What is Linux ?

Linux is an operating system that evolved from a kernel created by Linus Torvalds when he was a student at the University of Helsinki. Generally, it is obvious to most people what Linux is. However, both for political and practical reasons, it needs to be explained further. To say that Linux is an operating system means that it’s meant to be used as an alternative to other operating systems, Windows, Mac OS, MS-DOS, Solaris and others. Linux is not a program like a word processor and is not a set of programs like an office suite. Linux is an interface between computer/server hardware, and the programs which run on it.

A brief history of Linux
When Linus Torvalds was studying at the University of Helsinki, he was using a version of the UNIX operating system called ‘Minix’. Linus and other users sent requests for modifications and improvements to Minix’s creator, Andrew Tanenbaum, but he felt that they weren’t necessary. That’s when Linus decided to create his own operating system that would take into account users’ comments and suggestions for improvements.

Free Software pre-Linux
This philosophy of asking for users’ comments and suggestions and using them to improve computer programs was not new. Richard Stallman, who worked at the Massachusetts Institute of Technology, had been advocating just such an approach to computer programming and use since the early 1970’s. He was a pioneer in the concept of ‘free software’, always pointing out that ‘free’ means ‘freedom’, not zero cost. Finding it difficult to continue working under conditions that he felt went against his concept of ‘free software’ he left MIT in 1984 and founded GNU. The goal of GNU was to produce software that was free to use, distribute and modify. Linus Torvalds’ goal 6 years later was basically the same: to produce an operating system that took into account user feedback.

The kernel
We should point out here that the focal point of any operating system is its ‘kernel’. Without going into great detail, the kernel is what tells the big chip that controls your computer to do what you want the program that you’re using to do. To use a metaphor, if you go to your favorite Italian restaurant and order ‘Spaghetti alla Bolognese‘, this dish is like your operating system. There are a lot of things that go into making that dish like pasta, tomato sauce, meatballs and cheese. Well, the kernel is like the pasta. Without pasta, that dish doesn’t exist. You might as well find some bread and make a sandwich. A plate of just pasta is fairly unappetizing.
Without a kernel, an operating system doesn’t exist. Without programs, a kernel is useless.

1991, a fateful year
In 1991, ideal conditions existed that would create Linux. In essence, Linus Torvalds had a kernel but no programs of his own, Richard Stallman and GNU had programs but no working kernel. Read the two men’s own words about this:


Sadly, a kernel by itself gets you nowhere. To get a working system you need a shell, compilers, a library etc.


The GNU Hurd is not ready for production use. Fortunately, another kernel is available. [It is called] Linux.So combining the necessary programs provided by GNU in Cambridge, Massachusetts and a kernel, developed by Linus Torvalds in Helsinki, Finland, Linux was born. Due to the physical distances involved, the means used to get Linus’ kernel together with the GNU programs was the Internet, then in its infancy. We can say then that Linux is an operating system that came to life on the Internet. The Internet would also be crucial in Linux’s subsequent development as the means of coordinating the work of all the developers that have made Linux into what it is today.

Linux is introduced
Late in 1991, Linus Torvalds had his kernel and a few GNU programs wrapped around it so it would work well enough to show other people what he had done. And that’s what he did. The first people to see Linux knew that Linus was on to something. At this point, though, he needed more people to help him. Here’s what Linus had to say back in 1991.


Are you without a nice project and dying to cut your teeth on an OS you can try to modify for your needs?… This post might just be for you.

People all over the world decided to take him up on it. At first, only people with extensive computer programming knowledge would be able to do anything with that early public version of Linux. These people started to offer their help. The version numbers of Linux were getting higher and higher. People began writing programs specifically to be run under Linux. Developers began writing drivers for different video cards, sound cards and other gadgets inside and outside your computer could use Linux. Nevertheless, throughout most of first part of the 1990’s Linux did not get out of the ‘GURU’ stage. GURU is a term that has evolved to mean anyone who has special expertise in a particular subject. That is, you had to have special expertise in how computers worked to be able to install Linux in those days.
Linux, at first, was not for everybody

Other popular software companies sold you a CD or a set of floppies and a brief instruction booklet and in probably less than a half an hour, you could install a fully working operating system on your PC. The only ability you needed was knowing how to read. Those companies had that intention when they actually sat down and developed their operating systems. Linus Torvalds didn’t have that in mind when he developed Linux. It was just a hobby for him. Later on, companies like Red Hat made it their goal to bring Linux to the point where it could be installed just like any other operating system; by anyone who can follow a set of simple instructions, and they have succeeded. For some reason, though, Linux hasn’t completely lost its ‘Gurus only’ image. This is largely because of the popular tech press’ inability to explain in a meaningful way what Linux is. The truth is that few tech reporters have real life experience with Linux and it is reflected in their writing.

Where Linux is Today
Today, Linux is enjoying a favorable press for the most part. This comes from the fact that Linux has proven to be a tremendously stable and versatile operating system, particularly as a network server. When Linux is deployed as a web server or in corporate networks, its down-time is almost negligible. There have been cases when Linux servers have been running for more than a year without re-booting and then only taken down for a brief period for routine maintenance. Its cost effectiveness has sold it more than anything else. Linux can be installed on a home PC as well as a network server for a fraction of the cost of other companies’ software packages. More reliability and less cost – it’s ideal.

If you’re reading this, you’re obviously here to learn how to use Linux. Any learning experience means opening up to new ideas and new ways of doing things. As mentioned before, Linux is in the UNIX family of operating systems. UNIX is primarily designed to be used by professionals. You will have to learn some UNIX concepts in this lesson, but that doesn’t mean that Linux is a professionals-only operating system. In fact, most major versions of Linux are designed to be as user-friendly and as easy to install as any other operating system on the market today.

Now that you know what Linux is and how good it is, there’s one more thing we have to do – install Linux!


Selecting A Linux Distribution

What is a Linux Distribution and Which Linux Distribution is Right For Me?
There are many different versions of Linux, and unlike other commercial operating systems that are controlled, distributed and supported by only one company, the core of Linux is free to distribute and use. This creates a situation in which numerous companies, organizations and individuals have developed their own specific version of the Linux operating system. When these versions are made publically available for use, they are known as “distributions”.

Normally distributions are made for specific reasons and have been tailored to address a series of concerns. There are many versions of Linux that were developed specifically to be installed on servers that receive heavy traffic, like web servers. Some distributions of Linux were developed to be used in networks where security is a priority; where sensitive information should only be accessed by a privileged few. In fact, Linux is at the core of many of today’s most advanced Firewalls! There are versions of Linux that are meant to be installed on top of an existing operating system like Windows so people can try out Linux under familiar conditions. There are versions of Linux that are designed to be installed on platforms like Macintosh.

Linux also makes its appearance in many embedded devices, like routers, switches, phone systems, smart phones, gps systems, and the list goes on and on. There are versions of Linux with funny names like “Chainsaw Linux” (no kidding). And, of course, there are distributions of Linux that are designed to be used as a PC Desktop operating system.

So, which Linux distribution should you use? My answer, based on over 12 years of experience with Linux and deployments in multiple companies, is “it depends”. However, here are some questions that you can ask yourself when trying to select a Linux distribution.

1) Is the code base stable
2) Does it change much
3) Is it easy to update software packages? (features like Debian’s “apt-get” or Red Hat’s “Yum” update system)
4) Is it easy to upgrade from one major version to the next?
5) Does it have a large developer base? (translates into a large software selection to choose from)

There is no “best” Linux distribution. To use an analogy, if you were going mountain climbing, you would need specific clothes to protect you from the cold, wind, rain and the terrain. However, if you were going to a formal dinner, I would need a tuxedo (or a nice suit!). However, if you were going about your daily routine, you would wear “normal” clothes (normal being a relative word). There are computer world equivalents of mountain climbing and formal dinners as well as just sitting around the house. Linux has been fit into all those environments and more. There is even the equivalent of a swimsuit in Linux – a lightweight and compact version – just enough to cover the essentials.

Most PC users probably just need the everyday version. This kind of Linux has been widely available for some time now. Since Microsoft makes its living selling people “ordinary” operating systems, they have a lot to lose if Linux ever gets popular with the masses. For this reason they have done everything in their power to “warn” the public that Linux is something that you probably don’t want and don’t need. But in reality, Linux is just as easily installed and supports just as wide a range of hardware as Microsoft Windows does.

The three most popular Desktop distributions of Linux are;
1) Fedora
2) Ubuntu
3) Linux Mint

The five most popular Server versions of Linux are;
1) Red Hat
2) Debian
3) OpenSUSE
4) Slackware
5) CentOS ( runs on a CentOS Linux VPS)

The two most popular Virtual Server versions of Linux are;
1) VMWare
2) XenServer ( runs on XenServer Enterprise) DOES NOT Promote Any Particular Linux Distribution
It would be impossible to cover all of the different distributions of Linux, so this lesson will only deal with standard versions of Linux that are meant to be installed on Personal Computers in your home or office. There are several well known distributions of Linux that run well as a Desktop. You may have even heard of some of the companies/organizations that have created distributions for this platform, like Debian, Ubuntu, Fedora, Linux Mint and SuSE.
There are many others as well. There are even versions of Linux that offer documentation and installation programs in languages other than English. It is not our intention to endorse the distributions/products of the companies we have mentioned here nor do we want to slight those companies that we haven’t mentioned. Distrowatch maintains a list of all kinds of distributions. We invite you to consult that list before deciding on installing any version of Linux.

Get Ready to Install
All of the major versions of Linux have perfected their products to such a degree that they are very easy to install. Well designed guided wizards will take you through the process of installation step by step so that you will be able to get Linux up and running in a relatively short period of time without any headaches. But even commercial operating systems that are billed as being the most user-friendly in the world can’t guarantee a 100% problem-free installation. If you are using unusual hardware peripherals, then you may encounter driver incompatibility problems. This has always been one of the weak points of Linux. It just doesn’t have the same driver support that Windows does. However, don’t fret. Over the past several years Linux has made up major ground and much of what is commonly available at your local PC retail store will work well in Linux.


What Type of Installation

What type of installation should I do? (Dual Boot / Live CD / Fresh Install / Virtual Installation)
One of the things that makes Linux special is that it can “play nice” with other operating systems. You can run Linux alongside of other operating systems quite easily. The most popular installation process for installing Linux is to install a “Fresh Installation of Linux” with no other operating system in place. This allows the computer to dedicated 100% of its resources to running Linux. However, it is quite easy to install Linux as a one of a series of operating systems that a computer has available to it.
Here are the most popular ways to install/run Linux on your computer

Dual Booting – If you want to keep an existing operating system, and install Linux as well, you will have what is known as a “dual-boot” system. That means that you have a PC that can use two different operating systems, and during the boot process you will need to decide which one you would like to boot into.

Author’s Note: Dual Booting between Windows and Linux is becoming somewhat less popular due to the rise of Virtual Machines. If you like the idea of running two operating systems, then you may want to consider running Linux as a VM inside of another operating system instead.

Live CD/DVD Booting Linux – If you are just looking to try Linux out to see if you like it, but don’t want to commit to wiping out your main operating system, you may want to consider trying Linux from a “Live CD/DVD”. Many Linux installations provide the option of downloading and running Linux as a “Live CD”, which means that Linux runs as a completely bootable operating system from the CD/DVD. The files are loaded into your computer’s memory, rather than being run for a hard disk drive. In layman’s terms, this means that you can run Linux from a CD/DVD, and then when you reboot your PC, and remove the CD/DVD, it will boot back into its old operating system without any difference to your PC. This gives you an easy way to try out several distributions of Linux until you find the one that you like!

Using a “Live CD/DVD” is also a popular method of rescuing files from a corrupted operating system, more on this later…

Linux as a VM inside another Operating System – If you like your current (non-linux) desktop operating system, but would like an easy way to access a Linux desktop or run your favorite open source software, you may want to consider running Linux as a VM inside another operating system. There are a number of ways to do this, but one simple one would be to download and install a Virtual Server application, and then install your Linux distribution under that host software. This topic is covered in the more advanced tutorials on this website… I think that I should pause here and say that everything that you can do with your “other” operating system, you can do with Linux. That means word processing, databases, spreadsheets, Internet browsers, e-mail, photo touch-ups, MP3, CD Players, cameras and then there are a lot of things that Linux has to offer on top of all that that other operating systems don’t.

Fresh Install of Linux – This method is by far the most popular installation method available. In this approach, you “take the plunge” and format your computer’s hard drive and install Linux from a CD/DVD. Linux then runs as your computers only operating system.



My laptop is using Fedora 16 … !