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Four GB drive protects head from fall

Posted: 01 Sep 2005 ?? ?Print Version ?Bookmark and Share

Keywords:hard-disk drive? solid-state flash? cornice? hdd? mp3 player?

Unlike hard-disk drives, solid-state flash has the advantage of not being harmed when dropped. Now, Cornice Inc.'s 1-inch 4GB HDD includes head-retraction features that protect the storage media in the event the drive is dropped. Such protection mechanisms are designed to give extra utility to microdrives in handheld portables such as MP3 players, cellphones and pdas.

Flash memory will always lag HDD storage in terms of density, said marketing VP David Feller. Cornice believes it will be four years before flash can catch up to its product's 4GB capacity. And the use of one side of the disk for recording!only one head-disk assembly!makes the Cornice drive more economical than drives that depend on two, he said.

The main innovation, though, is an electronic sensing mechanism that retracts the read/write head from the surface of the disk in the event it is dropped. Called Crash Guard II, the mechanism depends on an accelerometer to sense a potential fall and lift the head.

When dropped, the most common damage to a hard drive occurs when the head scrapes across the surface of the disk. It's not unlike the needle scratching across an old vinyl LP record when the turntable is bumped, Feller said.

Crash Guard II can sense when the HDD is dropped, even if the drive is in the middle of reading or writing data to the disk. It will react by latching the head away from the disk surface well before the unit actually strikes the ground.

The drive is rated to survive a drop from as high as 1.5m. From a shorter height, it's possible the accelerometer will not have time to react. But with Crash Guard II, the head-retraction mechanism will kick in anywhere from 58cm to 4cm, said Feller. Below 4cm is considered a "safe zone," in which no protection is needed.

"The drive's host CPU cannot respond in time to a 'Help, I'm falling' signal from the drive," Feller noted. As a consequence, the drive electronics must provide their own protection. The accelerometer is attached to a dedicated pin with an active-low signal, which tells whether the drive is falling or not. "It took us several years to get this right," Feller said. But now, Cornice has a two-year lead on its competitors, he believes.

Founded in 2000, Cornice already claims significant design wins for its microdrives. Its primary markets include MP3 players, USB storage devices, digital video players, GPS and cellphones. Drive-based MP3 players by themselves will account for as many as 20 million to 24 million units per year, Cornice estimates.

Early this year, Apple Computer Inc. transformed the MP3 player market by offering 4GB and 6GB iPod Minis at $199 and $250, respectively, Cornice notes. This effectively reduced the retail price of 4GB products to $199 from $250. Competitors in the disk-based MP3 player market need to come in at a much lower price point to stand a chance against Apple!or offer higher disk capacity (5GB or 6GB) in that price race, Feller said.

"Margins will be tight or non-existent, with a 4GB, $179 unit using a Hitachi or Seagate drive," Feller said. He sees $149!what he calls the "Wal-Mart price"!as the target price for a potential iPod competitor.

- Stephan Ohr

EE Times

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