Professional Linux Kernel Architecture

Appendix B

Working with the Source Code

Over the years, Linux has grown from a minor hacker project to a gigantic system that effortlessly competes with the largest and most complex software systems. As a result, developers must deal with more than just the technical problems relating to how the kernel functions. The organization and structure of the sources are also key issues whose importance should be not underestimated. This appendix addresses the two most interesting questions in this context. How can the kernel be configured so that the corresponding parts of the source can be selected not only for a given architecture but also for a specific computer configuration? And how is the compilation process controlled? The second question is of particular importance when the kernel is repeatedly compiled for different configurations. Parts not involved in a configuration change obviously need not be recompiled, and this can save a great deal of time.

Everyone concerned with the kernel sources is impressed by their sheer size. Because the prime purpose of this book is to promote an understanding of the sources, this appendix examines various methods that are best suited to browsing and analyzing the source code. These include predominantly hypertext systems. This appendix also describes the options available to debug running kernels and to provide an insight into their structures—both are useful aids to understanding. The appendix delves into User-Mode Linux (UML), a kernel port ...