9.4. GRUB Terminology
9.4.1. Device Names
hdfor a hard disk or
fdfor a 3.5 diskette. A lesser used device type is also available called
ndfor a network disk. Instructions on configuring GRUB to boot over the network are available online at http://www.gnu.org/software/grub/manual/.
0and a secondary IDE hard drive is numbered
1. This syntax is roughly equivalent to that used for devices by the kernel. For example, the
hdafor the kernel is analogous to the
hd0for GRUB, the
hdbis analogous to the
hd1, and so on.
0. However, BSD partitions are specified using letters, with
1, and so on.
1. Failing to make this distinction is one of the most common mistakes made by new users.
(hd0)and the second as
(hd1). Likewise, GRUB refers to the first partition on the first drive as
(hd0,0)and the third partition on the second hard drive as
- It does not matter if system hard drives are IDE or SCSI, all hard drives begin with the letters
hd. The letters
fdare used to specify 3.5 diskettes.
- To specify an entire device without respect to partitions, leave off the comma and the partition number. This is important when telling GRUB to configure the MBR for a particular disk. For example,
(hd0)specifies the MBR on the first device and
(hd3)specifies the MBR on the fourth device.
- If a system has multiple drive devices, it is very important to know how the drive boot order is set in the BIOS. This is a simple task if a system has only IDE or SCSI drives, but if there is a mix of devices, it becomes critical that the type of drive with the boot partition be accessed first.
9.4.2. File Names and Blocklists
nd. Replace <device-number> with the integer for the device. Replace </path/to/file> with an absolute path relative to the top-level of the device.
chainloadercommand with a similar blocklist designation at the GRUB command line after setting the correct device and partition as root:
9.4.3. The Root File System and GRUB
(hd0,0)/grub/splash.xpm.gzis located within the
/grub/directory at the top-level (or root) of the
(hd0,0)partition (which is actually the
/boot/partition for the system).
kernelcommand is executed with the location of the kernel file as an option. Once the Linux kernel boots, it sets up the root file system that Linux users are familiar with. The original GRUB root file system and its mounts are forgotten; they only existed to boot the kernel file.
kernelcommands in Section 9.6, “GRUB Commands” for more information.