Booting from MAC partition, linux partitions, kernel images. - newbie information.


Subject: Booting from MAC partition, linux partitions, kernel images. - newbie information.
jlhagen@collins.rockwell.com
Date: Sun Oct 22 2000 - 07:59:53 MDT


Hi,

I'm new to linux on mac and since it took me a little while to first figure
it out I thought I would post my current situation for the list archives.
Maybe some new people will find this and it will be useful to them. First
this is a brand new G4 machine. The keyboard will work with the latest
1.2.1 version only.

We kept a small mac partition, hd10(using mac partition software). The
unix/linux partition is hd11(we didn't create separate /home /usr etc you
probably should). In the "system" folder on the mac partition we have
vmlinux, yaboot.conf, yaboot. It's this vmlinux kernel that will normally
be loaded by the different loaders for most people. We build and boot new
kernel images often so we made some changes in the yaboot.conf file to make
things easier.

I have set things up to boot into linux by default. If I want to boot the
mac os again I get into open firmware (hold O-F-alt-APPLE(?) keys at start
up) and
' printenv boot-device ' (first time you should see ' /AAPL,ROM ')
' setnenv boot-device /AAPL,ROM '
' mac-boot ' (this boots the mac os for us)

To get yaboot to run on this machine I boot into open firmware again and
' setenv boot-device hd,yaboot ' (this is a little odd as you'll see the
syntax in the yaboot.conf file is different)
' boot ' (yaboot loads and I choose my kernel image)
I've seen different hd,\yaboot or hd,\\yaboot suggestions but these didn't
work for us. I find this a little odd because the ' hd,\\ ' syntax is used
in the yaboot.conf file. ???? Oh well the ' hd,yaboot ' loads my loader
that's for sure.

My yaboot.conf file is like this:
-- snip --
timeout=150
default = linux

image = hd,\\vmlimux
   label = linux
   root /dev/hda11
-- snip --

Note the ' \\' syntax!!! Don't ask me..??? This image is the default image
on the MAC partition. You can replace this image and boot from it but I
keep it as insurance and mostly boot from images in /boot on hd11.

-- snip (cont.)--
image = hd:11,/boot/vmlinux-2.2.17-0.6.2
  label = 1
  root = /dev/hda11

image = hd:11,/boot/vmlinux-2.2.17-0.6.3
   label = 2
   root = /dev/hda11
-- snip --

These are the images on the linux partition under /boot. To get to them I
again set the open-firmware boot-device to ' hd,yaboot ' and type ' boot '.
The green text comes up and I type in my kernel image of choice ' 2
<return> ' for example (hit TAB to see choices). ' uname -a ' confirms that
I did indeed boot the /boot/vmlinux-2.2.17-0.6.3 kernel. If I let the
time-out hit it will boot the vmlinux image from the system folder on the
mac partition instead.

As I said earlier we boot into yaboot by default by setting the boot-device
to yaboot and leaving it. In this configuration I have noticed from a cold
start that I have a video issue and don't actually see the loader's text
but a gray screen. It will still work, just type the label of the image you
want and hit return or just wait until the loader times out and it will
load the default image.

One thing that confused me was that there is a vmlinux sim link to
vmlinux-2.2.17-0.6.1 in /boot on the linux partition. At first I thought
yaboot.conf was pointing to that one but it is not. It can by modifying the
image to ' image = hd:11,/boot/vmlinux ' but otherwise it's not used, the
vmlinux image in the system folder on the mac partition is. Remove the sim
link and see for yourself.

I've rambled on enough, I hope this might be helpful to someone just
getting started.

John



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