Installation guide

This sample blocklist specifies a file that starts at the first block on the partition and uses blocks 0

through 49, 100 through 124, and 200.

Knowing how to write blocklists is useful when using GRUB to load operating systems which require

chain loading. It is possible to leave off the offset number of blocks if starting at block 0. As an

example, the chain loading file in the first partition of the first hard drive would have the following

name:

(hd0,0)+1

The following shows the chainloader command with a similar blocklist designation at the GRUB

command line after setting the correct device and partition as root:

chainloader +1

9.4 .3. T he Root File Syst em and GRUB

The use of the term root file system has a different meaning in regard to GRUB. It is important to

remember that GRUB's root file system has nothing to do with the Linux root file system.

The GRUB root file system is the top level of the specified device. For example, the image file

(hd0,0)/grub/splash.xpm.gz is 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).

Next, the kernel command 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.

Refer to the root and kernel commands in Section 9.6, “ GRUB Commands” for more information.

9.5. GRUB Int erfaces

GRUB features three interfaces which provide different levels of functionality. Each of these interfaces

allows users to boot the Linux kernel or another operating system.

The interfaces are as follows:

Note

The following GRUB interfaces can only be accessed by pressing any key within the three

seconds of the GRUB menu bypass screen.

Menu Interface

This is the default interface shown when GRUB is configured by the installation program. A

menu of operating systems or preconfigured kernels are displayed as a list, ordered by

name. Use the arrow keys to select an operating system or kernel version and press the

Enter key to boot it. If you do nothing on this screen, then after the time out period expires

GRUB will load the default option.

Press the e key to enter the entry editor interface or the c key to load a command line

interface.

⁠Chapt er 9 . T he G RUB Boot Loader