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Re: What is this Apple Bootstrap thing of which the installer speaks?

On Tue, May 3, 2011 at 10:00 PM,  <annathemermaid@hush.com> wrote:
> Hash: SHA1
> Hello!
> So, I was trying to install Debian on this old iBook, and
> apparently yaboot wants an Apple Bootstrap partition of a
> particular size. I don't see a way to create such a thing in the
> partitioner, and I would think it is something Mac OS X ought to
> have created?

No, the Apple Bootstrap partition has nothing to do with Apple or the
Mac OS. I think I've finally got this thing figured out, so I'll try
explaining it.

(I haven't done debian on my iBook yet, my G4 is borken (stupid cold
solder problem on a chip that I understand is supposed to the graphics
controller) and my clamshell has been claimed by my son. :-/  Part of
the reason I'm playing with Debian is precisely that Fedora dropped
the PPC from F13 to F15. Bad luck is good luck. 8-)

Apple used to use what it called "blessed folders" to boot. (Don't
know if they still do, I bailed when I learned the switch to intel was
a one-way trip.) Nothing really special, the "blessing" was a way to
let the boot selector application figure out where system stuff was
when you multi-boot different versions of the Mac OS. The Boot
selector would tell the actual bootstrap code where to find the
appropriate bootstrap, and it had its own 8G limits back before the
iBook days. I blogged about installing Fedora on the old clamshell
iBook, not sure if it will be more informative or more confusing to
look at:


Short version is that the bootstrap code on Macintosh style
partitioning was expected to be in an HFS volume. So you need an HFS
partition to hold yaboot's bootstrap code.

openBSD just lets you use any old HFS partition, including one being
used to boot either the now-ancient classic system or the older PPC
Mac OS X system. (Things have changed a bit for the intel Macs.) But
they warn you about the 8G limits in early "new world" machines and
expect you to deal with that yourself, and they also expect you to be
able to type commands in at the openfirmware prompt. (I like openBSD,
even if I tend to work in the more dressed-out Linux environments.)

yaboot avoids direct interaction with the openfirmware prompt by
making its own tiny bootstrap volume. That's the so-called
applebootstrap partition/volume. It's separate to make sure it's small
and can fit under the 8G limit, I think.

That means that if you want to use LVM, you'll need at least three
basic (Macintosh volume) partitions: (1) the tiny one to pass control
from the Apple boostrap code ("ROM" that isn't) to the Linux kernel,
(2) then usual root partition, and (3) the LVM partition to split up
into Linux partitions for the rest.

Dual booting does work, but you really have to practice a couple of
times before you get it right for you. Don't expect to avoid backing
up anything you would rather not lose, you're going to wipe that disk
completely at least once.

> Unfortunately, the Mac OS X partitioner really isn't
> that powerful.

Well, yes and no. But I tended to use both the classic HD Utility and
the Mac OS X HD Utility on machines that boot classic. That helped
with making sure I had a readable classic partition (for triple boot).
There is also a pdisk utility that you can use in the Mac OS side of
things, that might help, in addition to the mac-fdisk mentioned by
Roger Leigh. I'm not sure which is newer and more supported.

You might be able to try tricks like allocating one partition for the
Linux stuff with the Mac OS partitioning utility, then using the
installer's partitioner (gparted?) to remove it and add the three
Linux partitions.

The Fedora installer was able to make the small partition on my
iBooks, except, not on my clamshell if the drive was larger than 120G.


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