The following are a collection of utilities for manageing source code on OpenVMS. Some are open source, some are proprietry and in some cases they offer only client functionality.
Concurrent Version System
Otherwise known as CVS, this is a distributed version control system that grew out of RCS on UNIX-like systems. Unfortuantely there has never been a port of the server-side functionality of CVS to OpenVMS. Client support has been available for sometime and older releases can be found on the Freeware V3 and V4 CDs.
Another Java-based CVS implementation is available, called jCVS. Although there has been mention of work into supporting OpenVMS there does not appear to be anything more than this post to the jCVS forum.
Jouk Jansen has ported the latest unstable release, 1.12.13 to OpenVMS. It is available from his website here.
Code Management System
Otherwise known as CMS, this is a non-distributed code management system developed and maintained at HP as part of the DECset collection of tools. It runs on OpenVMS VAX, Alpha and I64.There are a number of supporting tools that add some level of a distributed nature to the system.
For Windows environments there is the DECset CMS and MMS clients. Although details of these utilities seem to be missing from the HP website they are available and allow integration of CMS into the Visual Studio suite of tools.
For OpenVMS Alpha and I64 environments there is the Distributed Netbeans IDE. Although this runs on Windows, the source code itself is located elsewhere on an OpenVMS system.
It is also worth mentioning the VDE software. This is the code management system used to maintain OpenVMS. It is available on the Freeware V4 and V7 distributions for those interested. It does require a number of extra products, including CMS and Oracle Rdb.
Mercurial is often referred to by its command name, hg. Mercurial is another distributed code management system, this time written in Python (there is no support for Python on OpenVMS VAX). It does have support for client and server functionality on OpenVMS and can be used with both WASD and HP's port of Apache, Secure Web Server.
The OpenVMS port of Python, Mercurial and a host of other Python software has been performed by Jean-François Piéronne and is available from his website, here. There is also a forum for discussing Python and MySQL here.
Tim Sneddon is currently in the process of adding OpenVMS support to the Python subprocess module to enable the SSH client functionality available on other platforms.
Subversion, also known as SVN, is yet another distributed code management system. It was started as a project to replace CVS, providing many new features and fixing long standing bugs. Since its creation it has grown and has replaced CVS in many areas.
Support for OpenVMS Alpha and I64 is provided through the Java client implementation, SVNkit. It can be downloaded here. There was also mention of the release of version 1.1.1 at OpenVMS.org.