In perpendicular recording, the tiny magnets are standing up and down. Adjacent alternating bits stand with north pole next to south pole; thus, they want to attract each other, are more stable and can be packed more closely. This is the key to making the bits smaller without superparamagnetism causing them to lose their memory.
Earlier this year, Hitachi demonstrated a perpendicular recording-data density of 230 Gigabits per square inch -- twice that of today's density on longitudinal recording -- which by 2007 could result in a 20GB microdrive.
Though it departs from the current method of recording, perpendicular recording is technically the closest alternative to longitudinal recording, enabling the industry to capitalise on current knowledge while delaying the superparamagnetic effect.
The superparamagnetic barrier is drawing nearer, forcing the industry to slow the historically rapid pace of growth in disk drive capacity -- a pace that, at its peak over the past decade, doubled capacity every 12 months. Using perpendicular recording, the effects of superparamagnetism can be further forestalled, which would create opportunities for continued growth in real density at a rate of about 40 percent each year.
Perpendicular magnetic recording represents an important opportunity for companies in the hard drive industry to continue to grow capacities at a reasonable pace. Such growth is needed to satisfy the burgeoning information requirements of society: A 2003 University of California at Berkeley study estimates that more than 4 million terabytes of information were produced and stored magnetically in 2002 -- more than double the 1.7 million terabytes produced and stored in 2000. There are no signs that the requirements for hard-disk storage is ebbing.
Industry analysts have predicted that hard drives for consumer electronics will account for 40 percent of all hard drive shipments by 2008, up from 9 percent in 2003 and 15 percent in 2004. More than ever, consumers are holding their entertainment and personal data in digital formats and have demonstrated an insatiable appetite for storing music, photos, videos and other personal documents. In the next five to 10 years, the average household will have 10 to 20 hard drives in various applications -- a situation that will require the successful adoption of perpendicular recording. Companies that research and produce their own hard drive technologies will be better positioned to do this when the industry demands it.
Confidence for the future
Fifty years ago, when the first 5MB drive was introduced, few if any observers could have predicted the current state of the industry. They would likely not have believed that a read/write head could fly 100mph over a spinning platter at a distance that is less than 1/10,000th the width of a human hair. Or that hard drives the size of matchbooks would be capable of storing entire music libraries. This all would have been in the realm of science fiction.
Yet they would likely understand the scientific concepts and physical laws that have made these advances possible. While there has been a great deal of invention, the basic science -- like Danish inventor Valdemar Poulsen's discovery of magnetic recording more than 100 years ago -- has remained relatively constant.
Such constancy gives rise to confidence across the industry that the challenge of superparamagnetism will be met. Perpendicular recording is most likely the first technology bridge in this realm, but it is by no means the last.
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