Free or open source software (known also under the generic term FLOSS — Free Libre Open Source Software) is software whose use, study, modification and distribution are allowed under a license agreement, also called free or open source licence. Access to the source code is fundamental, so as to benefit from these rights; these last ones being nevertheless subjected to certain conditions, which must be respected.
Free and open source software have existed in fact for decades. It became quite popular thanks to Linux and some key software, such as Firefox or LibreOffice. Free or open source licences most frequently used are GNU GPL, BSD or Apache licenses. This web site itself uses free / open source software.The concepts of free software and open source software were respectively introduced by the Free Software Foundation (FSF) and by the Open Source Initiative (OSI) and distinguish themselves by their approach: guarantee the freedom for software for the FSF, on one hand, and facilitate the co-development and re-use of the software for the OSI, on the other hand.
Free / open source software are supported by communities of developers and led by:
- Community projects, having fewer rules and process with decisions being taken using a consensus model, or by a set of trusted founders or senior community members, this lighter model is well suited for smaller projects. Examples include Django; or
- Foundations, defining rules and processes for decision making, with a board or council that is usually elected in some way. Many larger open source projects are lead by a foundation, such as The Document Foundation, Eclipse, Apache, etc.; or
- Companies, running projects. Decisions are made by a single company. In such a project the product is often available under a dual licence, either a free / open source licence free of charge or a commercial licence. Examples include MySql.
Besides that, independent consortia also federate projects to revitalise communities and make their promotion. Sponsoring companies are represented in their boards of directors. For example: OW2, of which Orange is a co-founder and strategic member.