> I have the two serial lines going, each at 38400 baud.  I have heard that
> 57600 bogs down MacBSD.

Just FYI, you can get some idea of how many interrupts you're getting
due to serial traffic.  vmstat -i reports something like:
interrupt         total     rate
via1           53508518       69
via2           10554612       13
clock          46280513       59
Total          110343643      143

(that's off puma)  With any serial traffic, there would be a line for
'scc.'  Incidentally, the 59 for the clock interrupt shows that the
clock is still having some problems (it should be 60 ints/sec)...
'clock' is a subset of via1.

Unless I'm mistaken, two serial ports going all-out at 57600 could have
the rate up in the 1000's.  That's a lot...  At that point, you're not
doing much more than servicing interrupts--which is why you were getting
the ring overruns.  It was too busy getting data to ever process it.

-allen

-- 
  Allen Briggs - end killing - briggs@bev.net ** MacBSD == NetBSD/mac68k **
   Where does all my time go?  <a href="http://www.netbsd.org/">Guess.</a>