Ed’s Threads 060915
Musings by Ed Korczynski on 15 September 2006Middle-life Crisis for the HDD; Can’t Afford a Flashy Sports CarSeptember 13, 2006 was the 50th birthday of the hard-disk drive (HDD), and hundreds of people gathered to acknowledge RAMAC’s birthday with a panel of luminaries at the Diskcon tradeshow in Santa Clara, California. Floppies and tapes have come and gone, and the HDD is still the champion of magnetic storage with theoretical room to increase density by yet another factor of 100 over current records. Flash chips may take away much of the <1” form-factor market, but chips need backup so HDD demand is expected to only increase. Despite all of this, HDDs are commodity products with very thin profit margins.
One of the birthday celebration anecdotes shared by Hitachi Global Storage Technologies, the current custodian of all that began humbly in a rented lab space at 99 Autumn Street in downtown San Jose, included details that RAMAC’s first magnetic recording media were iron-oxide bits. Rust particles in solution strained through a pair of nylon stockings for size control prior to spin casting upon the disk was part of the first manufacturing process for RAMAC. It worked…though head-crashes due to stray particles were not uncommon.
Ever since RAMAC, it’s been longitudinal recording with bits stored length-wise, but we are finally getting close to the minimum bit size. If we try to magnetize smaller magnetic domains they just don’t “hold” in a single-layer. However, we can add another layer to the disk media, and then use perpendicular recording between layers to store even smaller bits. Perpendicular recording technology was used with magnetic drums over 100 years ago, and 50 years after it was first considered for disks, it is now in use.
The Magnetic Disk History Center maintains wonderful archives such as
Al Hoagland’s 2002 IEEE Transactions on Mangetics paper, which recounts the early years (1955-1960) of developing the modern flying recording head and informs us that the initial prototypes used perpendicular recording. Censtor did some work with perpendicular in the late 1980s to mid-1990s, but it just wasn’t needed then. The HDD biz has been running on thin profit margins for decades; play it safe, keep the same manufacturing methods, you can’t afford the flashy sports car.
Giant- and Colossal-Magneto Resistance thin film heads extended relatively simple coil designs, which combined with reduced flying heights over smoother media surfaces to push the limits of longitudinal recording. Now perpendicular multi-layer media with 100Gb/in2 density is shipping today, 300Gb/in2 have been shown in R&D;, and 500Gb/in2 seems to be the current limit. Recording at 230Gb/in2 density which would enable a
one terabyte 3.5-inch drive, according to Hitachi.
Shrinking domains beyond perpendicular requires revolutions in both the media and the head: discretely engineered ~20nm grains for media, and thermally assisted writing using a nano-scale laser integrated inside the write-head. Thermally-Assisted Recording (TAR) of patterned media should allow 100-Terabyte drives in 10 years. Serious investments in nanotechnology R&D; and sophisticated manufacturing equipment will be needed.
The HDD biz has grown to a point where
equipment supplier Veeco’s CEO Ed Braun observes, “An equipment supplier base is almost viable, if we don’t listen to Wall Street.” Braun showed forecasts that the HDD industry will invest ~10% of revenue in capital equipment spending, increasing from ~US$3B to ~5B over 2005-2010. This is good, but the fun sports car is probably still out of reach.
— E.K.
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060915: HDD Mid-life Crisis; Can't Afford a Flashy Sports Car
