Why Is Linux An Open Source Software?

Linux is known as open source software because its source code is available to every one. Any one can do modifications in the source code and can launch a new version of Linux. You will see many versions of Linux as Red Hat Linux, Ubuntu, fedora, Mandriva, SUSE, Caldera, NimbleX, Berry Linux, Gentoo, Debian, Xandros, Slackware and many more but you will see only few windows versions against Linux as Windows 95, windows 98, windows XP, Windows NT and  windows vista.  

Main reason of this is, Linux is open source and Windows is not. Even you will see Linux is distributed to every person free of cost, who wanted to use it, on the other hand you cannot get windows free of cost.

All the soft wares which are used on Linux are also known as open source because there source code is available and people do modification according to their wishes.
Linux has many versions as i told u earlier but windows has very few because source course is available to every one of Linux so whenever  a user of Linux think that there are some functions missing in a  particular version then He/She do modification in that While source code of windows is not available to public. So only programmers of Microsoft can modify windows.

I myself call for latest Linux version to one of a company in Pakistan who distribute Linux free of cost. They send those CDs to my house without taking any charges. Initially, Linux was not friendly but its new versions are very much user friendly and that's why many people around the world are switching from windows to Linux.