- 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.
Virtual mode. Hm. What's if the VGA-rom wants to write to a port we didn't accept? This could cause in no display. :) The best Idea is to support Standard-VGA-Cards. Nearly every card is compatible with it (look at the Linux-kernel, i think it's got it's own VGA-driver, right?)
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.
That's the reason why we NEED a modulary-design like the linux-kernel. a gzip-compression like the linux kernel (an analogy to the LHA-compression of Award-Bioses)
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?".
By writing the standard data onto the ports. (i hope so, i think we have to test this)
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.
Funny. :)
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".
Yeah, i've got a FIC VA503+ (Via MVP3-based) Rulez! :) But my father's got a VB601 (Intel 440BX-based), of course we need drivers for this chipset, too I think we should make a list of the most popular chipsets. And, of course, a generic-driver. But the biggest problem is: If somebody decides to flash his board with the openBIOS, there is no turning back, if it isn't working he has got a problem! :)
Ciao, Stephan [SpaceNet-Systems]