I originally wrote this in 2005. Some of the information may be dated, however, the basics should all remain the same.
GNU General Public License
Open Source License
An introduction to the Free Software Licenses
Lesson 01- 05.01.11.02
What is GNU?
The GNU Project was launched in 1984 to develop a complete UNIX style operating system which is free software: the GNU system.
GNU is a recursive acronym for “GNU's Not UNIX”; it is pronounced “guh-noo.”
Variants of the GNU operating system, which use the kernel Linux, are now widely used; though these systems are often referred to as “Linux,” they are more accurately called GNU/Linux systems.
Philosophy of the GNU Project
The Free Software Definition
We maintain this free software definition to show clearly what must be true about a particular software program for it to be considered free software.
``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.''
Free software is a matter of the users' freedom to run, copy, distribute, study, change and improve the software. More precisely, it refers to four kinds of freedom, for the users of the software.
The freedom to run the program, for any purpose.
The freedom to study how the program works, and adapt it to your needs. Access to the source code is a precondition for this.
The freedom to redistribute copies so you can help your neighbour.
The freedom to improve the program, and release your improvements to the public, so that the whole community benefits. Access to the source code is a precondition for this.
A program is free if . . .
A program is free software if users have all of these freedoms.
Thus, you should be free to redistribute copies, either with or without modifications, either gratis or charging a fee for distribution, to anyone anywhere.
Being free to do these things means (among other things) that you do not have to ask or pay for permission.
What else can you do?
You should also have the freedom to make modifications and use them privately in your own work or play, without even mentioning that they exist.
If you do publish your changes, you should not be required to notify anyone in particular, or in any particular way.
Who can use it and how?
The freedom to use a program means the freedom for any kind of person or organization to use it, on any kind of computer system, for any kind of overall job, and without being required to communicate subsequently with the developer or any other specific entity.
What can be published?
The freedom to redistribute copies must include binary or executable forms of the program, as well as source code, for both modified and unmodified versions.
(Distributing programs in runnable form is necessary for conveniently installable free operating systems.)
It is ok if there is no way to produce a binary or executable form for a certain program (since some languages don't support that feature), but you must have the freedom to redistribute such forms should you find or develop a way to make them.
What is the license?
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 - 1307, USA.
Open Source Software - What is Open Source Software?
The basic idea behind open source is very simple:
When programmers can read, redistribute, and modify the source code for a piece of software, the software evolves. People improve it, people adapt it, people fix bugs. And this can happen at a speed that, if one is used to the slow pace of conventional software development, seems astonishing.
What does Open Source mean?
Open source doesn't just mean access to the source code.
The distribution terms of open-source software must comply with the following criteria:
00. 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.
Rationale: By con-straining the license to require free redistribution, we eliminate the temptation to throw away many long-term gains in order to make a few short-term sales dollars. If we didn't do this, there would be lots of pressure for cooperators to defect.
01. 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 pre processor or translator are not allowed.
Rationale: We require access to un obfuscated source code because you can't evolve programs without modifying them. Since our purpose is to make evolution easy, we require that modification be made easy.
02. 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.
Rationale: The mere ability to read source isn't enough to support independent peer review and rapid evolutionary selection. For rapid evolution to happen, people need to be able to experiment with and redistribute modifications.
03. 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.
Rationale: Encouraging lots of improvement is a good thing, but users have a right to know who is responsible for the software they are using. Authors and maintainers have reciprocal right to know what they're being asked to support and protect their reputations.
Accordingly, an open source license must guarantee that source be readily available, but may require that it be distributed as pristine base sources plus patches.
In this way, "unofficial" changes can be made available but readily distinguished from the base source.
04. No Discrimination Against Persons or Groups
The license must not discriminate against any person or group of persons.
Rationale: In order to get the maximum benefit from the process, the maximum diversity of persons and groups should be equally eligible to contribute to open sources. Therefore we forbid any open source license from locking anybody out of the process.
Some countries, including the United States, have export restrictions for certain types of software. An OSD conformance license may warn licensees of applicable restrictions and remind them that they are obliged to obey the law; however, it may not incorporate such restrictions itself.
05. No Discrimination Against Fields of Endeavour
The license must not restrict anyone from making use of the program in a specific field of endeavour. For example, it may not restrict the program from being used in a business, or from being used for genetic research.
Rationale: The major intention of this clause is to prohibit license traps that prevent open source from being used commercially. We want commercial users to join our community, not feel excluded from it.
06. 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.
Rationale: This clause is intended to forbid closing up software by indirect means such as requiring a non disclosure agreement.
07. 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.
Rationale: This clause forecloses yet another class of license traps.
08. 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.
Rationale: Distributors of open source software have the right to make their own choices about their own software. Yes, the GPL is conformant with this requirement. Software linked with GPLed libraries only inherits the GPL if it forms a single work, not any software with which they are merely distributed.
09. License Must Be Technology Neutral
No provision of the license may be predicated on any individual technology or style of interface.
Rationale: This provision is aimed specifically at licenses which require an explicit gesture of assent in order to establish a contract between licensor and licensee. Provisions mandating so called "click wrap" may conflict with important methods of software distribution such as FTP download, CD-ROM anthologies, and web mirroring; such provisions may also hinder code re use.
Con-formant licenses must allow for the possibility that (a) redistribution of the software will take place over non Web channels that do not support click wrapping of the download, and that the covered code (or re used portions of covered code) may run in a non GUI environment that cannot support popup dialogues.
The Open Source License
Licensor hereby grants You a worldwide, royalty free, non exclusive, perpetual, sub licensable license to do the following:
- to reproduce the Original Work in copies;
- to prepare derivative works ("Derivative Works") based upon the Original Work;
- to distribute copies of the Original Work and Derivative Works to the public, with the proviso that copies of Original Work or Derivative Works that You distribute shall be licensed under the Open Software License;
- to perform the Original Work publicly; and
- to display the Original Work publicly.
So what does it mean to me?
- Both GNU GPL and Open Source software are free to use by anybody.
- Both place copy write on the software.
- Both require that all source code be available to anybody using their software.
- GPL licenses allow any user to modify the software in any way, without notifying the original creator.
- Open Source licenses normally require that any modifications be reported to the original author, so that he may retain full copy write.
So is Linux GPL or Open Source?
- Both GNU GPL and Open Source software apply to Linux.
- The original kernel core is still the property of Linus Thorvalds, free to use by anybody.
- Modifications made to the kernel are monitored by a committee, that then incorporates them in future releases.
- Add on programs are the property of the original authors, who created them.
- They can be released as either GPL or Open Source.
Edited by Naught McNoone, 16 June 2015 - 11:55 AM.