What is Open-Source

Open Source Softwares

As the term suggests, An open source software is a software program whose source code is freely available. You can download the source code of any open source software from the internet. Also you are free to modify it, copy it & redistribute it. Some people consider this as Open source philosophy and others consider it a pragmatic methodology.

Open source softwares are free. The term free doesn't necessarily mean the software is free of cost. Indeed they are available free of cost but the term “Free” refers to the freedom, freedom to modify, freedom to customize, freedom to copy, freedom to redistribute, freedom to share.

Where it all started:

In 1983 American Computer programmer Richard Stallman started GNU project to create free unix-like software. He pioneered the concept of copyleft (its opposite to copyright). As you all know that you can not copy any product which is copyright protected. But copyleft products can be copied & shared among others. Stallman also founded the Free Software Foundation to promote & develop free & open source softwares (FOSS). Stallman also authors the GNU General Public License (GPL) now known as GPL only. GPL is the most famous & widely used license for the free & open source softwares.

Open source softwares are developed through community contribution. Thousands of developers across the globe contribute to develop world class softwares. The open source softwares are indeed world class. Take a look at the following list of some very famous open source softwares & you will know the power of open source :

Application software

• 7-Zip — file archiver
• Blender — 3D graphics editor
• Eclipse — development environment comprising an IDE
• GIMP — graphics editor
• Inkscape - Vector graphics editor for .svg
• Mozilla Firefox — web browser
• Mozilla Thunderbird — e-mail client
• NASA World Wind — virtual globe, geobrowser
• OpenOffice.org (and the LibreOffice fork) - office suite
  

Operating systems

• FreeBSD — operating system derived from Unix
• Linux — family of Unix-like operating systems
• OpenIndiana — a free Unix-like operating system
• Symbian — real-time mobile operating system
• ReactOS — operating system built on Windows NT architecture
• Haiku — free and open source operating system compatible with BeOS
  

Programming languages

• PHP — scripting language suited for the web
• Python — general purpose programming language
  

Server software

• Apache — HTTP web server (World's more than 65% web servers run on Apache)
• Drupal — content management system
• MediaWiki — wiki server software, the software that runs Wikipedia
• MongoDB — document-oriented, non-relational database
• Moodle — course management system or virtual learning environment
• WordPress — blog software
  

Open source culture is fast gaining popularity around the globe.

Relation of Linux & GNU
When Richard Stallman started GNU project to create a unix-like free operating system, he created many applications & utilities for the operating system but one thing was lacking & that was a stable Kernel. In 1991 Finnish computer science student Linus torvalds created a Kernel which was clone of unix & named it Linux. Then many developers took interest in this project. They implemented GNU applications on the top of a Linux Kernel & made an operating system. So it was called GNU/Linux.
Still Linux is always referred to as GNU/Linux.
Note:
For novices I would like to provide some detail about what is a Kernel – A Kernel can be said as a heart of any operating system. A kernel is a chunk of code mainly written in C language. This code is loaded on the RAM during the boot process when you start your computer. The Kernel is a very important part of an Operating system as it resides just on the top of hardware. All application softwares of the operating system runs on the top of kernel only. Kernel manages some of the most important tasks such as Input/Output communication, process and memory management, Interrupt handling etc.
Furthur I will give details of evolution of Linux & different types of Linux distribution.