Special Edition Using Linux®, Sixth Edition

init: Where It All Begins

Figure 13.1 shows default boot, assuming initrd is not used. This boot procedure can be short-circuited or changed in different ways, but this figure will give you a good idea of how a vanilla installation boots.

Figure 13.1. A default boot sequence.

After the kernel loads into memory (refer to Chapter 12, "Boot Loaders" ), you have a running Linux system—but it isn't very usable because the kernel doesn't interact directly with the user or user space (see Chapter 14, "Customizing Your Shell Environment," for more details). The kernel runs one program: init. This program is responsible for everything else, and is ...