[ ... frakely keyboard on Personal DECstation ... ]
> The driver for the Serial Desktop Bus can easily miss data when it can't
> respond to the interrupt fast enough.  At one time, I was trying to
> utilize DMA for this, but so far it's much less reliable.  Someday I need
> to get back to that, but there other other things I have to get done
> first.

As you might already know, ULTRIX does not use IOASIC DMA channel to
handle Serial Desktop Bus data.  According to ULTRIX include files,
DMA/non-DMA is #ifdef conditionalized, and kernel has no DMA
code. ULTRIX manipulates Serial Desktop Bus data using complicated
timeout()/untimeout() sequences in which I have not figured out the
details.

Tohru Nishimura
Nara Institute of Science and Technology