Okay I'm assume the semi fixed resolution has to do with matching your art assets nicely however particularly in this day and age of LCDs it is nice to have the screen at native or near native resolution. Please consider post processing your frame buffer with something like HQ3X to upscale the frame buffer. http://www.hiend3d.com/hq3x.html You can probably find alot of useful information on this kind of stuff at dos box project ( however remember their code is GPL so don't go copying and pasting ( http://www.dosbox.com/ ).