A software license is actually the contract in which the user accepts the terms and conditions of the manufacturer to be able to use a certain program. Within this general concept there are numerous variants or types of software licenses (free or paid, limited geographically or temporarily, with more or less restrictions...) that we are going to list and explain here.
These contracts establish the terms, conditions and clauses that must be fulfilled by those who wish to use a certain program. All users who download, install or use it are obliged to observe these rules.
One detail to keep in mind is that when we buy or download a program, regardless of the type of license it has, what we really acquire is a license to use. It is a concept that should be clear to avoid errors and misunderstandings.
Broadly speaking, user licenses can be divided into two large groups: free software and proprietary software, although if we want to be more precise we distinguish even many types, each of them with its own characteristics. Let's see them one by one below:
Free software license
This class of licenses not only allow users to run a program, but also to study its operation, improve it and adapt it to their own needs. With a free software license, the user is also free to copy and redistribute it.
There are many well-known examples of free software licenses. Within this category, two subtypes must be included:
Copyleft protected
In this case, the free software distribution terms do not allow users to add any
additional restriction or make any changes when redistributing it. In other words: distributed copies must remain free software.
No Copyleft
In contrast, free software not protected by copyleft has the approval by the author for this to be redistributed adding additional modifications and restrictions. This can lead to versions of the program being created during distribution that are no longer completely free. That is, they would become part of other types of licence.
GPL Software License
The GNU Lesser General Public License, or GNU LGPL. It is a very particular type of license, in principle free software, although it does not have a strong copyleft. Its terms allow it to be integrated with non-free software modules and do not hinder its commercialization.
Debian software license
As many people already know, Debian GNU / Linux is a free operating system developed by thousands of volunteers from all over the world. Your software license (Debian Free Software Guidelines) is a contract signed between Debian and its community of software users specifying a series of criteria. These are some of the most important:
- Free redistribution.
- Obligation to include the source code.
- Obligation not to discriminate against any person or group of people. neither to any
way of using the software.
BSD software license
It is one of the most permissive types of software licenses that exist. It was created expressly for the distribution of software of Berkeley Software Distribution, It is characterized by imposing very few restrictions on the way of use, modifications and redistribution of the software.
MPL Software License
The characteristics of these licenses are similar to the BSD licenses, although not as permissive. They are also very well known, since they are the licenses that use Mozilla Firefox, Mozilla Thunderbird and others.
X.Org Software License
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this is a guy hybrid license, since it includes distributions under license of free software and also other distributions that are not. The best known example is the X Windows System, a system created to provide a graphical interface to Unix-based systems.
Freeware license
It is a license freely offered by the author to use and copy freely, although under the particular conditions that it imposes. One of them is the total prohibition of being copied or sold to third parties. There are well-known examples of this type of license, such as CCleaner, Adobe Flash or Adobe Reader.
There are some peculiar variants of Freeware that add some special requirements. These are some examples:
- donationware, which invites the user to contribute with a voluntary donation.
- postcardware, invites to send a postal letter.
- Careware, invites you to make donations to support humanitarian and solidarity causes.
Shareware License
The peculiarity of the Shareware license is that it allows the user use the software for a limited time, or indefinitely but with restricted functions. These obstacles can be removed by paying a certain amount to its author. It does not include the source code, so it is not possible to make any kind of modification. There are three subtypes of Shareware licenses:
- Trial, with a time restriction (this is, for example, the license used by the popular antivirus from Kaspersky)
- Book demo, with restricted functions. Used by most video games.
- Adware, including advertising.
Abandonware license
Probably the most curious case on this list. This type of license is the one that applies to programs that have been abandoned by their authors, being free of all their copyright rights (yes, the author must specify this point clearly). Thus, any user can use these programs, make the changes they want to them and share them.
OEM software license
This type of license conditions its use to the purchase or acquisition of a computer product. The buyer has complete freedom to use the software, although manufacturers may sometimes impose certain limitations. For example, a maximum number of times it can be reinstalled. The license Original Equipment Manufacturer It is usually associated with the acquisition of operating systems.
Retail Software License
It is a paid license whereby the buyer can do almost anything they want with the software: install it unlimitedly, transfer it, and even sell it.
Proprietary / Commercial Software License
They are two different licenses, but very similar. In the first (proprietary software license), the author of the project is the one who defines the rights of copying, modification and redistribution, terms that can be revoked in exchange for a payment; the second (commercial software license) is granted to programs designed with the aim of being commercialized, although it can be perfectly free to use.