Chapter 1 An Introduction to Slackware Linux

1.1 What is Linux?

Linus Torvalds started Linux, an operating system kernel, as a personal project in 1991. He started the project because he wanted to run a Unix-based operating system without spending a lot of money. In addition, he wanted to learn the ins and outs of the 386 processor. Linux was released free of charge to the public so that anyone could study it and make improvements under the General Public License. (See Section 1.3 and Appendix A for an explanation of the license.) Today, Linux has grown into a major player in the operating system market. It has been ported to run on a variety of system architectures, including HP/Compaq's Alpha, Sun's SPARC and UltraSPARC, and Motorola's PowerPC chips (through Apple Macintosh and IBM RS/6000 computers.) Hundreds, if not thousands, of programmers all over the world now develop Linux. It runs programs like Sendmail, Apache, and BIND, which are very popular software used to run Internet servers. It's important to remember that the term “Linux” really refers to the kernel - the core of the operating system. This core is responsible for controlling your computer's processor, memory, hard drives, and peripherals. That's all Linux really does: It controls the operations of your computer and makes sure that all of its programs behave. Various companies and individuals bundle the kernel and various programs together to make an operating system. We call each bundle a Linux distribution.

1.1.1 A Word on GNU

The Linux kernel project began as a solo endeavor by Linus Torvalds in 1991, but as Isaac Newton once said, “If I have seen further, it is by standing on the shoulders of giants.” When Linus Torvalds began the kernel the Free Software Foundation had already established the idea of collaborative software. They entitled their effort GNU, a recursive acronym that means simply “GNU's Not Unix”. GNU software ran atop the Linux kernel from day 1. Their compiler gcc was used to compile the kernel. Today many GNU tools from gcc to gnutar are still at the basis of every major Linux distribution. For this reason many of the Free Software Foundation's proponents fervently state that their work should be given the same credit as the Linux kernel. They strongly suggest that all Linux distributions should refer to themselves as GNU/Linux distributions.

This is the topic of many flamewars, surpassed only by the ancient vi versus emacs holy war. The purpose of this book is not to fan the fires of this heated discussion, but rather to clarify the terminology for neophytes. When one sees GNU/Linux it means a Linux distribution. When one sees Linux they can either be referring to the kernel, or to a distribution. It can be rather confusing. Typically the term GNU/Linux isn't used because it's a mouth full.