In any discussion of what free means in relation to software, you'll often see the expressions "free as in speech" or "free as in beer." In this case, free isn't a question of cost, although you can get a free copy (as in free beer) of Linux and install it on your system without breaking any laws. As Robert A. Heinlein would have said, "There ain't no such thing as a free lunch." A free download will still cost you connection time on the Internet, disk space, time to burn the CDs, and so on. In the case of Ubuntu Linux, you can have a free CD mailed to you, so free in this case starts to feel pretty, well . . . free.
Linux is also free, as in speech, in that you have the right to view the source code and modify it to suit your needs. This is very unlike other operating systems when looking at or changing the code could get you in legal trouble.
Perhaps this is where a little French helps. You'll also see the delineations free (libre) and free (gratis). The first, libre, means free in the sense that you have freedom of expression, the freedom of speech, and the freedom to think. The second, gratis, refers to no cost. Imagine yourself at a friend's party. Your friend walks up and hands you a beergratis.
What's a Distribution?
Linux comes in many flavors, often referred to as distributions. Ubuntu Linux is just one of many distributions out there. You have probably heard of Red Hat, SUSE, or Mandriva (formerly Mandrake). These are all popular and well-respected distributions. A distribution is a collection of software, usually free software, with the Linux kernel at its core and hundreds, sometimes thousands, of applications. Different manufacturers may offer boxed sets that come with documentation, support, and CDs, the latter saving you time and energy downloading and burning discs. Furthermore, there are boxed sets of varying prices, even within a distribution. For instance, you can buy a Red Hat personal or professional edition. The difference is there may be additional software, documentation, or support.
Ubuntu Linux is a distribution based on yet another, very popular distribution known as Debian. Debian's popularity has spawned a number of distributions including Xandros, Linspire, Knoppix, and several others.
What sets one distribution apart from another is not always easily defined, but there are some basics. For instance, most distributions provide their own administrative interfaces. They include their own unique desktop themes and organization of applications in a menu.
Speaking of applications, this is one of Ubuntu's strengths and something that attracts many people. Ubuntu has selected a simplified core set of applications that makes sense. To understand why this is such a great idea, you need to understand that some distributions give you three terminals, five Web browsers, two word processors, and so on. Ubuntu Linux makes it easy with intelligent choices for applications that do the job.
Linux and the GPL
Linux is distributed under the GNU General Public License (GPL), which, in essence, says that anyone may copy, distribute, and even sell the program, so long as changes to the source are reintroduced back to the community and the terms of the license remain unaltered. Free means that you are free to take Linux, modify it, and create your own version. Free means that you are not at the mercy of a single vendor who forces you into a kind of corporate servitude by making sure that it is extremely costly to convert to another environment. If you are unhappy with your Linux vendor or the support you are getting, you can move to the next vendor without forfeiting your investment in Linux.
In other words, it's "free as in speech"or freedom.
The GNU GPL permits a distributor to "charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee." This is further qualified by the statement that the distributor must release "for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code." In other words, the GPL ensures that programs like Linux will at best be free of charge. At worst, you may be asked to pay for the cost of a copy.
You should take some time to read the GNU GPL. For your convenience, I've reprinted it in Appendix A of this book.