Preface

The Internet is now a household term in many countries and has become a part of life for most of the business world. With millions of people connecting to the World Wide Web, computer networking has moved to the status of TV sets and microwave ovens. You can purchase and install a wireless hub with just about an equal amount of effort. The Internet has unusually high media coverage, with weblogs often "scooping" traditional media outlets for news stories, while virtual reality environments such as online games and the rest have developed into the "Internet culture."

Of course, networking has been around for a long time. Connecting computers to form local area networks has been common practice, even at small installations, and so have long-haul links using transmission lines provided by telecommunications companies. A rapidly growing conglomerate of worldwide networks has, however, made joining the global village a perfectly reasonable option for nearly everyone with access to a computer. Setting up a broadband Internet host with fast mail and web access is becoming more and more affordable.

Talking about computer networks often means talking about Unix. Of course, Unix is not the only operating system with network capabilities, nor will it remain a frontrunner forever, but it has been in the networking business for a long time and will surely continue to be for some time to come. What makes Unix particularly interesting to private users is that there has been much activity to bring free Unix-like operating systems to the PC, such as NetBSD, FreeBSD, and Linux.

Linux is a freely distributable Unix clone for personal computers that currently runs on a variety of machines that includes the Intel family of processors, but also PowerPC architectures such as the Apple Macintosh; it can also run on Sun SPARC and Ultra-SPARC machines; Compaq Alphas; MIPS; and even a number of video game consoles, such as the Sony PlayStation 2, the Nintendo Gamecube, and the Microsoft Xbox. Linux has also been ported to some relatively obscure platforms, such as the Fujitsu AP-1000 and the IBM System 3/90. Ports to other interesting architectures are currently in progress in developers' labs, and the quest to move Linux into the embedded controller space promises success.

Linux was developed by a large team of volunteers across the Internet. The project was started in 1990 by Linus Torvalds, a Finnish college student, as an operating systems course project. Since that time, Linux has snowballed into a full-featured Unix clone capable of running applications as diverse as simulation and modeling programs, word processors, speech-recognition systems, World Wide Web browsers, and a horde of other software, including a variety of excellent games. A great deal of hardware is supported, and Linux contains a complete implementation of TCP/IP networking, including PPP, firewalls, and many features and protocols not found in any other operating system. Linux is powerful, fast, and free, and its popularity in the world beyond the Internet is growing rapidly.

The Linux operating system itself is covered by the GNU General Public License, the same copyright license used by software developed by the Free Software Foundation. This license allows anyone to redistribute or modify the software (free of charge or for a profit) as long as all modifications and distributions are freely distributable as well. The term "free software" refers to freedom of application, not freedom of cost.