On Fri, 9 May 2008, Ali, Saqib wrote:
| >        Edwards said the Seagate hard drive -- which was
| >        about eight years old in 2003 -- featured much
| >        greater fault tolerance and durability than current
| >        hard drives of similar capacity.
| I am not so sure about this statement. The newer drives are far more
| ruggedized and superior in constuction. For e.g. the newer EE25 are
| designed to "operate" @
| 1) Operating temperatures of ?30?C to 85?C
| 2) Operating altitudes from ?1000 feet to 16,400 feet
| 3) Operating vibration up to 2.0 Gs
| 4) Long-duration (11 ms) shock capability of 150 Gs
| where as the older ST9385AG:
| 1) Operating temperatures of 5? to 55?C (41? to 131?F)
| 2) Operating altitudes from ?1,000 ft to 10,000 ft (?300 m to 3,000 m)
| 3) Operating vibration up to 0.5 Gs
| 4) shock capability of 100 Gs
Well, he's the guy who actually recovers data from the things.

I think the main issue here is that the older drives used much larger
magnetic domains on the disk, inherently providing a great deal of
physical redundancy, for those with the equipment to make use of it.
Also, the encodings were much simpler and the controllers much less
sophisticated.  Today the controller/head/disk are effectively a single
unit, tightly coupled by complex feedback loops.  The controller writes
data that it will be able to read, adjusting things based on what it
actually reads back.  I've been told - I can't verify this - that in
practical terms today, if you lose the controller, the data is toast:
Another nominally identical controller won't be able to read it.

                                                        -- Jerry

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