd-h]

Sorry, I didn't use SVN enough to answer that. Basically, they're distributed VCSs like git, but where git stores commits, that is, snapshots of what the files look like at a specific commit, patched-based VCSs in the darcs "lineage" store diffs. Obviously the end result looks similar - git gives you diffs by comparing commits, darcs replays diffs to instantiate what the files actually look like at any given time - but it (allegedly) makes it much easier to handle arbitrary merges and do things like maintain a branch that's just like another branch but with a single commit on top.