Subject: Re: tftp boot
To: Ted Lemon <mellon@hoffman.vix.com>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: port-pmax
Date: 07/06/1997 12:56:10
>I think you're on the right track, but I don't know what specifically
>you'd need to do to make the PROM do the right thing.  It may be a
>section alignment problem.

I have a (very ugly) version of elf2ecoff which produces ECOFF kernels
which will boot on a rev 2.1k 5000/150.  I tried a *lot* of changes;
in the end, I found I had to do two things:

	* fill out the section names and flags for the three
	  previously-uninitialized sections as .rdata, .sdata, and .sbss.

	* output a (broken) debugging symbol table.

Just truncating the ECOFF sectionheader to three section headers
wasn't enough.  I'm guessing the PROM is being dumb and reading
page-sized chunks.  If so, writing a page of paddding to the end of
the file would work, too.

But fixing an ECOFF symbol table means net-booters could TFTP an ECOFF
kernel directly from their diskless-boot root directory, and we could
maybe get rid of a.out kernels altogether.

I've put the new elf2ecoff on ftp.netbsd.org, if anyone wants to try
it.