A disk array unit connected to {TAIL ~ a host unit} to give {HEAD ~ information} thereto and receive information therefrom 
A disk array unit connected to { TAIL ~ a host unit } to give { HEAD ~ information } thereto and receive information therefrom
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH