Whats the difference between a USB key and a USB harddrive

Question

I have a DVD player that can play files on a USB key.
It also works with a cable to my MP3 player (4gb chipod)

But it doesn't recognize any external USB hardrive. Even one <32Gb, fat32, single partition, everything I can think of to make it look simple.

Any ideas?

Answer 1

USB Mass Storage devices provide the device to which they are connected with their mass storage class which is defined in a specifcation. As a result, the DVD player can differentiate between a flash drive and a USB hard disk drive, regardless of its size.