EMU71 and TCP/IP

[Egan Ford]

While getting DOSBox setup on my Linux machines so that I could run EMU71 I noticed that DOSBox supports serial port virtualization using TCP/IP. (DOSBox is an x86/DOS emulator, a bit like Bochs, but DOS emulation is part of it and it is much easier to use. It runs on top of Linux, OS/X, Windows, and many other platforms.)

The setup is pretty straightforward (I tested this with DOSBox on Windows/XP).

Put the following in your configuration file.

[serial]

serial1=nullmodem server usedtr port:5000

serial2=dummy

serial3=disabled

serial4=disabled

DOSBox uses your existing filesystem--no need to create an image. Create a dosbox directory with EMU71 (http://membres.lycos.fr/jeffcalc/emu71.html) and BNU (http://www.pcmicro.com/bnu/) installed, then mount as drive C, e.g. my dosbox directory on Linux is /home/egan/dosbox, for Windows/XP c:\home\egan\dosbox. The command for any OS to mount within dosbox is:

mount c /home/egan/dosbox

First run bnu.com. BNU provides INT 14 needed by EMU71 serial port emulation.

c:

cd bnu

bnu.com

Next make sure you have SERIAL1 in your EMU71.INI file. I have mine as my 6th HPIL device.

That’s it.

To test it I created a small reverse echo service using Perl. It will run on any computer with Perl. I tested it with Windows/XP.

#!/usr/bin/perl

use strict;

use IO::Socket;

use IO::File;

my $host = shift;

my $port = shift;

my $sock = IO::Socket::INET->new(

        PeerAddr => $host,

        PeerPort => $port,

);

if(!defined($sock)) {

        die "could not open socket";

}

while(<$sock>) {

        chomp();

        my $line = $_;

        $line =~ s/[^[:print:]]//g;

        my $revline = reverse($line);

        print "recv: $line\n";

        print "send: $revline\n";

        print $sock "$revline\n";

}

exit(0);

All this service does is connect to the host and port passed on the command line and waits for a message and then returns the reverse string of the message.

To test start up the service:

echorev.pl localhost 5000

From EMU71 type:

10 DIMA$[64] @ DIMB$[64]

20 INPUT "STRING: ";A$

30 OUTPUT :6 ;A$

40 ENTER :6 ;B$

50 DISP "GNIRTS:";B$

60 GOTO 20

RUN

Example session:

Windows/XP + Cygwin/X (for Perl):

$ ./echorev.pl localhost 5000

recv: FOO BLAH BLEH BAR

send: RAB HELB HALB OOF

recv: aaaabbbbCCCCddddEEEE

send: EEEEddddCCCCbbbbaaaa

Windows/XP + Dosbox + EMU71:

I am sure that there are other serial port virtualization solutions that may run natively on Windows so that EMU71 would not need to run in DOSBox.

[Howard Owen]

Oh, man!

What a neat shortcut to the 71B enthusiast's dream: an HP-IL<->TCP/IP gateway!

OK, so this won't let us work on HP-IL/IP, which is what I'd really like to do. But it's very, very cool nonetheless.

You've got mail. 8)

Regards,
Howard

[GE]

This deserves an entry in the Articles Section.

[Howard Owen]

I absolutely agree.

Egan, if you have time, could you consider transferring what you've written to the articles forum? I think it would do fine just like it is, but you'd be free to bend, fold and/or mutilate as you saw fit. 8)

Regards,
Howard

[Egan Ford]

I have a few more things to test first then I will post a more complete article.