Summary:

Not anytime soon, but some day in the near future one could expect IPod with a massive 200 GB drive, and one would have to thank PMR for it. Perpendicular magnetic recording (PMR) will be the next big leap in the hard drive storage technology, and […]

Not anytime soon, but some day in the near future one could expect IPod with a massive 200 GB drive, and one would have to thank PMR for it.

Perpendicular magnetic recording (PMR) will be the next big leap in the hard drive storage technology, and while it is too early to predict its long term business implications, the hard disk drive makers are banking on this new technology. Why? because it changes the current status quo of profitless prosperity in the HDD industry. From 1990 through 2002, HDD makers have given customers more of the same. HDD capacity increased by a compound growth rate of 93% per year, with equally spectacular price declines.

The reason it was made possible was due to industry’s move from oxide media to thin film media. Then, in the early 1990’s, in quick succession, the readback heads – which were inductors akin to miniature electrical transformers – were repand then by giant magnetoresistive (GMR) heads.


Well those technologies are coming to an end of their life-cycle, and as a result industry doyens are looking at PMR as their salvation. So what is PMR and how is it different from the current disk drive technologies. Today, the data is stored as microscopic magnets. The magnetization of the recorded bits lays parallel to the surface of the disc. This is called longitudinal recording.

In the case of PMR, as you by now might have guessed it, the magnetization of the bits is oriented perpendicularly to the surface of the disk, like corn stalks on a level field, according to Ashok Kumar, analyst with Raymond James, who goes on to say that PMR ensures longevity of the data, which cannot be compromised as easily. Kumar, in a recent research note, points out that the PMR has a higher thermal decay, and as a result, one could pack more data on to the drive using PMR. Now that is the good news.

Practical implementations of PMR have been far and few. “There are many unresolved technical and manufacturing issues in the implementation of PMR that rival in difficulty those encountered in longitudinal recording,” says Kumar. So why are we getting our knickers in a twist? Well for two reasons – PMR will make it possible to cram a lot of data in really tiny drives. Just think a 200 GB IPod!

If achievable at low cost, such a development would make disk drive storage ubiquitous in hand-held gadgets and in devices detached from a computer’s operating system, Kumar predicts and points out that it could profoundly affect the flash memory gigabyte is about $200 in 2004, says Kumar. This is the main reason you have folks like Toshiba, Hitachi and Maxtor putting a lot of their resources into PMR.

Here are some other data storage technologies currently under development.

  • Millipede: IBM at its Zurich, Switzerland, Research Center, is working on the development of a radically new storage concept, based on mechanical nanotechnology. Dubbed the “millipede,” the device is able to record and read patterns similar to Braille ode: raised dots and depressions, formed on a polymer layer, each dot of nanometric dimensions.
  • Patterned Media, where the magnetic bit allowed locations are preordained when manufacturing the disk
  • Self-organized magnetic array media, or SOMA, based on very regular aggregates of nanoparticles
  • Heat-assisted magnetic recording, or HAMR, a variant of PMR touted to enable recording densities of 1,000 Gb/in(2), or approximately 12 times higher than in any product in 2004.
  • (Adapted from Kumar’s HDD Business Model: from Linear Growth to Product Diversity report of June 30, 2004, Icon courtesy Elpincho/Xicons)

    Realted reading: The Disk Drive Conundrum

    By Om Malik

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