Your computer, despite being a collection of highly sophisticated parts, is really just . . . well, a collection of highly sophisticated parts. On its own, it can do nothing other than switch on and off and spin a disk or two. In order for it to do anything truly useful, it needs an operating system (OS) to guide it.
The OS takes an essentially well-endowed but completely uneducated hunk of a machine and educates it, at least enough so that it will understand what you want it to do. You already know of and have probably used at least one of the many operating systems that exist today.
Windows, DOS, and the Mac OS are all such operating systems, and Linux is yet another. Linux is, however, different from these other operating systems, both in terms of its capabilities and its heritage. Linux was not created by a corporation or by some corporate wannabes out to make money.
The Linux core, referred to as the kernel, was created by computer enthusiast Linus Torvalds, a Finn and a member of Finland’s Swedish ethnic minority, who wanted to create a better Unix-like system that would work on home computers, particularly his.
Rather than keeping his creation to himself, Torvalds opened it up to the world, so to speak, and the Linux kernel, which communicates with the hardware, and makes it accessible to the other applications and support libraries created by compu-geeks around the globe who work to make Linux better and more powerful.
It is this combination of applications built around the core of the Linux kernel that is the essence of all Linux distributions today. Linux has acquired many fans and followers since its creation in 1991. Such devotees praise Linux for its many features, as well as for being robust, reliable, free, and open. Despite these positive characteristics, however, Linux is, on its own, just a text-based system.
There is no pretty desktop, and there are no windows or charming little icons to make you feel safe and comfy once you are behind the keyboard. Powerful though it may be, Linux is still strictly a black-screen, command line–driven operating system. I guess you could think of it as DOS on steroids, though a Linux purist will surely cringe at the thought. Sorry.
Although you can use Linux by itself, accomplishing all your tasks by typing commands on a black screen (the most common way of doing things when Linux is used as a server), you don’t have to. It is fair to say that with the advent of the Macintosh and its easy-to-use graphical user interface (GUI, pronounced goo-ee) in 1984, users of other operating systems began suffering something akin to GUI envy.
They began clamoring for a GUI to call their own. The final result was Windows, which gave DOS a GUI and eased many command-wary users into the Microsoft world. Similarly, many members of the Linux world felt the need and desire to go graphical.
Various GUIs (called window managers and desktop environments) and a subsystem with which to handle them (somewhat confusingly referred to as the X Window System) were developed by the community at large to bring about the change. The graphical desktop environment, GNOME, that is included in your Ubuntu distribution is one example of the fruit of that development.