QuoteWith the new, elegantly named current perpendicular-to-the-plane giant magneto-resistive heads (CPP-GMR heads to you laypeople), drive makers will be able to come out with 4 terabyte drives in 2011 and/or 1 terabyte notebook drives. The CPP-GMR drive essentially changes the structure of drive heads. Current drives come with a tunnel magnetoresistance head. In these, an insulating layer sits between two magnetic layers. Electrons can tunnel through the layer. Precisely controlling the tunneling ultimately results in the 1s and 0s of data.