On Wed, 22 May 1996, Davyd Norris wrote:

> Hi all, > > I am still experiencing character lossage over the com ports
Hi all,
> 
> I am still experiencing character lossage over the com ports at higher speeds.  This is evident 
> as frame errors and CRC errors during PPP sessions.

Are you also experiencing silo overflows at these higher rates?  I get a
fair number of silo overflows (some times over 15 a minuite) on 486/33
with internal USRobotic modems which have 16550 ports.  I've tweaked the
com.c code to lower the trigger level (possibly the TTYHOG parameter) but
still get silo overflows aparently corelated with noise comming from the
disk drive.

While these overflows significantly reduce thru put I don't think it has
caused actual failures on transfers.

This is on a system running 1.1 on one end and 1.0 on the other.  The number
of silo overflows increased when moving the one machine from 1.0 to 1.1.  
I have suspected the timeouts in the wd driver while interupts are disabled
are the cause of these silo overflows but have not had time to verify this.

...
> 
> Dave.
johnh...