Further copyright challenges to Linux are unlikely; patents, however, could be used against it. But every programmer and software company has to worry about soft- ware patents; Linux and free software are no more at risk than any other software. Although the workings of free software are entirely open to inspection, and therefore might be more tempting to target with a patent lawsuit, the only purpose of such a lawsuit would be to maliciously shut down a project, because free software cannot support license fees. Open Source and the Philosophy of Linux When new users encounter Linux, they often have a few misconceptions and false expectations of the system. Linux is a unique operating system, and it's important to understand its philosophy and design in order to use it effectively. At the center of the Linux philosophy is a concept that we now call open source software. Open source is a term that applies to software for which the source code--the inner workings of the program--is freely available for anyone to download, modify, and redistribute. Software covered under the GNU GPL, described in the previous sec- tion, fits into the category of open source. Not surprisingly, though, so does soft- ware that uses copyright licenses that are similar, but not identical, to the GPL. For example, software that can be freely modified but that does not have the same strict requirements for redistribution as the GPL is also considered open source. Various licenses fit this category, including the BSD License and the Apache Software License. The so-called open source and free software development models started with the Free Software Foundation and were popularized with Linux. They represent a totally different way of producing software that opens up every aspect of development, debugging, testing, and study to anyone with enough interest in doing so. Rather than relying upon a single corporation to develop and maintain a piece of software, open source allows the code to evolve, openly, in a community of developers and users who are motivated by a desire to create good software, rather than simply to make a profit. O'Reilly has published two books, Open Sources 1.0 and Open Sources 2.0, that serve as good introductions to the open source development model. They're collections of essays about the open source process by leading developers (including Linus Tor- valds and Richard Stallman). Another popular text on this topic--so often cited that it is considered nearly canonical--is The Cathedral and the Bazaar, by Eric S. Ray- mond. Open source has received a lot of media attention, and some are calling the phenom- enon the next wave in software development, which will sweep the old way of doing things under the carpet. It still remains to be seen whether that will happen, but there have been some encouraging events that make this outcome seem likely. For Open Source and the Philosophy of Linux This is the Title of the Book, eMatter Edition Copyright © 2007 O'Reilly & Associates, Inc. All rights reserved. | 25