Chapter 1: Introduction
Despite its large code base (over seven million lines of code), the Linux kernel is the most flexible operating system that has ever been created. It can be tuned for a wide range of different systems, running on everything from a radio-controlled model helicopter, to a cell phone, to the majority of the largest supercomputers in the world. By customizing the kernel for your specific environment, it is possible to create something that is both smaller and faster than the kernel provided by most Linux distributions. This book will go into how to build and install a custom kernel, and provide some hints on how to enable specific options that you will probably wish to use for different situations.
No Linux distribution provides the exact kernel most of its users want. Modern distributions have gotten very accommodating, compiling in support for every known device, for sound, and even for power conservation. But you will likely have a need that’s different from the majority of users (and every distribution has to try to meet the needs of the majority). You may just have different hardware. And when a new kernel comes out, you may want to start using it without waiting for a distribution to be built around it.
For a host of reasons, you will want during your Linux career to sometimes build a kernel, or to tweak the parameters of one you are running. This book gives you the information you need to understand the kernel from a user’s point of view, and to make the most common changes.
There are also good reasons to remove features from the kernel, particularly if you are running it on an embedded system or one with a small form factor.
When tweaking, it’s helpful to understand the internals of kernel behavior. These are beyond the scope of this book, except for brief summaries that appear with certain options. Appendix B includes references to other books and material that can give you more background.