Just a comment that there is a version of Linux designed
for real-time systems called "RT Linux". Unlike the tenth
of a second interrupt timing of DOS, RT Linux allows you
to schedule interrupts at the microsecond level.
One if the systems described at IAUC 183 uses this and my
understanding is that Gaspar Bakos would be willing to
share some of his work. See:
http://www.konkoly.hu/staff/bakos/HAT/
Cheers,
Doug