GIS – What IS free software exactly?

We’ve all been there – “Hey guys, I just found this real cool software AND it’s free!!”, you then go to download the software and notice that the licence is only for companies with under 100 employees (Yes I have a software with a licence stating that!).  So what exactly is “Free” software?

Well, the answer isn’t as clear as you would believe, just because something is free, doesn’t mean it is free…for example, take Adobe Reader, it is free software but heavily licensed to protect the author. Another example may be seen in the mobile apps we see nowadays where the game/app is free but heavily advertised to create revenue for the author.

Below I have listed some of the common free software licence types I have encountered with a little explanation as to what it actually covers.

GNU Licence

The GNU General Public License (GNU GPL or GPL) is the most widely used free software license, which guarantees end users (individuals, organizations, companies) the freedoms to use, study, share (copy), and modify the software. Software that ensures that these rights are retained is called free software.

The GPL grants the recipients of a computer program the rights of the Free Software Definition and uses copyleft (the opposite of copyright) to ensure the freedoms are preserved whenever the work is distributed, even when the work is changed or added to. The GPL is a copyleft license, which means that derived works can only be distributed under the same license terms. This is in distinction to permissive free software licenses, of which the BSD licenses are the standard examples. GPL was the first copyleft license for general use.

The GNU Lesser General Public License or LGPL (formerly the GNU Library General Public License) The LGPL allows developers and companies to use and integrate LGPL software into their own (even proprietary) software without being required to release the source code of their own software-parts. Merely the LGPL software-parts need to be modifiable by end-users (via source code availability): therefore, in the case of proprietary software, the LGPL-parts are usually used in the form of a shared library (e.g. DLL), so that there is a clear separation between the proprietary parts and open source LGPL parts.

The following is an excerpt of paragraph 5 of the LGPL version 2.1:

“A program that contains no derivative of any portion of the Library, but is designed to work with the Library by being compiled or linked with it, is called a “work that uses the Library”. Such a work, in isolation, is not a derivative work of the Library, and therefore falls outside the scope of this License.”

Freeware

Freeware is software that is available for use at no monetary cost or for an optional fee, but usually (although not necessarily) closed source with one or more restricted usage rights. Freeware is in contrast to commercial software, which is typically sold for profit, but might be distributed for a business or commercial purpose in the aim to expand the marketshare of a “premium” product. According to the Free Software Foundation, “freeware” is a loosely defined category and it has no clear accepted definition, although FSF says it must be distinguished from free software.

Popular examples of closed-source freeware include Adobe Reader, Free Studio and Skype.

Creative Commons Licence

A Creative Commons (CC) license is one of several public copyright licenses that enable the free distribution of an otherwise copyrighted work. A CC license is used when an author wants to give people the right to share, use and build upon a work that they have created. The difference with a CC licence is that the author may restrict the licence for only non-commercial use and protects the people who use or redistribute an author’s work, so they don’t have to worry about copyright infringement, as long as they abide by the conditions that are specified in the license by which the author distributes the work.

BSD Licence

BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the redistribution of covered software.

Two variants of the license, the New BSD License/Modified BSD License (3-clause),  and the Simplified BSD License/FreeBSD License (2-clause)  have been verified as GPL-compatible free software licenses by the Free Software Foundation, and have been vetted as open source licenses by the Open Source Initiative,  while the original, 4-clause license has not been accepted as an open source license and, although the original is considered to be a free software license by the FSF (Free software Foundation) , the FSF does not consider it to be compatible with the GPL due to the advertising clause(s).

Beerware

Beerware is  software released under a very relaxed license. It provides the end user with the right to use a particular program (or do anything else with the source code).

The term came about through the University faculties around the world. Should the user of the product meet the author and consider the software useful, he is encouraged to buy the author a beer “in return”

So what is OPEN SOURCE?

This is defined by the OSI (Open Source Initiative) where the distribution terms of open-source software must comply with the following criteria:

1. Free Redistribution

The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.

2. Source Code

The program must include source code, and must allow distribution in source code as well as compiled form. Where some form of a product is not distributed with source code, there must be a well-publicized means of obtaining the source code for no more than a reasonable reproduction cost preferably, downloading via the Internet without charge. The source code must be the preferred form in which a programmer would modify the program. Deliberately obfuscated source code is not allowed. Intermediate forms such as the output of a preprocessor or translator are not allowed.

3. Derived Works

The license must allow modifications and derived works, and must allow them to be distributed under the same terms as the license of the original software.

4. Integrity of The Author’s Source Code

The license may restrict source-code from being distributed in modified form only if the license allows the distribution of “patch files” with the source code for the purpose of modifying the program at build time. The license must explicitly permit distribution of software built from modified source code. The license may require derived works to carry a different name or version number from the original software.

5. No Discrimination Against Persons or Groups

The license must not discriminate against any person or group of persons.

6. No Discrimination Against Fields of Endeavor

The license must not restrict anyone from making use of the program in a specific field of endeavor. For example, it may not restrict the program from being used in a business, or from being used for genetic research.

7. Distribution of License

The rights attached to the program must apply to all to whom the program is redistributed without the need for execution of an additional license by those parties.

8. License Must Not Be Specific to a Product

The rights attached to the program must not depend on the program’s being part of a particular software distribution. If the program is extracted from that distribution and used or distributed within the terms of the program’s license, all parties to whom the program is redistributed should have the same rights as those that are granted in conjunction with the original software distribution.

9. License Must Not Restrict Other Software

The license must not place restrictions on other software that is distributed along with the licensed software. For example, the license must not insist that all other programs distributed on the same medium must be open-source software.

10. License Must Be Technology-Neutral

No provision of the license may be predicated on any individual technology or style of interface.

So it that ALL the free software licenses?

No, just a quick look on Wikipedia will show that there are over 40 different free software licence, varying from the basic FOSS (Free Open Source) mentioned above through to multi-user licenses which may restrict users based on functionality.  A full list can be found on Wikipedia: HERE

So how do you know which are true FOSS and safe to use in both a commercial & home environment? Luckily the OSI has a list of licences which have been approved as Open Source, this can be found HERE

Next time you get told about that really cool free software, just look it up and check the licence……:)

Nick D

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