DOSemu serial port problem

["Edenyard" <mail@edenyard.co.uk>]

   I'd very much appreciate help with this serial port problem:

   I've installed DOSemu V1.1.99 from source an an Athlon and have
got it running quite well on Slackware 9.1 (2.4.22 kernel). It
recognises the DOS partition on the HDD, boots from the IBM DOS there
and will run programmes like Xtree and Wordstar without any problems.

   However, I have a programme written in Turbo Basic that accesses the
DOS COM1 serial port hardware (UART registers, etc.) directly and I'm
having trouble getting it to talk to the port properly under DOSemu.
The port is a standard 16550A UART on the motherboard and works
correctly under Linux.

   This is the error message I get as DOSemu is coming up:

      ERROR: PORT: conflicting devices: COM1 & std port io

   The programme appears to be able to send out of the port but cannot
get any data coming back in. I've set /etc/dosemu/dosemu.conf to deal
with the COM1 port like this:

      $_com1 = "/dev/ttyS0 irq 4"
      $_ports = " device /dev/ttyS0 fast range 0x3f8,0x3ff"
      $_irqpassing = "4"

   but I can't stop the 'conflict' message or get any data from the
port into my programme. The remainder of the programme appears to work
properly, even printing to what it thinks is LPT1.

   I'm running DOSemu as root (which I believe I have to do in order to
gget access to the UART at /dev/ttyS0 - is this true?) and it's running
in an Xterm window.  I've an idea that I need to tell Linux to ignore
COM1 (ttyS0) so that the DOS programme can have it, but I don't know
whether this idea is sensible and, if so, how to do this. Is there
a parameter to give to a module or the kernel at boot time, or
something like that?

   I've tried DOSemu V1.0.2 and get the same problem, so I'm sure it's
something I'm doing that's messing it up, rather than a DOSemu bug.

   Hope this isn't a dumb question I'm asking. Thanks for any help
on this!

      Gerald.