IN THIS CHAPTER
Examining booting concepts
init and runlevels
Understanding boot managers
Using the SUSE Rescue System
Booting a machine is something most of us do every day. The routine of sitting in front of the machine with the morning coffee, turning it on, and waiting for the operating system (OS) to load so that you can read your e- mail is something most of us take for granted.
It may seem that the whole thing is easy, smooth, and predictable day in, day out, but the reality is that booting the operating system is no small feat, and the OS has to make sure that the system is in a consistent state for you to do your daily work.
This chapter explains how SUSE and most other Linux distributions boot and start a set of predefined processes and services, grouped together by what is known as a runlevel. We discuss the boot loader (the software that actually helps your machine load the operating system), what Linux actually does during the boot process, how to configure your system to boot two different operating systems, and how to diagnose and correct problems in the boot process.
The term booting comes from the saying "Pull yourself up by your bootstraps," which is fundamentally what a machine must do. When power is applied to the processor, it carries out a self-check to make sure it is healthy and jumps to a predefined address in memory called the BIOS (basic input-output system) ...