Public domain software

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Public domain software is software that has been placed in the public domain, in other words 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; this is unlike the common case of software under copyright protection where software licenses granting or restricting usage rights.

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 Berne Convention also covers programs. Therefore, a program is automatically subject to a copyright, and if it 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. In some regions, some rights (in particular moral rights) cannot be disclaimed.


Early academic public domain software ecosystem[edit]

In the 1950s to the 1990s software culture, as original academic phenomena, "public domain" (usually abbreviated to "PD") software was popular. This kind of freely distributed and shared "free software" combined the nowadays differentiated software classes of Freeware, Shareware and Free and open source software. 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 program) in computer magazines (like Creative Computing, SoftSide, Compute!, Byte etc) and books, like the bestseller BASIC Computer Games.[1] Early on, closed source software was uncommon until the mid-1970s to the 1980s.[citation needed]

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.",[2] software was not copyrightable and therefore always in 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, who maintained a mail-order catalog of more than 300 disks with an average price of US$6.[3] 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 money donation to be sent by mail.[4]

The public domain "free sharing" and "donationware" commercialization models evolved in following years to the (non-voluntary) Shareware model,[5][6] and software free of charge, called Freeware.[7] Additionally, due to other changes in the computer industry, the sharing of source code became less usual.[8]

With the Berne Convention Implementation Act of 1988 (and the earlier Copyright Act of 1976), the legal base for public domain software changed drastically. Before the act releasing a software without Copyright notice was enough for dedicating to public domain. With the new copyright act, software was by default copyright protected and needed an explicite waiver statement or license of the author.[9][10]

Reference implementations of algorithms, often cryptographic algorithms, meant or applied for standardization are still often given into the public domain, examples are CERN's httpd[11] in 1993 and Serpent cipher in 1999. The Openwall Project maintains a list of several algorithms and their source code in the public domain.[12]

Free and open source software as successor[edit]

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

In 1980s Richard Stallman, who worked long in an academic environment of "public domain"-like software sharing, noticed the emerge of proprietary software and the decline of the public domain software ecosystem. As approach to preserve this ecosystem he created a software license, the GPL, which encodes the "public domain" rights and enforces them irrevocable on software. Paradoxically, his copyleft approach relies on the enforceability of the copyright to be effective. Copyleft free software shares therefore many properties with public domain software, but doesn't 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.[13] 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 has the source code always available.

Post-copyright public domain[edit]

With the 2000s and the emerge of peer-to-peer sharing networks and sharing in web development, a new copyright critical developer generation made the "license-less" public domain software model visible again, also criticising the FOSS license ecosystem as stabilizing part of the copyright system.[14][15][16][17] New non-FOSS licenses and waiver texts were developed, notable the Creative Commons "CC0" (2009) and the "unlicense" (2010), and a growing popularity of permissive software licenses was noticed. Also, the growing problem of orphaned software and digital obsolescence of software raised the awarness of the relevance of passing software into PD again for a better Digital preservation of the digital heritage, unrestricted by copyright and DRM.[18][19][20][21]

Passing of software into public domain[edit]

Release without copyright notice[edit]

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 just releasing it without a explicte Copyright notice. After that, all works were by default copyright protected and needed to be actively given into public domain by a waiver statement.[9][10]

Leaving the copyright term[edit]

Copyrighted works, like software, are meant to pass into 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 public domain by leaving copyright terms. The question how fast works should pass into public domain has been a matter of scientific[22][23][24] and public debates, also for software like video games.[19][20][21]

Public domain like licenses[edit]

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

In 2000 the WTFPL was released as public domain like license.[25] In 2009 the Creative commons released the CC0, which was created for compatibility with also law domains (e.g. Civil law of continental Europe) which don't have the concept of dedicating into public domain. This is achieved by a public domain waiver statement and a fall-back all-permissive license, for the case the waiver is not possible.[26][27] The Unlicense, published around 2010, has a focus on an Anti-copyright message. The unlicense offers a public domain waiver text with a fall-back public domain-like license inspired by permissive licenses but without attribution.[28][29]

Examples of public domain software[edit]

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

Classical PD video games[edit]

Video games are among the earliest examples of shared PD software, which are still notable today. They were shared as type-in program 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 and shared as public domain software.

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 and creating therefore a legal problem. On the other hand magazins started in the mid-1980s to claim copyright even for type-in programs which were seen as PD before.[30][31] Only slowly PD software authors started to include explicit relinquishment or license statement texts.

Examples of modern PD software[edit]

These examples of modern PD software (after the Berne Convention Implementation Act of 1988) is either under proper public domain (e.g. created by an US governmental organization), under a proper public domain like license (like CC0) or have a clear waiver statement of the author.

See also[edit]


  1. ^ Ahl, David. "David H. Ahl biography from Who's Who in America". Retrieved 2009-11-23. 
  2. ^ Lemley, Menell, Merges and Samuelson. Software and Internet Law, p. 34 "computer programs, to the extent that they embody an author's original creation, are proper subject matter of copyright."
  3. ^ Kristina B. Sullivan (1986-01-14). "Hackers Create Public-Domain Software for the Sheer Joy of It.". PC Week 3 (2). pp. 121–122. 
  4. ^ April 1987: Ballerburg - Zwei Spieler, zwei Burgen und ein Berg dazwischen... on "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)
  5. ^ "Bob Wallace Timeline". Erowid. Jan 12, 2004. Retrieved March 7, 2013. 
  6. ^ Article about Jim "Button" Knopf, from Dr. Dobbs Journal
  7. ^ the-history-of-shareware-psl on
  8. ^ 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 
  9. ^ a b publicdomain on
  10. ^ a b Copyright Notice, U.S. Copyright Office Circular 3, 2008.
  11. ^ The birth of the web Licensing the web on (2014)
  12. ^ Source code snippets and frameworks placed in the public domain on
  13. ^ Shankland, Stephen (February 28, 2008). "Is public domain software open-source?". 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. 
  14. ^ The Surprising History of Copyright and The Promise of a Post-Copyright World by Karl Fogel (2006)
  15. ^ Younger developers reject licensing, risk chance for reform on by Luis Villa (on 12 Feb 2013)
  16. ^ Pushing back against licensing and the permission culture Luis Villa (January 28, 2013)
  17. ^ Post open source software, licensing and GitHub on by Richard Fontana (on 13 Aug 2013)
  18. ^ 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."" (Microsoft Word). Kingston upon Hull: Information Law and Technology Unit, University of Hull. Retrieved 23 March 2011. 
  19. ^ a b 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. 
  20. ^ a b 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. 
  21. ^ a b Rouner, Jef (April 28, 2015). "U.S. Copyright Office to Explore Making Some Video Games Public Domain". Houston Press. Retrieved 2016-02-03. 
  22. ^ Watt, Richard (September 26, 2014). Handbook on the Economics of Copyright: A Guide for Students and Teachers. Edward Elgar Publishing. Retrieved 2015-01-11. 
  23. ^ 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. 
  24. ^ 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. 
  25. ^ Version 1.0 license on
  26. ^
  27. ^ 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 Dr. Till Kreutzer, attorney-at-law in Berlin, Germany
  28. ^ The unlicense a license for no license on by Joe Brockmeier (2010)
  29. ^ The Unlicense on
  30. ^ Compute-Gazette-Issue-11-01.pdf
  31. ^ 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"
  33. ^ disclaimer on
  34. ^ 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)
  35. ^ copyright on
  36. ^ copyrights-and-licensing on
  37. ^ Igor Pavlov (2008). "LZMA SDK (Software Development Kit)". Retrieved 2013-06-16. 
  38. ^ 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: 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."

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