On Sat, 13 Mar 1999, [iso-8859-1] Stephan M�ller 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 -- David Coffin Evening: 781-397-9932 967 Salem Street Daytime: 978-686-6468x341 Malden, MA 02148-4515 E-mail: dcoffin@shore.net