Hi Cristian: Novice to Arduino community so trying to educate myself.

How come Arduino sketch make instantiation of class File
eg File myFile

but no one instantiate class SD...Should one instantiate SD mySD as well?

Secondly. In header file of SD.h I noticed that card, volume and root are declared private, yet how come we can use outside of class in sketch? Why mix up private v. public declaration?

I love Arduino :-) but am puzzle