CVS Documentation
CVS is a short term for Concurrent Versions System and can help a programmer/ program developer keep track of and manage the records that are found in a source code. As there can be many versions of a source code, keeping them at reach and particularly to be able to put them up to date is important. This is what CVS will help you out with. You will even be able to manage the different codes at the same time without having to check out pairing between different items.
The link to the documentation on CVS below is meant for the people/programmers who know how the program works and have already used it before.
Link:
http://ximbiot.com/cvs/wiki/CVS--Concurrent%20Versions%20System%20v1.12.12.1
More information:
http://www.nongnu.org/cvs/
Tutorial
http://users.csc.calpoly.edu/~dbutler/tutorials/winter96/cvs/