OpenFreeSoftware: All about Free Software and Open Source!

Free software is distinct from "freeware" which is proprietary software made available free of charge. Users usually cannot study, modify, or redistribute freeware.

Since free software may be freely redistributed, it generally is available at little or no cost. Free software business models are usually based on adding value such as support, training, customization, integration, or certification. At the same time, some business models which work with proprietary software are not compatible with free software, such as those that depend on a user paying for a licence in order to lawfully use a software product.
 

Definition

• Freedom 0: The freedom to run the program for any purpose.
• Freedom 1: The freedom to study and modify the program.
• Freedom 2: The freedom to copy the program so you can help your neighbor.
• Freedom 3: The freedom to improve the program, and release your improvements to the public, so that the whole community benefits.

Freedoms 1 and 3 require source code to be available because studying and modifying software without its source code is highly impractical.

Thus, free software means that computer users have the freedom to cooperate with whom they choose, and to control the software they use. To summarize this into a remark distinguishing libre (freedom) software from gratis (zero price) software, Richard Stallman said: "Free software is a matter of liberty, not price. To understand the concept, you should think of 'free' as in 'free speech', not as in 'free beer'".

In the late 90s, other groups published their own definitions which describe an almost identical set of software. The most notable are Debian Free Software Guidelines published in 1997, and the Open Source Definition, published in 1998.

The BSD-based operating systems, such as FreeBSD, OpenBSD, and NetBSD, do not have their own formal definitions of free software. Users of these systems generally find the same set of software to be acceptable, but sometimes see copyleft as restrictive. They generally advocate permissive free software licenses, which allow others to make software based on their source code, and then release the modified result as proprietary software. Their view is that this permissive approach is more free. The Kerberos, X.org, and Apache software licenses are substantially similar in intent and implementation. All of these software packages originated in academic institutions interested in wide technology transfer (University of California, MIT, and UIUC).

Free software licenses

All free software licenses must grant people all the freedoms discussed above. However, unless the applications' licenses are compatible, combining programs by mixing source code or directly linking binaries is problematic, because of license technicalities. Programs indirectly connected together may avoid this problem.

The majority of free software uses a small set of licenses. The most popular of these licenses are:

• the GNU General Public License
• the GNU Lesser General Public License
• the BSD License
• the Mozilla Public License
• the MIT License
• the Apache License

The Free Software Foundation and the Open Source Initiative both publish lists of licenses that they find to comply with their own definitions of free software and open-source software respectively.

• List of FSF approved software licenses
• List of OSI approved software licenses

These lists are necessarily incomplete, because a license need not be known by either organization in order to provide these freedoms.

Apart from these two organizations, the Debian project is seen by some to provide useful advice on whether particular licenses comply with their Debian Free Software Guidelines. Debian doesn't publish a list of approved licenses, so its judgments have to be tracked by checking what software they have allowed into their software archives. That is summarized at the Debian web site.

However, it is rare that a license is announced as being in-compliance by either FSF or OSI guidelines and not vice versa (the Netscape Public License used for early versions of Mozilla being an exception), so exact definitions of the terms have not become hot issues.

Permissive and copyleft licenses

The FSF categorizes licenses in the following ways:

• Public domain software - the copyright has expired, the work was not copyrighted or the author has abandoned the copyright. Since public-domain software lacks copyright protection, it may be freely incorporated into any work, whether proprietary or free.
• Permissive licenses, also called BSD-style because they are applied to much of the software distributed with the BSD operating systems. The author retains copyright solely to disclaim warranty and require proper attribution of modified works, but permits redistribution and modification in any work, even proprietary ones.
• Copyleft licenses, the GNU General Public License being the most prominent. The author retains copyright and permits redistribution and modification provided all such redistribution is licensed under the same license. Additions and modifications by others must also be licensed under the same 'copyleft' license whenever they are distributed with part of the original licensed product.
  

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