Hardware

PPC macs used open firmware to boot, and their videocards contained forth code in their rom. There are even custom roms for PC video cards which contain code for the PPC mac open firmware.

Could such a card be initialized as the primary display device on an Ultra 5?

I'm betting I'm going to be answered with 'use a sun branded card'. I can't imagine the rom on these cards is so much different than that used on the PPC mac?

What exactly does Open Boot do to find a videocard? Are there any documents on this? I assume it finds some forth routine in the cards rom and runs that to initialize it and identify it's capabilities? Again, I would really appreciate some direction on where to look for docs.

I'm confused on the difference between openfirmware (apparently a spec), and open boot (sun's implementation? Are all implementations compatible with eachother?)

http://www.openbios.org/Welcome_to_OpenBIOS
"Open Firmware is found on many servers and workstations and there are several commercial implementations from SUN, Firmworks, CodeGen, Apple, IBM and others."

Additionaly, what is the sun4u architecture? sun4v architecture? Which workstations are which? System handbook doesn't seem to say under 'hardware specs'.

So, if all else fails and using a card with an openfirmware rom doesn't help me, how do I go about doing this myself?

I know how to work VGA console mode via the stardard vga registers, Is there a way to get open boot to do exactly what I tell it in terms of registers and addresses?

Can I get an uncompiled form of my Open Boot Prom for my Ultra 5?

All I'm really looking for is good docs/source on how Open Boot/ Open Firmware work, specificly conerning PCI video devices.

Thanks for any tips.