On Mon, Jul 20, 2020 at 7:51 AM Larry McVoy <lm@mcvoy.com> wrote:

This isn't quite the same but Victor Yodaiken wrote a real time kernel
that ran all of Linux as a user process. Super cool idea and it worked
great, he would demo it sampling the parallel port while Linux was running
some X11 perf thing, tarring up /usr and untarring on nfs://server/tmp/usr
and doing a ftp transfer. Basically beating the crap out of Linux as
hard as he could while running a real time sampler and it never missed.

Clem should pay attention, in my opinion, this is how you do Unix and
real time. Because Unix is time sharing and throughput, that is the
opposite of what real time is. Wedging real time into Unix is a mistake.

http://mcvoy.com/lm/papers/rtlmanifesto.pdf

As often true, I really don't disagree with you. Around the time I left Masscomp for Stellar we were working on a rewrite with some ex-CMU folks (Doug ... I don't remember is his last name now) that used a preemptive RT microkernel under the covers and then supplied RTU system calls. Tom and I left for Stellar and a couple of other people left too. This was time of the reign of Mr. Potato Head (ex-IBM guy that was named CEO) and things blew up.