IDEA: Linux kernel and pcbios compatibility...

Peter Lister prl at peterlister.co.uk
Sun Dec 21 18:28:01 CET 2003


On Fri, 2003-12-19 at 00:36, Eric W. Biederman wrote: 
> Brainstorming earlier today I think I have found a way to use
> an linux kernel for the boot loader and to implement pcbios
> compatibility without too much cost.   The idea is to use
> a uclinux kernel.  And implement a ``user space'' aplication
> that is a user space shim that makes kernel calls.
> 
> There are a few nasty details to work out like how to handle
> services that are expected to work in vm86 mode.  But I'm
> not certain I care.  
> 
> Other thoughts?

Curse you, Eric, this was my idea. :)

But I approached it from a different angle. Getting Etherboot (the
driver library and higher level code) to export PXE - effectively
Intel's retrofit of networking code into the legacy BIOS - is similar to
exporting LinuxBIOS's hardware initialisation library and a non-trivial
OS via PC BIOS services. If VMWare, bochs or whatever can do it as a
user space process, then it can be done all of a pece in firmware,
right?

[For those of you not on etherboot-developers, I've waved my arms about
recently at Eric, Ken Yap and others about how to resurrect the PXE code
in Etherboot].

And yes, the "interesting" stuff is how to switch modes as appropriate
and to sort out how to organise memory without frightening the horses.
I'm on a very steep learning curve. And on the bottom of it, frankly.

The only difference between us is that I was thinking of building this
on eCos, not uclinux. eCos is designed to minimally load only those bits
of functionality needed. I don't think this affects the basic idea.





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