Case-sensitive is easier to implement; it's just a string of bytes. Case-insensitive requires a lot of code to get right, since it has to interpret symbols that make sense to humans. So, something over wondered about:
That's not hard for ASCII, but what about Unicode? Is the precomposed Γ§ treated the same lexically and by the API as Latin capital letter c + combining cedilla? Does the OS normalize all of one form to the other? Is Γ the same as SS? What about alternate glyphs, like half width or full width forms? Is it i18n-sensitive, so that, say, E and Γ are treated the same in French localization? Are Katakana and Hiragana characters equivalent?
I dunno, as a long-time Unix and Linux user, I haven't tried these things, but it seems odd to me to build a set of character equivalences into the filesystem code, unless you're going to do do all of them. (But then, they're idiosyncratic and may conflict between languages, like how ΓΆ is its letter in the Swedish alphabet.)
