Subject: Re: Dramatic Serial Port Speed Reduction
To: Michael L. VanLoon -- Iowa State University <>
From: Robert Shady <>
List: current-users
Date: 03/22/1994 14:56:26
> >Has anybody else noticed a dramatic speed loss since Chris fixed the Com
> >driver?  I am noticing a STEADY decrease of ~300 CPS...

> The point of the fifo is to give the machine time to process things
> after receiving an interrupt, and before it has time to finish
> servicing it.  Can we have the old default setting of 4 again?  Either
> that, or could we have like FreeBSD where it's just FIFO_TRIGGER in
> the com.c and is only assigned a level if you don't specify your
> preferred trigger level in your config file (options FIFO_TRIGGER=
> FIFO_TRIGGER_4, or something to that effect).

I too am interested in something like this, as we will be starting to 
put the new Hayes serial cards with 128 byte buffers in our machines here
for dialup networking.  Hayes claims that "It uses the 128 byte buffers
automatically with 16550 'AWARE' software, and doesn't need to be told
to use it."  Of course, the guy I was talking to probably doesn't know
his nose from a whole in the ground, but I am assuming he probably meant
that the board DEFAULTS to 128 byte buffers (actually probably something
like 100 bytes), or it just multiplies what the standard 16550 buffer
setting is by 7 or something...  Regardless, we would like to support
these cards.  Anybody have working DigiBoard code yet?  I have some source
to examples and I will start hacking one out if nobody else has started.

Also, if anybody is interested in a Computone Intelliport driver, please
let me know as well..