Subject: slattach and baud rates
To: None <macbsd-general@NetBSD.ORG>
From: Ben Cottrell <benco@ucsee.EECS.Berkeley.EDU>
List: macbsd-general
Date: 04/06/1995 18:16:42
Here's my problem. I have a 14.4 kbps modem and use SLIP. Currently,
I cu at 19200 baud, then exit and slattach at 19200. That works,
insofar as I can do pretty much anything with the net.

The problem comes when I try to send a large file (bigger than the
modem's buffers). Normally, when the buffers get full, the modem
drops CTS and the computer stops sending for a bit... for
some reason, this doesn't happen. Correct me if I'm wrong, (it's
certainly possible that I have some dip switch set wrong or
the wrong cable or something), but it appears that MacBSD doesn't
do flow control?

One solution is, of course, to drop down to 9600. I've tried that,
and it's pretty slow :-( Another is to use ppp, but at the moment
I don't have access to a ppp server. What I'd *like* to do
is somehow tell slattach that it should ioctl the modem device
to talk to the modem at 19200 bps, but make sure it sends
less than or equal to 1440 characters in a given second...
I've seen this feature in things like term, so I know it isn't
too unreasonable.

Is that possible? I'm comfortable with modifying code, but I'm
not sure where to start because the way in which slattach
interacts with the kernel is weird, and I'm a bit
confused by it...

If that's not feasible, or even if it is, could someone also
tell me if/when the gurus are planning to add support for
flow control?

Thanks :-)