Is my programming knowledge contaminated? We know that ideas are not copyrightable (except for patent related issues), but expressions are (idea–expression dichotomy). However, after reading about clean room design, I got somewhat confused. Wikipedia states: The term implies that the design team works in an environment that is &quot;clean&quot; or demonstrably uncontaminated by any knowledge of the proprietary techniques used by the competitor. Typically, a clean-room design is done by having someone examine the system to be reimplemented and having this person write a specification. [...] The specification is then implemented by a team with no connection to the original examiners. This description suggests that mere knowledge of copyrighted implementation details can become an issue. And therefore the clean room method was devised as a technique to circumvent this issue. To me this implies that as soon as I read a programming book (with code samples) or open source code, my knowledge is contaminated or biased and the code that I write might infringe copyright. Is this true or did I misunderstand the clean room design principle?
Clean room design is intended to protect against not only copyright liability, but possible trade secret liability as well. It avoids any possibility that any part of the expression of the source work has been included in the re-implemented work, because the designers and creators of the latter work only from a specification. There is never a legal requirement to use clean-room design. It is a strategy used to ward off possible legal action by demonstrating in advance that no unauthorized and protected elements have entered the re-implemented product. It does not follow that someone who has learned concepts and ideas from a protected work must employ clean room principles to use that knowledge. Someone looking to sue for copyright infringement would need to show some aspect of the protected expression that had been copied. Without that there is no prima facie case to answer.
If you change a single character, that's clearly a partial copy. Copyright protection has a limited extent, however. The protected work must be original and not obvious. For example, there are only so many ways to write a function that computes the average of two numbers, so the copyright owner of one body of code cannot claim infringement by the author of a second body of code simply because they both have a function float Average(float a, float b) { return (a + b) / 2; } A surefire way to avoid infringing copyright is to specify the function of the code and then have someone who has never seen the code write it from scratch. This is sometimes called clean-room engineering. Otherwise, there is no way to answer your question definitively. If you create a modified copy of the code (a "derived work" in copyright terminology), there is no strict formula available to evaluate the extent of the infringement. It comes down to a case-specific analysis of the facts by a judge. Depending on the jurisdiction, which you have not specified, there may be specific laws or judicial precedent that guide the judge, but the determination will still require a specific analysis of the facts. For example, if the alleged infringer raises these arguments, the judge would have to determine how obvious the code is, or whether the copyright claimant even owns the copyright to the code.
The legal issues are too black and white to have any meaningful impact on an ethics discussion. The IP belongs to A and B can't use it. A's not planning to build a product around the patent is irrelevant to the law and I do not see it bring up any ethical issue, but some people who do not understand patent law might. There might be ethics issues if A hired Josh with the specific plan to fire him as soon as the application was filed and intentionally misled him about these plans. Another issue might be Josh's duty to not disclose A's confidential information (the application does not become public right away), and Josh's duty to not draw B into developing an infringing product.
At least in the United States (and I'm pretty sure this is true around the world), facts and information cannot be copyrighted. Just because a work is copyrighted, doesn't mean every part of that work is copyrighted, and factual information conveyed by the work is a part which is not subject to copyright. Copyright on a collection of facts is limited to the selection and arrangement of those facts, and only if that selection and arrangement has some bare minimum amount of originality. See Feist v. Rural, 499 U.S. 340. In this case, it looks at first glance like the person who made that site made their own selection of which materials and which sources would be included; the one place where they really seem to have copied their selection is from glass catalogs with datasheets from specific manufacturers, who would have a hard time arguing that "everything we manufacture in this widely-recognized class of substances" is an original selection. What the author of the website has done is relinquish his rights in his selection and arrangement of the data. In some places, there are other rights besides copyright that do apply to databases; for instance, the EU recognizes database rights to protect significant investment in compiling a database of stuff. But the US does not have that concept. For citing stuff, that's not really a legal question, and has more to do with academic standards. Ask your adviser or teacher if you have one.
Can an idea be a trade secret? Certainly -- most trade secrets are ideas. The thing is, unlike copyright, patents, or trademarks, trade secret isn't a very strong form of protection. Trade secret legislation only protects against certain "unfair" methods of obtaining the secret. Independent invention is perfectly fine: if I figure out on my own what the secret formula for Coca-Cola is, there's nothing the Coca-Cola company can do to stop me. Reverse engineering is also fine: if I take a bottle of Coke to a chemistry lab and analyze the ingredients, there is again nothing the Coca-Cola company can do. Additionally, a company wishing to make something a trade secret needs to take active steps to preserve that secret. Continuing the Coca-Cola example, they might require anyone reading the formula to first sign an agreement to not disclose what they read.
No, it means you can't copy it. By default, the copyright to a work is owned by its creator, and nobody else is allowed to copy it, or create derived works, without their permission. That permission can be granted by a license. "License unknown" doesn't really tell us anything, but it certainly isn't clearly granting you permission. So you don't have permission to copy, and thus you cannot. You would have to seek permission from the copyright holder. See also If no licence is distributed with an application/source code, what license applies by default if any? (Some jurisdictions do allow for "fair use" exceptions, which allow you to copy a work without permission. You haven't said what jurisdiction you are in.)
You would be in poorly-tested waters under US law. The invented name &quot;Cthulhu&quot; as appearing in a novel is not protected by copyright. A collection of invented names and other words assembled into a dictionary (e.g. of Klingon) might be found to constitute a copyright-protected creative work. In Paramount Pictures v. Axanar Productions (complaint), plaintiffs partially base their claim on infringement of language; defendants sought to dismiss the suit on various grounds (&quot;questions of law&quot; rather than questions of fact), but the court denied defendant's motion for summary judgment. Subsequently, defendants settled the case. Constructed languages are highly creative expressive works whose elements are deliberately selected for an artistic purpose, and they are not naturally-occurring facts. The copyright office has no position on copyright protection of a constructed language, and any such position would have to come from so-far non-existent (definitive) case law. The dismissal in Paramount v. Axanar doesn't clearly indicate that a constructed language is protected. The primary legal question would be whether the database that you copy into your system is protected. There is a colorable legal argument that a collection of language-like objects. The statutory language in 17 USC 102 does not specifically preclude protection of a wholely-creative database, and the copyright office does not say whether a conlang can be protected because the courts have not ruled one way or the other. The situation in Feist is very different from the case of a work which invents a language from nothing.
This supposes that the patentable concept can’t be learned form the operation of the whole program and hiding the invention while making use of the invention in public is not a disclosure. However, in the US there is a famous case In re Blaisdell, 242 F.2d 779, 783, 113 USPQ 289, 292 (CCPA 1957); Hall v. Macneale, 107 U.S. 90, 96-97 (1882); Ex parte Kuklo, 25 USPQ2d 1387, 1390 (Bd. Pat. App. &amp; Inter. 1992) that concluded a public demonstration that didn’t expose the inner workings did start the clock on a bar to patentability. See previous question https://patents.stackexchange.com/questions/20886/would-the-demonstration-of-an-invention-be-considered-public-disclosure The answer (from me) has the caveat that this is a pre-AIA case and courts might come to a different answer under that current law. The U.S. has viewed public use, especially commercial public use, as disqualifying (after a grace period) but the rest of the world puts its emphasis on actual disclosure of the inventive concept so this result might be different elsewhere. One thought experiment would be to analogize with an article in a widely available journal with the words Don’t read the article that starts on page 19 on the cover. From a disclosure point of view I do not think that is different from it being possible, but illegal, to read.