more on PROM linux

[Albert Cahalan]

> So, at least to start, I am trying to figure
> out how much of the BIOS Linux needs; I am thinking
> of popping out the BIOS and having the system
> make a jump to the kernel.

Linux can optionally use the BIOS for PCI setup and APM support.
If you can eliminate PCI and power management stuff, then you
won't really need the BIOS. Of course, you must then find some
other way to tell Linux what the system looks like.

> Also, the BIOS  does things like power-on self test,
> interrupt handling, initialization of the verious ports
> and such.  How much of this do I need?

It depends on the motherboard. With a nice standard one, you will
only need to replace the 16-bit code that loads Linux from disk.
If you use the special AMD 486 chip w/o real mode, you could even
start with 32-bit code.

Once the system is running you won't need the BIOS. Before that,
you are going to need to get system information somehow. The
kernel does take command line arguments for hard disk geometry,
memory size, and other stuff.