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From: Toerless Eckert <eckert@i4.informatik.uni-erlangen.de>
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In-Reply-To: <XFMail.20030411144252.jhb@FreeBSD.org> from John Baldwin at "Apr
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To: jhb@FreeBSD.org (John Baldwin)
Date: Sat, 12 Apr 2003 01:57:14 +0200 (MEST)
Organisation: CSD IMMD IV, University of Erlangen, Germany
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Subject: Re: boot2 broken ? (booting from pst fails)
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> > - Q: Is btx actually switching to real mode for int 13 ? Could it be
> >      that there's a bug in that code ?
> 
> No, we run it in virtual 86 mode, and it is likely that their BIOS
> routine just can't handle that.
>
> > - Q: Are there any alternatives how i could boot a 4.8 or 5.0 freebsd
> >      solely from the disk ? (I guess i could try to install a linux and
> >      then use liloboot, but that also uses the btx code from loader...)
> 
> Nope. :(  Other than get promise to fix their BIOS maybe.

- Why is the BIOS routine not run in real mode ? Would it be hard trying
  to change BTX so that it executes the interrupt in real mode ?

- Is there actually a requirement for a BIOS to work correctly
  in virtual mode ? I was under the assumption that BIOS is always
  only assumed to need to work correctly in real mode. If this is
  not true, then i would welcome if you could point me to an official
  PC98, .. (or whatever) document WIntel , or
  whoever leads the conspiracy what officially are requirements for a "PC").

  Without such a reference i think anybody would have a hard time arguing
  the case of requesting support for virtual mode from the BIOS of some
  HW vendor, right ?
  
- Do you know wether Linux relies on virtual mode in booting their kernel ?
  because the vendor in my case is officially suporting linux. I guess i
  need to test setting that up and see if i can boot it from the disk.
  

Thanks
	Toerless