I am glad they did, given that exFAT is widely used and pre-formatted on SD XC cards and the only cross-platform file system without the 4 GB filesize limit, but what did Microsoft gain from open-sourcing exFAT?

They wouldn't do it from the goodwill of their hearts, would they? Whenever they say "we love Linux", it appears insincere.

What is the actual reason Microsoft did it?

There is a lot of issues working at a huge company like MS,IBM,HP,Exxon or such. Who knows where the ideas come from but all these companies eventually open some stuff.

https://www.zdnet.com/article/micros...d-open-source/

1 members found this post helpful.

Some ways of looking at it:

https://www.joelonsoftware.com/2002/...tegy-letter-v/

1 members found this post helpful.

There's no grand conspiracy here. The question isn't really about what they gained. It's more about what they didn't lose (or what they managed to keep) by doing this.

Open-sourcing the FAT filesystem didn't cost them anything, because it didn't really give away any 'inside knowledge' about the internal workings of Windows. It had already been reverse engineered to the point that Linux VFAT arguably works better than the original, despite not sharing any code. The UEFI spec requires the use of FAT, but works quite well on EFI system partitions created and formatted using Linux VFAT.

The second major point is that FAT is simply not a good filesystem compared to anything halfway modern. It would only take a a few major vendors to decide to use something else, and they could easily switch the majority of the market away from FAT. There are many, many, free and open-source filesystems which are well ahead of FAT in terms of features, performance and reliability. They really had no choice if they wanted hardware vendors to continue using it on their removable storage devices.

Don't look at this as receiving mana from Heaven, because it's not. It's actually quite far removed from that. In fact, I'd suggest that it's more like the 'gift' that the neighbour's dog leaves on your front lawn.

1 members found this post helpful.

Makes sense, thanks.

Not a grand one, just your small garden variety M$ conspiracy. They know that lots of people subscribe to wishful thinking and would not read all the relevant licenses but instead give them free advertising crowing, incorrectly, that ExFAT is available for use.

Those that bothered to read the actual licenses would check beyond the copyright aspects alone and learn that anyone actually using ExFAT in production would be on the hook for software patent royalties in the US.

Better yet, for m$ at least, those that did not bother to read the license and started using ExFAT anyway are also on the hook for software patent royalties in the US. The USPTO's awful web app does not seem to allow deep linking, but searches there for just 2009/0164440 A1 by itself will bring up at least 28 related software patents. A search for "ExFAT" brings up 18 pages of results.

Patents are about usage, not distribution or provenance. You could write your own ExFAT driver, and either sell it or give it away, but as long as it reads or writes ExFAT anyone using it would be on the hook for patent royalties.

That's why m$ lied to get people to mistakenly claim that ExFAT is "open source". That's also why some of the OSS license mention patents explicitly.

I always use an extfs or a BSD one on all my disks, only ever using VFAT where necessary, like EFI, or when an O/S won't read my regular disks.

From a patenting pov, there's nothing original in ex-fat to patent. So if they nag, they get a patent on that exact spec, where nobody can do a carbon copy of it. So their patent (if they have one) is basically worthless anyhow.

Yes, it is a worthless patent (on a worthless technology at that) except from a litigation perspective. Most (all) software patents are invalid or in some other way worthless, but for that litigation which is apparently the main reason for patent thickets, patent arsenals, etc: Those using exFAT have the choice of paying a "small" licensing sum up front or going through dragged out litigation lasting years and costing millions. That is the choice because debunking a patent used to cost an average of $4M a while back, though the price has gone up substantially during the last decade or so. Even so, once that one specific patent is invalidated, m$ will come at you with the next patent on the list. Check the USPTO's "web app" for patents related to exFAT. It returns about 20 full pages of search results. Check OIN? None. Zilch.

Anyway, the business case for m$ promoting exFAT with lies about it being open is that m$ gets credit for an announcement of openness. It also gets to control the peripheral market. Pretty much anything with a microSD card or USB stick defaults to (and pays for) exFAT and more or less 0% can handle EXT2 even though it is a much better and much more appropriate and, best of all, unencumbered format.

Apparently, OIN declined to respond to a recent inquiry on the topic of the patent encumberance ExFAT. Since the patents don't expire for a few years and there are companies collecting royalties, it looks like the rumor about m$ having opensourced ExFAT has been debunked.

More information would be welcome though.

Not quite. They got one of those obscenities called a software PATENT approved. That means the SOFTWARE can be shared, but anyone who uses the protocol MIGHT be subject to litigation on that basis. By opening it up they encourage companies and projects to USE it, then they can leverage that use to attack them. The licensing trolls are using that for things that I really HATE.

OIN has been asked to clarify the status of those issues, and has been remarkably quiet and unresponsive!