I'm trying various ways of Linux installation (from iso, flash, iso on flash, kernel on flash, root FS in iso-file on flash...) and want to understand what's going on.
My question is: is it possible, given the built kernel and ramfs files from a distribution (vmlinuz and initrd), to find out, where they are going to look for the "/" file system? Is it possible to configure this without re-compiling the kernel?
And one more: when kernel loads the root filesystem from loopback device, created from .iso-filesystem, how can I configure this process? Thanks!
EDIT: In fact, GRUB configuration contains GRUB root, which is not the real kernel root filesystem location, but just a folder that contains GRUB's belongings,.
The real root is configured in
init script in
initrd as described here.
That's how Debian kernel finds an ISO file on hard drive, when booting from it - initramfs finds it: http://www.debian.org/releases/stable/i386/apas02.html.en#howto-getting-images-hard-disk; note that GRUB configuration doesn't contain any reference to ISO location.