[syslinux] Etherboot & pxelinux (was: thank you)

Peter Lister P.Lister at sychron.com
Wed Feb 6 11:04:23 PST 2002

> > In way way better and easier? When I have criticised pxelinux I think

Or "what way"... finger trouble, sorry

> I've looked into etherboot - my problems were:
> - Network card must be supported, and should (must?) be ethernet.
> I am booting token-ring clients with pxelinux.

Fair enough. It would be nice to have Etherboot ignore PXE's DHCP/TFTP
but use UNDI. I don't think there's inherently anything restricted to
ethernet, despite the name; IEEE 802 addressing, perhaps, and the
availability of polling drivers.

> - Configuration directly burned into the rom - no easy way to 'just change' the configuration.
> - The etherboot rom is card specific - no 'all purpose'-driver available

As mentioned, Etherboot can be pxe'd, and booted from other media; it's
pretty configurable via DHCP; indeed that made me prefer it to pxelinux.

> These come in part from the purpose it's designed for - it's designed 
> as a boot rom, not a bootloader. In some part one could argue about 
> doing things different in etherboot. I personally don't like the concept
> of putting together one file that contains everything (configuration, 
> kernel, initrd etc.pp), but like to have these in separate files as in pxelinux.

I concede that etherboot's origins as a rom image still show through,
but "not a bootloader"? OK, to be accurate, NBI is the OS specific
loader which knows about Linux or DOS, not Etherboot itself. Etherboot
loads an NBI image with OS specific bootloader, kernel and initrd; I
perceive that as a *good* thing. Together they start Linux with no other
help, so that sounds like a bootloader to me.

Etherboot and NBI could be extended to tftp a separate initrd, but
equally, pxelinux could be ported to Etherboot.

> BTW, would it really be possible to have some extension for etherboot
> to support PXE booting (e.g. via pxelinux)? So could etherboot create
> some PXE stack that other bootloaders would use? Did anybody already
> try this?

I don't know if anyone has tried (Ken Yap would probably know). If NILO
can be bugfixed and ported to Etherboot's dhcp, tftp and drivers, why
not? It could give a degree of control over PXE not normally possible
with Intel derived clients "free" with nic roms and wouldn't be as
broken. No need for pxelinux as such, since Etherboot is perfectly
capable of initiating Linux directly by NBI. It might also be
interesting for the 'doze users - e.g. an image with the pxe stack and
NTLOADER in one (no reason to go through the PXE cycle if you don't need
to), maybe BIOS code for a ramdisk and an "initrd", or even a "hard
vmware" virtual machine.

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