Toshiba spins 2.5-Tbit hard disk

SAN JOSE, Calif. – Toshiba Corp. has successfully flown a recording head over a track on a disk that packs 2.5 terabits of data per square inch, five times the density of today's hard disks.

The report gives a boost to backers of bit patterned media, a technique for tightly arranging data locations on a disk seen by some as the next big leap in denser hard drives. But drive makers are still far from agreement about the road map for rotating media.

Three of the largest drive makers recently agreed to form an alliance to define an industry road map and coordinate research toward its goals. But even the members of that group say it is still unclear whether it will back patterned media or one of several approaches based on heat- or energy-assisted magnetic recording.

"In our labs, we are evaluating both and there are potential technical hurdles with both solutions, but with this development it looks like bit pattern media is a strong contender," said Maciek Brzeski, vice president of marketing for Toshiba's storage group.

Toshiba will describe it's work Wednesday (Aug. 18) in a paper at the Magnetic Recording Conference 2010 in San Diego. The company used an etching mask as a template to create a servo pattern readable by a hard drive using 17nm self-assembling polymer dots. Each dot represents a single bit of memory (see below).

Toshiba claims it is the first time a drive maker has been able to control a head flying over a dense data track made of self assembling polymer dots. The company has yet to prove it can read and write data using the approach.

Japan's New Energy and Industrial Technology Development Organization which is sponsoring work on dense magnetic memory funded part of Toshiba's work. The drive maker has also worked closely with Japan's Storage Research Consortium. It has not yet decided whether it will join the Storage Technology Alliance formed by competitors Hitachi GST, Seagate and Western Digital.

William Cain, vice president of technology at Western Digital, expressed some skepticism about patterned media because it will require high volume manufacturing of 10nm-sized features. "Technologies don’t exist in the supply base to create such small features cost effectively," he said.

"We probably have a bias on energy-assisted recording as the next major transition, but it's too soon to call it," Cain said.

Historically, two of the largest drive makers have taken opposing sides in the debate. Seagate has backed heat-assisted magnetic recording (HAMR). Hitachi GST has focused mainly on patterned media. However, at this week's conference, Hitachi is presenting two papers on HAMR and Seagate has at least three on patterned media.

"It's not a black-and-white race of two competing technologies or entities," Cain said. "But if heat-assisted wins out, we need to get laser diode suppliers on line," he said.

One thing that appears more certain is today's perpendicular recording technology may be extended further than previously expected. Cain and others said a technique called shingled magnetic recording (SMR) could emerge in as little as two years and deliver drives with 1.5 to 2 terabits of data per square inch of a disk.

The technique uses overlapping tracks. But drive makers need cooperation from operating system and PC developers to figure out some of the intricacies of reading and writing data using the approach.

The International Disk Drive and Equipment Materials Association has a group that has been working on SMR for at least six months and is making "pretty good progress," Cain said. IDEMA is also sponsoring the new research alliance that hopes to define a long term road map for hard disks.

The SMR work shows drive makers "there is still some runway, but the sooner we can come to a conclusion [about the long term road map] the better," Cain said.

Toshiba laid down 17nm self-assembling polymer dots, one per bit

An etching mask helped Toshiba lay down the dots in a servo pattern readable by a hard drive