Learning Red Hat Linux

Boot Parameters

When you boot your system by using loadlin, you specify several parameters that control the boot process. Such parameters are sometimes needed to take advantage of unusual hardware devices, large amounts of RAM (more than 128 MB), and so on. Similarly, when you boot by using lilo, you can also boot parameters to control the boot process; you can specify lilo’s boot parameters by using linuxconf or by editing lilo’s configuration file. You can also specify boot parameters to lilo by typing them in response to lilo’s prompt.

Boot parameters are specified using a three-part directive that includes:

• the name of the parameter

• an optional list of options, which consists of an equals sign (=) followed by a comma-separated list of option values

No spaces may appear in the directive. As an example, the following directive specifies the identity of the Linux root partition:

root=/dev/hda1

You can specify multiple directives by separating them with a space. For example, the following specifies the identity of the Linux root partition and specifies that the root partition is initially mounted read-only, so that a thorough check of its filesystem can be performed:

root=/dev/hda1 ro

Most directives are interpreted by the kernel, though lilo is also capable of processing directives. If you specify a directive that neither the kernel nor lilo understands (assuming you’re using lilo), a directive that includes an equals sign is passed to the init process as an environment variable. You’ve ...