Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!lakesys!davef
From: davef@lakesys.UUCP (Dave Fenske)
Newsgroups: comp.unix.xenix
Subject: Re: ports, ports, and more ports.
Summary: Multiple, serial IO ports.
Message-ID: <1074@lakesys.UUCP>
Date: 9 Sep 89 13:33:52 GMT
References: <1989Sep8.200323.294@ka3ovk.uucp>
Reply-To: davef@lakesys.UUCP (Dave Fenske)
Organization: Lake Systems - Milwaukee, Wisconsin
Lines: 18

My motto is: be nice to the people from the IRS and they will be nice to you.

As far as I know, there is no limit on the number of ports, other than the
practical ones.  That is, when you run out of slots to plug boards into, or
the response time is over a minute, you definietly have too many.

I have several installations where the users use 17 serial ports on a 16Mhz
386, under SCO.  I know of places where they use 34 ports.

You need to be aware of several things.  1)  More users require more memory.
The general rule is .25 - .5 megs per user.  2) use serial cars from only
one manufacturer in one machine (unless you feel adverturesome).  3) The
more active users your have, the less resourses (cpu, disk, memory, etc) you
have to go around.

In short, the reasons are practical more than technical.

DF