Feeds

Shingle me timbers! Seagate brags of 1m SMR drives - where are they?

Disks with tiny tracks shipping, 5TB boxes by 2014, we're told

HP ProLiant Gen8: Integrated lifecycle automation

Seagate has said it's shipped a million shingled disk drives to date.

Shingled Magnetic Recording (SMR) increases a device's capacity by squeezing more readable tracks of data onto a platter's surface, albeit by hammering rewrite speeds.

When committing bytes to disk, the tiny electromagnet in the disk head that writes the tracks is much wider than the adjacent coil in the head that reads data from the surface. In other words, tracks can be thin when read but are wide when written.

If you partially overlap tracks when writing, leaving just enough width per track for the read coil to pick up, you can fit more information onto the platter than drives that don't overlap tracks. These overlaying tracks are grouped together into bands with gaps either side.

Unfortunately, therefore, when the data in an existing thin track needs to be updated, the head's wide write electromagnet will obliterate the adjacent track partially covering it. So, this adjacent track and all subsequent overlapping tracks to the end of the band must be read, stored in chip memory, and written back after the update operation.

Shingling drives slows down write access speeds, although reads are unhindered, we're told. In the diagram below, in a given band N, the magnolia-coloured tracks must be rewritten after the orange-coloured area is updated. The tracks in green can remain untouched.

Seagate SMR band structure

Seagate SMR band structure.

We touched upon Seagate's SMR boffinry here last month. The tech gives rise to 1.25TB platters, and 5TB-plus disk drives. The company expects shingling to increase a device's capacity by up to a quarter, and such disks should be used for read-intensive applications.

Seagate says SMR drives should provide better value because SMR gear uses the same number of platters as today's non-shingled drives but offers greater data capacities. Meanwhile, rival HGST is cramming more platters and heads into low-friction helium-gas-filled drives to ramp up storage capacity. Seagate suggests that increasing platter and head counts can decrease reliability.

As far as SMR drive value versus helium-filled drive value is concerned, that's a matter for supplier pricing tactics.

Seagate says we can find out more about the SMR technology on this webpage.

"The architecture of a band within an SMR drive is customised for the application in which the drive will be integrated," the disk giant states. "Each drive family addresses its specific product needs and uses SMR to deliver the best results by application."

In other words, there will be different SMR hard drive models touted for different use cases.

The company is not saying exactly when the hoi polloi can order capacity-boosted SMR drives, although it will be sometime in 2014, nor how much the hardware will cost or what branding it will use.

In a statement, Seagate declared "it has shipped over one million drives using shingled magnetic recording". That's shipped, not merely manufactured. So its computer-making partners and others have been testing a million of these little suckers in one way or another. Drives boosted by the tech should at least be in the wild by next year. ®

Reducing security risks from open source software

More from The Register

next story
Sysadmin Day 2014: Quick, there's still time to get the beers in
He walked over the broken glass, killed the thugs... and er... reconnected the cables*
Amazon Reveals One Weird Trick: A Loss On Almost $20bn In Sales
Investors really hate it: Share price plunge as growth SLOWS in key AWS division
US judge: YES, cops or feds so can slurp an ENTIRE Gmail account
Crooks don't have folders labelled 'drug records', opines NY beak
Auntie remains MYSTIFIED by that weekend BBC iPlayer and website outage
Still doing 'forensics' on the caching layer – Beeb digi wonk
SHOCK and AWS: The fall of Amazon's deflationary cloud
Just as Jeff Bezos did to books and CDs, Amazon's rivals are now doing to it
BlackBerry: Toss the server, mate... BES is in the CLOUD now
BlackBerry Enterprise Services takes aim at SMEs - but there's a catch
The triumph of VVOL: Everyone's jumping into bed with VMware
'Bandwagon'? Yes, we're on it and so what, say big dogs
Carbon tax repeal won't see data centre operators cut prices
Rackspace says electricity isn't a major cost, Equinix promises 'no levy'
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.