WD Gives Hard Drives New Spin

Article By : Rick Merritt, EE Times

Western Digital said it will start shipping in 2019 a new recording head technology that will enable 40 TByte hard disk drives by 2025.

SAN JOSE, Calif. — Western Digital demonstrated a new technology for recording heads it claims will keep hard disk drives spinning for years to come. It will ship by mid-2019 drives using microwave-assisted magnetic recording (MAMR), a technology it expects can lead to 40 TByte drives by 2025.

The technique was born in a Carnegie Mellon lab in 2006. WD struggled for years to implement the technique until two years ago when a researcher at the former IBM plant here where the hard drive was born had an “a-ha moment” that paved the way to commercial products.

Today, WD believes MAMR should enable 15 percent declines in terabytes/dollar on hard drives through 2028. The company showed a working prototype at its headquarters here, promising engineering samples of a 14+ TByte drive by mid-2018 and production drives a year later.

Rival Seagate has said it will ship drives next year using a heat-assisted recording process called HAMR it has been developing for many years. Seagate generally splits about 80 percent of the hard drive market with WD, and Toshiba is in third place at about 20 percent share.

The new recording techniques won’t alter an ongoing decline in annual shipments of hard disks. NAND flash-based solid-state drives continue to replace hard drives, particularly in size- and power-constrained devices such as notebooks.

Eight years' work on MAMR got hot and heavy about three years ago, said Sridhar Chatradhi, senior director of WD's technology and architecture group. (Image: EE Times)

Eight years’ work on MAMR got hot and heavy about three years ago, said Sridhar Chatradhi, senior director of WD’s technology and architecture group. (Image: EE Times)

The new technology will fuel the highest capacity drives used in servers. They represent about 42 million units a year industry-wide, a little more than 10 percent of all HDD units sold each year, but a much higher percentage of dollars and capacity.

Long term, both MAMR and HAMR may enable drive makers to pack as much as 4 Tbits/inch2 on a disk. That’s up from about 1.1 Tbits/in2 in today’s drives that use a perpendicular recording technique that is running out of gas.

WD said HAMR will require new materials and techniques, driving up cost. In addition, HAMR briefly heats small zones of a disk up to 700 degrees C, introducing reliability concerns.

By contrast, MAMR uses mainly existing head and media technologies. However, it does require damascene, an electroplating process applied in some semiconductors that WD has been using to make recording heads for several years.

WD claims rival Seagate still employs an alternative dry pole technique that uses ion milling to shape heads created by material deposits. Since 2010, WD has spent an estimated $300 million developing the damascene process which it says creates finer features than dry pole.

[Next page:  A tale of two a-ha moments](https://www.eetimes.com/document.asp?doc_id=1332435&page_number=2)

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