Western Digital claims laptop drives could have 640GB 3.5in drives by 2010, while desktop PCs could have 3TB equivalents.

The hard drive maker claims to have achieved 520GB/square inch areal density, the industry's highest demonstrated density to date using continuous media.

"WD was the first hard drive manufacturer to ship in volume the 250GB capacity point in the 2.5in form factor," said Hossein Moghadam, chief technology officer for WD.

The high density has been achieved through use of the company's proprietary perpendicular magnetic recording (PMR)/tunnelling magneto-resistive (TuMR) head technology.

Products employing this are expected to be made available in 2010.