DOSBox-X in a container

Introduction

This project is DOSBox-X in a Debian Linux container, complete with sound support. It was largely inspired by https://github.com/classic-containers/dosbox and includes suitable general computing changes, some coming with DOSBox-X along with other usability tweaks:

• Multi-stage build (retain only necessary libraries in the runtime)
• Uses Debian 12 (Bookworm)
• Uses DOSBox-X in order to support general computing (unlike the gaming only focus of the DOSBox project)
• Use native alsa packages, instead of building them
• Up to date version of DOSBox-X (which is obtained directly through GitHub)
• During runtime user is non-root
• Provide canned dosbox-x.conf, to mount C and A drives (see below)

Running

In order to use, you'll need to provide X11 and Pulse audio support to the container.

Linux

Audio for Linux is currently untested; I'm not sure if the asound.conf supplied to the container will negate the ability to use /dev/snd.

$ docker run \
    -e DISPLAY=unix$DISPLAY \
    -v /tmp/.X11-unix:/tmp/.X11-unix \
    --device /dev/snd
    godfollower/dosbox-x-containerized

Docker for Windows

After installing Docker for Windows,

1. Install X11 Server, such as VcXsrv.
   • Make sure to turn Access Control Off.
2. Install and configure Windows port of Pulse Audio
   • In config.pa, set auth-ip-acl to the Docker bridge network (or full private subnet 172.16.0.0/12); see Pulse Audio Docs for examples.
3. Enable X11 and Pulse Audio through Windows firewall
   • I enabled them for Public and Private networks and set the Remote IP addresses to 172.16.0.0/12
   • The need for this step might depend on whether you use the WSL2 backend for Docker. Currently, Windows considers the WSL2 network interface "Public", so you'll need to allow both programs on public networks and then you'll probably want to lock it down to the Private 172 CIDR for security
   • Pulse Audio has firewall rules for both TCP and UDP; make sure to update both
4. Run the docker container, exporting appropriate variables

   $ docker run \
       -e DISPLAY=host.docker.internal:0 \
       -e PULSE_SERVER=host.docker.internal \
       godfollower/dosbox-x-containerized

Saving persistent user data

At startup, DOSBox-X is configured to mount the A drive to /var/dos/dosbox-x. If you would like to retain persistent user data between container runs, simply mount a local directory to /var/dos/dosbox-x inside the container.

$ docker run \
    -v /home/user1/savedata:/var/dos/dosbox-x \
    godfollower/dosbox-x-containerized

Anything you or an application saves to the A drive should then be available on your local machine, and you should be able to load data from the same location on future runs of the container.

I was originally going to use the D drive for the save mount, but I imagine some things out there expect the D drive to be a CD-ROM, and people probably more commonly used the floppy drive at A for transferring saves (and other random stuff) anyway. Hopefully your downstream application/whatever won't barf when it sees a large drive or files on the A drive.

Configuring DOSBox-X & Extending

This image comes with a canned dosbox-x.conf which is loaded via the ENTRYPOINT when the container runs; included in the file are autoexec commands to mount the C drive to /home/dosbox-x and the A drive to /var/dos/dosbox-x (as above).

Since the A and C drives are already in use, you'll need to put elsewhere any image mounts (for floppy or CD-ROM images) you need. See documentation on MOUNT

DOSBox-X will automatically load a ~/.dosbox-x/dosbox-x-{version}.conf file or a ./dosbox-x.conf file if found. In an attempt to be maintainable with future DOSBox-X version(s), this image uses ./dosbox-x.conf, but explicitly loads it with the -conf parameter.

NOTE Remember to chown (or chmod) the file so that the dosbox-x user can read it!

Example dosbox-x conf:

[autoexec]
c:
myapplication.exe

Example Dockerfile:

FROM godfollower/dosbox-x

# fetch application zip
ADD --chown=dosbox-x:dosbox-x https://oldapplications.net/oldapplication.zip oldapplication.zip

RUN unzip myapplication.zip

COPY --chown=dosbox-x:dosbox-x dosbox-x_oldapplication.conf dosbox-x_oldapplication.conf

CMD ["-conf", "dosbox-x_oldapplication.conf"]

Disclaimer

This project is targeted for the hobbyists/vintage computing enthusiasts as a general use vintage DOS-x86-Win3.x-9x/pre-2000 environment for use on modern technologies via being a container (and not just for vintage gaming such as DOSBox is)