New to Linux?
Linux is a kernel....
It is not the operating system, it's one of the essential major components of the system. The system as a whole is more or less the GNU system, with Linux added.
Linux is the kernel: the program in the system that allocates the machine's resources to the other programs that you run, it can only function with a complete operating system.
The available free software added up to a complete system, because of the GNU Project which had started since 1984, many people have made major contributions to the free software.
More in detail at - http://www.itmission.org/Main/HistoryOfLinux
Linux shares similar architecture and concepts (as part of the POSIX standard) but does not share non-free source code with the original Unix or MINIX.
Getting the very best return on your IT investment is not always straightforward, and that's where the Linux Community can be of help.
Did you know: Linux source code for all supported architectures is contained in about 4500 C and Assembly files stored in about 270 subdirectories; it consists of about 2 million lines of code, which occupy more than 58 megabytes of disk space.
Linux is a tiny operating system when compared with other commercial giants. Micro$oft Windows 2000, for example, reportedly has more than 30 million lines of code. Linux is also small when compared to some popular applications; Netscape Communicator 5 browser, for example, has about 17 million lines of code.
One of the more appealing benefits to Linux is that it isn't a commercial operating system: its source code under the GNU Public License is open and available to anyone to study, the official site is http://www.kernel.org/ The GNU project is coordinated by the Free Software Foundation, Inc. (http://www.gnu.org/); its aim is to implement a whole operating system freely usable by everyone. The availability of a GNU C compiler has been essential for the success of the Linux project.
In some ways, Linux is the champion of a set of ideals. Whether you buy into these ideals is a separate issue from whether you use the technology, of course, but nonetheless a complete understanding of Linux and Linux-based systems requires at least an awareness of the legacy.
Linux-based operating systems are extremely powerful and flexible, but unlocking that power and flexibility requires knowledge and understanding of how the system works. Note:Linux is "merely" a kernel. That is, Linux is a piece of software that manages resources and processes, but provides no system libraries or user interface.
Since Linux is just a kernel, it requires a set of system libraries to become a useful environment. If Linux is just a kernel, where do these system libraries come from? Who writes them? Who maintains them? Obviously, whoever maintains these libraries makes a huge contribution to Linux systems in general. In the vast majority of Linux installations, the system libraries are the GNU utilities, written and maintained by the Free Software Foundation.
Comparison_of_Linux_distributions