This is pretty cool. MP/M is something I've only read about (I ran CP/M on my TRS-80 as much as I did TRSDOS). Never saw it in operation before. My first exposure to something like this was Xenix on the TRS-80 Model 16/6000 - my friend and I hung out at the local computer center so much that they set us up with accounts to play around with the store demo system.
My first job after college, one of the things I worked on was fixing a machine tool controlled by a PDP-11/23 with RSX-11. I had two terminals, so it was really neat watching the system time slice between my two sessions, all with I think a mere 4K words of memory. Been a long time but there was some sort of monitor utility that would how an updating view of the memory and cpu and what process was using what - on a VT100 CRT this would nicely refresh every few seconds, while my actual FORTRAN program controlling the machine tool ran on a DECWriter so I could get a hard copy output of the test results.
I have a machine that can run CP/M, an old NEC PC8800, which also has the 16 bit card and can run MSDOS, but part of me wants to build a more pure Z80 system with simple terminals - though once I got it all up and running, I'm not sure what I'd do with it - which is the only thing stopping me.