[lug] need init parameter

Tim Klein teece at silverklein.net
Fri Jul 20 11:29:27 MDT 2001


On Friday 20 July 2001 01:10 am, D. Stimits wrote:

> Hmm. I know some parameters can be built into the kernel (such as
> bzImage), and rdev works by hexedit of certain bytes. One of those
> parameters is major and minor number of the root filesystem (which can
> be overridden via command line). Mostly I'm told that it is considered
> old and not too good of a style to rely on the kernel bytes for
> major/minor of root, that most init scripts pass this information.
> Sometimes via a detection routine. What I have not found is a case of
> whether the filesystem type is also embedded in the kernel image. It
> appears that most likely the filesystem type is embedded (as a default)
> along with the root device at the time the kernel is compiled. So if you
> were to build on one machine or partition then boot another, you'd need
> to either pass parameters or run rdev to hex edit; what I suspect is
> that if you were to change filesystem *type* from ReiserFS, it would
> panic and be unable to mount, due to not truly detecting partition type,
> but I don't know. And if rdev works on major/minor number, I see no
> reason why it wouldn't also attempt to get partition type at the same
> time. What would be *very* interesting is if you have found a way to
> create a rescue disk for your system which will boot with iso9660 as
> root? Have you worked on any kind of rescue system? Also, what is the
> content of your init file?


Well, I tried this.  My current system is Debian unstable, on hda2, ext2.  I 
have another bootable system that I am working on, LFS on hda7, resiserfs.  
The kernel for LFS was compiled in a chrooted environment, running on a 
reiserfs partition, thus it mounts that reiserfs partition as root just fine. 
I decided to change the root parition for that kernel, though (the LFS reiser 
one) to hda2, so it would try to mount a ext2 partition.  It was not built on 
an ext2 partition, so maybe this would give it trouble.

Well, it didn't.  It booted just just fine, mounting root as the ext2 hda2.  
So the kernel figured it out ok.  Of course, it was an ext2 partion, which 
might make a difference because that is so standard.  I don't have an ISO 
file system or the like right now to try, but I will have one soon.  I will 
let you know what happens then.

You are using initrd?  I am not, I wonder if that is causing the problem.  Of 
course, I thought initrd was made to solve these kinds of problems, but ... ?

Tim
-- 
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== Timothy Klein || teece at silverklein.net   ==
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== "Hello, World" 17 Errors, 31 Warnings... ==
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