How to organize two options for connecting arduino to a computer?

Question

Arduino

There is (planned) an arduino-based device with a connected SD card
, is it possible to organize its connection to a computer in two options
with a choice
of 1 - like arduino for programming, etc.
2 - as a drive (flash drive)

Answer 1

It is possible, but difficult. We will have to rewrite the standard libraries, adding the same choice, and add the USB MasStorage implementation.
The controller will most likely be Atmega32u4 - since it has its own USB.

Answer 2

can be used as a second microcontroller as a switch
to connect to a computer or main controller or card