Open Source Software/Free Software programs are programs whose licenses give users the freedom to run the program for any purpose, to study and modify the program, and to redistribute copies of either the original or modified program (without having to pay royalties to previous developers).
The freedom to run a program, for any purpose;
The freedom to study how a program works and adapt it to a person’s needs. Access to the source code is a precondition for this;
The freedom to redistribute copies so that you can help your neighbour; and
The freedom to improve a program and release your improvements to the public, so that the whole community benefits. Access to the source code is a precondition for this.
Linux is the most frequently heard FOSS buzzword in the mass media today. However, because of its common usage, the term Linux has been used to refer to broader and broader definitions. It is important to understand the different definitions of Linux to be able to follow the discussions on FOSS.
Linux the kernel.
Linux the distribution: contains the Linux kernel at its heart and all the FOSS components required to produce full operating system functionality
Most Linux distributions are free and downloadable from the Internet. The following is a table of some of the most popular distributors of Linux:
Popular Linux Distributors
The advantages of going with distributions of Linux are many. The single most important advantage of vendor Linux over “stock” Linux is that it saves users time, and provides ready to use set of applications.
FOSS is released under a variety of different licenses. There are two primary types of licenses and countless variants. The GNU General Public License and the BSD-style licenses.
GPL: Users are allowed to do pretty much anything they want to a GPL program, including copying, distributing and modifying. The conditions of the license primarily affect the user when it is distributed to another user.
BSD: These are among the most permissive licenses possible, because they basically permit users to do anything they wish with the software as long as:
Attribution is given to the original licensor by including the original copyright notice in source code files; and
No attempt is made to sue or hold the original licensor liable for damages.
BSD-style licenses do not require the distribution of source code.