
Chapter 4. GRUB 79
Note
When changes are made to the GRUB configuration file, it is not necessary to restart GRUB. Any
changes made are automatically detected. If GRUB is restarted, the user will be dropped to the
command line GRUB shell.
4.1.3. Installing GRUB
If GRUB was not installed during the Red Hat Linux installation process, the following explains how
to install it and make it the default boot loader.
Note
If LILO has been installed and is currently the system boot loader, it is not necessary to remove it in
order to use GRUB. Once installed, GRUB will be the default boot loader for the system.
First, make sure to have the latest GRUB package available. The GRUB package from the Red Hat
Linux installation CD-ROMs can also be used.
From a shell prompt, run the command /sbin/grub-install
location , where
location is the location where GRUB should be installed. For example:
/sbin/grub-install /dev/hda
Finally, reboot the system. The GRUB graphical boot loader menu should appear.
4.2. Terminology
One of the most important things to understand before using GRUB is how the program refers to
devices, such as system hard drives, and partitions. This information is very important to know in
order to configure GRUB to boot multiple operating systems.
4.2.1. Device Names
The first hard drive of a system will be called (hd0) by GRUB. The first partition on that drive is
called (hd0,0), and the fifth partition on the second hard drive is called (hd1,4). In general, the
naming convention for filesystems when using GRUB breaks down in this way:
( type-of-device bios-device-number , partition-number )
The parentheses and comma are very important to the device naming conventions. The type-of-
device
refers to whether a hard disk (hd) or floppy disk (fd) is being specified.
The bios-device-number is the number of the device according to the system’s BIOS, starting
with 0. The primary IDE hard drive is numbered 0, while the secondary IDE hard drive is numbered 1.
The ordering is roughly equivalent to the way the Linux kernel arranges the devices by letters, where
the a in hda relates to 0, the b in hdb relates to 1, and so on.
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