Public-domain software

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The Creative Commons Public Domain Mark indicates works that are in the public domain Cc-public domain mark white.svg
The Creative Commons Public Domain Mark indicates works that are in the public domain

Public-domain software is software that has been placed in the public domain, in other words, software for which there is absolutely no ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, or sold even without any attribution by anyone; this is unlike the common case of software under exclusive copyright, where licenses grant limited usage rights.

Contents

Under the Berne Convention, which most countries have signed, an author automatically obtains the exclusive copyright to anything they have written, and local law may similarly grant copyright, patent, or trademark rights by default. The Convention also covers programs, and they are therefore automatically subject to copyright. If a program is to be placed in the public domain, the author must explicitly disclaim the copyright and other rights on it in some way, e.g. by a waiver statement. [1] In some jurisdictions, some rights (in particular moral rights) cannot be disclaimed: for instance, civil tradition-based German law's " Urheberrecht " differs from Anglo-Saxon common law tradition's "copyright" concept.

History

Early academic public-domain software ecosystem

From the software culture of the 1950s to 1990s, public-domain (or PD) software were popular as original academic phenomena. This kind of freely distributed and shared "free software" combined the present-day classes of freeware, shareware, and free and open-source software, and was created in academia, by hobbyists, and hackers. [2] As software was often written in an interpreted language such as BASIC, the source code was needed and therefore distributed to run the software. PD software was also shared and distributed as printed source code (type-in programs) in computer magazines (like Creative Computing , SoftSide , Compute! , Byte , etc.) and books, like the bestseller BASIC Computer Games . [3] Earlier on, closed-source software was uncommon until the mid-1970s to 1980s. [4] [5] [6]

Before 1974, when the US Commission on New Technological Uses of Copyrighted Works (CONTU) decided that "computer programs, to the extent that they embody an author's original creation, are proper subject matter of copyright", [7] [8] software was not copyrightable and therefore always in the public domain. This legislation, plus court decisions such as Apple v. Franklin in 1983 for object code, clarified that the Copyright Act gave computer programs the copyright status of literary works.

In the 1980s, a common way to share public-domain software[ verification needed ] was by receiving them through a local user group or a company like PC-SIG of Sunnyvale, California, which maintained a mail-order catalog of more than 300 disks with an average price of US$6. [9] Public-domain software with source code was also shared on BBS networks. Public-domain software was commercialized sometimes by a donationware model, asking the users for a financial donation to be sent by mail. [10]

The public-domain "free sharing" and donationware commercialization models evolved in the following years to the (non-voluntary) shareware model, [11] [12] and software free of charge, called freeware. [13] Additionally, due to other changes in the computer industry, the sharing of source code became less common. [6]

With the Berne Convention Implementation Act of 1988 (and the earlier Copyright Act of 1976), the legal basis for public-domain software changed drastically. Before the act, releasing software without a copyright notice was enough to dedicate it to the public domain. With the new act, software was by default copyright-protected and needed an explicit waiver statement or license from the author. [14] [15]

Reference implementations of algorithms, often cryptographic meant or applied for standardization are still often released into the public domain; examples include CERN httpd [16] in 1993 and Serpent cipher in 1999. The Openwall Project maintains a list of several algorithms and their source code in the public domain. [17]

Free and open-source software as successor

As a response of the academic software ecosystem to the change in the copyright system in the late 1980s, permissive license texts were developed, like the BSD license and its derivatives. Permissive-licensed software, which is a kind of free and open-source software, shares most characteristics of earlier public-domain software but stands on the legal basis of copyright law.

In the 1980s Richard Stallman, who for long worked in an academic environment of "public-domain"-like software sharing, noticed the emergence of proprietary software and the decline of the public-domain software ecosystem. In an effort to preserve this ecosystem he created a software license, the GPL, which encodes the public-domain rights and enforces them irrevocably on software. Paradoxically, his copyleft approach relies on the enforceability of the copyright to be effective. Copyleft free software, therefore, shares many properties with public-domain software, but does not allow relicensing or sublicensing. Unlike real public-domain software or permissive-licensed software, Stallman's copyleft license tries to enforce the free shareability of software also for the future by not allowing license changes.

To refer to free software (which is under a free software license) or to software distributed and usable free of charge (freeware) as "public-domain" is therefore incorrect. While public domain gives up the author's exclusive rights (e.g. copyright), in free software the author's copyright is still retained and used, for instance, to enforce copyleft or to hand out permissive-licensed software. Licensed software is in general not in the public domain. [18] Another distinct difference is that an executable program may be in the public domain even if its source code is not made available (making the program not feasibly modifiable), while free software always has the source code available.

Post-copyright public domain

With the 2000s and the emergence of peer-to-peer sharing networks and sharing in web development, a new copyright-critical generation of developers made the "license-free" public-domain software model visible again, also criticizing the FOSS license ecosystem ("Post Open Source") as stabilizing part of the copyright system. [19] [20] [21] [22] New non-FOSS licenses and waiver texts were developed, notably the Creative Commons "CC0" (2009) and the "Unlicense" (2010), and there was a noticeable rise in the popularity of permissive software licenses. Also, the growing problem of orphaned software and digital obsolescence of software raised awareness of the relevance of again passing software into the public domain for better preservation of the digital heritage, unrestricted by copyright and digital rights management. [23] [24] [25] [26]

Around 2004, there was debate on whether public-domain software could be considered part of the FOSS ecosystem, as argued by lawyer Lawrence Rosen in the essay "Why the public domain isn't a license", [27] a position that faced opposition by Daniel J. Bernstein and others. [28] In 2012, the status was finally resolved when Rosen changed his mind and accepted the CC0 as an open-source license, while admitting that, contrary to previous claims, copyright could be waived, as backed by a Ninth Circuit decision. [29]

Passing of software into the public domain

Before the Berne Convention Implementation Act of 1988 (and the earlier Copyright Act of 1976, which went into effect in 1978) works could be easily given into the public domain by releasing them without an explicit copyright notice and no copyright registration. After 1988, all works were by default copyright protected and needed to be actively given into the public domain by a waiver statement. [14] [15]

Copyrighted works, like software, are meant to pass into the public domain after the copyright term, losing their copyright privilege. Due to the decades-long copyright protection granted by the Berne Convention, no software has ever passed into the public domain by leaving copyright terms. The question of how quickly works should pass into the public domain has been a matter of scientific [30] [31] [32] and public debates, as well as for software like video games. [24] [25] [26]

Public-domain-like licenses and waivers

WTFPL license logo, a public-domain-like license WTFPL logo.svg
WTFPL license logo, a public-domain-like license
CC0 license logo, a copyright waiver , and public-domain-like license Cc-zero.svg
CC0 license logo, a copyright waiver , and public-domain-like license

While real public domain makes software licenses unnecessary, as no owner/author is required to grant permission ("Permission culture"), there are licenses that grant public-domain-like rights. There is no universally agreed-upon license, but there are multiple licenses that aim to release source code into the public domain.

In 2000 the WTFPL was released as a public-domain-like license/waiver/anti-copyright notice. [34] In 2009 the Creative Commons released the CC0, which was created for compatibility with various law domains (e.g. civil law of continental Europe) where dedicating to public domain is problematic. This is achieved by a public domain waiver statement and a fallback all-permissive license, in case the waiver is not possible. [35] [36] The Unlicense, published around 2010, has a focus on an anti-copyright message. The Unlicense offers a public domain waiver text with a fallback public-domain-like license inspired by permissive licenses but without attribution clause. [37] [38] In 2015, GitHub reported that of the approximately 5.1 million licensed projects it hosted, almost 2% used the Unlicense. [39] Another popular option is the Zero Clause BSD license, released in 2006 and aimed at software. [40]

As result, such licensed public-domain software has all the four freedoms but is not hampered by the complexities of attribution (restriction of permissive licensed software) or license compatibility (issue with copyleft licensed software).

Public-domain software

See also Category:Public-domain software with source code, Category:Public-domain software

Classical PD software (pre-1988)

Public domain software in the early computer age was, for instance, shared as type-in programs in computer magazines and books like BASIC Computer Games. Explicit PD waiver statements or license files were at that time unusual. Publicly available software without a copyright notice was assumed to be, and shared as, public-domain software.

Notable general PD software from that time include:

Video games are among the earliest examples of shared PD software, which are still notable today:

Many PD software authors kept the practices of public-domain release without having a waiver text, not knowing or caring for the changed copyright law, thus creating a legal problem. On the other hand, magazines started in the mid-1980s to claim copyright even for type-in programs that were previously seen as PD. [45] [46] Only slowly did PD software authors start to include explicit relinquishment or license statement texts.

Examples of modern PD software (post 1988)

These examples of modern PD software (after the Berne Convention Implementation Act of 1988) are either under proper public domain (e.g. created by a US governmental organization), under a proper public domain like license (for instance CC0), or accompanied by a clear waiver statement from the author. Whilst not as widespread as in the pre-2000s, PD software still exists nowadays. For example, SourceForge listed 334 hosted PD projects in 2016, [47] and GitHub 102,000 under the Unlicense alone in 2015. [39] In 2016, an analysis of the Fedora Project's packages revealed PD was the seventh most popular "license". [48]

The award-winning video game developer Jason Rohrer releases his works into the PD, as do several cryptographers, such as Daniel J. Bernstein, Bruce Schneier and Douglas Crockford, [49] with reference implementations of cryptographic algorithms.

See also

Related Research Articles

<span class="mw-page-title-main">Free software</span> Software licensed to be freely used, modified and distributed

Free software, libre software, or libreware is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed "free" if they give end-users ultimate control over the software and, subsequently, over their devices.

The MIT License is a permissive software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts very few restrictions on reuse and therefore has high license compatibility.

<span class="mw-page-title-main">Open-source license</span> Software license allowing source code to be used, modified, and shared

Open-source licenses are software licenses that allow content to be used, modified, and shared. They facilitate free and open-source software (FOSS) development. Intellectual property (IP) laws restrict the modification and sharing of creative works. Free and open-source licenses use these existing legal structures for an inverse purpose. They grant the recipient the rights to use the software, examine the source code, modify it, and distribute the modifications. These criteria are outlined in the Open Source Definition.

<span class="mw-page-title-main">Apache License</span> Free software license

The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software under the terms of the license, without concern for royalties. The ASF and its projects release their software products under the Apache License. The license is also used by many non-ASF projects.

An anti-copyright notice is a specific statement that is added to a work in order to encourage wide distribution. Such notices are legally required to host such specific media; under the Berne Convention in international copyright law, works are protected even if no copyright statement is attached to them. However, "anti-copyright" statements typically do not take the form of either sophisticated public copyright licenses or a simple dedication to the public domain; instead, they usually just encourage wide distribution. Depending on jurisdiction, it is possible to denounce all claims to copyright in a work including moral rights in a written disclaimer.

A software license is a legal instrument governing the use or redistribution of software. Under United States copyright law, all software is copyright protected, in both source code and object code forms, unless that software was developed by the United States Government, in which case it cannot be copyrighted. Authors of copyrighted software can donate their software to the public domain, in which case it is also not covered by copyright and, as a result, cannot be licensed.

A permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license which instead of copyleft protections, carries only minimal restrictions on how the software can be used, modified, and redistributed, usually including a warranty disclaimer. Examples include the GNU All-permissive License, MIT License, BSD licenses, Apple Public Source License and Apache license. As of 2016, the most popular free-software license is the permissive MIT license.

This comparison only covers software licenses which have a linked Wikipedia article for details and which are approved by at least one of the following expert groups: the Free Software Foundation, the Open Source Initiative, the Debian Project and the Fedora Project. For a list of licenses not specifically intended for software, see List of free-content licences.

<span class="mw-page-title-main">WTFPL</span> Permissive free software license

The WTFPL is a permissive free software license. As a public domain like license, the WTFPL is essentially the same as dedication to the public domain. It allows redistribution and modification of the work under any terms. The name is an abbreviation of Do What The Fuck You Want To Public License.

<span class="mw-page-title-main">Public-domain-equivalent license</span> License that waives all copyright

Public-domain-equivalent license are licenses that grant public-domain-like rights and/or act as waivers. They are used to make copyrighted works usable by anyone without conditions, while avoiding the complexities of attribution or license compatibility that occur with other licenses.

License proliferation is the phenomenon of an abundance of already existing and the continued creation of new software licenses for software and software packages in the FOSS ecosystem. License proliferation affects the whole FOSS ecosystem negatively by the burden of increasingly complex license selection, license interaction, and license compatibility considerations.

License compatibility is a legal framework that allows for pieces of software with different software licenses to be distributed together. The need for such a framework arises because the different licenses can contain contradictory requirements, rendering it impossible to legally combine source code from separately-licensed software in order to create and publish a new program. Proprietary licenses are generally program-specific and incompatible; authors must negotiate to combine code. Copyleft licenses are commonly deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being re-licensed under a proprietary license, turning it into proprietary software. Many copyleft licenses explicitly allow relicensing under some other copyleft licenses. Permissive licenses are compatible with everything, including proprietary licenses; there is thus no guarantee that all derived works will remain under a permissive license.

<span class="mw-page-title-main">Free-software license</span> License allowing software modification and redistribution

A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.

BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.

<span class="mw-page-title-main">Copyleft</span> Practice of mandating free use in all derivatives of a work

Copyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in derivative works. In this sense, freedoms refers to the use of the work for any purpose, and the ability to modify, copy, share, and redistribute the work, with or without a fee. Licenses which implement copyleft can be used to maintain copyright conditions for works ranging from computer software, to documents, art, scientific discoveries and even certain patents.

<span class="mw-page-title-main">Public domain</span> Works outside the scope of copyright law

The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because no one holds the exclusive rights, anyone can legally use or reference those works without permission.

<span class="mw-page-title-main">GNU General Public License</span> Series of free software licenses

The GNU General Public License is a series of widely used free software licenses or copyleft that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general use and was originally written by Richard Stallman, the founder of the Free Software Foundation (FSF), for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition. The licenses in the GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. It is more restrictive than the Lesser General Public License and even further distinct from the more widely used permissive software licenses BSD, MIT, and Apache.

A free license or open license is a license which allows others to reuse another creator’s work as they wish. Without a special license, these uses are normally prohibited by copyright, patent or commercial license. Most free licenses are worldwide, royalty-free, non-exclusive, and perpetual. Free licenses are often the basis of crowdsourcing and crowdfunding projects.

A public license or public copyright licenses is a license by which a copyright holder as licensor can grant additional copyright permissions to any and all persons in the general public as licensees. By applying a public license to a work, provided that the licensees obey the terms and conditions of the license, copyright holders give permission for others to copy or change their work in ways that would otherwise infringe copyright law.

<span class="mw-page-title-main">Unlicense</span> Anti-copyright license

The Unlicense is a public domain equivalent license for software which provides a public domain waiver with a fall-back public-domain-like license, similar to the CC Zero for cultural works. It includes language used in earlier software projects and has a focus on an anti-copyright message.

References

  1. ↑ Open Source: Technology and Policy by Fadi P. Deek, James A. M. McHugh "Public domain", page 227 (2008).
  2. ↑ Shea, Tom (1983-06-23). "Free software - Free software is a junkyard of software spare parts". InfoWorld . Retrieved 2016-02-10. In contrast to commercial software is a large and growing body of free software that exists in the public domain. Public-domain software is written by microcomputer hobbyists (also known as "hackers") many of whom are professional programmers in their work life.
  3. ↑ Ahl, David. "David H. Ahl biography from Who's Who in America" . Retrieved 2009-11-23.
  4. ↑ Object code only: is IBM playing fair? IBM's OCO policy protects its own assets but may threaten customers investment on Computerworld - 8 Febr. 1988
  5. ↑ Firm sidestep IBM policy by banning software changes on Computerworld (18 March 1985)
  6. 1 2 Gallant, John (1985-03-18). "IBM policy draws fire – Users say source code rules hamper change". Computerworld . Retrieved 2015-12-27. While IBM's policy of withholding source code for selected software products has already marked its second anniversary, users are only now beginning to cope with the impact of that decision. But whether or not the advent of object-code-only products has affected their day-to-day DP operations, some users remain angry about IBM's decision. Announced in February 1983, IBM's object-code-only policy has been applied to a growing list of Big Blue system software products
  7. ↑ Apple Computer, Inc. v. Franklin Computer Corporation Puts the Byte Back into Copyright Protection for Computer Programs in Golden Gate University Law Review Volume 14, Issue 2, Article 3 by Jan L. Nussbaum (January 1984)
  8. ↑ Lemley, Menell, Merges and Samuelson. Software and Internet Law, p. 34.
  9. ↑ Kristina B. Sullivan (1986-01-14). "Hackers Create Public-Domain Software for the Sheer Joy of It". PC Week. Vol. 3, no. 2. pp. 121–122.
  10. ↑ April 1987: Ballerburg - Zwei Spieler, zwei Burgen und ein Berg dazwischen... on eckhardkruse.net: "Ich habe das Programm als Public Domain veröffentlicht (die Unterscheidung in Freeware, Shareware usw. gab es damals nicht), mit der Bitte um eine 20 DM Spende. Dafür gab es dann die erweitere Version und den Quellcode." (in German).
  11. ↑ "Bob Wallace Timeline". Erowid. Jan 12, 2004. Retrieved March 7, 2013.
  12. ↑ Article about Jim "Button" Knopf, from Dr. Dobb's Journal .
  13. ↑ the-history-of-shareware-psl on asp-software.org.
  14. 1 2 publicdomain on cornell.edu
  15. 1 2 Copyright Notice , U.S. Copyright Office Circular 3, 2008.
  16. ↑ The birth of the web Licensing the web on cern.ch (2014).
  17. ↑ Source code snippets and frameworks placed in the public domain on openwall.info.
  18. ↑ Shankland, Stephen (February 28, 2008). "Is public domain software open-source?". cnet.com. Retrieved 2016-02-03. There's no doubt that open-source software and that in the public domain are similar. But even experts differ about just how closely linked they are.
  19. ↑ The Surprising History of Copyright and The Promise of a Post-Copyright World by Karl Fogel (2006).
  20. ↑ Younger developers reject licensing, risk chance for reform on opensource.com by Luis Villa (on 12 Feb 2013).
  21. ↑ Pushing back against licensing and the permission culture Luis Villa (January 28, 2013).
  22. ↑ Post open source software, licensing and GitHub on opensource.com by Richard Fontana (on 13 Aug 2013).
  23. ↑ Charlesworth, Andrew (5 November 2002). "The CAMiLEON Project: Legal issues arising from the work aiming to preserve elements of the interactive multimedia work entitled "The BBC Domesday Project"". Kingston upon Hull: Information Law and Technology Unit, University of Hull. Archived from the original (Microsoft Word) on 6 February 2011. Retrieved 23 March 2011.
  24. 1 2 Walker, John (2014-01-29). "GOG's Time Machine Sale Lets You CONTROL TIME ITSELF". Rock, Paper, Shotgun . Retrieved 2016-01-30. As someone who desperately pines for the PD model that drove creativity before the copyright industry malevolently took over the planet, it saddens my heart that a game two decades old isn't released into the world.
  25. 1 2 Walker, John (2014-02-03). "Editorial: Why Games Should Enter The Public Domain". Rock, Paper, Shotgun . Retrieved 2016-01-30. games more than a couple of decades old aren't entering the public domain. Twenty years was a fairly arbitrary number, one that seems to make sense in the context of games' lives, but it could be twenty-five, thirty.
  26. 1 2 Rouner, Jef (April 28, 2015). "U.S. Copyright Office to Explore Making Some Video Games Public Domain". Houston Press . Retrieved 2016-02-03.
  27. ↑ Lawrence Rosen (2004-05-25). "Why the public domain isn't a license". rosenlaw.com. Retrieved 2016-02-22.
  28. ↑ Placing documents into the public domain by Daniel J. Bernstein on cr.yp.to: "Most rights can be voluntarily abandoned ('waived') by the owner of the rights. Legislators can go to extra effort to create rights that can't be abandoned, but usually they don't do this. In particular, you can voluntarily abandon your United States copyrights: 'It is well settled that rights gained under the Copyright Act may be abandoned. But abandonment of a right must be manifested by some overt act indicating an intention to abandon that right. See Hampton v. Paramount Pictures Corp., 279 F.2d 100, 104 (9th Cir. 1960).' " (2004).
  29. ↑ Lawrence Rosen (2012-03-08). "(License-review) (License-discuss) CC0 incompliant with OSD on patents, (was: MXM compared to CC0)". opensource.org. Archived from the original on 2016-03-12. Retrieved 2016-02-22. The case you referenced in your email, Hampton v. Paramount Pictures, 279 F.2d 100 (9th Cir. Cal. 1960), stands for the proposition that, at least in the Ninth Circuit, a person can indeed abandon his copyrights (counter to what I wrote in my article) – but it takes the equivalent of a manifest license to do so. :-) [...] For the record, I have already voted +1 to approve the CC0 public domain dedication and fallback license as OSD compliant. I admit that I have argued for years against the "public domain" as an open source license, but in retrospect, considering the minimal risk to developers and users relying on such software and the evident popularity of that "license", I changed my mind. One can't stand in the way of a fire hose of free public domain software, even if it doesn't come with a better FOSS license that I trust more.
  30. ↑ Watt, Richard (September 26, 2014). Handbook on the Economics of Copyright: A Guide for Students and Teachers. Edward Elgar Publishing. ISBN   9781849808538 . Retrieved 2015-01-11.
  31. ↑ Pollock, Rufus (2007-10-01). "OPTIMAL COPYRIGHT OVER TIME: TECHNOLOGICAL CHANGE AND THE STOCK OF WORKS" (PDF). University of Cambridge. Archived from the original (PDF) on 2013-02-21. Retrieved 2015-01-11.
  32. ↑ Pollock, Rufus (2009-06-15). "FOREVER MINUS A DAY? CALCULATING OPTIMAL COPYRIGHT TERM" (PDF). University of Cambridge. Archived from the original (PDF) on 2013-01-12. Retrieved 2015-01-11. The optimal term of copyright has been a matter for extensive debate over the last decade.
  33. ↑ "Downloads". Creative Commons. 2015-12-16. Retrieved 2015-12-24.
  34. ↑ Version 1.0 license on anonscm.debian.org.
  35. ↑ "11/17: Lulan Artisans Textile Competition". 18 June 2009.
  36. ↑ Validity of the Creative Commons Zero 1.0 Universal Public Domain Dedication and its usability for bibliographic metadata from the perspective of German Copyright Law by Till Kreutzer, attorney-at-law in Berlin, Germany.
  37. ↑ The unlicense a license for no license Archived 2017-01-22 at the Wayback Machine on ostatic.com by Joe Brockmeier (2010)
  38. ↑ The Unlicense Archived 2018-07-08 at the Wayback Machine on unlicense.org.
  39. 1 2 Balter, Ben (2015-03-09). "Open source license usage on GitHub.com". github.com . Retrieved 2015-11-21. 1 MIT 44.69%, 2 Other 15.68%, 3 GPLv2 12.96%, 4 Apache 11.19%, 5 GPLv3 8.88%, 6 BSD 3-clause 4.53%, 7 Unlicense 1.87%, 8 BSD 2-clause 1.70%, 9 LGPLv3 1.30%, 10 AGPLv3 1.05% (30 mill * 2% * 17% = 102k)
  40. ↑ "BSD 0-Clause License (0BSD) Explained in Plain English" . Retrieved 25 February 2020.
  41. ↑ "Alan Turing at 100". Harvard Gazette. 13 September 2012. Retrieved 2016-02-22.
  42. ↑ The Genealogy of Eliza by Jeff Shrager
  43. ↑ history-of-spice on allaboutcircuits.com "The origin of SPICE traces back to another circuit simulation program called CANCER. Developed by professor Ronald Rohrer of U.C. Berkeley along with some of his students in the late 1960s, CANCER continued to be improved through the early 1970s. When Rohrer left Berkeley, CANCER was re-written and re-named to SPICE, released as version 1 to the public domain in May of 1972. Version 2 of SPICE was released in 1975 (version 2g6—the version used in this book—is a minor revision of this 1975 release). Instrumental in the decision to release SPICE as a public-domain computer program was professor Donald Pederson of Berkeley, who believed that all significant technical progress happens when information is freely shared. I for one thank him for his vision."
  44. ↑ Classic Games on oilzine.com "Space War (Asteroids) - Steve Russell – MIT - Tech Model Railroad Club (TMRC) - PDP-1 In 1961, the game that would eventually become Asteroids started life, humbly, at MIT (Massachusetts Institute of Technology). [...] It was also open source, so the code was public domain, available for anybody to utilize and improve upon."
  45. ↑ Compute-Gazette-Issue-11-01.pdf
  46. ↑ Transactor_v8i3.pdf: "though our disk labels show a copyright notice, up until this issue we stated right on our policies page (page 2) that our programs are 'public domain; free to copy, not to sell'. This notice goes back about 4 years – a popular phrase originally designed to prevent one's program from being 'acquired' by someone in the software business".
  47. ↑ 334 PD projects on sourceforge.net (February 2016)
  48. ↑ Anwesha Das (22 June 2016). "Software Licenses in Fedora Ecosystem". anweshadas.in. Retrieved 2016-06-27. In the above bar-chart I have counted GPL and its different versions as one family, and I did the same with LGPL too. From this diagram it is very much clear that the MIT License is the most used license, with a total number of use case of 2706. Therefore comes GPL (i.e GNU General Public License) and its different versions, BSD, LGPL (i.e. GNU Lesser General Public License) and its different versions, ASL (i.e Apache Software License) family, MPL (i.e. Mozilla Public License). Apart from these licenses there are projects who has submitted themselves into Public Domain and that number is 137.
  49. ↑ douglascrockford on GitHub
  50. ↑ PUBLIC DOMAIN CERN WWW SOFTWARE (1993)
  51. ↑ disclaimer on rsb.info.nih.gov
  52. ↑ SERPENT - A Candidate Block Cipher for the Advanced Encryption Standard "Serpent is now completely in the public domain, and we impose no restrictions on its use. This was announced on the 21st August at the First AES Candidate Conference." (1999)
  53. ↑ copyright on sqlite.org
  54. ↑ copyrights-and-licensing on docutils.sourceforge.net
  55. ↑ "youtube-dl GitHub page". GitHub. Retrieved 2 October 2016.
  56. ↑ Igor Pavlov (2008). "LZMA SDK (Software Development Kit)" . Retrieved 2013-06-16.
  57. ↑ tinyspeck (2013-11-18). "Glitch is Dead, Long Live Glitch! - Art & Code from the Game Released into Public Domain". glitchthegame.com. Retrieved 2013-12-11. The entire library of art assets from the game, has been made freely available, dedicated to the public domain. Code from the game client is included to help developers work with the assets. All of it can be downloaded and used by anyone, for any purpose.
  58. ↑ Blackwell, Laura (2013-11-18). "Afterlife of an MMO: Glitch's offbeat art enters public domain". pcworld.com. Retrieved 2013-12-11.
  59. ↑ KeccakReferenceAndOptimized-3.2.zip in mainReference.c: "The Keccak sponge function, designed by Guido Bertoni, Joan Daemen, Michaël Peeters and Gilles Van Assche. For more information, feedback or questions, please refer to our website: http://keccak.noekeon.org/Implementation%5B%5D by the designers, hereby denoted as 'the implementer'. To the extent possible under law, the implementer has waived all copyright and related or neighboring rights to the source code in this file. https://creativecommons.org/publicdomain/zero/1.0/".
  60. ↑ Skipping Steam: Why Jason Rohrer independently distributes One Hour, One Life on Gamasutra by Richard Moss "you're paying for an account on the server that I'm running. [...], and it's actually in the public domain — the source code's all available." (on August 30, 2018)
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