PVCS

For the company, see PV Crystalox Solar

PVCS Version Manager (originally named Polytron Version Control System) is a software package by Serena Software Inc., for version control of source code files.

PVCS follows the "locking" approach to concurrency control; it has no merge operator built-in (but does, nonetheless, have a separate merge command). However PVCS can also be configured to support several users simultaneously attempting to edit the file; in this case the second chronological committer will have a branch created for him/her so that both modifications, instead of conflicting, will appear as parallel histories for the same file. This is unlike Concurrent Versions System (CVS) and Subversion where the second committer needs to first merge the changes via the update command and then resolve conflicts (when they exist) before actually committing.