IANAL and I haven't read up on everything, but I thought it was just the long filename support that was patented. My understanding is that if you just support 8.3 names it's unencumbered.
Edit with further detail: The thing that's unique about LFN are the rename and delete behaviors. Lots of filesystems support more than 8.3 or multiple names for files (hardlinks) but I don't think any of them have alternate names for files that "stick" when you move them into another dir, or that behave somewhat cleanly when a non-LFN-aware OS does so.
Comments
IANAL and I haven't read up on everything, but I thought it was just the long filename support that was patented. My understanding is that if you just support 8.3 names it's unencumbered.
Edit with further detail: The thing that's unique about LFN are the rename and delete behaviors. Lots of filesystems support more than 8.3 or multiple names for files (hardlinks) but I don't think any of them have alternate names for files that "stick" when you move them into another dir, or that behave somewhat cleanly when a non-LFN-aware OS does so.