The difference between Mnt,media and the dev directory in Linux

A few days ago, the hands of the cheap, accidentally deleted/usr. So carved a BACKTRACK3 boot disk, go into the system backup.
I mounted the home with mount/dev/sda6/mnt/home and then tar cf/mnt/usb0/bak.tar/mnt/home back up.
After the backup, I backtrack3 in the virtual directory around, suddenly, I found/media directory also has a home folder, open a look, found and/mnt/home exactly the same!
Originally, the/MNT directory holds the hardware that is mounted manually, the/media directory holds the Automatically mounted hardware (the load point is automatically created and deleted by the system), there is no special difference between the two.

Tell me more about/dev.
/dev is not a driver for a device, but an interface for accessing external device files. For example, our USB stick, after inserting the Linux system, use Fdisk-l to view the partition, display the file as/dev/sda1. Then we can mount the U-disk to/mnt/usb0, mount/dev/sda1/mnt/usb0.

The above is the difference between the three.

Reference documents:

The "/mnt/media/dev directory Difference" about/dev is a copy of this.

The difference between MNT and media (LINUX, whichhas not figured out the relationship between the/media directory and the/mnt directory) , shows the difference between the /mnt directory and the/media directory in two articles.