[TUHS] Circuit design tool mentioned in AT&T Unix promotion

Christian Dreier via TUHS tuhs at tuhs.org
Sat Feb 11 18:06:34 AEST 2023

Thanks for mentioning Carver Mead. After entering his name in Google, I 
stumbled across a paper "Introduction to VLSI Systems" by Lynn Conway 
and him.


This paper mentions a software "ICARUS" (Integrated Circuit ARtwork 
Utility System) that also appears to be a pioneering EDA tool. But 
clearly not the particular thing, I'm asking for and it is for Xerox 

Hopefully, someone has some more information about this "L-Gen" software. :)


Am 10.02.23 um 13:56 schrieb Douglas McIlroy:
> CDL was for designing wired circuit boards, not integrated circuits..
> It was used to design the Datakit switch, the Belle chess machine and
> other hardware.
> I suspect the cited IC-design tool was one that Steve Johnson created
> for use in a short course that Carver Mead taught at Bell Labs. I am
> not aware that it saw use outside of that course.
> Doug
> On Fri, Feb 10, 2023 at 12:37 AM Christian Dreier via TUHS
> <tuhs at tuhs.org> wrote:
>> Hello there,
>> I recently watched an old Unix promotion video by AT&T on YouTube (AT&T
>> Archives: The UNIX Operating System: https://youtu.be/tc4ROCJYbm0) and
>> they mention a design tool for integrated circuits (apparently named
>> L-Gen or lgen; timestamped link: https://youtu.be/tc4ROCJYbm0?t=1284).
>> Part of this software is a language implemented with YACC that appears
>> to describe the behavior of digital logic, like modern hardware
>> description languages, i.e. Verilog and VHDL.
>> Does anyone have information about this, in particular:
>> - Documentation
>> - Which projects were realized with this?
>> - Source code, if possible
>> I asked this question on retrocomputing.stackexchange.com (see
>> https://retrocomputing.stackexchange.com/q/26301/26615) but so far there
>> is no satisfying answer. A "Circuit Design Language" (CDL) is mentioned
>> and there is some good information about it but it has another syntax
>> (as shown in the video vs. the documentation about CDL) and apparently
>> another purpose (description of board wiring vs. logic behavior).
>> Best regards,
>> Christian

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