Hitachi claims to have made a breakthrough in increasing hard drive capacities. By successfully shrinking the read head using nanotechnology, Hitachi claims that they expect to quadruple the current capacity of hard disks by 2011.
Researchers at Hitachi have successfully reduced existing recording heads by more than a factor of two to achieve new heads in the 30-50 nanometer (nm) range, which is up to 2,000 times smaller than the width of an average human hair (approx. 70-100 microns). Called current perpendicular-to-the-plane giant magneto-resistive*1 (CPP-GMR) heads, Hitachi's new technology is expected to be implemented in shipping products in 2009 and reach its full potential in 2011.
In essence, 4 Terabyte (TB) desktop (3.5") drives and 1 TB laptop (2.5") drives can be expected.
While not specifically mentioned in the release, Hitachi also produces 1.8" drives currently found in Apple's iPod Classic, and we expect similar gains to be expected in those form factors as well. Recent advancements were also announced by Toshiba that can be expected by 2009.
Raw Data: Press Release