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Data Storage Systems Center



Charap Receives IEEE Reynold B. Johnson Data Storage Device Technology Award

November 21, 2007

ECE Emeritus Professor Stanley Charap was selected for the IEEE Reynold B. Johnson Data Storage Device Technology Award. His citation was "for quantitative prediction of the superparamagnetic limit for magnetic recording."

The award, sponsored by Hitachi Global Storage Technologies and one of the IEEE's most prestigious honors, is presented for "outstanding contributions to the advancement of information storage with emphasis on technical contributions in computer data storage device technology."

Charap will be presented with a bronze medal, certificate, and honorarium. He was honored for recognizing the superparamagnetic limit on the area storage density in hard disk drives in papers published as early as 1994. Most importantly, the research published in January 1997 brought industry attention to this fundamental problem.

"The research work was so timely and so critical and it jump-started an extensive research effort, still continuing today, in the entire hard disk drive industry to develop technologies overcoming the predicted superparamagnetic limit," said ECE professor and Data Storage Systems Center (DSSC) director Jimmy Zhu.

In the 1997 paper, Charap and his student Pu-Ling Lu, pointed out that if researchers continued to scale hard disc drives as they had been, the technology would be limited to less than 36 gigabits per square inch areal density, because above that density the media would become superparamagnetic or thermally unstable.

At the rate that area density was increasing, this represented only about five years life remaining for the industry, pointed out Mark Kryder, founding director of the DSSC and retired CTO and VP Research at Seagate in his letter of support for Charap's nomination.

"Now you may ask, 'Why then is Seagate and other hard disc drive manufacturers still in business?'" said Kryder. "Well, the answer is that Stan's publications focused the industry's attention on the problem sufficiently early that we could do something about it."

In response to Charap's research, the Information Storage Industry Consortium (INSIC) launched a collaborative program in Extremely High Density Recording (EHDR) for advanced hard disk drive recording technology with financial support from both industry and the National Science Foundation. One of the first grants of the EHDR program went to Charap and colleagues in the DSSC.

The initial goal of the EHDR program was developing the underlying technology required to circumvent the limits suggested by Charap's work (36 gigabits/in2) and achieving a recording density of 100 gigabits/in2 by 2001. With this goal met, the new goal has been set at 1 trillion transistors per square inch (or 1 terrabit/in2) by late 2008.

Mark Kryder, who has returned to ECE's faculty after his years at Seagate, says that Charap's paper also caused the entire industry to again look seriously at perpendicular recording. "Today, Seagate is shipping perpendicular recording drives with areal densities above 130 Gbpsi. It is projected that perpendicular recording will ultimately enable them to extend the recording density to the 500-1000 Gbpsi range," Kryder said.

"Without Charap's early work, areal densities on disc drives would likely be much less than they are today," Kryder continued, "not because we wouldn't have recognized the superparamagnetic problem by now, but because we would have only recognized this problem while trying to make drives work around 30-40 Gbpsi, too late to make the changes in technology required to circumvent the problem Stan identified."

Kevin O'Grady, Professor of Physics in the Magnetic Materials Research Group at the University of York, England, and former president of the IEEE Magnetics Society says that in a large industry with annual sales in the tens of billions of dollars, it is rare that a paper in area of rapidly advancing technology would still be routinely referred to 15 years later. Said O'Grady, "From my prospective, I am sure there is hardly an engineer working in this area who is not aware of this original work in defining this limitation."

Charap joined our department in 1968 after a program in magnetics had begun by one of the pioneers in the area, Leo Finzi. The 1980's ushered in an exciting era for the advancement of magnetics research in the department. In 1982, Charap was a founding member of the Magnetics Technology Center, which was the forerunner of the DSSC. He served as associate director of the DSSC from its formation in 1990 until his retirement at the end of 1996.

Throughout his career and continuing into retirement, Charap has been a leader in the IEEE Magnetics Society, serving in many positions including president of the society. In 1998 he received both the Technical Achievement Award from the National Storage Industry Consortium and the Achievement Award from the IEEE Magnetics Society. In 2000 he was awarded the IEEE Millennium Medal and the College of Engineering's Outstanding Research Award in 2005.

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