The dosemu HOWTO

4. Parallel ports, serial ports and mice

4.1 Port access worked with older version, but doesn't work now!

Read ../doc/README.txt and the port-section in ../etc/config.dist

4.2 Port access was faster with older versions!

To have a chance to log port access, by default every port access produces an exception out of vm86-mode. This takes some time. If you don't want to log port access, use the keyword "fast" in the appropriate port statement.

4.3 Where are the (microsoft compatible) mouse drivers?

Tom Kimball (tk at pssparc2.oc.com) reported (93/11/24) that

Several people said to use a different mouse driver and suggested some. I found a couple that seem to work fine.

   oak.oakland.edu:/pub/msdos/mouse/mouse701.zip   (mscmouse)
   oak.oakland.edu:/pub/msdos/mouse/gmous102.zip   (gmouse)

4.4 Why doesn't the mouse driver work?

Mark Rejhon (mdrejhon at magi.com) reported (95/4/7) that

If you start the mouse driver and it just hangs (it might actually take 30-60s), but if you are waiting longer than a minute for the mouse driver to start, try specifying the COM port that the mouse is on, at the mouse driver command line.

4.5 Why does dosemu clobber COM4?

Rob Janssen (rob at pe1chl.ampr.org) reported (94/3/24) that

According to jmorriso at bogomips.ee.ubc.ca, "dosemu still clobbers COM4 (0x2e8, IRQ 5). 0x2e8 isn't in ports{} in config. I have to run setserial /dev/cua3 irq 5 on it after dosemu exits."

This is caused by your VGA BIOS. I have found that by enabling the IO port trace and seeing where it was clobbered.

Disable the "allowvideoportaccess on" line in config and it will work fine. When you then have problems with the video, try to enable more selective ranges of IO addresses (e.g., 40-43).

4.6 How do I use dosemu over the serial ports?

4.7 How can I switch between dosemu and a shell over the serial line?

John Taylor (taylor at pollux.cs.uga.edu) reported (94/5/25) that

I am running Linux 1.1.13 and want to point out a great feature that should be protected and not taken out (IMHO). With the 52 version, I can run the program, "screen." From screen, i can invoke dos -D-a. What is really great (IMHO) is the screen commands (the CTRL-A cmds) still work. This means I can do a CTRL-A C and add another unix shell, and switch between the two (DOS / UNIX). This allows me to use dosemu over the serial line really well, because switching is made easy.

4.8 How can I get the parallel ports to work?

The dosemu.conf has lines at the end to redirect printers to either lpr or a file. If you want direct access to the bare metal, comment out these emulation lines, and add the line

$_ports { device /dev/lp0 fast range 0x3bc 0x3bf } # lpt0

$_ports { device /dev/lp1 fast range 0x378 0x37f } # lpt1

$_ports { device /dev/lp1 fast range 0x278 0x27f } # lpt2

Hans Lermen (lermen at dosemu.org) writes:

But NOTE: these lines should not be _added_ simply, the string should be concatenated such as:

$_ports = "...." $_ports = $_ports, " device /dev/lp0 fast range 0x3bc 0x3bf" = This blank is important