What made Microsoft open-source exFAT in 2019?

[Ertio]

In 2019, Microsoft officially released the exFAT specifications. Before then, everything known about it was only known from reverse engineering, mainly by the heroes at the SANS institute.

 

Did Microsoft do it from the goodness of their hearts or was there some motive behind it?     

 

Why it matters: exFAT is the pre-loaded file system on exFAT memory cards and pretty much all SD XC cameras and camcorders use it. Portable external hard drives and SSDs use it too. Only exFAT is fully read-and-write supported all three of Windows, Mac, and Linux. It the common denominator for storing any files beyond the debilitating 4 GB.

[Basix]

Presumably they wanted to include the drivers in the Linux kernel and they had to sort out the legal status. They wrote a blog post when they published the specification: https://opensource.microsoft.com/blog/2019/08/28/exfat-linux-kernel/

[Ertio]

  14 hours ago, Basix said:

Presumably they wanted to include the drivers in the Linux kernel and they had to sort out the legal status. They wrote a blog post when they published the specification: https://opensource.microsoft.com/blog/2019/08/28/exfat-linux-kernel/

Interesting.

Perhaps they realized exFAT had already been reverse-engineered, so there was no point in keeping it a trade secret anymore.

 

But this begs the question: Why didn't they do that with NTFS too? NTFS is also reverse-engineered at this point. But exFAT is far simpler than NTFS.

 

Another possibility would be Microsoft feared that the world outside Microsoft's ecosystem would switch to ext4 (the default Linux file system) or something else that is already open-source and not patent-encumbered and has no 4 GB file size limitation. Microsoft have thought digital cameras and smartphones will start using ext4 or something else that is open-source and patent-free. This would cause Windows to be locked out or forced into adapting ext4.

 

Microsoft said they love Linux. Not enough to support ext4.