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Hi,

I'd like to ask some opinion from lawyer-blooded forum members according the current status of FAT file systems. As far as I know, there's an upper time limit for all patents counted from the date they were filed. So am I wrong assuming patents older than 20 years must be public domain without any legal possibility to sue their users?

• FAT12/16/32 with 8+3 names, there's absolutely no patents about these, so anyone can use them for free, I'm 100% sure about this
• FAT32 with LFN, there were patents (this and this). and the newer being 24 years old. So patent-trolling should not be possible by MS any more, right?
• exFAT, although it's not proprietary any more, you still can't use it in your hobby OS project

According to wikipedia,

exFAT was proprietary until 28 August 2019, when Microsoft published its specification. Microsoft owns patents on several elements of its design.
...
On 28 August 2019, Microsoft published the exFAT specification and released the patent to the OIN members.
...
A Linux kernel implementation has also been released, written by Samsung Electronics. It was initially released on GitHub unintentionally, and later released officially by Samsung in compliance with the GPLv2 in 2013. (This release does not make exFAT royalty-free, as licensing from Samsung does not remove Microsoft's patent rights.)

So this means the only reason why Linux can have an exFAT driver is because the Linux driver was written by an OIN member, Samsung.

And now is the really tricky part: exFAT driver in Linux is licensed under GPLv2. What is going to happen if someone ports that code into their own hobby OS? The GPL is pretty clear that you can do that and that Samsung has no say in the matter, because you don't "license the driver from Samsung", rather the GPL terms apply:

Any licensee who adheres to the terms and conditions is given permission to modify the work, as well as to copy and redistribute the work or any derivative version.
...
The GPL additionally states that a distributor may not impose "further restrictions on the rights granted by the GPL". This forbids activities such as distributing of the software under a non-disclosure agreement or contract.

Question 1: is it true that FAT32 LFN patents are expired and are public domain by now?

Question 2: MS' open source patent exception only allows OIN members to use exFAT without a royalty, but GPL forbids imposing further restrictions on the GPL granted rights. So WTF happens if you port the Linux driver?

Cheers,
bzt

Read this interesting article I found with a quick search https://linux.slashdot.org/story/19/08/ ... pen-source

bzt wrote:FAT32 with LFN, there were patents (this and this). and the newer being 24 years old. So patent-trolling should not be possible by MS any more, right?

It's funny, I was just about to ask this exact question.

The ExFAT issue isn't tricky at all. All it means is that Samsung doesn't have a copyright claim against you, if you should incorporate their driver. Microsoft still has a valid patent claim. Your Samsung license does not free you from your duties towards other rights holders, as they are not parties to the contract.

nexos wrote:Read this interesting article I found with a quick search https://linux.slashdot.org/story/19/08/ ... pen-source

Thanks, I've already read that. MS only guarantees not to patent troll OIN members, but it talks nothing about other OSS developers (basically the vast majority of developers not in the big money corp club). FYI: only companies can be OIN members.

Gigasoft wrote:The ExFAT issue isn't tricky at all. All it means is that Samsung doesn't have a copyright claim against you, if you should incorporate their driver. Microsoft still has a valid patent claim. Your Samsung license does not free you from your duties towards other rights holders, as they are not parties to the contract.

Okay, you missed the real issue here. There's no such thing, "your Samsung license", since the driver was licensed under GPL, that's just not possible. But does MS really has a valid patent claim for those? I mean, they allowed the GPL'd driver to be written and to be used without a fee, they gave up on the royalty for that code. Now anybody can create a derivative of a GPL'd code without any further restrictions (MS patent claims included, because they have already given up on those for that particular GPL'd driver).

BTW, does anybody have a good list of exFAT related patents? I could only find these,

• 8321439, Quick filename lookup using name hash. I'd argue that's a valid patent at all, because it's not exFAT-specific, and MS wasn't the first to use hashed file names (and it's damn easy to avoid that patent by not using that particular proprietary 2 byte hash).
• 8606830, Contiguous file allocation in an extensible file system, likewise looks like invalid to me, because it ain't exFAT-specific either and I'm pretty damn sure MS wasn't the first to allocate contiguous areas in bitmap allocations (and easy to avoid if you don't care about enforcing fs defragmentation in run-time at all costs).
• 7613738, FAT directory structure for use in transaction safe file system, easy to avoid if you just mirror the two FAT tables and you don't use the second table for tracking changes.
• 7174420, Transaction-safe FAT file system, pretty much invalid too as it says you must keep both FAT tables and free-space indicators up-to-date on data modification, which method was well-known and already existed for decades before exFAT come along (and impossible to avoid if you want to keep the on-disk data consistent)

Now are there any other patents? Wikipedia says so, but I can't find them...

Cheers,
bzt

Sounds like that its in legal limbo. That would be a question for a lawyer.

bzt wrote:MS only guarantees not to patent troll OIN members, but it talks nothing about other OSS developers (basically the vast majority of developers not in the big money corp club).

Yes. Also, a press release is not a binding contract. So MS is not guaranteeing anything even for OIN members. They still have the right to defend their patents, and if they choose not to exercise that right, that is on them. But they can change their mind at any moment, and there is nothing legally stopping them.

bzt wrote:There's no such thing, "your Samsung license", since the driver was licensed under GPL, that's just not possible.

Yes there is (that's what the L in GPL means). Samsung wrote a driver, so they have the copyright on it, for pretty much as long as you and I will live (life of the author plus another number of years. Was it 70? 90? Excessive, in any case). You cannot copy it unless you have a license to do so. Samsung have granted a license to you, with conditions attached, called the GPL. (They've granted the license to everyone, so a fortiori they have given the license to you) Violate the GPL yourself if/when you pass your copy on, and the license granted to you will become invalid, and you will have committed copyright infringement. I was taught this in corporate training about Open Source licenses a few years ago.

bzt wrote:But does MS really has a valid patent claim for those? I mean, they allowed the GPL'd driver to be written and to be used without a fee, they gave up on the royalty for that code. Now anybody can create a derivative of a GPL'd code without any further restrictions (MS patent claims included, because they have already given up on those for that particular GPL'd driver).

Samsung cannot grant you a license for Microsoft's patents, for the same reason I cannot sell your car. Further, the exFAT drivers I found were released under GPLv2, which does not touch on patents. GPLv3 does (As I recall, this was one of the points of contention between Linus and the FSF when he failed to adopt GPLv3). Therefore, Samsung releasing source code under the GPLv2 does grant you a license for their copyright (provided you stick to its terms), but not a license for their or any other patents.

Patents are quite a different beast from copyright. You could get around copyright claims by reimplementing the driver (using a clean-room protocol to be safe, but in theory, merely writing such a thing yourself would be enough). No such luck for patents. The invention itself is protected, not any particular version of it. However, just because a patent is issued doesn't mean it's valid. The PTO is supposed to only grant valid patents, but they are overworked and understaffed, so often, invalid patents are issued, and then thrown out only during a legal altercation. So nothing is ever easy.

As for the actual patents, I agree with you that they look invalid or avoidable. Whether there are any other ones, tho, is something you will likely only find out when they sue you. Suing you is unlikely, however, since MS is currently investing lots of money into changing their image to be friendly on Open Source, and it is unlikely they could extract enough money from one lone Hungarian professor to make up for all the lost goodwill if they took you to court. That is, at the moment, and for the foreseeable future. But who can really say what the future will bring? Remember that this severe course change of MS happened due to a change in leadership, which can happen again at any moment.

nullplan wrote:Also, a press release is not a binding contract. So MS is not guaranteeing anything even for OIN members. They still have the right to defend their patents, and if they choose not to exercise that right, that is on them. But they can change their mind at any moment, and there is nothing legally stopping them.

Yeah, that's how I understand too.

nullplan wrote:

bzt wrote:There's no such thing, "your Samsung license", since the driver was licensed under GPL, that's just not possible.

Yes there is (that's what the L in GPL means). Samsung wrote a driver, so they have the copyright on it, for pretty much as long as you and I will live

Actually that's not so. Since Samsung licensed their code under GPLv2, they gave up their rights and offered the code to the public (under GPL's terms). This sentence in the GPL makes this clear:

The GPL additionally states that a distributor may not impose "further restrictions on the rights granted by the GPL". This forbids activities such as distributing of the software under a non-disclosure agreement or contract.

So if you create a derivative work of the exFAT driver in the Linux kernel, and you GPL license it as well, and you fulfill all the requirements and terms of the GPL, then neither Samsung nor MS can do nothing about it. That's what makes this case tricky.

nullplan wrote:Violate the GPL yourself if/when you pass your copy on, and the license granted to you will become invalid, and you will have committed copyright infringement.

That's clear, but what if you don't violate the GPL?

nullplan wrote:Samsung cannot grant you a license for Microsoft's patents

They don't have to, because MS already granted those patents royalty-free for this GPL'd code. You just use the rights granted by the GPL to create a derivative work from it, and GPL explicitly forbids imposing further restrictions on a GPL'd code.

nullplan wrote:As for the actual patents, I agree with you that they look invalid or avoidable. Whether there are any other ones, tho, is something you will likely only find out when they sue you. Suing you is unlikely, however, since MS is currently investing lots of money into changing their image to be friendly on Open Source

I agree, but I don't trust MS. Should they get a new CEO and things could change within a blink of an eye as you've pointed out. It would be better to find a solution that's safe.

By the way MS has no chance to sue me or any other developer in the EU because EU law does not recognize software patents as inventions the way US law do. Patent-trolling is an USA only specialty, the rest of the world is just laughing at it, how much money companies spend on something that's completely a non-issue outside of the US. But it sucks if you want to go to the US market as well. Making your OS "for non-US users only" is a perfectly viable solution too, but probably not the best.

Cheers,
bzt

Actually that's not so. Since Samsung licensed their code under GPLv2, they gave up their rights and offered the code to the public (under GPL's terms). This sentence in the GPL makes this clear:

The GPL additionally states that a distributor may not impose "further restrictions on the rights granted by the GPL". This forbids activities such as distributing of the software under a non-disclosure agreement or contract.

Your reading of the GPL is completely flawed. First of all, that's not even a "sentence in the GPL", it's a Wikipedia quote. The GPL contains no promise that the rights holder will not engage in any particular activity. The prohibition on imposing further restrictions applies to the licensee when he redistributes the artifact.

Samsung is themselves bound by another GPL, namely regarding the Linux kernel as a whole. This is what they may not redistribute while imposing further restrictions. However, they are of course free to create non-public variants of their ExFAT driver, and deliver them as standalone artifacts without being impacted by the GPL.

So if you create a derivative work of the exFAT driver in the Linux kernel, and you GPL license it as well, and you fulfill all the requirements and terms of the GPL, then neither Samsung nor MS can do nothing about it. That's what makes this case tricky.

Wrong. The GPL is entirely a matter between you and Samsung. It does not bind Microsoft in any way.

They don't have to, because MS already granted those patents royalty-free for this GPL'd code. You just use the rights granted by the GPL to create a derivative work from it, and GPL explicitly forbids imposing further restrictions on a GPL'd code.

They licensed those patents to Samsung. You are not Samsung, and do not own a license for the patents. Redistributing the code is a violation of the patent, even if Samsung allows such redistribution, unless the patent licensing agreement explicitly authorizes them to transfer the right to redistribute. If the code can not be redistributed without violating Microsoft's patent, then it becomes a matter between Samsung and the Linux developers, as Samsung would then have violated their agreement (namely, GPLv2 article 7).

By the way MS has no chance to sue me or any other developer in the EU because EU law does not recognize software patents as inventions the way US law do.

Anyone can sue anyone for any reason. It is up to the courts to determine whether ExFAT is a patentable invention. The fact that something relates to computer software, doesn't in itself mean it can't be patented.

Gigasoft wrote:First of all, that's not even a "sentence in the GPL", it's a Wikipedia quote.

Don't say you haven't actually read the original GPL. Here's a copy for you. GPLv2, section 6:

Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein.

Gigasoft wrote:The GPL contains no promise that the rights holder will not engage in any particular activity. The prohibition on imposing further restrictions applies to the licensee when he redistributes the artifact.

And Linux is that licensee who redistributes the GPL'd code. What is your question supposed to be exactly?

Gigasoft wrote:they are of course free to create non-public variants of their ExFAT driver

Obviously, but we are talking about one particular code that they licensed under GPL. This discussion is about that code, and that code only.

Gigasoft wrote:The GPL is entirely a matter between you and Samsung. It does not bind Microsoft in any way.

Yes it does, section 7 binds MS too, and you have already concluded that Samsung is bound by the GPL. Neither Samsung nor MS can legally stop you from using the Linux kernel's source (as long as you adhere to the GPL terms of course).

Gigasoft wrote:They licensed those patents to Samsung.

No, they provided the patents not to Samsung, but to the Linux kernel (GPL wouldn't allow otherwise).

Gigasoft wrote:Redistributing the code is a violation of the patent

Here's where the problem comes in. It can't be a violation according to the GPL. GPL section 7 explicitly states that if that would be the case, then the exFAT driver couldn't be distributed in the Linux kernel:

if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program.

So the one and only way for MS to have a GPL'd exFAT driver in Linux is to give up asking for royalty for all those who receive copies (and who also have the right to create derivative works from the Linux source).

Gigasoft wrote:Anyone can sue anyone for any reason.

Not so. When they file a case to the court in the EU, they must refer the law article which they think was violated. In EU law no such article exists, there's nothing to refer to, so the case will be thrown back as incomplete and formally invalid without any actual trial. And if they mistakenly refer to EPC Article 52, then it's going to be thrown back because patents do not apply to computer programs, again, without any trial.

"Anyone can sue anyone for any reason"? Thank God that we're not living in America!

Gigasoft wrote:The fact that something relates to computer software, doesn't in itself mean it can't be patented.

Nobody said that. We are not talking about inventions that have a software component too, the exFAT patents and the exFAT driver in the Linux source are purely about computer software, computer software only and nothing else. EPC Article 52 absolutely clear that "programs for computers" are not regarded as inventions for the purpose of granting European patents.

Like it or not, all EU developers can use all software patents for free, and there's nothing MS could do about it outside of the USA. For example MS sued TomTom in federal court, and not in EU court; and they asked for banning the import of TomTom devices into the USA, and not that TomTom should stop selling their devices altogether.

Cheers,
bzt

Who cares about supporting exFAT? Microsoft's other FAT patents have expired. I am happy enough about that. People have been trying to explain, bzt.

nexos wrote:Who cares about supporting exFAT?

Evidently bzt does. Besides, the question might be interesting by analogy for other things someone might have a software patent on. Anyone remember Oracle using Sun's Java patents to go trolling to Google? I, for one, have no interest in exFAT, nor in brain-dead hardware that requires a proprietary FS to work correctly, but I am quite interested in the law, and staying on the right side of it.

I personally want to do things legally as well. I personally have never had to use exFAT in my life, I have no plans to support it in my OS. I think this might just be another Microsoft rant...

In case it wasn't obvious, I'm too looking for a way to implement all FAT in a legally correct way, hence the topic. Even though in the EU I shouldn't care about not violating MS patents, I still want a legally correct solution.

Having vFAT/exFAT support wasn't the question at all, how it can be done correctly was. So answers like "I don't need exFAT" are completely irrelevant and off-topic.

Cheers,
bzt

bzt wrote:

Gigasoft wrote:The ExFAT issue isn't tricky at all. All it means is that Samsung doesn't have a copyright claim against you, if you should incorporate their driver. Microsoft still has a valid patent claim. Your Samsung license does not free you from your duties towards other rights holders, as they are not parties to the contract.

Okay, you missed the real issue here. There's no such thing, "your Samsung license", since the driver was licensed under GPL, that's just not possible.

How do you come to this conclusion? There is a copyright holder (Samsung) and a person granted the right to use the software under certain terms (you/me). But software patents and even copyright of third parties (read: MS) is NOT "turned off" by the GPL. If Samsung violates or ignores patents or copyright, it does NOT give the end user the right to use the software. (Maybe we are simply cross-talking...)

Greetings
Peter