Re: parted and partition types

[Hollis Blanchard]

On Sat, 11 Nov 2000, Andrew Clausen wrote:

> Hollis Blanchard wrote:
> > 
> > I understand the problem. The DOS partition number do have corresponding
> > text labels though, so I think it would be possible to print that (along
> > with Apple labels).
> 
> It still doesn't help with changing the "labels" though.  With Mac's, you
> could set the type to any name, but with msdos/pc98/bsd, you have to set
> it to a name corresponding to a number.  These are still different
> semantics.

Parted does handle differing semantics already, for example with the 'boot'
flag... but I think you're correct that arbitrary partition types are not
especially useful.

> > Well, here's my problem. I want to install ybin (basically a bootloader).
> > ybin needs to be on an HFS partition (for the firmware to be able to boot),
> > but the Mac OS automatically mounts Apple_HFS partitions (and can do bad
> > things sometimes). So ybin likes to be on a partition of type
> > Apple_Bootstrap - that way nobody except ybin will mess with it.
> 
> RTFM ;-)
> 
> set X boot on

Nice!

But I have an important clarification for the manual. The type
'Apple_Bootstrap' is artificial - Ethan Benson made it up. The Mac OS looks at
the type, doesn't recognize it, and so skips it (doesn't mount it), which is
what Ethan wanted.

Setting a partition to type 'Apple_Bootstrap' alone does nothing for the
firmware or affect booting. It's the Open Firmware 'boot-device' variable that
specifies the boot partition and binary. With a vague boot-device (like the
default, hd:,\\:tbxi), OF will search for something to boot, attempting to boot
from the first non-driver partition on the disk (be it Apple_HFS,
Apple_Bootstrap, or whatever).

Also, yaboot does not require its own boot partition - it runs quite happily
in any directory on an HFS or HFS+ partition, including out of the Mac OS
System Folder. If you want OF to boot yaboot automatically (without fussing
with the boot-device variable), *then* it needs to be on its own partition.

Oh, and quik is far from popular. :)

> > Oh, another problem: for PReP machines (old IBM PPC workstations), the
> > firmware will only boot from a partition of type 0x41 (PPC Boot). That
> > partition does NOT contain a filesystem, only a zImage dd'ed there.

[snip]

> I'd rather add more flags, than introduce partition type names, or
> something.

Ok, would you add a flag that sets a partition type (in a DOS partition map) to
0x41 so that the firmware will boot from it?

-Hollis