Open source software is software for which the original source code is made freely available and may be redistributed and modified by users under certain licensing agreements.

Examples:

1. Linux
2. Apache
3. Mozilla Firefox a Web browser that competes with Internet Explorer.
4. VLC Media Player.
5. Open Office – a competitor to Microsoft Office.
6. MySQL, Ingres, and Enterprise DB – open-source database software
   packages that each go head-to-head with commercial products from
   Oracle, Microsoft, Sybase, and IBM.