Chapter 1. Introduction to Linux
This is a book about Linux, a free, open source operating system that supports full multitasking, the X Window System, TCP/IP networking, and much more. Hang tight and read on: in the pages that follow, we describe the system in meticulous detail.
Linux has generated more excitement in the computer field than any other development of the past several years. It has spread surprisingly fast, and the loyalty it inspires recalls the excitement of do-it-yourself computing that used to characterize earlier advances in computer technology. Ironically, it succeeds by rejuvenating one of the oldest operating systems still in widespread use: Unix. Linux is both a new technology and an old one.
In narrow technical terms, Linux is just the operating system kernel, offering the basic services of process scheduling, virtual memory, file management, and device I/O. In other words, Linux itself is the lowest-level part of the operating system.
However, most people use the term "Linux" to refer to the complete system — the kernel along with the many applications that it runs: a complete development and work environment including compilers, editors, graphical interfaces, text processors, games, and more.
This book will be your guide to Linux's shifting and many-faceted world. Linux has developed into an operating system for businesses, education, and personal productivity, and this book will help you get the most out of it.
Linux can transform any personal computer into a high-end workstation and server. Corporations are installing Linux on entire networks of machines, using the operating system to manage financial and hospital records, distributed-user computing environments, telecommunications, and more. Universities worldwide are using Linux for teaching courses on operating system programming and design. And, of course, computing enthusiasts everywhere are using Linux at home, for programming, document production, and all-around hacking. People use Linux on high-end desktop machines, handheld PDAs, mobile laptops, and even old clunkers sitting in the closet doing nothing more than spooling print jobs.
Apart from workstation and personal use, Linux is also being used to drive big servers. Increasingly, people are discovering that Linux is powerful, stable, and flexible enough to run the largest disk arrays and multiprocessor systems — with applications ranging from World Wide Web servers to corporate databases. Linux drives many mission-critical business applications, Internet sites, search engines, and content delivery networks. Scientists are connecting arrays of Linux machines into enormous "clusters" to solve the most computationally intensive problems in physics and engineering. With the Samba software suite, Linux can even act as a Windows file and print server — with better performance than Windows!
What makes Linux so different is that it's a free implementation of Unix. It was and still is developed by a group of volunteers, primarily on the Internet, who exchange code, report bugs, and fix problems in an open environment. Anyone is welcome to join in the Linux development effort: all it takes is interest in hacking a free Unix clone and some kind of programming know-how.
In this book, we assume you're comfortable with a personal computer (running any operating system, such as Windows 98, or some other version of Unix). We also assume that you're willing to do some experimentation to get everything working correctly — after all, this is half of the fun of getting into Linux. Linux has evolved into a system that is amazingly easy to install and configure, but because it is so powerful, some details are more complex than you'll find in the Windows world. With this book as your guide, we hope you'll find that setting up and running your own Linux system is quite easy and a great deal of fun.
1.1. About This Book
This book is an overview and entry-level guide to the Linux system. We attempt to present enough general and interesting information on a number of topics to satisfy Unix novices and wizards alike. This book should provide sufficient material for almost anyone to install and use Linux and get the most out of it. Instead of covering many of the volatile technical details — those things that tend to change with rapid development — we give you enough background to find out more on your own.
This book is geared for those people who really want to exploit the power that Linux provides. Rather than gloss over all the tricky details, we give you enough background to truly understand how the various parts of the system work, so you can customize, configure, and troubleshoot the system on your own. Linux is not difficult to install and use. However, as with any implementation of Unix, there is often some black magic involved to get everything working correctly.
In this book, we cover the following topics:
There are a million things we'd love to show you how to do with Linux. Unfortunately, in order to cover them all, this book would be the size of the unabridged Oxford English Dictionary and would be impossible for anyone (let alone the poor authors) to maintain. Instead we've tried to include the most salient and interesting aspects of the system and show you how to find out more.
While much of the discussion in this book is not overly technical, it helps to have previous experience with another Unix system. For those who don't have Unix experience, we have included a short tutorial in Chapter 4, for new users. Chapter 5 is a complete chapter on systems administration that should help even seasoned Unix users run a Linux system.
If you are new to Unix, you'll want to pick up a more complete guide to Unix basics. We don't dwell for long on the fundamentals, instead preferring to skip to the fun parts of the system. At any rate, while this book should be enough to get you running, more information on using Unix and its many tools will be essential for most readers. See Appendix A, for a list of sources of information.
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