An Alternative exFAT Linux File-System Driver Based On Samsung's sdFAT

[phoronix]

Phoronix: An Alternative exFAT Linux File-System Driver Based On Samsung's sdFAT

While the upcoming Linux 5.4 kernel cycle is finally bringing a driver for Microsoft exFAT file-system read/write support, it's dated on an old Samsung code drop that has seen little public work over the years. Since queued for staging-next, there has been a big uptick in clean-ups and other activity, but there also exists another alternative out-of-tree exFAT Linux driver...

http://www.phoronix.com/scan.php?page=news_item&px=exFAT-sdFAT-Alt-Driver

[skeevy420]

Why can't we ditch FAT for something newer? Does anyone actually use FAT for anything if it isn't forced on them (EFI, certain SD card readers, etc)?

I mean, it's not like anyone actually goes "Hot damn, a new 8TB HDD. 4 FAT partitions are so sweet. Legacy limitations kick ass".

[Slithery]

Why can't we ditch FAT for something newer?

You mean like exFAT?

[skeevy420]

You mean like exFAT?

More like F2FS or even XFS (thinking Stratis). exFAT only extends keeping an unnecessary file system like FAT around instead of retiring it and giving it a modern replacement. We need exFAT like we need EXT2.5 -- we just don't.

The same can be said for NTFS as well.

[Britoid]

More like F2FS or even XFS (thinking Stratis). exFAT only extends keeping an unnecessary file system like FAT around instead of retiring it and giving it a modern replacement. We need exFAT like we need EXT2.5 -- we just don't.

The same can be said for NTFS as well.

F2FS and XFS are not a replacement for exFAT. They're too "advanced" and any replacement needs to be implementable in dumb firmware (exFAT is).

There really isn't any alternative for removal-able media right now. Now that exFAT is "open" and can be used in Linux without patent concerns, I'm perfectly happy with it being adopted.

[birdie]

Random IO benchmarks clearly show how horribly slow and inefficient FUSE based filesystems are in general. What's more they cannot work without /tmp backstore (maybe not all but the ones I've tested) which also limits file sizes in case the user mounts tmpfs to /tmp (I've been doing that for the past 15 years or more).

[DanL]

Does anyone actually use FAT for anything if it isn't forced on them?

SD cards, digital cameras, USB sticks, TV's...
Like it or not, exFAT has a foothold in the market, and until there is a need for replacement, it will see increased use as non-volatile memory storage becomes larger/faster. The issue with exFAT has been legal (not technical). Now that the legal hurdle is cleared, we really do not need another filesystem/standard to worry about.

[illwieckz]

Random IO benchmarks clearly show how horribly slow and inefficient FUSE based filesystems […]

This is not a FUSE based filesystem, you probably miss older articles:

• Native Linux Kernel Module Is Out For Microsoft exFAT
• Samsung Accidentally Leaked The exFAT Linux Driver
• Samsung Properly Open-Sources exFAT File-System
• There's Still Work On Mainlining exFAT Linux Support
• Merging exFAT Support For Linux Is Being Talked About - Waiting On Microsoft's Blessing
• Microsoft Publishes exFAT Specification, Encourages Linux Support
• The Existing Linux exFAT Code Is "Horrible" But Could Soon Be In Staging
• The Initial exFAT Driver Queued For Introduction With The Linux 5.4 Kernel
• An Alternative exFAT Linux File-System Driver Based On Samsung's sdFAT ← the current one

[tg--]

More like F2FS or even XFS (thinking Stratis). exFAT only extends keeping an unnecessary file system like FAT around instead of retiring it and giving it a modern replacement. We need exFAT like we need EXT2.5 -- we just don't.

The same can be said for NTFS as well.

These are just silly points to make.

Of course we need exFAT. If we like it or not, it is one of the most heavily used filesystems on the planet (by far outnumbering F2FS and XFS), and not only is it used, it is basically mandated by modern SD-card standards.
These SD-cards are used in literally BILLIONS of consumer devices, almost all of which use exFAT.
For that reason alone we need exFAT support in Linux.

Apart from that, there's also a reason that exFAT is used, and that's not just because Microsoft said so.
SD-cards are used in a huge amount of devices not powerful enough to run a F2FS, let alone XFS implementation. Those filesystems are far to complex.
exFAT can be easily implemented in microcontrollers and all kinds of low-power hardware with little RAM.

[skeevy420]

SD cards, digital cameras, USB sticks, TV's...
Like it or not, exFAT has a foothold in the market, and until there is a need for replacement, it will see increased use as non-volatile memory storage becomes larger/faster. The issue with exFAT has been legal (not technical). Now that the legal hurdle is cleared, we really do not need another filesystem/standard to worry about.

The whole point of exFAT is because FAT32 needed a large format replacement and nothing more. If it were truly 100% legal and nothing else, EXT2 would have been adopted (and possibly extended to support larger file and drive sizes) since EXT2 does have R/RW drivers on Windows or simply use EXT4 with the journaling disabled and make a complete Windows driver for EXT4 (last time I checked, 10ish years ago, EXT4 was read-only on Windows).

Open source so it's extendable as necessary without pesky legal hurdles, compatible with most everything BSD or Linux based, and no new file system or standard to worry about.

On another note, is a 4TB thumb drive/sd card/whatever without a journaled file system necessarily a good thing in the long run? I can understand wanting a dumb file system on older devices without power safety, but damn-near every new/modern device either has a power down when out of power function or is expected to have a dedicated power source and the only risk is an actual power outage so the power loss file corruption with newer file systems isn't as good of as reason to not use them these days. With how advanced some of these devices are and the kind of data they process (and how some are semi-permanent like sd cards that are installed behind a phone's battery), going with anything non-journaled seems like a bad idea.