QNX is a very cool operating system, which
unfortunately (from my
perspective) runs only on the Intel platform.  It's a true microkernel and
unlike Mach (which is about the only microkernel that is widely known) it
actually runs fast!  And it has an incredible network filesystem/message
passing paradigm that blows Unix out of the water (imagine being able to run
a program on one computer, pipe the output to a program on a second computer
and send that to a printer on a third computer---all from the command line
ala Unix?). 
Do some research, QNX runs on a *LOT* more than IA, and yes, it seems to be
pretty cool.
                Zane
--
| Zane H. Healy                    | UNIX Systems Administrator |
| healyzh(a)aracnet.com (primary)    | OpenVMS Enthusiast         |
|                                  | Classic Computer Collector |
+----------------------------------+----------------------------+
|     Empire of the Petal Throne and Traveller Role Playing,    |
|                   and Zane's Computer Museum.                 |
|                 
http://www.aracnet.com/~healyzh/              |