Subject: Re: Choosing between kernels
From: Patrick Callahan (pac1@tiac.net)
Date: Sun Jun 17 2001 - 05:35:54 MDT
On Saturday 16 June 2001 17:52, you wrote:
> The 2.4.4 kernel I installed is giving me sound problems.
>
> How can I choose between kernels?
> If a decide to dump that kernel, how can I uninstall it?
>
You can have as many kernels installed as you want. There is no need to
un-install a kernel, but you could do it by deleting the appropriate files.
For each installed version of the kernel you need 4 things:
o a version of kernel itself /boot/vmlinux-version
o Data file /boot/System.map-version
o Data file /boot/module-info-version
o Directory /lib/modules/modules-version
In order to do anything with your kernel you will also need a way to boot it:
o a boot loader (bootX or yaboot). The bootloader will serve this purpose
for all versions of the kernel. You'll need only one. I use two BootX and
yaboot.
Where to put the kernel:
o If you're running Bootx to start linux, put the kernels in your Linux
Kernels folder or in the folder containing Bootx.
o If you are running yaboot put the kernels in /boot, the boot directory
under one of your linux installations.
Note that /boot is not the bootstrap partition. The bootstrap partition
another thing entirely and it contains what? I don't know but ybin puts
whatever it is there so you can use yaboot to start a Linux kernel.
In either case, BootX or yaboot, the /boot directory in linux must contain
the right System.map and module-info files corresponding to the kernel you
want to use. Also in either case you will need to have the set of modules
for the kernel in a directory under /lib/modules.
ls -lah /boot/System.map* module-info*
lrwxrwxrwx 1 root root 20 Jun 16 15:50 /boot/System.map ->
System.map-2.2.19-1i
-rw-r--r-- 1 root root 280k Jun 29 2000
/boot/System.map-2.2.17-0.6.1
-rw-r--r-- 1 root root 315k May 14 21:04
/boot/System.map-2.2.19-1i
lrwxrwxrwx 1 root root 21 May 31 06:48 module-info ->
module-info-2.2.19-1i
-rw-r--r-- 1 root root 11k Jun 29 2000
module-info-2.2.17-0.6.1-rw-r--r-- 1 root root 11k May 14
21:04 module-info-2.2.19-1i
I believe these two links are set up automatically but at different times.
The date on the System.map link shown above is the date of my last reboot.
While the date on the module-info is the date of my installation of YDL2.0
I may be wrong about the modules-info link. If you want to run different
kernels, try booting without changing the modules-info link and observe what
happens. If it doesn't get changed you may have to change it manually. ( On
the other hand, someone told me that module-info does not actually get used
during booting. Anyone know the real story?)
Good Luck
Pat
P.S.
Because we're not supposed to mount the bootstrap partition in linux or in
macos, I can't do a directory to see what's there. So the following is
unverified. Your milage may vary...
(The bootstrap partition probably includes
o a bootstrap loader that gives you a menu so you can choose MacOS or Linux
o a copy of yaboot.conf which tells yaboot where to find the kernel.
o a copy of the yaboot program. yaboot actually loads the kernel
anyone know for sure?)
You can also have as many versions of linux installed in as many partitions
as you want.
This archive was generated by hypermail 2a24 : Sun Jun 17 2001 - 04:41:12 MDT