... which stands for Compatibly Stupid Source Control.
And there's more ...
In particular, the Heirloom Toolkit at <https://sourceforge.net/projects/heirloom/> contains the Solaris version of SCCS, and SRC source control <http://www.catb.org/~esr/src/> provides a modern-style front-end over either RCS or SCCS; it is designed for maintaining single files, possibly in the same directory, without entangling their versioning.