Developing an iOS apps, there was a thing that drove me mad: executing the same app that created the same files at the same path, the iPhone simulator worked the correct way, while a real iPhone didn't. I eventually discovered that i mistyped a character (uppercase instead of lowercase) and consequently the iPhone created a folder starting with an uppercase character, while putting the file in a path with that folder starting with the lowercase version of that character. The simulator however, didn't care of that difference. I suppose that was because the simulator, running on a case-insensitive system (OS X/mac OS), inherits its "case-insensitivity", while the iPhone (seems to me) is natively case-sensitive.

Mi question is:

**Given that iOS's core is based on OS X's, and OS X is case-insensitive (even if case-preserving), why is iOS case-sensitive?**
 Is there a particular reason for this? It's not case-sensitive and I misinterpreted what happened with my problem? It's due to some differences in the adopted file systems? It's an architectural requirement for some iOS characteristic that doesn't apply to OS X? Thanks for any clarification.