Japanese researchers boost data density in 1-inch disk

A Japanese university has shown a prototype 1-inch hard disk drive that packs data on the disk surface more densely than existing hard drives.

The density with which information can be packed onto the disk is particularly important in the tiny hard drives used in handheld electronic devices such as digital music players.

The prototype 10GB drive packs data with an areal density -- the number of bits per unit of disk surface area -- of 138Gb per square inch, said Yoshihisa Nakamura, who heads the project at Tohoku University's Research Institute of Electrical Communications. His laboratory developed the prototype drive as part of a project to increase the storage capacity of handheld electronics devices.

The prototype drive uses perpendicular recording technology to achieve its higher areal density, Nakamura said. The technology works by standing the magnetic fields that represent data bits upright. In commercially available drives, those fields lay flat on the surface of the disk. Standing these fields upright means they take up less space, enabling more data to be crammed on the disk.

"For one-inch [drives], 138Gb areal density is a world record. Somebody may have a higher density in a lab somewhere, but they haven't shown them," Nakamura said.

Many of the world's leading drive vendors have announced they plan to sell drives using perpendicular technology. Of these companies, Japan's Hitachi Global Storage Technologies (HGST), Fujitsu, and Toshiba worked with Nakamura to develop the prototype, he said.

HGST is considering commercializing the drive, although the company has not said when, he said.

Nakamura said his lab should be able to boost the areal density of 1-inch disks to about 500Gb per square inch in 2007. This could enable 1-inch drives to have capacities as high as 30GB a few years from now, he said. Currently, the highest-capacity 1-inch drives on sale store a maximum of 6GB of data.

Tohoku University researchers aren't the only ones looking to perpendicular recording as a way to boost areal density. Last month, Japanese public broadcaster Nippon Hoso Kyokai (NHK) showed a prototype 10GB 1-inch hard drive that also employed the technology.

That drive, which was developed by NHK and Sony, has an areal density of 120Gb per square inch, according to Eiichi Miyashita, senior research engineer at NHK's Science and Technical Research Laboratories. There are no plans to commercialize this drive yet, he said.