A drum is a musical percussion instrument, consisting of a membrane which is usually stretched taut over a cylindrical tube that is open at the other end. The membrane is struck, either with the hand or some other object, and the tube forms a resonating chamber for the resulting sound. A drummer is a person who plays the drums.
...
Examples of existing "digital rights management" and "copy protection" systems:
Serial copy management system[?] (SCMS)
Macrovision
iTunes
Windows media ...