From my little experience with Android I know that a typical Android device will have 2 types of memory- device memory and SD memory.

But today my brother came with a strange problem. He is using a Galaxy Note and he is having 3 types of memory- device memory, USB memory, SD memory.
Being a technical guy I know the device memory is where the ROM is installed, USB memory is the free internal space which we can use and SD memory is obviously the external SD card attached.

Now the problem is while moving the apps to SD card its actually getting moved to USB memory. And as a result he has got no internal memory left in his phone and the total device is hell slow. It takes 5 minutes to open anything and literally unusable.

The question here is

1. Why this phone shows 3 memory partitions instead of usual 2?
2. How to move the apps to the actual SD card and not to the inbuilt storage (USB memory)?