Regarding *Codeville* version control system: if I remember it correctly, it used novel merge algorithm, which was often better than the diff3 merge algorithm that RCS, CVS, Subversion, Git and other version control systems use.

However, if there was a problem with merge (a conflict), it was, from what I heard, much harder to resolve - because the algorithm was more complex. And with the introduction of the recursive merge the diff3 algorithm was deemed good enough in practice, easy to understand, and lacking sharp corner cases.