[ygra]

Well, history sadly dictates that the interface to the upper layers it based around code units because those have always been fixed-length. Unicode came to late to most operating systems to really be ingrained in their design and where it was (Windows springs to mind) it all got a turn for the worse with the 16-to-21-bit shift in Unicode 2 with Unicode-by-default systems being no better than 8-bit-by-default systems had been a decade earlier.

That NTFS uses GUIDs internally to reference streams is news to me, though. But I think on Unix-like systems the equivalent would be inodes, I guess, right?