Microsoft's only gone and published the exFAT spec, now supports popping it in the Linux kernel

Microsoft has published the technical specification for exFAT, a file system widely used for removable storage devices.

exFAT stands for Extended File Allocation Table and is widely used for things like memory cards. It is the most recent iteration of Microsoft's FAT series, a simple file system that is lightweight but lacks the resiliency and security of file systems like NTFS.

The original FAT was used by DOS in the late 1970s. It was expanded to 8-bit, 16-bit, and then to FAT32, which allows a maximum disk size of 16TB and a maximum file size of 4GB. The 4GB restriction is a problem for things like high definition video, so exFAT was developed to remove this limit.

Microsoft has several FAT-related patents, and in 2009 took action against TomTom for infringement, a matter which was later settled out of court, but which signalled to the Linux community that FAT was not safe to use. Microsoft currently offers exFAT as a licensed technology and states that "more than 100 companies license exFAT." It is possible for Linux users to add exFAT support to their systems via FUSE or non-mainline code, however, it's all unofficial due to the patent situation.

Today's publication of the exFAT specification is the first stage in what Microsoft hopes will be its inclusion in the Linux kernel. The Windows giant says it will support the inclusion of exFAT in a future revision of the Linux System Definition published by the Open Invention Network (OIN). This would mean that the exFAT patent would be covered by the OIN patent non-aggression pact.

The initiative may have been sparked by a discussion on the Linux Kernel Mailing List here. A developer offered to upload an implementation of exFAT, causing a discussion about the patent issues. "If Microsoft is going to be unfriendly about not wanting others to use their file system technology by making patent claims, why should we reward them by making their file system better by improving its interoperability?" wrote Theodore Ts'o, a software engineer who is well known for Linux contributions.

Eventually Ky Srinivasan, general manager in the Enterprise Open Source Group at Microsoft, chipped in with "I have started an internal discussion on this," and perhaps today's announcement is the outcome.

>> Does anyone know if NTFS does anything that EXT4 doesn't do?

> NTFS can compress files, can do deduplication, EXT4 can’t do snapshots (natively). Honestly, they are very similar- EXT4 of course has things I wish Microsoft would do like allow file names of any character.

EXT4, like most native Unix/Linux filesystems, is based on a fixed-at-format-time pool of "inodes", with one inode required for each directory and each file. So if you allocate, say, 1M inodes when you format the volume (mkfs), and you try to put more than 1M files and directories on it, you lose. (Actually more than 95% -- generally 5% are reserved.)

NTFS is expandable in that regard -- there's no enforced upper limit on the number of directories and files in a volume, other than the volume's capacity.

NTFS has many of the more advanced, esoteric capabilities of EXT4, but most of them are blocked in Windows usage because "they would confuse users". Like for example symbolic links (no, Windows shortcuts are not true symlinks). NTFS is much better than Windows lets it be.

I think the reason NTFS in Windows disallows a bunch of punctuation characters in filenames is back-compatibility with MS-DOS. I'm not sure whether that prohibition is inherent in NTFS, or whether it's another artifact of Windows usage; I suspect the latter.

But what would that be? The advanced filesystems like ext4, NTFS, APFS (and HPFS+), nevermind ReiserFS and others, are all far too different in complex ways for use as a portable filesystem. I deal with filesystem incompabilities every day.

Heck, even something relatively simple like configuring a common network drive, used by Windows, Mac, and Linux users, to both export over NFS and share over CIFS/SMB3.,x causes enough hiccups.

Yup. exFAT is the only drive formatting that works well for thumb drives and SD Cards.
FAT and FAT32 can't handle big files. NTFS can have allocation issues, permission issues, and isn't fully compatible with Mac (new Mac maybe?). Obviously any Mac formatting is useless, as regular computers generally can't read or write to them. Same with ext2/3/4 and other Linux formats - Windows and Mac don't like 'em. And of course any proprietary formats from Sony or Panasonic or whomever, definitely aren't good options unless your camera requires it.

That leaves exFAT as the main one that works best between Windows and Mac, some Linux; and hopefully with this news, all Linux here soon!

Same with ext2/3/4 and other Linux formats - Windows and Mac don't like 'em

Linux Reader for Windows from DiskInternals enables read-only access of Ext2/Ext3/Ext4, HFS and ReiserFS files in Windows. However, in another example of corrupt moral "coding," its license agreement states,

display or distribution of this SOFTWARE together with material that is racist...abusive, promoting hatred,discriminating or displaying prejudice based on religion, ethnic heritage, race sexual orientation or age is strictly prohibited.

However, there is http://sourceforge.net/projects/ext2read/

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