DOSEMU VGA graphics on a FrameBuffer (Was: Re: DosEMU, Ghost: VGA screen garbled...)

["Frantisek Rysanek" <Frantisek.Rysanek@post.cz>]

On 18 Sep 2009 at 21:11, Alain Mouette wrote:
>
> Would it be possible to run dosemu over a simple system like framebuffer?
> 
> I am interested in making a simple linux, with something like BusyBox, 
> only to run dos programs...
> 
> Alain
> 
While I was looking for some solutions to my problem, I noticed 
there's vgaemu - the emulator that's used to display VGA graphics in 
a window under XWindows. Immediately it occurred to me that it might 
be useful to run run vgaemu outside of X, in "console mode", i.e. 
rendering its output into a (Linux standard) framebuffer.
According to some notes in the documentation, this is possible if you 
compile DOSEMU with support for SDL (configure --with-SDL, if memory 
serves). The SDL library can work without X and in that case, it 
renders its output into a framebuffer device. Obviously you need to 
have SDL installed in the build system first (and included in your 
target distro). SDL support is a DOSEMU plugin and you need to 
explicitly ask for that at compile time (configure time, really) as 
well as at runtime, by including the -S cmdline switch.

I do have that compiled in, but I haven't gotten as far as actually 
testing that feature, because others have pointed out a better way of 
making VGA graphics work for me :-)

BTW, what graphics hardware do you have in mind? Have you met some 
framebuffer graphics device coupled to an x86 CPU, that is not VGA 
compatible? Okay, I know the VGA compatibility can have glitches... 
If you did have some such VGA-incompliant graphics device, you might 
face other challenges, such as getting a Linux kernel framebuffer 
graphics driver for that, or direct support (driver) in SDL...

Good luck with your DOSEMU mini-distro. I suggest that you include a 
bootloader option to boot plain DOS (FreeDOS?) straight on bare metal 
:-)

Frank Rysanek