What Is Linux?

There are two ways of looking at a PC. The first is to see it as a magical box, which lets you do cool stuff like browse the Internet or play games. Seen in this way, it's like a VCR—put in a tape, press a button, and a picture appears on your TV. On your PC, you click the Internet Explorer icon, type a web address, and a web site somehow appears. The astonishing technical complexity behind these simple procedures isn't important to most people.

The other way of looking at a PC is as a collection of components that are made by various manufacturers. You might be familiar with this way of thinking if you're ever tried to upgrade your PC's hardware. In that case, you'll know that your PC consists of a CPU, a hard disk, a graphics card, and so on. You can swap any of these out to put in newer and better components that upgrade your PC's performance or allow more data storage.

What almost no one realizes is that the operating system is just another component of your PC. It, too, can be swapped out for a better replacement. Windows doesn't come free of charge, and Microsoft isn't performing a public service by providing it. Around $50 to $100 of the price you pay for a PC goes straight into Microsoft's pocket. Bearing in mind that hundreds of millions of PCs are made each year, it's not hard to see why Microsoft is one of the world's richest corporations.

It would be difficult to question this state of affairs if Microsoft gave us our money's worth. But it often falls far short. Its products are full of serious security holes, which at best inconvenience us and at worst make us lose data. And that's before we consider the instability of Microsoft products—hardly a day goes by without something unexpected happening. One of the first things people are taught when attending Windows training is how to use the Ctrl+Alt+Delete keyboard combination, which resets the computer after a crash!

Microsoft became rich, and maintains its wealth, by a virtual monopoly over PC manufacturers. While the intelligent computer buyer can choose between components to make for a better PC—deciding between an AMD or Intel processor, for example—you usually have little choice but to buy Windows with a new PC. Try it now. Phone your favorite big-name computer retailer. Say that you want a PC but you don't want Windows installed. Then listen as the salesperson on the other end of the phone struggles to understand.

Note 

Some PC manufacturers actually will sell you a PC without Windows installed on it. All you have to do is ask, although you might need to speak to a senior salesperson to get through to somebody who understands your request. Smaller local companies, in particular, will be more than willing to sell you a PC without Windows. Some retailers, such as Wal-Mart, even sell PCs with Linux preinstalled. These are usually inexpensive, largely because of the savings made when you don't pay the Microsoft tax!

Wouldn't it be terrific if you could get rid of Windows? Would you like to finally say goodbye to all those security holes and not have to worry about virus infections anymore, yet not lose out on any features or need to make sacrifices or compromises?

There is an alternative. Welcome to the world of Linux.

Linux is an operating system, which is to say that it's a bit like Windows. It's the core software that runs your computer and lets you do stuff on it. By the strictest definition of the term, an operating system is the fundamental software that's needed to make your PC work. Without an operating system installed on your PC, it would merely be an expensive doorstop. When you turned it on, it would beep in annoyance—its way of telling you that it can't do much without a whole set of programs to tell it what to do next.

An operating system allows your PC's hardware to communicate with the software you run on it. It's hundreds of programs, system libraries, drivers, and more, all tightly integrated into a whole. In addition, an operating system lets programs talk to other programs and, of course, communicate with you, the user. In other words, the operating system runs everything and allows everything to work.

Note 

Some companies and individuals, including Microsoft, define an operating system as much more than this fundamental software. They add in the basic tools you run on an operating system, such as web browsers and file management programs.

Linux consists of a central set of programs that run the PC on a low level, referred to as the kernel, and hundreds (if not thousands) of additional programs provided by other people and various companies. Technically speaking, the word Linux refers explicitly just to the core kernel program. However, most people generally refer to the entire bundle of programs that make up the operating system as Linux.

GNU/Linux

Although most of us refer to Linux as a complete operating system, the title "Linux" hides a lot of confusing but rather important details. Technically speaking, the word Linux refers merely to the kernel file: the central set of programs that lie at the heart of the operating system. Everything else that comes with a typical version of Linux, such as programs to display graphics on the screen or let the user input data, is supplied by other people, organizations, or companies. The Linux operating system is the combination of many disparate projects. (I'll explain how this works in the next chapter.)

The GNU organization, in particular, supplies a lot of vital programs and also system library files, without which Linux wouldn't run. These programs and files were vital to the acceptance of Linux as an operating system in its early days. Because of this, and the fact that Linux completed a long-running goal of the GNU project to create a Unix-like operating system, some people choose to refer to Linux as GNU/Linux.

A fierce debate rages over the correct way to refer to the Linux operating system and whether the GNU prefix should be used. For what it's worth, an equally fierce debate rages over how we should define an operating system. It can all get very confusing. It's also very easy to accidentally offend somebody by not using the correct terminology!

It's not the purpose of this book to get involved in this debate. Suffice it to say that I acknowledge the vital input of the GNU project into the operating system many people refer to simply as Linux, as well as that of other vital projects. However, readers should note that when I refer to Linux throughout this book, I mean the entire operating system. If I intend to refer simply to the kernel programs, I will make that clear.