Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios

[Jamie Lokier <jamie@shareable.org>]

Sebastian Herbszt wrote:
> >We could have qemu do a soft reset (not reload rom) on a triple fault
> >or keyboard controller reset, and then have SeaBIOS request a hard
> >reset (have qemu reload rom) if it detects a soft reset that is not a
> >"resume" request.
> >
> >I'm also not sure what qemu does today.
> 
> I don't think such an interface would add a long time benefit and
> would prefer a proper solution which will not tie seabios even more
> to qemu. One day it might be possible to run a commercial BIOS on
> qemu, just like it is possible on Bochs.  Adding this interface
> might prevent that.

What does a real BIOS on real hardware do?

Do real BIOSes make a decision as described above, and we're just
assuming they don't?

One way to answer may be: On a real PC with i440FX, what kind of reset
are the different reset methods (triple fault, keyboard etc.) normally
configured to do?

IIRC, HIMEM.SYS in DOS must use at least one of the
switch-to-real-mode methods to work, and that driver is needed by
Windows 3/3.11/95/98/ME, but I'm a bit vague on the details.

-- Jamie