Problems with the loader

[Peter Grehan]

Hi Philip,

>  1. Hold down 'C' while booting: I can hear the CD spin up, it seems
> like there is disk activity but then the drive spins down again and Mac 
> OS X is started.

  Hmmm, that one's supposed to work. I even tried this out on the same 
model Powerbook, but a 15", the other day.

  One big advantage of these models is that the internal keyboard/mouse 
are USB so will work without an external keyboard.

>  2. At the Open Firmware prompt, type "boot cd:,\boot\loader": The
> loader starts, but says: "can't load 'kernel'" and then "no bootable 
> kernel"

  Close ! :)

  For a manual load from the cd, you have to pass 'cd:0' as an 
additional parameter e.g.

  boot cd:,\boot\loader cd:0

  The problem is that giving a colon without an explicit partition 
number  means the loader will use the 'default', or bootable, partition. 
Since cd's have to be created in hybrid HFS/CD9660 format to be 
understood by OFW, they have a partition table which has a partition 
that contains data but not the pre-iso9660 sectors (cd:3). This confused 
the loader since the partition it reads from have iso9660 offset values 
that appear to be incorrect, since offset 0 is actually the start of cd:3.

  I did hack up a loader to add this value to iso9660 offsets if the 
sniff test failed, but even this didn't work on all systems. The easier 
workaround was to use the extra parameter to boot.

>  3. I have tried to explicitely tell the loader where to load the kernel 
> from by issuing "set currdev=cd:," and then try to type "boot" again. 
> Unfortunately that didn't work, either. Makes sense, since the loader 
> prints the correct boot device when started. Tried "boot /boot/kernel" 
> and then the loader complains "Cant't find /boot/kernel".

  Close: as above you need 'cd:0'. At the loader prompt you can issue 
'ls /' to see if that worked, or even 'ls cd:0/' before currdev is changed.

>  4. Also I have tried to copy boot/ from the CD to the internal harddisk 
> an boot from there by saying "boot hd:,\boot\loader" at the Open 
> Firmware prompt. Same effect as in 2.

  Makes sense: the loader will use the volume it was booted from to try 
and load the kernel. Since 'hd:' is most likely HFS+ formatted, the 
loader won't be able to read it.

later,

Peter.