Subject: Re: netbooting rev C iMac without NFS and ofwboot?
To: None <port-macppc@netbsd.org>
From: Kirill Levchenko <kirill@lava.net>
List: port-macppc
Date: 03/16/2004 21:45:56
On Tuesday, March 16, 2004, at 03:31  PM, Chris Tribo wrote:

> 	Is there a reason this shouldn't work?

The kernel ELF executable is probably not "properly conditioned" to be 
loaded with Open Firmware. For example, for XCOFF loading on earlier 
revisions, the sections have to be on page boundaries; I suspect this 
is what is causing your error. The kernel image is meant to be loaded 
by ofwboot.xcf.

> Why is ofwboot.{xcf,elf} trying to connect to portmapper to
> find the kernel on NFS?

This is how ofwboot works; it fetches the kernel via NFS.

> What's wrong with sending it out over tftp?

This is a good question, and one that I have recently asked myself. 
Perhaps some of the more experiences users can comment on this. My 
guess is that having it on the NFS server, together with the rest of 
the file system, gives the booted machine the same "view" as a machine 
with a real disk, in the sense that the kernel image is sitting the 
root directory. This may be useful for debugging, etc. Another 
possibility is that Open Firmware's TFTP is not reliable enough for 
transmitting such a large image, though this is probably handled 
well-enough at the link (ethernet) level.

For the same reason, why don't we boot the kernel directly from the 
first-stage bootloader? From the Apple partition map info it looks like 
we certainly have enough room to place a capable-enough bootloader 
there.

> 	The same thing happens with netbsd-INSTALL ungzipped. Does
> everyone set up an NFS server just to netboot an install kernel?

Yes. Presumably, the idea is that the reason you are netbooting is 
because you want to run the machine diskless.

Kirill