legacy BIOS usage

Ryan Underwood nemesis-lists at icequake.net
Mon Dec 8 07:48:01 CET 2003


Hi,

I had the idea of using LinuxBIOS but also maintaining a legacy BIOS for
debugging and dual boot scenarios.  It would be linked into the
LinuxBIOS image and jumped to alternatively depending on the user input.
However, thinking about this gave me 2 questions:

1. Are there any forms of user input possible into LinuxBIOS loader?  Is
the system initialized enough to accept a keyboard input, or ACPI system
button, or even something sillier like checking if a PS/2 mouse is
plugged in (the user can unplug the mouse to signal LinuxBIOS to jump to
the legacy BIOS instead).

2. Is it possible to get the machine into a state where it can check
whatever form of user input is possible, but still be able to then put
the machine back into a state where the legacy BIOS won't be confused.

Or could something like this be done via the reboot vector instead?
Power on clean gets you LinuxBIOS, but reboot goes to legacy BIOS... I
guess the problem there again would be putting the hardware back into a
state that the legacy BIOS can use.

any ideas on that topic?  It would be nice to use FreeDOS occasionally
for testing some external hardware control programs, but FreeDOS
requires a PC BIOS, of which there are no open source implementations
that I know of. :(  Maybe that can be a project for the future, but
somehow I see a lack of interest in putting any new effort into a dead
platform, so using the legacy proprietary BIOS might be the only real
world choice.

p.s. there is a broken Microsoft link in the FAQ, it is here now:
http://www.microsoft.com/whdc/hwdev/archive/BUSBIOS/pciirq.mspx

-- 
Ryan Underwood, <nemesis at icequake.net>
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