[gui-talk] Article: Fujitsu Hard Drives: Toward 1TB per Square Inch

[Steve Pattison]

This article is taken from the Beta News home page at 
www.betanews.com.  -Steve.

Fujitsu Hard Drives: Toward 1TB per Square Inch
By Scott M. Fulton, III,
BetaNews
November 29, 2006, 7:08 PM

A laser capable of being focused to a spot on a rotating disk just 80 
nanometers
across, is what Fujitsu needed to be able to beat competitors Toshiba 
and Seagate,
in the race toward terabit areal densities. Yesterday, Fujitsu 
announced they'd achieved
that goal.

While Toshiba and Seagate have been in competition with one another 
to drive up the
areal density of hard drives using new perpendicular recording 
technology, the scientists
at Fujitsu -- whose own consumer drives have had to play catch-up 
recently in the
quality department -- have been planning to leap-frog their 
competitors in one fell
swoop. There's a physical maximum, they found, to how densely data 
can be packed
even with perpendicular mechanisms.

Their objective is to overcome that physical barrier by means of a 
curious physical
trick involving at least three devices a hard drive has never had to 
use thus far:
a very small space heater, a virtual refrigerator just as small, and 
an optical reading
mechanism.

You read correctly: an optical
  element, not a magnetic one, but not for reading the data. It's to 
locate the spot
on the rotating disk where the heating element will work its alchemy. 
Up to now,
Fujitsu has had two of the three elements in its back pocket. 
Yesterday, it announced
the third: an optical element that will help future hard drives 
achieve areal densities
greater than the 1 terabyte (TB) per square inch theoretical maximum.

The blame for the maximum limit on magnetic recording, according to 
Fujitsu scientists
Koji Matsumoto, Akihiro Inomata, and Shin-ya Hasegawa, has to do with 
the size of
ferromagnetic (iron) grains. You can theoretically make them as small 
as you want,
but if you make them any smaller than they already are, they won't 
retain their magnetic
charge over a sustained period of time. The act of writing data 
literally heats these
grains up, which helps them retain data; but over time, as they very 
gradually cool,
the likelihood that they'll lose their data increases as they fall 
victim to what
Fujitsu scientists call thermal fluctuation.

As a result, you can't miniaturize the magnetic grain enough to 
enable read/write
heads, using the current technology, to store data up to an areal 
density of 1 TB/sq2.
Fujitsu's proposed solution is extraordinary, involving changing the 
physical properties
of the storage media temporarily, just at the point of the write 
operation, using specifically focused heat. At room temperature, it 
takes a relatively sizeable magnetic charge (
coercivity) to erase the state of stored data on a disk so it can be 
changed. But as the temperature
in the vicinity rises, the amount of charge required decreases. If 
you heat a material
up just enough, to what's called the Curie temperature, it loses its 
magnetism altogether.
For the Fujitsu process to work, a heating element needs to bring the 
write spot
on the disk up to as close to the Curie temperature as possible, 
though just below.
As you might have guessed, what Fujitsu needs is a laser, but one 
which is integrated
directly into the magnetic write head of the drive. Its spot size 
needs to be no
greater than 50 nanometers (nm).

This way, the laser can heat up the precise spot on the drive where 
data can be stored
using a minimal charge. When the spot is rapidly cooled, it then 
holds its charge
for a theoretically long period of time.

Up to now, it's all been theory; what Fujitsu needed was what others 
would consider
a miracle in near-field optics. Yesterday, the company's labs 
announced they'd achieved
something at least very close to that miracle: While scientists were 
hoping for 50
nm x 50 nm with 2% optical efficiency, they achieved 80 nm x 60 nm, 
though with 17%
optical efficiency.

It might just work. If it does, the terabit barrier will be broken, 
and the mechanism
that takes manufacturers past that barrier will have a Fujitsu patent 
stamped all
over it. If Seagate and Toshiba were wondering what's been holding 
Fujitsu up for
so long, they just got their answer.


Regards Steve
Email:  srp at internode.on.net
Skype:  steve1963
MSN Messenger:  internetuser383 at hotmail.com