SDXC cards

Newer high capacity SD cards (64GB and above) are using exFAT to get round the 4GB file limit of Fat32. RISC OS users cannot use SDXC cards if exFAT (default) formatted because format is unrecognisable. Is there support/expertise for a bounty to develop software that is compatible?

Jeff Doggett’s Fat32FS is based on a heavily hacked efsl. There are several exFAT capable libs around which could be used instead:

• http://elm-chan.org/fsw/ff/00index_e.html
• https://github.com/relan/exfat
• https://trac.netlabs.org/fat32

Maybe Jeff would like to have a go…the first lib is 1-clause BSD and C89, so ideally suited even for inclusion directly in RISC OS.

On the other hand, RISC OS cannot use most of exFATs advantages compared to FAT32 (like larger files, properly defined filename encoding/unicode support), so the easiest solution is to just reformat to FAT32.

Just because exFAT exists, doesn’t mean it’s freely available for use…

https://www.microsoft.com/en-us/legal/intellectualproperty/mtl/exfat-licensing.aspx

Just because exFAT exists, doesn’t mean it’s freely available for use…

To use or implement exFAT you don’t need a licence from Microsoft. You are probably in murky territory wrt patents, however. Would be interesting to see a court case weighing patents against the right to reverse engineer to ensure interoperability.

To use or implement exFAT you don’t need a licence from Microsoft

I think you’ll find you do need a license as its patented. Someone from RISC OS Developments Ltd should submit a Licensing request and see if MS will allow it to be implemented license free within RISCOS. Its available in other open-source OS, so either MS have embraced open-source or there’s money changing hands.

I think you’ll find you do need a license as its patented.

So how is it Linux is using it via the exfat-fuse package?
Since the last automated update, my chromebook now only reads exfat and ext on the usb or sd card ports, Fat32 is gone.
Haven’t found an answer yet, was expecting a later update with a fix.
May be time to go into developer mode and switch to proper linux distro?

Edit: I sent a bug report via the ChromeOS hot key and a week later, I notice I can read all of my ordinary Fat usb sticks again, All of this happened behind the scenes, but at least I have compatibility with RISC OS again.

So how is it Linux is using it via the exfat-fuse package?

http://www.linux-magazine.com/Issues/2013/156/exFAT-Filesystem

So how is it Linux is using it via the exfat-fuse package?

Either its inclusion is breaking intellectual property law, or a licensing deal has been agreed with Microsoft. If it’s the former, they’re in dodgy territory as patents have to be enforced to remain valid.

I think you’ll find you do need a license as its patented.

There are surely patents around from Microsoft that might touch a specific implementation of exFAT. This is just the same as it was before with VFAT, FAT32 and SMB/LanMan stuff. We don’t seem to worry about these, so I wonder why we should worry about possible exFAT-related patents?

We don’t seem to worry about these, so I wonder why we should worry about possible exFAT-related patents?

As software patents aren’t a “thing” for us, we could in theory ignore them. But then this could create complications for any users living in a place where patents are a thing.

Specifically, FAT32 is an incomplete implementation designed to bypass the stuff that is patented. Likewise SMB doesn’t make use of the parts covered under patent. In both cases the parts that are being used are – as far as I know – patent free due to lapse or never having been enforced. However it is messy given the behaviour of the USPO and the general “sort it out in court” attitudes.

exFAT is newer, more heavily encumbered, and – personally speaking a bad option for having been recommended for large capacity media for that reason, but it is what it is. The bloke who created exFAT fuse was a Russian who didn’t give a crap about American patents. Should we? In our countries in Europe, probably not. For now.
But exFAT support isn’t something that could ever be built into RISC OS until such time as a licence is agreed or the patents expire. But, then, FAT32FS is an add on and this hasn’t dented it’s popularity, so…

[disclaimer for Americans: IANAL ;-)]

exFAT is newer, more heavily encumbered, and – personally speaking a bad option for having been recommended for large capacity media for that reason, but it is what it is. The bloke who created exFAT fuse was a Russian who didn’t give a crap about American patents. Should we? In our countries in Europe, probably not. For now.

There were various expensive patent settlements in Germany wrt several FAT patents. Those patents were upheld in court despite going heavily against common sense.

So no, no help being in Europe. In fact, EU seems to be determined to make things worse by the hour (upload filtering anyone?).

However, to get back on topic – I must have missed that big source code audit making sure that RISC OS is not violating any patents. I can’t see how support for exFAT would make things worse. I don’t think anyone has identified those patents that protect exFAT?

There is a possible legal way around the issue. Microsoft joined the Open Invention Network last year, if RISC OS Developments Ltd also joined, the issue of legal recourse can be avoided as its a non-aggression agreement.

The issue however is OIN is centred around Linux and RISCOS clearly isn’t Linux.