Description of problem:

When attempting to figure out what was going on at boot time I wanted
to fiddle with the initrd image. The kernel doc file
Documentation/initrd.txt only talks about loopback devices and
filesystem images. Meanwhile, the files actually being used by
the kernel these days are simply compressed cpio archives. (A fact
only learned after much web searching).

Version-Release number of selected component (if applicable):

kernel-doc-2.6.17

How reproducible:

always

Steps to Reproduce:
1. try to understand initrd images by reading kernel docs
  
Actual results:

Total confusion and misinformation.

Expected results:

Useful data :-).

Additional info:

Much web diving finally produced this command to examine an initrd
image:

gzip -cd ../old/initrd.img|cpio -imd --quiet

And this command to rebuild the image after modifying it:

find . | cpio --quiet -c -o | gzip -9 -n > ../initrd.img

They actually seemed to work. It would sure be handy if the initrd.txt
file mentioned those commands up front and then went on to the historical
information for older kernels it already contains.