vss2svn is a Perl script (vss2svn.pl) and accompanying C program (ssphys.exe) to migrate revision history from a Microsoft Visual SourceSafe (VSS) database to a Subversion repository. This combination of programs was designed by reverse-engineering the backend database structure of Microsoft's VSS repository. In doing so, the authors have made progress towards overcoming the inability of even Microsoft's own API to properly recover deep history from VSS. This also means that you don't actually need a copy of VSS or its libraries to convert your repository.
