Any sort of fair use clause for software using methods years before they get patented?

Question

This question probably was already asked thousands of times, yet I could not find any similar question.

One creates a software. An innovative one with lots of fancy new things which were never applied. Lets say, a networking system between Earth and Mars on top of SMTP. That software is fully FOSS, and as such is probably financially poor and its devs have no money to patent things they do.

Some years later, one does patent the same method of networking as something generic, such as "Interplanetary networking on SMTP". Does the former need to cease to exist if the one who made the patent demands pay? Also don't forget there's almost no money to fight in court.

PS: Nobody would build a networking system on top of a mail transfer protocol, make it a "something which nobody ever made" sort of thing.

Answer 1

In

One creates a software [...]

and

Some years later, one does patent the same method of networking as something generic [...]

is "one" the same person? And is the patent first submitted "some years later"? If so, that would be an example of "fraud on the patent office" since the patent could only be obtained by withholding key information that the applicant knows about prior use of the method in the U.S.

If the patent isn't filed until "years later", the FOSS would almost certainly be prior art against the patent, and could be used to invalidate it. This is assuming that the FOSS, even in its early versions, really was an example of the patented method.

Does the [innovative software] need to cease to exist if the one who made the patent demands pay? Also don't forget there's almost no money to fight in court.

If you can't fight in court, you are at the complete mercy of the patent holder. But this isn't true only in patent law. Anyone can take you to court for anything, and if you don't defend yourself, you lose.

That being said, it's rare that a patentee will file suit against parties who are "sitting on prior art". Even patent trolls are smarter than that. They may file frivolous lawsuits, but not against victims who actually stand a chance of invalidating their patents.

Obviously, if you're facing such a situation, consult a competent attorney who can drill down to the facts and accurately establish if you have a case rather than blindly continuing infringement.