Feeds

Will magnetic switching by light keep storage vendors spinning?

Circularly polarised lasers - the new magnetism

Security for virtualized datacentres

Hard drive storage is based on switching magnetic states by magnetism. Switching by laser light could be much faster and could be used on non-spinning media.

Laser light switching of a magnetic medium is described in a PhD thesis, Laser-Induced Femtosecond Magnetic Recording, written by Dr Daniel Stanciu, currently a researcher for Océ Technologies in The Netherlands. He and Dr Fredrik Hansteen discovered how to use light to reverse magnetic polarity in 2006. Stanciu developed the idea more as an intern at Seagate's Pittsburgh research centre in 2007.

The PhD thesis was published last year and can be downloaded here (pdf).

Light-induced femtosecond

Front cover of Stanciu's thesis.

The background is that magnetic-induced switching of a magnetic field becomes progressively harder as the size of the magnetic field shrinks. We want to reduce the size of the magnetic area so as to increase the storage capacity of the medium, such as a hard disk drive. Current shipping hard disk drives (HDD) have a storage areal density at or in excess of 325Gbit/sq inch.

Post-perpendicular recording technologies such as discrete track recording, bit-patterned media and HAMR (Heat-Assisted Magnetic Recording) are set to take this to and perhaps beyond 1Tbit/sq inch.

Unless the write and read time per bit increases in speed as the areal density increases then the I/O rate of the disk will appear slower and slower relative to its capacity. Stanciu reckons that, in 2007, disk drives were operating at an internal data transfer rate of approximately 200 MB/sec, corresponding to a channel data rate of about 1.6 Gbit/s. He says that the writing time for a single bit is a little less than one nanosecond (billionth of a second) at that speed.

(For reference here a picosecond is one trillionth of a second. A femtosecond is one billionth of one millionth, or one quadrillionth of a second.)

Stanciu asserts that HDDs with terabit areal densities will need sub-nanosecond switching times; their data bits will need their magnetic polarities set at such speeds. How could it be done?

One way is to increase the strength of the applied magnetic field and this, he says, can get us into speeds measured in picoseconds. But the smallness of the bits requires magnetic material with a high anisotropy (directional differences in magnetic field strength).

The strength of the writing magnetic field must be high to overcome this and it must also be very narrow in focus or else contained some how so that neighbouring bit values are not affected. He cites a potential limit on magnetic switching that indicates it can never be faster than two picoseconds.

Providing a secure and efficient Helpdesk

More from The Register

next story
It's Big, it's Blue... it's simply FABLESS! IBM's chip-free future
Or why the reversal of globalisation ain't gonna 'appen
IBM storage revenues sink: 'We are disappointed,' says CEO
Time to put the storage biz up for sale?
'Hmm, why CAN'T I run a water pipe through that rack of media servers?'
Leaving Las Vegas for Armenia kludging and Dubai dune bashing
Microsoft and Dell’s cloud in a box: Instant Azure for the data centre
A less painful way to run Microsoft’s private cloud
Facebook slurps 'paste sites' for STOLEN passwords, sprinkles on hash and salt
Zuck's ad empire DOESN'T see details in plain text. Phew!
Windows 10: Forget Cloudobile, put Security and Privacy First
But - dammit - It would be insane to say 'don't collect, because NSA'
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.