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A*STAR DSI in Collaboration With Taiwan’s National Tsing Hua University …

On flexible cable for 5mm hybrid HDD targeted at end of 2012

Singapore’s Data Storage Institute (DSI), a research institute of the Agency for Science, Technology and Research (A*STAR), has signed a collaboration agreement with Taiwan’s National Tsing Hua University (NTHU) to pursue research on flexible cable which will be assembled into the world’s first 5mm hybrid HDD, targeted to launch at the end of the year.

HDD manufacturers are constantly trying to push the limits of areal density to enable more information to be recorded on the device. In turn, this drives up the track density which places pressure on the track mis-registration (TMR). Adjustments have to be made on the TMR as read and write errors affect the accuracy of the data stored. If TMR becomes too large, stored data may be unreadable or cause data on subsequent tracks to be erased. Besides meeting the demand for high areal density, manufacturers also need to develop HDDs that are lightweight, thin, energy-efficient and robust for consumer usage.

As part of the agreement, both research partners will jointly develop a method to study the non-linear dynamic behaviours of flexible cable, quantify its effects on the TMR, as well as to integrate software codes developed from the project into DSI’s HDD mechanical platform for system testing and evaluation. The objective of the research is to develop a flexible cable design for HDD which is able to achieve high track density.

"DSI is constantly trying to refine key HDD components that can be incorporated into the iconic thin hybrid drive which is in the making. This agreement underscores DSI’s commitment to developing high-value performance technologies suited for commercialisation and mass production. We have garnered strong support from our industry partners and our collaboration with NTHU aims to further enhance the synergy between DSI and overseas universities with specialities in data storage," said Dr Pantelis Alexopoulos, DSI’s executive director.

"Ranked one of the top hundred engineering schools in the world, NTHU’s College of Engineering is devoted to cultivating future engineering leaders for the society equipped with solid scientific and technical background, well-versed in technology, humanity, social commitment and international view. Integrative approach in multidisciplinary research has allowed our faculty to conduct engineering research and produce results that are globally recognised. Leveraging on DSI’s calibrated HDD platform, NTHU’s experts in the field of high performance flexible cable analysis and characterisation are able to validate their theoretical and engineering research success. We strongly believe that the newly-designed flexible cable will prove to be superior and a powerful addition to DSI’s HDD," said Prof Nyan-Hwa Daniel Tai, NTHU College of Engineering’s acting dean.

Comments

The z-height of a standard 2.5-inch HDD was 12.5mm and is now 9.5mm - for a width of 70mm and a length of 100mm.

Into 9.5mm units, the maximum capacity currently available is 1TB with two disks and four heads.

The HDD manufacturers have designed thinner units to answer the demand for subnotebooks as well as tablets. They went from 9mm to 7mm in height. But you cannot put today more than one disk (and two heads) in this tiny volume, and consequently a capacity that cannot surpass 500GB. For more than 1TB, you need three disks and a bigger drive at 12.5mm z-height.

For all these 2.5-inch HDDs, it's possible to integrate motors rotating at 5,400 rpm or 7,200rpm.

The smaller 1.8-inch form factor (5mm z-height) is dying because the surface is too small to record today more than 220GB and Toshiba is the last actor in this declining market.

There is a need for HDDs at less than 7mm. 5mm is a possibility, once more with only one disk. A*Star's DSI is pushing this technology to help HDD manufacturers and said that 5mm hybrid HDD - with flash cache -  are targeted at end of 2012.

Maybe this future 5mm devices will be the last chance for HDD makers to compete with SSDs for the primary storage of the smallest computers.

But today, the biggest difficulty is to push the areal density on the surface of the disk, to store more than 500GB on the two sides of a 2.5-inch magnetic platter. Current PMR (Perpendicular Magnetic Recording) is used by all manufacturers but we are not far to reach its limit in density.

In the old time, the makers were doubling the capacity of their next generation of HDDs. Now it's 50% and sometimes only 33%, meaning 750GB/disk or 666GB/disk respectively for 2.5-inch platter.

Next step will be probably SMR (Shingle Magnetic Recording) and then HAMR (Heat-Assisted Magnetic Recording) or BPR (Bit-Patterned Media). It will be a huge investment for the industry to move to these new technologies and it will take several years before their introduction into available commercial products.


Read also:
A*Star Aims to Produce HDD With Only 5mm Thickness for Tablets
Any future?

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