What a load of crap. A hard drive does not have a unique IP address. Hell a hard drive does not know what an IP address is. An IP address is a VIRTUAL address that is given to each 'logical host interface' of every machine connected to an IP network such as the Internet.
Every Hard drive has a unique IP address. An IP address is used by the internet so the governmnet can keep track of you. That way if someone is doing something illegal, such as hacking, the government or police can identify this person by their IP address, simmilar to a cars liscence plate.
@ssslayer: You are correct. Each network interface card (or NIC) has a 48 bit (or MAC-48) Media Access Control address burned into it which is unique to every machine.
Since the creation of the Internet, the Earth's rotation has been fueled, primarily, by the collective spinning of English teachers in their graves. (QDB #754533)