Sun Open Firmware - insiders?

[Guy Sotomayor]

On Mon, 2005-12-19 at 12:23 +0100, Arno Kletzander wrote:
> Stan Barr <stanb at dial.pipex.com> wrote:
> 
> > (...) Open Firmware - a superset of ANS-Standard Forth used for 
> > detecting and setting up the hardware etc. on Sun, Apple and some 
> > IBM machines.  It can be accessed from the console as well, allowing
> > you  to probe and set up hardware manually should you need to, or 
> > as a normal Forth of course...
> 
> This seems like a good time to tap into the collective knowledge on this
> list once more...
> 
> I have a question regarding Sun OpenFirmware that's been bugging me for
> some time now. I'm still struggling for a setup that allows a Sun to netboot
> off a Windows 9x PC (just get a bootstrap, no fancy NFS exports required).
> I'm making do with SuSE Linux 7.0 dual-boot right now, but that's not it.
> 
> What I'm imagining here is to have a look at the code that is responsible
> for the netbooting operation of the Sun. Why does it have to obtain the
> machine's IP, that of the tftp server and what else via rarp? I'm by no
> means a Sun expert yet, but as I've understood it, you can define your own
> FCode commands and store them in NVRAM, so one could modify the boot code to
> use parameters stored in environment variables, either if a flag
> "use-stored-IP?" is set or as a fallback if there's no rarp server around.
> 
> I've already got myself a Forth book and the FCode manuals from Sun, and I
> had a look at some commands with "see". "see" however often spits out
> hexadecimal codes in parenthesis amidst of Forth words and I've yet to
> understand what they mean; the manual addresses the problem only far enough
> to tell that this doesn't happen if words are defined with the "headers"
> directive.
> 
> If somebody has been involved with FCode stuff far enough to give me some
> initial guidance, please contact me. Thanks in Advance.

You probably want to look at IEEE 1275 and various related specs.  '1275
was the IEEE spec that defines the open firmware specification.  The
best web site for it is:
	http://playground.sun.com/1275/home.html

BTW the "hex" codes you're seeing are the byte codes defined by Open
Firmware.  It is also true that to fully understand Open Firmware you
not only need to have a good understanding of forth but of the Open
Firmware environment.


> 
> Yours sincerely,
> 
-- 

TTFN - Guy