Hi,

> making bootable SPARC & sun3 cdroms is fairly simple.  here's the scoop:

[ Essentially correct description deleted ].

> (BTW, this is how the sunos4 cdroms work.  the solaris 2 ones put
> a UFS filesystem in place, rather than an iso one, and boot directly
> from the cdrom, rather than via a special kernel).

This might be a bit missleading.  Both sunos4 and solaris have a 9660
filesystem at the start and some UFS filesystems after that.

With solaris, all UFS partitions but the first (i.e. partitions 2-5) only
have a redirector, namely a file named ".SUNW-boot-redirect" with only
a line reading "1" in it.  Apparently this is interpreted by the prom
to boot from partition 1 instead.  This partition is a standard UFS
filesystem with all the stuff that is needed to run an OS and prepare
for the installation.

With sunos4, all partititons beyond the 9660 filesystem, i.e. partitions
1-n in the disklabel, have such filesystems.

The 9660 filesystem in partition 0 is mounted only during the installation
process to extract the files for the actual installation.

Now with NetBSD things are a bit different, as NetBSD doesn't interpret
the Sun disklabel on CDs.  I.e. CDs aren't considered to have partitions.

On the other hand, NetBSD can support a 9660 filesystem as the root
filesystem (actually, I'm not sure whether solaris supports this or not).

So with NetBSD you have to have all the utilities on the 9660 image.
The UFS filesystems behind that image are only used to get the boot code
and, if you want to make booting easier for the users, the kernel.
After that, when the kernel comes to mounting the root, it will mount
the 9660 image and look for /sbin/init etc. there.

Hope that makes things a bit clearer.

Ciao,
Wolfgang
-- 
ws@TooLs.DE     (Wolfgang Solfrank, TooLs GmbH) 	+49-228-985800