[TUHS] First Unix-like OSes not derived from AT&T code?

[Ron Natalie]

Mark Williams Coherent was one I worked with on the PC many years ago. 

> On May 1, 2022, at 11:34, Andrew Warkentin <andreww591 at gmail.com> wrote:
> 
> What was the first "clone" functional Unix (i.e. an OS not derived
> from genetic Unix code but highly compatible with genetic Unix)? Idris
> is the earliest such OS of which I am aware (at least AFAIK it's not a
> genetic Unix), but was it actually the first? Similarly, which was the
> first "outer Unix-like" system (i.e. one with strong Unix influence
> but significantly incompatible with functional Unix)? Off the top of
> my head the earliest such system I can think of is Thoth (which
> predates Idris by almost 2 years), but again I'm not sure if it was
> actually the first.