On Sunday, February 6, 2005, at 08:21 PM, Peter Seebach wrote:

> In message <CF70EB20-78A5-11D9-B735-000D93B85D1A@nosflow.com>, Michael 
> Wolfson
> writes:
>> On Feb 6, 2005, at 5:01 PM, Peter Seebach wrote:
>
>>> I am being totally stumped.  I have found a whole bunch of different
>>> documents
>>> which refer to versions at least as far back as 1.6.1, and I have not
>>> been
>>> able to form a cohesive view of things.
>
>> Huh?  None of the NetBSD-related documents released prior to Jan 2005
>> mention the Mini.  What's the confusing part that's within the scope 
>> of
>> documentation that can be fixed?
>
> Well, it's all pre-Mini stuff, but I've been assuming it's like any 
> other
> OF3 system.
>
>>> The Mini has a fairly recent version of Open Firmware.  My
>>> understanding
>>> is that I should be able to access an Apple UFS filesytem from Open
>>> Firmware.
>
>> Nope.  OpenFirmware doesn't support UFS, only netboot, MS-DOS,
>> ISO9660,, and "sector zero" bootloaders.  Open Firmware 3 systems also
>> support HFS/HFS+, but the "sector zero" bootloader doesn't seem to 
>> work
>> with the technique we use to create it on pre-OF3 systems.
>
> Hmm.  Okay, so how does the Mac boot from a UFS root?  I know I had 
> mine
> doing that for a while.

It doesn't, the osx install partially repartitions the drive, adds a 
HFS+ partition
around 8 meg in size, and will boot to that.  Its type  Apple_Boot
and called MOSX_OF3_Booter, sometimes eXternal booter , there's 1 for 
each UFS partition.
And reinstalling, and erasing a ufs part, and making it HFS+, still 
leaves some cruft.  Under a macosx one can mount it with mount_hfs, and 
it looks like
#find . -ls
      2    0 drwxr-xr-x    4 root     wheel         136 Jan 13 23:48 .
     17    0 drwxr-xr-x    3 root     wheel         102 Jan 13 23:48 
./External Booter
     18  304 -rw-r--r--    1 root     wheel      153778 Jan 13 23:48 
./External Booter/BootX

and df shows its only at 3% capacity, so there's room for other files.
There's also a partition of type Apple_Loader called SecondaryLoader 
that contains a
Mach-O executable ppc.
An opendarwin list has some info:
  http://www.opendarwin.org/pipermail/discuss/2003-September/004163.html

I was able to recreate a MOSX_OF3_Booter partition as hfs, not hfs 
plus, and boot
10.2.1 from it ( as a test ).  I did it adhoc, but it might be possible 
to do with the right osx bless command -- which has a -format option.  
There is room for ofwboot.xcf and
a few kernels,  I was able to share this boot partition and boot netbsd 
or osx from it.