Chapter 1
Introduction and Overview
Operating systems are not only regarded as a fascinating part of information technology, but are also the subject of controversial discussion among a wide public.1 Linux has played a major role in this development. Whereas just 10 years ago a strict distinction was made between relatively simple academic systems available in source code and commercial variants with varying performance capabilities whose sources were a well-guarded secret, nowadays anybody can download the sources of Linux (or of any other free systems) from the Internet in order to study them.
Linux is now installed on millions of systems and is used by home users and professionals alike for a wide range of tasks. From miniature embedded systems in wristwatches to massively parallel mainframes, there are countless ways of exploiting Linux productively. And this makes the sources so interesting. A sound, well-established concept (UNIX) melded with powerful innovations and a strong penchant for dealing with problems that do not arise in academic teaching systems—this is what makes Linux so fascinating.
This book describes the central functions of the kernel, explains its underlying structures, and examines its implementation. Because complex subjects are discussed, I assume that the reader already has some experience in operating systems and systems programming in C (it goes without saying that I assume some familiarity with using Linux systems). I touch briefly on several general ...
