- Mini-UNIX by Bob Eager
Mini-UNIX runs on a DEC PDP-11/10, 11/20 or 11/40 with at least the following equipment:
- 28KW (56kB) of memory; parity not used.
- RK05 disk (preferably two) or other supported disk (e.g. RP03 or RP04).
- Console typewriter.
- Clock: KW11-L or KW11-P.
Mini-UNIX is a simplified version of the full Sixth Edition UNIX system. It does not include these features:
- Separate instruction and data spaces on hardware that supports these.
- Group access permissions, or indeed anything to do with groups.
- Timer-interrupt sampling and interprocess monitoring for debugging and measurement.
- Unbuffered physical record I/O.
Note that Mini-UNIX does not require a memory management unit.
Also notable because this relates to a previous question:
the C compiler requires a minimum of 12kW (24kB) of memory to run
That Pico-hosted PDP-11 emulator is Pico_1140, “a PDP11/40 emulator that will run Unix v5/v6… an updated version of Dave Cheney’s CPP11”