Codeigniter 3.0 forced uppercase naming of controllers and classes

Thank you for you answer, Kilishan, after 20 years of working in php (ahem... at the beginning it was called php-fi) plus a variety of os's I'm proud to still be a listening person and to be always ready and eager to learn, especially from brilliant people.

However, it's still a bit unclear to me what you mean. Isn't the example below showing that windows+php are able to recognise case difference?

a) I created a file "fileA" and listed the dir with a small php program:

C:\Users\aa200_000\Desktop\cartella>php test.php
Array
(
   [0] => .
   [1] => ..
   [2] => fileA.txt
   [3] => test.php
)

b) Then renamed the file "filea", all lowercase and listed the dir once again:

C:\Users\aa200_000\Desktop\cartella>php test.php
Array
(
   [0] => .
   [1] => ..
   [2] => filea.txt
   [3] => test.php
)

It seems to me that the os and the language together have a clear view of the difference... please help me understand where I'm going wrong.

Thank you
S.