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Storage Density & Kryder's Law

Most people who deal with technology know about Moore's Law, which deals with the growth in the number of transistors on an integrated circuit. In the storage world, there is the hard-rive equivalent known as Kryder's Law, which states that the density of information on hard drives "increases by a factor of 1,000 every 10.5 years." That boils down to a doubling of storage density every 13 months.

We haven't come close. Industry analysts and storage experts all agree that attaining the growth posited by Kryder's Law with current hard drive technology is, in fact, impossible. During the past three years, the annual improvement in hard drive density has been more like 30 percent to 40 percent -- not even close to the Kryder density growth target of 100 percent per annum.

But new storage media technologies hold the promise of a return to Kryder-like growth, according to Jimmy Zhu, who directs the Data Storage Systems Center (DSSC) at Carnegie Mellon University, where Kryder, a former executive at
Seagate Technology Inc. (NYSE: STX), also works. The key, Zhu said, is to understand that we are at the end of one storage media technology era and on the cusp of another.

"We are kidding ourselves if we think that we can gain much more density in the conventional [hard drive] scheme," Zhu said. "We have run into physical limits of the media itself, and most people in the industry feel that we can expect no more than 30 percent to 40 percent annual density gains over the next few years."

According to Zhu, the limits with current hard-drive technology rest in the fact that you must have significant amounts of core receptivity in the media, and that there simply isn't enough magnetism to write all of the data to the disk. "We are going to hit an absolute limit to growth within the next two to three years," he predicted. "But the good news is that people are already thinking about other storage-media approaches."

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