Boot-time Kernel Parameters
By default, your system’s kernel parameters are set in your boot loader’s configuration file (/etc/lilo.conf or /boot/grub/menu.lst, and boot/grub/grub.conf on Red Hat and some other distributions). However, the Linux kernel also has the capability to accept information at boot time from a kernel command-line interface. You access the kernel command line through your installed boot loader. When your system boots, you can interrupt the “default” boot process when the boot loader displays and specify your desired kernel parameters. The kernel parameters on the command line look similar to giving arguments or options to a program during command-line execution.
For an example, let’s say you wanted to boot with a root
partition other than your default, /dev/hda1. Using LILO, you could enter the following at the
This command boots the kernel whose label is
linux and overrides the default value of
/dev/hda1 to /dev/hda9 for
the root filesystem.