Waiting for the never-ending increase in hard-disk capacities to slow down? Don't hold your breath. According to Hitachi Global Storage Technologies, its new read-head design will appear in shipping hard drives by 2009 and reach its full potential -- to the tune of a 1TB notebook or 4TB desktop hard disk -- by 2011.

At 30 to 50 nanometers, the Current Perpendicular-to-the-Plane Giant Magnetoresistive (CPP-GMR) heads are less than half the size of existing tunnel-magnetoresistive heads. Compared to the latter, CPP-GMR heads exhibit lower resistance due to their reliance on metallic rather than tunneling conductance, making them more suitable for high-speed operation. Hitachi believes the CPP-GMR technology will enable hard disk recording densities of 500Gb to 1Tb per square inch, a quadrupling of today's highest areal densities.