On Wednesday, June 5, 2024 at 06:51:54 AM EDT, Andrew Warkentin <andreww591@gmail.com> wrote:  
 
 On Wed, Jun 5, 2024 at 4:17 AM Andrew Lynch via TUHS <tuhs@tuhs.org> wrote:
>
> Hi
>
> Out of curiosity, what would be considered the most direct descendent of Unix available today?  Yes, there are many descendants, but they've all gone down their own evolutionary paths.
>
> Is it FreeBSD or NetBSD?  Something else?  I don't think it would be Minix or Linux because I remember when they came along, and it was well after various Unix versions were around.
>
> Does such a thing even exist anymore?  I remember using AT&T Unix System V and various BSD variants back in college in the 1980's.  System V was the "new thing" back then but was eventually sold and seems to have faded.  Maybe it is only available commercially, but it does not seem as prominent as it once was.
>
> Any thoughts?
>
What exactly do you mean by "most direct descendant of Unix"? Are you
specifically talking about Research Unix? Both USG (SysIII/SysV) and
BSD are actually more like side branches from Research Unix, and
neither is really a continuation of it. After V7, Research Unix
continued until V10, but was barely distributed outside Bell Labs and
had relatively little direct influence on anything else; these late
Research Unix versions did incorporate significant amounts of code
from the side branches that took over the mainstream (especially BSD,
although there may have been a bit of USG code incorporated as well).
I'd say the closest thing to "the most direct modern descendant of
Research Unix" would be Plan 9, which continued the development of the
networking and extensibility features of late Research Unix, but
significantly broke compatibility with Unix (sometimes in ways that
are IMO not really worth the incompatibility).


Hi
That's interesting.  I've been pondering this question for a while and suspected the answer is either "it doesn't exist" or "depends on who you ask" but I hadn't considered Research Unix.  
For a long time, I considered AT&T System V to be the primary Unix descendant but have changed my mind and now not sure.  The question is simple, but the answer seems quite complicated.
Thanks, Andrew Lynch