Running Linux, Fourth Edition

Booting the System

There are several ways of booting Linux on your system. The most common methods involve booting from the hard drive or using a boot floppy. In many cases, the installation procedure will have configured one or both of these for you; in any case, it’s important to understand how to configure booting for yourself.

Using a Boot Floppy

Traditionally, a Linux boot floppy simply contains a kernel image, which is loaded into memory when you insert the floppy and start the system.^[12]

Many Linux distributions create a boot floppy for you in this way when installing the system. Using a boot floppy is an easy way to boot Linux if you don’t want to bother booting from the hard drive. (For example, Windows NT/2000’s boot manager is somewhat difficult to configure for booting Linux. We’ll talk about this in the next section.) Once the kernel has booted from the floppy, you are free to use the floppy drive for other purposes.

We’ll include some technical information here in order to explain the boot process, but rest assured that in most cases, you can just insert the floppy disk, and booting works. Reading the following paragraphs will help you understanding your system, though.

The kernel image is usually compressed, using the same algorithm as the gzip or the bzip2 compression programs (more on this in Section 7.4.2 in Chapter 7 ). Compression allows the kernel, which may be a megabyte or more in size, to require only a few hundred kilobytes of disk space. Part of the kernel ...