AW: Here's a plan

[David J. Coffin]

On Sat, 13 Mar 1999, [iso-8859-1] Stephan Müller wrote:

> > 	Proposed OpenBIOS Boot Specification
> >
> > Pre-boot:
> >
> >      OpenBIOS performs the following steps:
> >
> > *  Switch the CPU to 32-bit protected mode.
> > *  Detect the DRAM and set chipset registers accordingly.
> > *  Enable devices on the Super I/O (floppy, COM ports, etc.)
> * initialize VGA-BIOS (call it), but this has to be done in Realmode, right?
> a little problem....

     Yes, that's a real problem.  You could switch to Real
Mode, execute the ROM, and switch back.  Or you could run
it in Virtual 8086 mode, which would provide more control.
Or we could just handle the device ourselves, like Linux
does.

     I don't like adapter ROMs.  They are, in effect, device
drivers written for an obsolete CPU architecture (the 8086)
and an antique operating system (DOS).  And they are always
closed-source, usually bearing the message "DECOMPILATION
OR DISASSEMBLY PROHIBITED".

     There are really two problems we need to solve:  VGA
and SCSI.  The OS can take care of everything else.

     All VGA cards support 80x25 text mode in hardware, and
that is sufficient for our needs.  We don't need any of the
INT 10h services, so the only question left is "How do I
turn on this card?".

     For SCSI, we'll offer stripped-down replicas of the
Linux SCSI drivers.  If your SCSI card is not yet supported
by OpenBIOS, you'll need to load the OS kernel off a floppy
or IDE drive.

     On another topic, should we all work on different
motherboards, or focus our efforts on one?  My choice would
be one of those new 100MHz Super-7 boards with a VIA Apollo
chipset, because it's the fastest board you can get with
"No Intel Inside".
				Dave Coffin  3/14/99
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