The name Open Source( OS) already indicates that it is a software whose source code is freely accessible: Open Source. This source code can be further developed and distributed. Software distributed under the name Open Source Software (OSS) is subject to certification by various bodies such as the Open Software Initiative( OSI) and must be published in full detail. In addition, the GNU General Public License( GNU-GPL) of the Free Software Foundation( FSF) sets the rules for the use of Linux, and the Berkeley Software Distribution( BSD) for Unix and its variants.
There are hundreds of different open source software licenses that can be reduced to two basic concepts: Copyleft and Permission.
Open source software reduces vendor dependency and opens up new business opportunities. There are no or only low acquisition and usage costs when using it, and no license management is required. On the other hand, there are costs for migration, employee training, development and maintenance. In addition, support is not sufficiently ensured in the event of errors, as it is provided by the community. However, there are service companies that offer professional support for OSS products. Another aspect for the use of OSS is their ability to work together with other established products.
Open source software exists for a wide variety of applications, for enterprise applications, collaboration, content management, portals, search engines, process management, development tools, application servers, directory services, DBMS, security, operating systems and virtualization. Well-known examples are the operating systems Linux and FreeBSD, the web serverApache, the script languagePerl, the development tools Eclipse and Netbeans as well as the content management systemTypo3. However, there are also areas in which there is not yet an adequate range of open source software. These include business applications, Enterprise Resource Planning( ERP), Customer Relationship Management( CRM), Supply Chain Management( SCM) and Project Portfolio Management ( PPM).