In some articles I have read about a "UNIX Circuit Design System", which was written originally in some version of
Research UNIX by Sandy Fraser.
Here is a quote from the article "A Research UNIX Reader: Annotated Excerpts from the Programmer's Manual", by Douglas McIlroy:
Even this page of a book recorded by "Google Books" describes in some extent its use.
However I could not find the source code nor the manual, even though 7th Edition UNIX nowadays is freely available. (I have searched through TUHS Archives)
Does anyone know why is is not included in V7 sources and how can I get it?