The Source Mage Initial Ram Disk Readme
by David Brown

Okay here's the scoop:
take a look at a few documents so you get an idea as to what you are doing, some
suggestions maybe:
/usr/src/linux/Documentation/early-userspace/README
http://lkml.org/lkml/2006/7/5/339
/usr/src/linux/scripts/gen_initramfs_list.sh
/usr/src/linux/usr/gen_init_cpio

But what it basically comes down to is that klibc is a replacement for an initrd
it is still an early userspace image that is close to the kernel, however it is
closer than an initrd in fact it doesn't have the same setup done by the kernel 
to start userspace. This setup has to be done by the userspace application
(either busybox or kinit).

Some reasons why you would want an early userspace image surround the idea that
there need to be some initial setup before the root filesystem is mounted:
1) root nfs
2) root lvm
3) crypto root
4) bootsplash
5) rescue image (root filesystem doesn't even work)
and I'm sure there are many more

To enable an initramfs image in your kernel set the INITRAMFS_SOURCE to a custom
script that looks something like the lvm-initramfs.lst file also take a look at
the kernels help dialogs in make menuconfig for specifics on the file.

The initramfs depends greatly on your kernel setup so before adding this to your
kernel config make sure you look over the values you put in INITRAMFS_SOURCE and
the files that they reference so you know what's getting executed.