Meaning of root in GRUB config file

Referring to here , with a configuration as > grub> root (hd0,0) > grub> kernel /vmlinuz-i686-up-4GB root=/dev/hda9 > grub> boot > > The preceding is usually sufficient to boot a Linux box. The standalone root statement tells the partition containing the kernel. The kernel statement describes the path and filename, _within the partition containing the kernel_, of the kernel. The argument to the root= argument to the kernel statement tells the partition containing /sbin/init, which of course turns out to be the root partition in the booted system. > > Be careful of these duelling root keywords. The standalone one is the root as seen from grub, and contains the kernel. The argument to the kernel statement is the root as seen from the fully booted system, and contains /sbin/init. I don't quite get the meaning of the 2 root configs. Does it mean the OS stays on /dev/hda9 to be mounted on (hd0, 0), or the OS is /vmlinuz to be mounted to /dev/had9 ?