Linux is a "KERNEL" not an Operating System :

Kerel(Linux) is a part of Operating System (GNU) :

For the past one year, i have been working with UNIX-like distros.., but i never give it a thought to know the difference between a "kernel" which is a linux and the Operating System which is a GNU, untill i came across a document by Richard Stallman, that corrected my "wrong" assumption of Linux as OS.

http://www.gnu.org/gnu/linux-and-gnu.html,


So, what is Linux:
Friends, Linux is just a "kernel", it can only function in the context of a complete operating system.( Kernal definition: The program in the system that allocates the machine's resources to the other programs that you run).

The "kernel" is an essential part of an operating system, but useless by itself; it can only function in the context of a complete operating system. Many users are not fully aware of the distinction between the kernel, which is Linux, and the whole system, which they also call “Linux”.


In simple layman words:
GNU an "UNIX-LIKE OS" was already created as a complete OS, with "Hurd" as a kernel in early 1990, but there were few problems with this kernel and it was still being developed, fortunately , it was during 1991, when "Linus Torvalds" wrote Linux (Free Unix like Kernel) and filled the last major gap, and that's all about it, Linux (kernel) together with the GNU system gave brith to a complete free Operating System called "GNU/Linux".

What is GNU:
If you are wonderfing what is "GNU", here is the information :GNU stands for “GNU's Not Unix. GNU is a project by community of people, conceived in 1983 as a way of bringing back the cooperative spirit that prevailed in the computing community in earlier days—to make cooperation possible once again by removing the obstacles to cooperation imposed by the owners of proprietary software, the main object was to create "FREE" software.

By "Free" it means:
Software that comes with permission for anyone to use, copy, and distribute, either verbatim or with modifications, either gratis or for a fee. In particular, this means that source code must be available. “If it's not source, it's not software.

Courtesy: Richard Stallman