Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 11-05-2007 Installation Manual page 409

The command root simplifies the specification of kernel and initrd files. The only
argument of root is a device or a partition. This device is used for all kernel, initrd,
or other file paths for which no device is explicitly specified until the next root com-
mand.
The boot command is implied at the end of every menu entry, so it does not need to
be written into the menu file. However, if you use GRUB interactively for booting, you
must enter the boot command at the end. The command itself has no arguments. It
merely boots the loaded kernel image or the specified chain loader.
After writing all menu entries, define one of them as the default entry. Otherwise,
the first one (entry 0) is used. You can also specify a time-out in seconds after which
the default entry should boot. timeout and default usually precede the menu entries.
An example file is described in
Naming Conventions for Hard Disks and Partitions
The naming conventions GRUB uses for hard disks and partitions differ from those
used for normal Linux devices. It more closely resembles the simple disk enumeration
the BIOS does and the syntax is similar to that used in some BSD derivatives. In GRUB,
the numbering of the partitions starts with zero. This means that (hd0,0) is the first
partition of the first hard disk. On a common desktop machine with a hard disk connected
as primary master, the corresponding Linux device name is /dev/hda1.
The four possible primary partitions are assigned the partition numbers 0 to 3. The
logical partitions are numbered from 4:
(hd0,0) first primary partition of the first hard disk
(hd0,1) second primary partition
(hd0,2) third primary partition
(hd0,3) fourth primary partition (usually an extended partition)
(hd0,4) first logical partition
(hd0,5) second logical partition
Being dependent on BIOS devices, GRUB does not distinguish between IDE, SATA,
SCSI, and hardware RAID devices. All hard disks recognized by the BIOS or other
controllers are numbered according to the boot sequence preset in the BIOS.
Unfortunately, it is often not possible to map the Linux device names to BIOS device
names exactly. It generates this mapping with the help of an algorithm and saves it to
Section "An Example Menu File" (page 392).
The Boot Loader 391