Types of free licenses

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Types of free licenses

The licenses can be Copyleft, as opposed to Copyright, or not Free licenses are not intended to guarantee the developer’s or software house’s profits, but the availability, for the user community, of software that can be modified and used as part of other applications. The idea behind the guarantees provided by these licenses, in particular the more “restrictive”, are based on the ethical ideals proposed by the philosophy of free software and therefore encourage sharing.

There is a large amount of free software licenses, but the most used

The types of free licenses:

Strong copyleft

They are licenses that contain Copyleft clauses that extend their effects to all derivative works, which means that the first creator of the works has the most rights, “inheritance” of Strong copyleft therefore makes it impossible to use proprietary software, even if only partly closed source, since it requires the application of the license and its clauses within the software.

The best known free software license (used by about 30% of free software projects) that uses a strong copyleft is the GNU General Public License. The Strong license is also a scientific design license that can be applied to art, music, sports photography and video.

Weak copyleft

It refers to the license where not all derivative works inherit the copyleft license, often depending on how they are derived. They limit the scope of the Copyleft clause to a greater or lesser extent, thus allowing different licenses to be applied to certain derivative works. The criterion used involves the imposition of the application of the same license, not on software that provides for use via linking, but only on the modified versions.

Weak copyleft licenses are mainly used for software libraries allowing links to other libraries (GNU Lesser General Public License and Mozilla Public License).

Cloud copyleft

Licenses require that the source code of the program be made available to users who use it remotely by connecting to the server where the software is operated as a service (GNU Affero General Public License and European Union Public License.

The Apache license. Public license created by the Apache foundation. The current version is the Apache 2.0 license. It is a non-copyleft permissive license that allows the sub-license and to re-use it with proprietary applications. Well-known software such as the Apache HTTP server, the Android or Twitter operating system, are licensed under the Apache license.

The MIT license. The Massachusetts Institute of technology license is a non-copyleft permissive license, allows the sub-license and allows the creation of commercial applications. It is also known as Expat license or X11 license.
The BSD license. Berkley Software Distribution licenses are a permissive license without copyright permission.