> 
> - There's a 'Unix' for the LSI-11, and with minor changes (the LSI-11 isn't
> 100% compatible with other MMU-less 11's, but the changes are minor, e.g.
> MOS, written in MACRO-11, was conditionalized to run on both the LSI-11
> and the -11/20) it should run on an /04.
> 
> 	Noel

There’s always MiniUnix.    https://www.tuhs.org/Archive/Distributions/USDL/Mini-Unix/ <https://www.tuhs.org/Archive/Distributions/USDL/Mini-Unix/>

We ran that on our MMU-less PDP-11/20s and 11/40 before the LSI-11 was even introduced.
It lacks obviously memory protection, traditional UNIX pipes (they’re simulated by the shell if I recall), and preemptive scheduling.