> > Is it possible to use the PC BIOS INT 0x13 call from user space? The aim
is
> > to figure out from which device an "El Torito" cd-rom booted. Or maybe
that
> > interface is totally gone when linux has booted?
>
> It is too late by then - you can call it from setup.S though and store the
> value somewhere the kernel can get it back
Thanx for the hint. I started working with the idea to make the El Torito
boot device available through "/proc/eltorito_bios" and in not to long, I
had a patch ready that "should" work. But then I realized the real world of
tech specs... I have tried several different PC's with BIOS'es from five
different vendors (Compaq, AMI, Phoenix, Award and Adaptec (SCSI)), and I
have yet to find a BIOS that confirms to the El Torito spec! By calling BIOS
INT 0x13 func 0x4B, you can get info about IDE or SCSI, controler idx and
device specification (master/slave or SCSI PUN/LUN) about the cdrom unit
that booted us up. Only one (Award) sets the proper IDE/SCSI flags, on all
the others you don't know even that! Some BIOS'es starts enumerate the
controlers on 0, some on 1... Phoenix (you should think _they_ get it right
since they host the spec) even return one byte more data than specified,
dangerous! It seems hard to make something usefull out of this, but I
haven't given up yet.
Cheers,
Peter
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