Yuk. I would think that a OS interface library might help here. Linux, Mac OS and *BSD are all pretty much the same for the basic I/O and all three support most of the basic low level OS stuff from open/close/read/write to mmap/semphores etc.. Where they differ is in UI and specifically GUI. I wonder if you considered something like QT for everything but DOS, I would like the amount of OS specific code you had to deal with I would hope would drop substantially. QT would look like ass, frankly, esp on OS X. I'd go for SDL and just make the UI a framebuffer thats a DOS screen with the same inputs as the DOS version. No need to write any manuals either :) Or SDL and a Star Trek interface or whatever, but all the cross-platform GUI stuff looks TERRIBLE on OS X. Sampsa