Dosbox.conf

dosbox.conf is a configuration file located inside the same folder as the DOSBox binary. It contains various system settings and initialization values that define your emulated environment. Everything can be controlled by editing this file or if you like through more graphically oriented Front Ends. You can also create separate dosbox.conf files for multiple host environments (which is helpful in playing various DOS games that expect various types of hardware).

The configuration file is broken into separate sections which contain section settings. Many of these settings do not need to be fully understood to configure DOSBox, but it is helpful to know where to look. You should also be aware that anything to the right of the a # to the end of the line is considered a comment as is totally ignored by DOSBox when it loads.

[sdl]

This section contains all of the low level system settings for how DOSBox interacts with your real hardware. You can define what resolutions are emulated, how DOSBox should treat errors or listen to your keyboard and mouse. You can often achieve a fair level of optimization by working with these setting, though for the most part leaving them at their default settings will create the best experience. These settings are passed on to the SDL Library which handles low level things like input and thread priority.

fullscreen = true | false

Start DOSBox directly in fullscreen.

Default is false.

fulldouble = true | false

Use double buffering in fullscreen. See [1]

Default is false.

fullresolution = width x height | original | desktop

Scale the application to this size IF the output device supports hardware scaling (i.e. any output other than surface). Original is the game's default or chosen (through setup.exe or in-game menu) resolution. If original resolution is less than desktop resolution, DOSBox will switch the screen resolution to the closest match requested by the game or application. For example, if a game in DOSBox is requesting a graphics screen resolution of (320 x 240) while your desktop is (1920 x 1200), DosBox will switch to (320x240) or the next highest resolution supported by your GPU drivers, e.g. (800 x 600) if the former is not available. Many games will be below the minimum resolution supported by modern video cards, so DOSBox will scale the game up to at least that minimum. Note: the scaler setting under [render] is also able to scale up the original resolution to some degree. Those changes are performed before any additional scaling done with fullresolution setting.

Default is original.

windowresolution = width x height | original | desktop

Scale the window to this size IF the output device supports hardware scaling (i.e. any output other than surface). Original is the game's default or chosen (through setup.exe or in-game menu) resolution. Note: the scaler setting under [render] is also able to scale up the original resolution to some degree. Those changes are performed before any scaling done with windowresolution setting.

Default is original.

output = surface | overlay | opengl | openglnb | ddraw

What to use for output. Surface does not support scaling or aspect correction. More information here: [2]

Default is surface.

autolock = true | false

Mouse will automatically lock, if you click on the screen.

Default is true.

sensitivity = 1..1000

Mouse sensitivity.

Default is 100.

waitonerror = true | false

Wait before closing the console if DOSBox has an error.

Default is true.

priority = when-focused,when-minimzed

Priority levels for DOSBox. Second entry behind the comma is for when DOSBox is not focused/minimized. Valid priorities are: lowest, lower, normal, higher, highest, and pause.

Default is higher,normal.

mapperfile = path-to-mapper-file

File used to load/save the key/event mappings from.

Default is mapper-<version>.txt.

usescancodes = true | false

Avoid usage of symkeys, might not work on all operating systems.

Default is true.

[dosbox]

These are emulator environment settings like language, display type, and amount of available memory. You can also define the folder where captured audio and video is stored. (more)

[render]

Here you can define display specific settings like the frame skip and any resolutions scalers. (more)

[cpu]

Here you can define how the CPU is emulated, as well as the pace (similar to its speed) at which is emulated. (more)

[mixer]

Here you can define the quality of emulated audio. (more)

[midi]

Here you can define any MIDI related settings. The term MIDI is commonly used to refer to background music found in games, but specifically it refers to synthesizer audio (which can be passed directly from emulated games to modern hardware. (more)

[sblaster]

Sound Blaster related settings. (more)

[gus]

Gravis Ultra Sound related settings. (more)

[speaker]

PC Speaker related settings. (more)

[joystick]

Joystick related settings. (more)

[serial]

Serial Port related settings. (more)

[dos]

Conventional Memory and Extended Memory related settings as well as the keyboard layout. (more)

[ipx]

IPX Networking related settings. (more)

[autoexec]

Here you can define the contents of the AUTOEXEC.BAT file (which is executed immediately after DOSBox is initialized). (more)