LINUX INTRODUCTION

Can Linux Replace Windows?

Until recently, running Unix meant investing in a powerful workstation that cost megabucks. Linux changes all that, because it's a complete version of the Unix operating system (software that controls the basic functions of the personal computer) that runs on ordinary personal computers. The added fact that it's freely available and "open source" makes it all the more attractive.

Linux is perfect for people who want to operate their own low-cost Internet servers, and it's robust enough to satisfy the needs of many Internet service providers. Linux is a multiuser and multitasking environment, and it can access huge amounts of me mory (gigabytes) and huge amounts of disk storage space (terabytes). Linux offers virtually everything that Windows has been promising for years and may not deliver in a truly stable form for some time to come.

Don't make the mistake of assuming that Linux is some kind of watered-down or underpowered Unix for the masses. Linux is Unix. POSIX certification (compliance with the industry standards for Unix) makes it official that Linux can do everything that a Unix system is supposed to do. The only difference is that Linux works on a personal computer, whereas other versions of Unix run on larger workstations or mainframes.

Linux is also being taken very seriously by the computer industry, with new Linux-compatible versions of popular software packages being announced every month. The Apache Web server software running on Linux platforms powers about half of all Web sites today. Even more telling, Microsoft considers Linux a major threat to its Windows empire.

What Is Linux?

In the early 90s, a geek named Linus Torvalds at the University of Helsinki in Finland thought it would be fun to write a Unix kernel from scratch. He called it Linux, and it was cool but pretty much useless without all the utility programs needed to make it a complete operating system. At the same time, Richard Stallman and his pals at the Free Software Foundation were writing a bunch of freeware Unix utilities collectively known as the GNU Project. It was cool but pretty much useless without a kernel to make it a complete operating system. Fortunately, the two parties decided to collaborate.

News of Linux spread quickly over the Internet, and many other Unix programmers joined the effort to enhance it. What we now know as Linux is a combination of Torvald's Linux kernel, the GNU Project software, and some other nifty software bit and pieces developed by programmers from all around the world.

Today Linux is a complete and reliable implementation of the Unix operating system, with the following notable features:

32-bit operation (it uses all the speed and power of your CPU, unlike 16-bit DOS systems)
Virtual memory (it can use all of your system's RAM; there's no 640K memory limit)
Full support for X Windows (Unix's standard graphical user interface)
TCP/IP networking support (allowing connection to the Internet)
GNU software support (including a huge amount of free Unix software from the GNU Project)

Note: GNU is one of those recursive acronyms that computer scientists love; it stands for GNU's Not Unix. The GNU Project is an effort sponsored by the Free Software Foundation to provide freely available Unix software. See http://www.gnu.org for related information.

Linux was written totally from scratch without using any of the original AT&T UNIX code. (Throughout this site, UNIX refers to the original trademarked UNIX project invented by AT&T. The term Unix is used here as a generic term for other variants of the operating system.)

Because of that (and because the author is a nice guy), Linux is free. You can obtain the source code, modify, sell or give away the software so long as you provide full source code and don't impose any restrictions on what others do with it.

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