Modes of operation

Modes of operation

There exist various ways of starting DOSEMU, depending on the environment and certain command line options. By default, in X, it will start using a special 'DOS in a Box' which provides a usual PC setup, using a 80x25 text mode. It also supports graphics. The box can be rescaled by dragging the window borders using the mouse.

However, in certain situation you may want to use a different mode.

Terminal mode

Terminal mode is automatically entered if you do not have X available, for instance when logging in remotely from a Windows system or at the Linux console. You can force it using:

$ dosemu -t 

In this mode the display of graphics is impossible, but you can use full-screen DOS text mode applications. It is advisable to give the terminal window a size of 80 by 25 characters, or use "stty cols 80 rows 25" on the Linux console, before starting it because many DOS applications are confused about other sizes.

You can use the $_internal_char_set option in ~/.dosemu/.dosemurc or dosemu.conf to change the code page that DOSEMU thinks that DOS is using.

Many terminals do not support various function key combinations. On the Linux console you can work around that by using the raw keyboard mode (-k flag, or $_rawkeyboard). xterm supports many key combinations. In other cases you'll have to work around it using the special Ctrl-^ shortcut (Ctrl-6 on US keyboards). Press Ctrl-^ h for help.

Dumb mode

For DOS applications that only read from standard input and write to standard output, without any full-screen usage, you can use dumb mode. To use this you must invoke DOSEMU like

$ dosemu -dumb 

this has the advantage that (A) the output of the DOS application stacks up in your scroll buffer and (B) you can redirect it to a file such as

$ dosemu -dumb dir > listing 

Note that editing is often restricted to BACKSPACE'ing.

SDL mode

You can start dosemu with the "-S" option to use the SDL library. In X it will just look like a regular DOS in a Box but with a different shaped text mode mouse cursor. You can also use this mode on frame buffer consoles.

Console graphics mode

Console graphics mode is the hardest to setup and may potentially lock up your system, but if it works it gives you direct VGA hardware access which may be quicker and more accurate than the emulation used in X.

You need root rights to use it. To enable it, it is recommended to use "sudo":

• install sudo if you haven't already done so

• use visudo as root to add entries such as

  joeuser   hostname=(root) PASSWD: /usr/local/bin/dosemu.bin 
  

  to your /etc/sudoers file, where "joeuser" is the user who is allowed to run privileged DOSEMU and "hostname" is the name of your current host (use "ALL" for any host).

• if you change PASSWD to NOPASSWD then joeuser does not need to type the user's password (not root's password) when invoking DOSEMU (a little less secure, if somebody hacks into joeuser's account).

• now invoke DOSEMU using dosemu -s