[Q] Porting FreeBSD to run on top of some proprietary hard real time OS on exotic HW?

[Alexander Bezprozvanny]

Hi all,

 We are facing the need to port FreeBSD to some (exotic) HW platform. I am
totally new to this business, so I need to do some homework before coming up
with a sensible project plan.

The target HW platform already has some sort of a primitive proprietary hard
real time OS running on it. Current plan is to have FreeBSD running in the
idle process of that OS.

The question is: what would be the requirements to that underlying OS from
FreeBSD? What services/APIs shall it provide for FreeBSD? How the HW
virtualization works in this case (RTC, etc)? If someone could point me to
some resources/discussions on this subject, that would be most appreciated.
Thank you!

Alexander Bezprozvanny

P.S. I have posted this to freebsd-platforms, but that mailing list seems to
be pretty dead: for the last 12 months only spam bots and yours sincerely
were posting there :-) so I decided to crosspost it to this list.