Chapter 0: Introduction

Overview

The very quick path to a quiescent pager? OpenBSD.

Welcome to Absolute OpenBSD ! This book is an introductory text to general management of the OpenBSD server operating system. OpenBSD is a member of the BSD family of operating systems and is widely regarded as the most secure operating system available anywhere , under any licensing terms. It's widely used by Internet service providers, embedded systems manufacturers, and anyone who needs security and stability. If you're an experienced UNIX systems administrator who wants to add OpenBSD to your repertoire , this book is for you!

By the time you finish this book you should be comfortable on an OpenBSD system. You will understand how to manage, upgrade, and patch computers running OpenBSD. You'll also have a basic understanding of OpenBSD's software, security, and network management features.

What Is BSD?

AT&T employees created UNIX in the early 1970s. At the time, the monster telephone company was forbidden to compete in the computer industry. The telecommunications company used UNIX internally, but could not transform it into a commercial product. As such, AT&T was willing to license the UNIX software and its source code to universities for a nominal fee. This worked well for all parties: AT&T got a few pennies and a generation of computer scientists who cut their teeth on AT&T technology, the universities avoided high operating system license fees, and the students were able to dig around inside the source code and see how computers really worked.

Compared to some of the other operating systems of the time, the original UNIX wasn't very good. But all these students had the source code for it and could improve the parts that they didn't like. If an instructor found a certain bug particularly vexing, he could assign his students the job of fixing it. If a university network engineer, professor , or student needed a feature, he could use the source code to quickly implement it. As the Internet grew in the early 1980s, these additions and features were exchanged between universities in the form of patches. The Computer Science Research Group (CSRG) at the University of California, Berkeley, acted as a central clearinghouse for these patches. The CSRG distributed these patches to anyone with a valid AT&T source code license. The resulting collection of patches became known as the Berkeley Software Distribution, or BSD.

This continued for a long, long time. If you look at the copyright for any BSD-derived code, you will see the following text.

Copyright 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994 The Regents of the University of California. All rights reserved.

Fifteen years of continuous development by the brightest students of the best computer science programs in the world, moderated by the faculty of one of the top technical schools in the country. That's more than a lifetime in software development. As you might imagine, the result was pretty darn good — almost everyone who used UNIX was really using BSD. The CSRG was quite surprised, near the end of these years, when it found that it had replaced almost all of the original AT&T code!

BSD Goes Public

In the early 1990s, the CSRG's funding started to run out. The University of California had to decide what to do with all this wonderful source code it owned. The simplest thing would have been to drop the original tapes down a well and pretend that the CSRG had never happened . In keeping with the spirit of academic freedom, however, it released the entire BSD collection to the public under an extremely liberal license. The license can be summarized like this:

Don't claim you wrote this.
Don't sue us if it breaks.
Don't use our name to promote your product.

Compare this with the software license found on almost any commercial operating system. The BSD license is much easier to understand and unobjectionable to almost anyone. Anyone in the world can take the BSD code and use it for any purpose they like, from desktop computers to self-guided lawnmowers. Not surprisingly, many computer manufacturers jumped right on BSD. Not only was the code free, but also every computer science graduate for the last 15 years was familiar with it.