A working file is a complete copy of some version of the file that is available. This file need not necessarily be the latest or current version, it can be any past version. The need for the terminology to differentiate working files from other files, is because RCS creates files to store versions to and operate with. Working files are no different from all the files you were previously familiar with working one.

A version file is used by RCS to store version information. These files are the same name as the working file except they end in a suffix, which is by default ,v. For example, if you wanted version to keep track of a working file named freedom.txt RCS would create and use a version file named freedom.txt,v. The extension ,v stands for version file (see section on file naming). Which extension RCS should recognize as version files can be modified with a command-line option.

Version files contain all the information necessary to retrieve any version. Besides storing past versions these files also contain the information related to each version, including date, version number and your notes.

The existence of version files is necessary for all RCS operations. These files must be available in the current directory or a subdirectory named RCS (see section on file naming).