Workaround - read but not create long file names

Workaround - read but not create long file names

Posted Mar 2, 2009 23:10 UTC (Mon) by tridge (guest, #26906)
In reply to: Workaround - read but not create long file names by tridge
Parent article: Third time is the charm?

I've just realised there is a corollary to this workaround. If a embedded device vendor doesn't currently have any interface that allows the user to create files with long file names then they are not infringing the VFAT patents, even without patching the kernel to remove the code that allows long file names to be created on VFAT. This is because there is no way that anyone can demonstrate infringement of a claim about "storing" when there is no way to make the device store names in the way that is described.

I think this applies to TomTom, and also to all the camera vendors and similar devices. They all create files with short file names. Many of them will happily read files that have long file names, but they tend not to have an interface to create them.

In part we are saved by the common way that these devices are accessed over USB. The devices present themselves as USB storage devices, so the Linux kernel is just presenting a block interface. The creation of VFAT directory entries when done on a device that is docked is done by the host computer, not by the device, so the device vendor is off the hook.

We should still consider having a kernel option that disables the creation of long file names in VFAT for all those vendors that do have an interface to creating arbitrary file names, but I think the above argument may help to reduce the impact of the VFAT patents on the embedded space quite a bit.

Cheers, Tridge

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