There are lots of real-time kernels for small microcontrollers out there. I
don't know if it would be worth the effort for commercial reasons, but you
might want to give it a try just to further your knowledge. Check out the book
"MicroC/OS-II: The Real-Time Kernel, 2nd Edition".

Good day.

My name is Michaelo Mitrofanov.
I'm of Ukraine.

I wanna to implement my old idea which I named "virtual kernel"
This technology allow to run UNIX-like OS on microcontrollers with
small data and code memory.
Small means really SMALL (!)
... for instance on PIC12C508A with 768 bytes ROM and 25 bytes of RAM.

Yes my software can't make a miracle,
there is no way to feel all the power of UNIX on such simple device.
But it's quite possible to make few fork()s and pipe()s.

So what is virtual kernel?
It's system of compiling a kernel with application[s] into solid
program,
with difficult system of optimization and automatic kernel
configuration.

That's it.
Bye.
        -Michaelo

My mailing address: (here my name spells differently)
        Mykhaylo Mytrofanov
        vul. Serafymovycha-3, kv. 127,
        Kyiv-152
        02152
        Ukraine