[TUHS] Unix Circuit Design System

Michele Ghisolfo ghisolfo.m at gmail.com
Fri Jan 1 04:20:40 AEST 2016

Hello all!

While I was reading the article "A Research UNIX Reader:  Annotated Excerpts
from the Programmer's Manual" from Douglas McIlroy, I learnt of a set of
utilities for designing electronic circuits.  Here is a brief quote of this

"CDL (v7 pages 60-63)

Although most users do not encounter the UNIX Circuit Design System, it has long
stood as an important application in the lab.  Originated by Sandy Fraser and
extended by Steve Bourne, Joe Condon, and Andrew Hume, UCDS handles circuits
expressed in a common design language, cdl.  It includes programs to create
descriptions using interactive graphics, to lay out boards automatically, to
check circuits for consistency, to guide wire-wrap machines, to specify
combinational circuits and optimize them for programmed logic arrays (Chesson
and Thompson).  Without UCDS, significant inventions like Datakit, the 5620 Blit
terminal, or the Belle chess machine would never have been built.  UCDS appeared
in only one manual, v7."

I looked it up on the 7th Edition's Manual and I haven't found references of
this system.  I also searched a v7 system image downloaded from TUHS and got no
results.  However I got some references of this system in USENET archives.  In
particular, two hierarchies, net.draw and after net.ucds were dedicated to it.
Apparently two of the binaries of the system were called "draw" and "wrap".  I
also found a manual of a similar system which I suppose is the UCDS descendant
in the 1st Edition of Plan 9.  This is the link of the document:


However that edition of Plan 9 is not publicly released and I could not find
it in following editions.  But since v7 Unix is available, I hope it may
be possible to get hold of an older release at least.

Does anyone have any information?

Thank you in advance!

    --- Michele

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