So if one were to start the attempt of porting an existing kext VFS filesystem, to use the new FSKit (Since presumably kexts could go away), how would that look now?
Is it ready? Are there any samples out there that already works (Filesystem using FSKit) ?
How is the documentation? ChatGPT did not seem to know much at all.
What would be Apple's reception to that?
How flexible is FSKit ? Is it locked to the idea of a mount is connected to a physical device (or partition)? Or is it more virtual, in that I will have a pool of disks, and present 1, or many, mount points?
FSKit is now available in the macOS 15.4 beta. Yay!
The API is conceptually similar to the earlier version that didn’t make the cut for macOS 15, but there are a lot of differences in the details.
The macOS Sequoia 15.4 Beta Release Notes say:
These file systems support integration with DiskArbitration.
I believe that’s trying to say that FSKit is currently focused on supporting Old School™ file systems, where there’s one underlying disk-like resource that maps to one user-visible volume. If you look in the headers, you’ll see this represented as FSUnaryFileSystem. Its superclass is FSFileSystem, which could potentially support other options but, for the moment, FSUnaryFileSystem is where it’s at.
Oh, and I should also mention that there’s an Xcode target template for this, under macOS > File System Extension.
Oh, and the docs are still available, just not linked in at the top (r. 144994645). For the moment, access them directly with this link.
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
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