This is a typical Red Hat Linux booting instruction.
The information inside the "kernel" statement is always in Linux and not in Grub notation because by such time the kernel would have take over. The kernel and the root filing system ("/") are stored in separate location in a Red Hat Linux. The latter can be in an ordinary partition like /dev/sda3 or in a LVM partition. It is Red Hat tradition to identify this partition by a label.
Red Hat typical stores the /boot separately so that the rest can be all inside a LVM. The former is the address of required by the "root" statement in Grub while the latter is the address for the root filing system. If a Red Hat Linux has multi partitions then the root is always referred to the partition holding "/".
There is nothing to stop /boot as a subdirectory of / and a Red Hat can run happily in a single partition. Thus my Red Hat family distros typically boot by
Code:
title Fedora 7 in 10th partition od 2nd disk sdb10
root (hd1,9)
kernel /vmlinuz-2.6.18-8.1.1.el5 ro root=/dev/sdb10 rhgb quiet
initrd /initrd-2.6.18-8.1.1.el5.img
There are several method the "root=" can be pointed to. Among them are
(1) by-path
(2) by-label
(3) by-id
(4) by-uuid
I have no by-label in my Ubuntu box and the above information is all contained in the /dev directory
Code:
root@saikee-desktop:/home/saikee# ls -l /dev/disk
total 0
drwxr-xr-x 2 root root 120 2007-12-29 14:25 by-id
drwxr-xr-x 2 root root 140 2007-12-29 14:25 by-path
drwxr-xr-x 2 root root 80 2007-12-29 14:25 by-uuid
root@saikee-desktop:/home/saikee# ls -l /dev/disk/by-id
total 0
lrwxrwxrwx 1 root root 9 2007-12-29 14:25 ata-Maxtor_6L300R0_L609G99H -> ../../hda
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 ata-Maxtor_6L300R0_L609G99H-part1 -> ../../hda1
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 ata-Maxtor_6L300R0_L609G99H-part5 -> ../../hda5
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 ata-Maxtor_6L300R0_L609G99H-part6 -> ../../hda6
root@saikee-desktop:/home/saikee# ls -l /dev/disk/by-path
total 0
lrwxrwxrwx 1 root root 9 2007-12-29 14:25 pci-0000:00:09.0-ide-0:0 -> ../../hda
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 pci-0000:00:09.0-ide-0:0-part1 -> ../../hda1
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 pci-0000:00:09.0-ide-0:0-part5 -> ../../hda5
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 pci-0000:00:09.0-ide-0:0-part6 -> ../../hda6
lrwxrwxrwx 1 root root 9 2007-12-29 14:25 pci-0000:00:09.0-ide-1:0 -> ../../hdc
root@saikee-desktop:/home/saikee# ls -l /dev/disk/by-uuid
total 0
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 67299b86-bdc6-4c90-a463-1ff2c8af9a5a -> ../../hda6
lrwxrwxrwx 1 root root 10 2007-12-29 14:25 fcaf92d3-825d-4bfa-8d80-0282ff9a9d66 -> ../../hda5
root@saikee-desktop:/home/saikee#
You can see the same /dev/hda5 can be called different names in different methods, all applicable in Linux. Ubuntu starts using by-uuid method and OpenSuse homes in the by-id method. Red Hat always sticks with the by-label method.