Katie is a revision control system, somewhat like a cross between CVS and NFS, that was inspired by Rational ClearCase. The three most interesting features are that the repository is mounted as a filesystem (rather than being copied to a local workspace), that all versions of all files (even deleted ones) are accessible through this filesystem (so the "katie diff" command is a convenience rather than a necessity like "cvs diff"), and that directories are versioned (just like files are). It is functional enough to be self-hosting, but there is much work still to go before it will be a generally useful tool. Features that are implemented already include VOBs, elements, branches, dynamic views, view-extended pathnames, config specs (including auto-make-branch rules), labels, hard links, and symbolic links.
