> I don't think people on HN understand what a derivative work is, considering how often I see it referenced incorrectly.

Very true.

> You can't make a derivative work without a license. T

You can, but it is a copyright violation to do so unless an exception (like Fair Use) applies.

A derivative work is also a work eligible for copyright in its own right, and as such is copyright by the creator by operation of law when fixed in a tangible form, whether or not it also violates someone else’s copyright.

> It derivates

“derives”

> from the copyrighted work and is therefore within the domain of the copyright and under the control of the copyright's owner.

No, producing it is within the legally exclusive rights of the copyright holder subject to the limitations on those rights, but once created the copyright in the derivative is not under the control of the copyright holder of the original (though transferring or licensing back may be part of the resolution of copyright violation lawsuit over its creation.)

I thought Pickett v Prince established precedent that you can’t copyright an unauthorized derivative work.

See 17 U.S.C. §103(a), which says that derivative works can be copyrighted, but that does not extend to any part of the work in which such material has been used unlawfully.

(not a lawyer but I did audit this class at a law school)

If the patch is distributed on its own, without the original binary, is it still a derivative work? Is the unique, creative work of writing "perform XYZ instruction at XYZ address," in lieu of the original executable, still derivative?

This is actually an unanswered/unproven question that comes up quite a bit in automotive tuning, where individuals and tuning companies modify OEM calibrations and create application software patches which, while they are unique and perform stand-alone functions, run on top of OEM ECU software.

The history of General Computer Corporation's[0] arcade enhancement boards is an interesting example of this kind of "derivative" work.

GCC made an enhancement board for Missile Command and later for Pac Man ("Crazy Otto", which became "Ms. Pac Man"). Rather than employing simple "ROM hacks" as other enhancement board manufacturers did, GCC specifically built their enhancement hardware not to contain any code copied from the original game ROM. Their hardware patched the existing ROM only by overlaying their code onto the original ROMs, not by copying any of the original code[1].

There's some neat detail in the background slides here[2]. I'd love to hear that talk but I'm not immediately a recording of it.

[0] https://en.wikipedia.org/wiki/General_Computer_Corporation

[1] https://web.stanford.edu/class/sts145/Notes/3_game_business/...

[2] https://trilobyte.com/pdf/golson_ReplayFX_2015.pdf

> If the patch is distributed on its own, without the original binary, is it still a derivative work?

Yes, just as annotations are recognised as being a derivative work even without the original.

> Is the unique, creative work of writing "perform XYZ instruction at XYZ address," in lieu of the original executable, still derivative?

If you can convince a judge that, on the balance of probabilities, you were divinely inspired to write it with no connection to the original executable, then it's not derivative. But good luck with that.

>you cannot sell copies of your Hermione spin-off, because that'd be copyright infringement, because it is a derivative work

But you can distribute it for free, as fanfiction.

Also, a no-CD crack does not contain any of the original work. It's akin to a program that you can use to modify, say, your legally-purchased Harry Potter ebook in order to change all instances of "wand" to "wang"

Fan fiction is basically illegal, or at best in a deeply gray area, it's just that most people realize suing your super-fans is a bad move. There are exceptions of course, Anne Rice was famously super litigious over any attempted fan fiction of her characters which generated a lot of bad feelings online.

https://www.vice.com/en/article/88gqjz/anne-rice-really-hate...

Paramount suing Star Trek fan productions is another great example. They recently took down the Wolf 359 audio book project for example.

> But you can distribute it for free, as fanfiction.

Not legally.

> Also, a no-CD crack does not contain any of the original work. It's akin to a program that you can use to modify, say, your legally-purchased Harry Potter ebook in order to change all instances of "wand" to "wang"

Doesn't matter, it's still a derivative work, just as a translation or annotation that doesn't contain any of the original text is a derivative work.

I'm not sure about american law but in EU (at least Sweden) you def get copyright to detivative work even if you don't have a license. If I create a derivative work based on Harry Potter the result will be that I have copyright to the derivative work BUT not to Harry Potter (I wish) so while I own the rights to my work I can't produce (etc) the work (at least not in a commerical capacity) because JK rowling owns the Harry Potter rights. However JK does not have the right to use my derivative work without a license from me.

A maybe more clear example is music. Songwriting is covered by copywrite. Singing is also covered by copywrite. If A writes a song and B sings the song without A:s premission it can be copyright infringment. However, A can not take a recording of B:s song and copy and sell it without B:s consent because B has the copyright to the performance (even if the performance was a copywright infringment).

You can skirt incredibly close, however - search Amazon for “unofficial Harry Potter”.

That just means they haven't been sued, there is no copyright czar that makes sure infringement never happens. Owners need to sue.

It won't happen, as factual details can't be copyrighted.

So I can't write a story with HP characters, but I can't be copyright struck for writing that there is a book called Harry Potter that has these characteristics.

(The above is in the USA, other countries have different policies and rights.)

Harry Potter isn't a fact. A book about the fact that Harry Potter was written and it's about wizards is about as long as that sentence.

There are at least four books so far in the "unofficial" series, and if you believe that the companies involved wouldn't copyright strike it if they could, that's protected by the first amendment.

https://www.mugglenet.com/site/publications/

You can also find unofficial and unauthorized books in other settings, such as Minecraft, but you can argue that it's explicitly permitted as seen here: https://www.minecraft.net/en-us/article/commercial-use-guide... - but you can ignore those in the USA in many cases - here's one already: https://www.amazon.com/Minecraft-Monarchies-UnOfficial-Story...

Okay, it's not "skirting incredibly close" to write those reference books, because they are in no way a substitute for the underlying fiction, which is why they would probably be considered a fair use.

>There are at least four books so far in the "unofficial" series, and if you believe that the companies involved wouldn't copyright strike it if they could, that's protected by the first amendment.

You have no idea what you are talking about. The first amendment isn't a defense to copyright infringement. transformative fair use with a de minimis copying is.

I was saying that if you believed that the companies involved wouldn't strike these if they could, that belief is covered by the first amendment freedom of religion.

You said they were strikingly close to the line, they aren't. The implicit suggestion being one can just write harry potter fiction by referring to harry potter facts, you can't!