New Western Digital format squeezes 11% more capacity from drives

"Advanced Format" technology also expected to improve error correction

Western Digital (WD) is beginning to use a new hard disk drive format that opens up between 7% and 11% more capacity on hard disk drives, meaning a 1TB drive could gain more than 100GB in capacity.

The disk expansion technique, known as Advanced Format, takes advantage of industry changes in drive sector sizes to consolidate overhead information and free up that additional space for data storage. Advanced Format is also being adopted by other drive manufacturers to wring more capacity out of existing hard drive technology.

There are 3 basic methods for increasing capacity on a hard drive: increase the bit density; increase the number of tracks per inch; or increase the number of surfaces (i.e. disk platters). WD chose to boost bit density because it takes advantage of additional space already available on every track of a hard disk drive platter, the company said in a document posted on its Web site.

Hard disk tracks are currently composed of 512-byte sectors. But for efficiency reasons, the industry as a whole is moving to larger sectors that store 4,096 bytes of data. Each sector on a drive has a natural gap that contains Sync/DAM (lead-in) and error correction code information (ECC). Multiple blocks of ECC require a lot of overhead.

The Advanced Format removes Sync/DAM blocks that handle data addressing, inter-sector gaps and 8 separate blocks of ECC, and consolidates that overhead into one block on the drive, gaining the extra disk space when compared to traditional formatting, the company said.

WD said Advanced Format also increases data integrity by providing a more efficient error correction scheme by using longer ECC code words, improving error correction by 50%, according to WD.

Currently, WD's Caviar Green, which are available in capacities of up to 2TB, are being built using Advanced Format. WD said more models and capacities will be added in the future.

Advanced Format is designed to work with Windows Vista, Windows 7 and Mac OS X; it's not optimized for Windows XP or older operating systems. For users on older OSes, the company's WD Align software utility . After a user installs the operating system or partition on one of the new Advanced Format drives, the software takes about 20 minutes to create partitions that ensure the drive runs at full performance.

Lucas Mearian covers storage; disaster recovery and business continuity; financial services infrastructure; health care IT for Computerworld . Follow Lucas on Twitter @lucasmearian, send e-mail at or subscribe to Lucas's RSS feed .

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags hard driveswestern digital

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Lucas Mearian

Computerworld (US)
Show Comments

Most Popular Reviews

Latest Articles


PCW Evaluation Team

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

David Coyle

Brother PocketJet PJ-773 A4 Portable Thermal Printer

I rate the printer as a 5 out of 5 stars as it has been able to fit seamlessly into my busy and mobile lifestyle.

Kurt Hegetschweiler

Brother PocketJet PJ-773 A4 Portable Thermal Printer

It’s perfect for mobile workers. Just take it out — it’s small enough to sit anywhere — turn it on, load a sheet of paper, and start printing.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?