klibc - Dec 2004 - Newbie Question

Hello,

   I'm attempting to convert some of my existing initrd images to the 
new initramfs format.  However, I have some questions as too what 
exactly /init in a iniramfs system is responsible for?  My current 
images probe/configure devices using devfs and libkudzu (basically, the 
same as knoppix detection setup) and create a tmpramfs root for use with 
pivot_root.  However, looking thru prepare_namespace, it appears that MD 
arrays need to be detected/fired up as well as the root changed.  Would 
my /init need to do something to startup MD arrays ?  Can I still just 
mount devfs on /dev as I do in the initrd images or do I need to do some 
lower level setup first?

  I'd also LOVE the ability to 'chain' initrd images - I use the
gentoo
splashboot stuff, and its a nuisance to recompile the kernel just to 
change the theme (themes are stored as part of the initramfs) so I'd be 
passing the initramfs via 'initrd=' on the command line.  However, that 
means I can't specifiy different initrd .... so it would be nice to be 
able to specify both on the command line, or to chain from the initramfs 
to a initrd image.  Can I do this just by adding something like 
MY_INITRD= foo on the boot line, then mounting the initrd on a ramdisk 
from inside the initramfs and handing off to the initrd when I'm done ?  
Or is it still too early in the boot process for that ?

Steve

On Fri, Dec 24, 2004 at 03:09:31PM -0800, steve wrote:
> it would be nice to be able to specify both on the command line, or
> to chain from the initramfs to a initrd image.
I _think_ the code that unpacks initramfs archives can handle
concatenated cpio files, but you'll have to try it to be sure.  You'd
still have to concatenate them into a single file ahead of time but
it'd be easier than creating a new initrd filesystem image.
> Can I do this just by adding something like MY_INITRD= foo on the boot
> line, then mounting the initrd on a ramdisk from inside the initramfs
> and handing off to the initrd when I'm done ?
That sounds like it might work, perhaps depending on exactly where in
the boot process you intend to do this.  Obviously if you want to do
it prior to the disk/bus/filesystem drivers being loaded, it could be
a problem :-)

                                                  -Dave Dodge