[belorn]

The 1976 Copyright Act did not address how copyright were to protect software. Congress didn’t want to further delay the passage of the Act and appointed the National Commission on New Technological Uses of Copyrighted Works (CONTU) to report back about computer programs and other new technologies and placed a placeholder provision in the Act. It was about a far from current copyright law that you can make it. You could register a copyright, but if it had any practical effect was up to congress to solidify in 1980.

Anyhow, I agree with jefurii comment. Public domain software, that is software that did not get copyright licenses added to them, was the norm before proprietary software. The free software movement was thus an reaction to the change of adding proprietary licenses to software and would not exist if that change had not happened. If people continued to not license software after 1980, along side the proprietary movement and the free software movement, is an interesting question to ask, and would be interesting to know if there is historical data about it.

[dragonwriter]

> The 1976 Copyright Act did not address how copyright were to protect software.

This is inaccurate. The 1976 Act did address how copyright protected software -- in that software was already recognized as within the scope of protection of copyright prior to the 1976 Act (as noted upthread, for, at a minimum, more than a decade prior) and 17 USC Sec. 117 under the 1976 Act stated explicitly that protections regarding covered works used in conjunction with computers were exactly identical to the general protections regarding such works [1] -- however Congress also recognized that that was likely not the best final answer, and so Congress also created the commission you refer to address how copyright protections should most appropriately be specialized to deal with new technology, especially computers.

> Public domain software, that is software that did not get copyright licenses added to them, was the norm before proprietary software.

Software without an explicit license was not public domain, it was and is software with an unspecified and implicit license determined by the context of the sale; public domain software is software delivered with an explicit dedication to the public domain [2].

[1] 17 USC Sec. 117 under the 1976 act, "Scope of exclusive rights: use in conjunction with computers and similar information systems. Notwithstanding the provisions of sections 106 through 116 and 118, this title does not afford the owner of copyright in a work any greater or lesser rights with respect to the use of the work in conjunction with automatic systems capable of storing, processing, retrieving, or transferring information, or in conjunction with any similar device, machine, or process, than those afforded to works under the law, whether title 17 or the common law or statutes of a State, in effect on December 31, 1977, as held applicable and construed by a court in an action brought under this title."

[2] Given the automatic effect of copyright and the lack of any explicit recognition of such declarations, its quite possible that this isn't really public domain but merely a very expansive gratuitous license that is still, e.g., revocable at will (a revocation whose effect against someone who had acted in reliance prior to the revocation may be subject to limitation by way of promissory estoppel) as are all gratuitous licenses, but this is as close to public domain as it gets.

[belorn]

If you can show any indication that there existed copyright licenses prior to 1980 with explicit dedication to the public domain, then that would indeed show how licensing software under public domain could be a norm before RMS and the free software movement was started.

For U.S. government works however, there was an implicit license of public domain. Works authored by U.S. government employees, on government time and as part of their job, are automatically in the public domain. The purpose of explicit licensing such work would be both unclear, but also questionable in a legal sense. Writing a copyright license for work already in public domain is kind of a grey zone.

As for the 1976 Act, there is to my knowledge no court case about software copyright infringement between 1976 and 1980. The definition of "any greater or lesser rights" when in "conjunction with automatic systems capable of storing, processing, retrieving, or transferring information" is not only extremely vague, there does not seem to been anyone who defined it before congress did it in 1980. If you again has any evidence to the contrary, I would be interesting to read it.

if you want to see early copyright cases for software, Stern Electronics, Inc. v. Kaufman from 1981 is a good example. Note that Konami did not register a copyright of the underlying code of the game, but instead registered the game as an audiovisual.