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Technology Stocks : Disk Drive Sector Discussion Forum -- Ignore unavailable to you. Want to Upgrade?

To: Robert Douglas who wrote (7519)	12/11/1999 6:58:00 PM
From: Stitch	Read Replies (1) \| Respond to of 9256

Re: Superparamagnetic Limits: The current projections of a "superparamagnetic limit" is around 100 Gb/sq.in. We need to keep in mind, however, that not long ago it was felt to be 40 Gb/sq.in. Assuming the industry keeps to a 100% per year rate of increasing areal densities then we hit the supposed limit by 2003 - 2004 (shippable products). Over the past 10 years or so both track density and linear density have averaged about 25% per year increases. However, continued scaling of linear density leads to media grain size that is too small and that becomes problematical from a thermal decay standpoint (the so-called superparamagnetic limit.) While increasing density in either dimension requires smaller grain size, to increase linear density requires a thinner magnetic layer (thus the thermal decay problem). This is the reason that the DD industry is chasing much higher track density, seeking to lower the bit aspect ratio from around 15:1 (3.0 uM to 0.2 uM) to 4:1 (0.17 uM to 0.04 uM) to achieve 100 Gb/sq.in. There is a whole host of hurdles associated with achieving this, I am going to avoid a discussion about increasing media coercivity, maintaining anisotropy constants, and improving grain distribution. Ditto re: head flying heights of 6 nano meters and read gaps of 30 nano meters. I also do not want to bore you with a discussion about disk flutter or "eddy currents" that will interfere with read/write SNR. Likewise, I wish to avoid mentioning much about the 10 nano meter domain spacing required and the problems of adjacent track interference (fringing) brought on by very high TPI. Finally, I am loathe to discuss the achievement of much higher data rates but I will mention that the industry is presently sampling 600 Mb/s channels while, in order to support the current projected density curve, we need a channel that performs at 1 Gb/s by 2001 which presents a whole other set of challenges. So maybe the overall challenge is too great to be a simple "innovator's dilemma" of too much too soon. I should not have been glib in my previous remark about the superparamagnetic limit nor do I want to trivialize the challenges. One question is how is the industry is going to support the R&D neccessary in the face of continued dwindling prices/profit? I do not think there is another technology on the radar screen that is going to simply displace magnetic storage within the next few years. Someone may have a paradigm-buster on the drawing boards but if they do I don't know about it. (Please, do not write to me about holographic recording.) I actually think that what must happen is the advent of new storage applications assisted by the broadening of available bandwidth and emergence of a host of new appliance-centric toys & tools. That and some consolidation as well as continued re-invention of business models. Maybe we are seeing the beginning of the end of the old PC/OEM market and anew one will emerge? I believe that ultimately, the consumer must pay for the innovations required. Forgive my earlier, rather glib, reference to the paramagnetic limit to which you responded. I think it is a great deal more important to keep our eyes on Tivo & ilk while listening closely to the guys that can tell us more about bandwidth deployment. Best, Stitch

To: Robert Douglas who wrote (7519)	12/12/1999 11:18:00 AM
From: Z Analyzer	Read Replies (1) \| Respond to of 9256

<<When Steve Luczo said the other day that areal densities could increase 100% a year for the next few years, I was quite disheartened. As Todd said once, this industry is getting killed by its own technology feats.>> True, it hurts on the PC front until broadband increases necessary storage but it comes with innummerable benefits-prolonging the life of the DD vs flash and if Gilder is correct, resulting in utilization of tiny DD in lieu of flash in future hand held products. Also, audio and visual storage are a huge opportunity and I assume that storing extensive quantities of HDTV full motion video takes us right up to the paramagnetic limit, even in a multi-platter drive. -Z