Display both Internal Memory & External SD Card files ?

I`ve got a samsung young GT-S6310N. Like the phone since it`s my first smartphone but it sucks you can`t write any memory sucking apps to the external sd card which is 16bg and more then big enough. now i have to do with the internal 4gb which is already halfway full with jusy the program and apps that come with the phone. As i understood i have to root my phone which is a pain in the butt and i also understood that with android 2 you could still write to the external card. If this is so why on earth did they change it. Ok music and video`s and photo`s can be big too but nothing compared with the apps. An as you all know now the internal sd is getting full with just a few extra apps. NO FUN AT ALL. SAMSUNG YOU NEED TO CHANGE THIS

Micromax a106 when connected to computer mass storage it display both internal and external memory it has kitkat why other android doesn't support mass storage

I have an android samsung s3 mini phone model no 18190 n. It have both internal and external memory but unfortunately external memory didnot work. If I open gallery igot only internal memory only. But if iam go to file then external tgen igot that files.
I requested to pls give an solution for this