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Date:      Thu, 9 Nov 1995 22:13:42 -0600 (CST)
From:      Joe Greco <jgreco@brasil.moneng.mei.com>
To:        geoff@schwing.ginsu.com (User GEOFF)
Cc:        hackers@freebsd.org
Subject:   Re: I/O woes.
Message-ID:  <199511100413.WAA23738@brasil.moneng.mei.com>
In-Reply-To: <Pine.NEB.3.91.951109182657.12275A-100000@schwing.ginsu.com> from "User GEOFF" at Nov 9, 95 06:44:07 pm

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> My configuration is pretty standard.  I'm using an older 486/33 with 16 
> megs of RAM and ISA bus.  The ports are all controlled by 16550s.  Do I 
> have to do anything special to get them operating with the 16550s 
> properly?  I've got one modem hooking me to the internet via 28.8 modem 
> and two dial-up 14.4 modems for user access.  Kinda a micro ISP.  ;)

I used to use a 386sx/16 with onboard 16450's to install FreeBSD via a
115200bps SLIP link.  I generally got around 5000cps.  I use 386DX/40's with
16550's for all sorts of things and had one machine that handled a
115200bps SLIP link, a 28.8K V.FC SLIP link, and ran several
uucico/compress/gzip sessions simultaneously, reliably, under 2.0R.

> I'm running FreeBSD 2.0, which was the most current CDROM I could get.  
> Is this a know problem?  Do I need more processing power to handle the 
> interupts?

No.  You appear to have some other issue you haven't addressed.

My guide for serial communications:

1) you should ALWAYS use hardware flow control unless you have a REALLY good
reason not to.  REALLY good, as in, the device you are talking to doesn't
support it.
2) note, I don't know if the current getty in FreeBSD will allow you to set
this up "right".  I've used my own severely hacked getty since the later
days of 386BSD/earlier days of FreeBSD because there was tons of lacking
functionality.  Part of this was to add "proper" hardware handshaking
support because there was no gettytab flag to turn it on.
3) set up modems, etc. to support FULL hardware handshaking (i.e. locked
data rate, RTS/CTS, DTR, CD, etc).
4) make sure you use good cables that support all signals.  Most do these
days.  Even the ones at Wal-Mart.
5) make sure FreeBSD probes the UARTs as 16550's.

Everything works pretty well for me out of the box (besides getty, which I
haven't looked at lately).

... Joe

-------------------------------------------------------------------------------
Joe Greco - Systems Administrator			      jgreco@ns.sol.net
Solaria Public Access UNIX - Milwaukee, WI			   414/342-4847



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