To achieve this, Hitachi has demonstrated the industry’s highest data density at 230 gigabits per square inch (Gb/in2) on perpendicular recording. Hitachi believes 230 Gb/in2, which represents a doubling of today’s highest longitudinal recording densities, will be implemented in commercial hard drive products in 2007. When fully realized over the next 5-7 years, perpendicular recording could enable a 10-fold increase in data densities over longitudinal recording, paving the way for new heights in capacity such as a 60 GB one-inch drive.
Perpendicular recording has its roots in the late 19th century work of Danish scientist Valdemar Poulsen, who is generally considered the first person to magnetically record sound using perpendicular recording. The technology gets its name from the vertical alignment of data bits on the plane of the disk, which takes less room in contrast to the horizontal orientation of today’s longitudinal recording technology. To be accurately recorded and read, the more closely-packed perpendicular bits also require a closer association between the read/write head and the recording media. Hitachi achieved the 230 Gb/in2 density by manipulating the head and media so that the distance between them is a mere 10 nanometers or 1/10,000th of a human hair.
While the hard drive industry has been using longitudinal recording successfully for five decades, it is now within two product generations of reaching its practical limit. Researchers are finding that longitudinal recording is losing its ability to maintain data integrity at areal densities much beyond 120 Gb/in2.
