Re: Booting from HDD

Good morning all,

This is from the color.lst

 92 008c E85F00           call whereami ;# set EBP to where we relocated
  93 008f E89E00           showprogress
  94 0092 66E80D01         data32 call protected_mode
  94      0000
  95                  .code32
  96 0098 E84F0100         call a20 ;# set A20 gate to enable access to 
addresses with 1xxxxx
  96      00
 
So it does look as if it is fine up until "call protected_mode" then the 
problem is somewhere after that point...
But please don't spend more time trying to work this one out for me--it 
works with the USB floppy so I'm happy now!  Of course, if anyone wants 
to go further then I'm happy to help.

And anyway, unless floppy emulation can be forced in BIOS, wouldn't the 
INT 13 read/write routines have to be changed to work on drive 0 instead 
of first floppy?  Hey, I might try anyway, but these things are never 
*that* simple are they?

Thank you,
Jason

Nick Maroudas said the following on 17/03/2008 09:16:
> Nick here,
>
> Thanks Ray, for your boot.asm printout (below).  It
> shows a boot process that has already set up video
> 4FO2/4117 and copied the 512 byte boot sector before
> relocating to "at0:" to copy the remaining code via
> floppy then jumping to "start2" via the floppy call
> "stop" motor.  For comparison, here is JC's boot.asm. 
> Unlike yours (or Howerd's original CFDOS4 floppy) this
> CD version does not set up video before relocating, and
> seems to rely on MSDOS or ElTorito (non-emulation
> mode) to have copied all of the code before setting up 
> the Graphic Output Display ("god"). See lines 98, 99 in
> JC's version (below). This is a long way from the
> simplicity of Chuck's original boot.asm (which one can
> consult on JC's site under "as/", together with a very
> helpful commentary by John himself). As Albert van der
> Horst has just remarked, "CF is simple but this is the
> other side of the coin".  I find that Howerd's
> CFDOS4.blk (simply DeeDee'd onto a floppy) boots a new
> Pentium D with no OS apart from BIOS, but John's CFDOS4
> CD does not.
>
> IMHO Jason is on the right track: floppy emulation; just
> dd a reliable floppy image onto the flash stick 
> (after all, CF is meant to be self booting). I could
> expatiate if anyone is interested.  
>
> Caritas, 
>
> NickM 
>
>
>   
>