1st note: you do not need to (and never needed to) disable shadowing if
you use graphics in xdosemu, which is quite usable nowadays, but in
certain cases too slow, for some graphical programs not perfect and not
full screen (your apps run in the "DOS in the BOX").

Only on the linux console, IF your graphics card is supported by DOSEMU
and IF you run DOSEMU as root or suid-root you *might* need to have to
turn off vbios shadowing. There are quite a few graphics cards out there
that DOSEMU does not support, and moreover suid-root is discouraged.

On Fri, 20 Sep 2002 [EMAIL PROTECTED] wrote:

> Why was it programmed this way? 

Nothing really intended - DOSEMU basically mmaps the contents of
/dev/mem to 0xc0000-0xc8000 or some such, if it has permission to do so.
Otherwise console graphics don't work.

> Why does one have to disable video/bios shadowing? 

I guess because the RAM that is used for the shadowing at boot time 
might be overwritten by Linux and things get messed up. This is highly
system dependent; that's why I said *might*.

> Is this the only programming solution that had to be done or could there have also 
> been another way that probably would've been a lot more challenging to 
> implement but would've allowed people to run there graphical games without 
> any requirements to disable video/bios shadowing in the first place? 

yes, that's called "vgaemu" and is what you use when you run graphical 
applications in xdosemu - no need for a graphics card specific video
BIOS, so shadowing is irrelevant.

simply run them in xdosemu or wait for "vgaemu on console or fullscreen 
X" support, that does not need the systems BIOS or root privileges.

Bart

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