PXE stack on bootrom [Was: Re: [syslinux] pxelinux fron Floppy disk?]

[H. Peter Anvin]

Martijn Bakker wrote:
> 
> If I understood well, there is a spec of the protocol. And it seems logical
> that there are specs of how to build such an image, because it's already done
> (correct me if I'm mistaking). Is there some special machine code the roms
> have to be in, or is it just plain old i386 ? It sounds like a nice project
> to freshen my (reduced-to-zero) ASM knowledge, and if it's not i386 then
> still it sounds pretty nice. 
> 
> Do you have more info about that ?
> 
> Another thing: _if_ I will do this (it's definitly not sure I will) I'd like
> to have some hardware sponsored for testing (not really big stuff, just a nice
> flasheable nic or so). I saw some big(ger) names passing this list, so I'm
> sure something can be arranged or so. *this is just an early request to see
> if there's animo for this. it's not nessecary, but it would be nice*
> 

There is a spec, and my understanding is that it is based at least in
part on the NDIS 2.0 specification, so it *MIGHT* be possible to create
a generic kit that uses an NDIS 2 driver.  Otherwise using a modified
Etherboot or Netboot would be a sensible option.

The ROMs are just i386 machine code, typically, with a special (not
particularly complicated) header.  A lot of them are written with a
compressed header in order to get more code.  The PXE stack is
invariably loaded into the high end of conventional (lower 640K) memory,
 although it frequently is at least partially written in protected-mode
code (there is a 32-bit PM entry point, which you must be able to handle.)

	-hpa