Chapter 3 Boot Process, Init, And Shutdown; Introduction; Behind The Scenes Of The Boot Process - Red Hat LINUX 7.2 Reference Manual

Section 3.2:Behind the Scenes of the Boot Process
3 Boot Process, Init, and Shutdown
This chapter contains information on what happens when you boot or shut down your Red Hat Linux
system.
This chapter focuses on LILO, the default boot loader for Red Hat Linux 7.1
and earlier versions. However, Red Hat Linux 7.2 contains an additional boot
loader, GRUB, which is discussed more thoroughly in Chapter 5, GRUB. For
more information concerning GRUB, see Chapter 5, GRUB.

3.1 Introduction

One of the most powerful aspects of Red Hat Linux concerns its open method of starting and stopping
the operating system, where it loads specified programs using their particular configurations, permits
you to change those configurations to control the boot process, and shuts down in a graceful and or-
ganized way.
Beyond the question of controlling of the boot or shutdown process, the open nature of Red Hat Linux
makes it much easier to determine the exact source of most problems associated with starting up or
shutting down your system. An understanding of this process is quite beneficial for even basic trou-
bleshooting.

3.2 Behind the Scenes of the Boot Process

This section looks at the x86 boot process, in particular. Depending on your
system's architecture, your boot process may be slightly different. However,
once the kernel is found and loaded by the system, the default Red Hat Linux
boot process is identical across all architectures. Please see Section 3.7, Dif-
ferences in the Boot Process of Other Architectures for more information on
a non-x86 boot process.
When a computer is booted, the processor looks at the end of the system memory for the BIOS (Basic
Input/Output System) and runs it. The BIOS program is written into read-only permanent memory
Note
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