Media Transfer Protocol

Looks like Nemo is trying to determine each file's type by reading their header. This deteriorates performance significantly on non-flash media.

Also, an unresponsive MTP device can cause Nemo to get very slow. When I click on a directory on any device while the MTP device is connected, I see a blank list for half a minute. No high CPU or I/O usage. No indication of what might be wrong. pkilling and restarting Nemo did not fix it. Only disconnecting the MTP device did.

To its credit, Nemo behaves better here than Windows Explorer. Windows Explorer locks up entirely if an MTP device is unresponsive, and since the task bar and desktop are the same process, they become unresponsive as well.