Once?, in the good old days of the first Android devices, you could connect the Google phones via the USB cable to the computer and data to be sent to mass storage mode on the unit push. No matter whether it was with Windows, MacOS X or Linux on the road: The process working across the system and without major complications. But then Google decided to completely to MTP to Transfer data between Android and PC. The Media Transfer Protocol helps a few unpleasant and to follow the rich iron out the weaknesses of the pure USB mass storage mode. In the future, you can use it also with the TWRP Recovery and about data rescue via Recovery-Mode from the phone.