The data density on hard disks (and thus their capacity) will double every two years over the next decade or so – mirroring Moore’s Law, which predicts a similar rate of increase in the transistor density of processors, according to a leading manufacturer.

And no technology seems likely to supersede magnetic recording for the foreseeable future, says Hitachi Global Storage Technology, in a forecast marking the 50th anniversary of the hard disk.

‘We have heard a number of times that holographic storage is about to break through. But then it is always a case of “it will happen in a couple of years”. It hasn’t happened yet,’ said Larry Swezey, Hitachi’s GST’s director of product strategy and marketing.

He points out that areal density (bits stored per square inch) has increased by a factor of 50 million over that of the first drive, IBM’s Ramac, which was launched on September 13, 1956, and packed 5MB spread over 50 2ft platters.

Hitachi claims to be the first company in the world to offer a half-terabyte 3.5in drive. Its new 7200rpm Deskstar T7K500 and Cinemastar 7K500, containing three platters storing 160GB apiece, are optimised respectively for data and mulitmedia use; low-capacity versions with fewer platers are also available.

The hard-disk industry is riding high with personal-video recorders, internet downloads and portable media players creating huge new markets and high-definition TV driving demand for high capacities.

Swezey cites IDC estimates that the industry will ship more drives in the next fives years than in the previous 50 – and that, within two years, an estimated one in four drives will be in consumer electronics devices rather than computers.

Hitachi GST has just opened a new factory in Shenzhen, China, to meet the demand and is increasing production at other plants. Its new 500GB drives are part of a complete refresh of its 3.5in product line.

Swezey said the Cinemastar products, which will be used in PVRs and set-top boxes, are quieter and run cooler than their desktop stablemates and can tolerate a wider range of temperatures.

A thermal feedback system ensures the read-write head maintains an optimal height whatever the temperature.