Re: UML support in 2.6

[Christophe Lucas <clucas@xxxxxxxxxxxxx>]

HC (hcubitt@xxxxxxxxx) wrote:
> Thanks for the note, Chris and Andy.
> 
> > > So I want to know if any of you folks have successfully
> > > used UML on 2.6.10?
> > 
> > Yes it works. I have using it. I have wrote one article on "how build it
> > on 2.6 and create a root_fs", but it will not help you, iit is in
> > french.
> 
> After some more research, I figured that although the project home page -
> http://user-mode-linux.sourceforge.net/
> mentions that kernels after the 2.6.9 support UML, the vanilla 2.6.10
> did not have it until I had patched it with the right patch from -
> http://www.user-mode-linux.org/~blaisorblade/
> 
> Now that I have compiled that, is my doubt- 
> How do I get a ext3 root_fs running? I am asking this because the
> suggested root_fs builder

The better thing if you really want to use UML to test it, is to built
by your own a root_fs:
 - dd if=/dev/zero of=root_fs count=1000 bs=1024 (it is an example,
 custumize it)
 - mkfs.ext3  root_fs
 - mount -o loop /mnt/dir_root_fs root_fs
 - cd /mnt/dir_root_fs
 - debootstrap sarge uml http://ftp.debian.org/testing (if you come from
   debian world)
 - modify : /etc/inittab to have : 
 	1:2345:respawn:/sbin/getty 38400 vc/0
	not :
	1:2345:respawn:/sbin/getty 38400 tty0

> http://umlbuilder.sourceforge.net/
> does not list a new distro like FC3 that I am using and it doesn't
> look like having support for ext3. And the pristine root_fs they have
> is for RH7.2
> 
> > > Can anyone suggest an better alternative to using UML for testing my
> > > changes to ext3 on 2.6?
> > 
> > UML is a good start.. You could test your changes on root_fs file :)
> >
> How? Supposing I have ext3 root_fs running, I copy my modified ext3 to
> the ../fs. directory in UML and compile another kernel in UML?

No you compile _your_ modified kernel (with your patches on ext3) and
boot it to a ext3 root_fs.

> I just checked out QEMU and from the first look it seemed like vserver or Xen.

Wow, I don't know vserver, but say that qemu is like Xen is a mistake.

Perhaps I say mistake, so correct me. It is like this I can go on and
improve.

	~Christophe


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