The goal is to allow user to use a USB that is ext-4.
I understand Minix 3 is similar to BSD, and ext-4 is GNU GPL. So as a user, I can port ext-4 to Minix 3 and make it GPL so I can use it.
But, what if I want to sell a device (computer) to other users? The device contains Minix 3 and this ported GPL ext-4. Does it make Minix 3 GPL now that Minix 3 communicates with the ext-4 tightly?