Microport serial communications

[Bill Michaelson]

I'm currently using Microport release 3.0e with the [Locus] Merge prod-
uct.

>From what I've heard from other Microport users, product quality and
system support was reputedly lousy in the past.  However, the situation
has been improving lately, so they say.  I think I agree, but I am not
thoroughly satisfied.

One extremely annoying problem with the software I'm running has been the
unreliability of serial communications devices under Merge/386.  Are
others experiencing problems similar to mine?  Do MS-DOS products such as
(or similar to) Procomm or Laplink work properly?  Do they operate at the
highest baud rates?  How are you attaching the devices (e.g. direct/kernel/
virtual)?

Another annoying problem (unrelated to Merge): I have four serial ports
on my '386 machine.  As is typical with many AT clones, the ports may
each be configured to one of four addresses (called COM1-COM4 in the MS-
DOS world), and one of two interrupt levels (IRQ2 and 3).  The device
drivers that come with the system apparently don't allow serial ports to
share interrupt levels.  It's puzzling because the documentation indi-
cates that multiport boards use single interrupt levels.  A command
called ttypatch is used to configure the drivers.

I've tried using ttypatch to configure two of my single ports (at dif-
ferent addresses, of course) to a single interrupt level.  I can start a
getty on the first device with no problem.  As soon as I start a getty on
the second device, the first one fails (the getty's appear to interfere
with each other).  Stopping the second getty removes the problem.  I can
reproduce the same problem by reversing the ports also.

So it seems that all four ports work.  But I can't let them share inter-
rupts, so I can only use two at a time!.  So how do the multiport boards
work?  I don't want to buy one - I figure the configuration I've got
ought to be supported - it's common enough.  Is there anyone out there
that has overcome this problem?

Thanks in advance for any suggestions.


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Bill Michaelson, COS, Inc.       \ "Better to keep your mouth shut, and let
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