Configuration: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. (since 0.??)
fulldouble = true | false
Use double buffering in fullscreen. Default is false. (since 0.??)
fullresolution = width x height | original
The resolution to use for fullscreen. If original is specified, DOSBox will try to switch the screen resolution to best match the resolution request by the application. For example, if a game in DOSBox is requesting a graphics screen resolution of (320 x 240) while your desktop is (1280 x 1024), DOSBox will perform the switch or try other resolutions that closely matches it, e.g. (400 x 300) if (320 x 240) is not available. Default is original. (since 0.62)
windowresolution = width x height | original
Scale the window to this size IF the output device supports hardware scaling (i.e. any output other than surface). Note that the window size actually has a fixed 1.6 aspect ratio, so if you ask for 1280x1024, you'll end up with a squished 1280x800 window. original means 1x zoom and will resize as the emulator switches graphics modes. Default is original. (since 0.62)
output = surface | overlay | opengl | openglnb | ddraw
What to use for output. Default is surface. (since 0.??)
autolock = true | false
Mouse will automatically lock, if you click on the screen. Default is true. (since 0.??)
sensitivity = 1..1000
Mouse sensitivity. Default is 100. (since 0.??)
waitonerror = true | false
Wait before closing the console if DOSBox has an error. Default is true. (since 0.??)
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: lowerest, lower, normal, higher, highest, and pause. Default is higher,normal. (since 0.??)
mapperfile = path-to-mapper-file
File used to load/save the key/event mappings from. Default is mapper.txt. (since 0.??)
usescancodes = true | false
Avoid usage of symkeys, might not work on all operating systems. Default is true. (since 0.??)
Deprecated parameters
fullfixed = true | false
Deprecated as of 0.65. See fullresolution. (since 0.??)
fullwidth = width
Deprecated with 0.62. See fullresolution. (since 0.61)
fullheight = height
Deprecated with 0.62. See fullresolution. (since 0.61)