My 386 laptop HD is dead. The solution: an IDE to CF adapter

Billy Pettit Billy.Pettit at wdc.com
Thu Jan 25 15:56:58 CST 2007


Brad Parker wrote:

Heh.  I remember someone asking me (at work) if a 3.5" ST-506 drive
would work in zero G.

I ask where it was installed and they said a KC-135 :-)

Apparently someone wanted to use one in the "vomit comet"...

and apparently it worked (at least they never complained that
it didn't)

I don't know how high those where pressurized, but I'd guess
around 8000ft.  No doubt the old drives didn't need as much
air density; the flying height was not that low.  I have no
idea how air pressure affects the boundary layer over the
surface - I assume less density translates to less drag and
then to a lower flight.

-brad

----------------------------------------

Cold is not nice to disk drives.  More than flying height, the mechanical
parts become stiffer and don't flex correctly.  Bearings becomse stiff and
generate vibration.  Seals shrink.

A lot of work is being done on self heating.  This will be needed when
drives go into cell phones in the near future.  The drive uses the
electronics to get to a certain temperature before loading the heads off the
ramp.

Air pressure does affect the boundary layer, especially at high RPM.  There
comes a point where it goes negative and sucks the heads down.  The testing
I saw showed this somewhere around 18-20K RPM.  For drives on the market
today, flying height is controlled and compensates for altitude.

As for cell phones and hard drives, yes, I know that Flash is getting
cheaper and is in a surplus situation right now.  And with 4 level cells
coming along, the cost per bit is going down.  But hard drives will still be
used in cell phones, because those devices have exploding storage
requirements, thanks to new features.

Look at Apple's iPhone, with all the bells and whistles.  And only 8GB of
storage.  They've sold millions of iPods with 20, 30, 40, and 60GB of
storage.  Those users will demand more storage as they use the iPhone.


Cell phones do now and will in the future use hard drives.  Cold is one of
the biggest unsolved problems.  Shock is looking so-so with free fall
sensors.  Power cosumption is the biggest detractor.  But a hybrid with a
big cache could solve that.

Billy




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