Re: OT: used hard disks

On 2 July, 12:32, "neverwas" <notahasb...@all.all> wrote:
> > As others have pointed out it's only really high temperatures that
> > kill
> > modern drives
>
> I don't think anyone has yet pointed to the Google study
> (http://labs.google.com/papers/disk_failures.pdf) which underlined this
> (and possibly required even more emphasis on the *really* high):
>
> "Failures do not increase when the average temperature increases. In
> fact, there is a clear trend showing that lower temperatures are
> associated with higher failure rates. Only at very high temperatures is
> there a slight reversal of this trend".
> --
> R

The google test was WAAAAAY too simplistic on the temp front, but then
given a sample of 100k units that is understandable.

e.g. google took SMART data which said "disk 87564 is currently at
44'C"

Which is all very well, but ...

1/ the the temp sensor is no more accurate than any other LM type mobo
temp sensor.

2/ the temp sensor reading assumes the entire physical drive is at the
same temperature.

3/ the temp sensor is not placed in the worst hotspots.

a thermal image of a hard disk shows just as much difference as of a
person outside in winter in warm clothing, in practice an "average"
SMART hard disk temperature reading of say 55 degrees can easily mean
that certain components are running at 90 degrees or more.

when you remember that the point at which electronics "burns up" is
usually around 150 to 175 degrees C, you can see that it is easy to
get that 90 degree hotspot up to burnout point simply by wrapping it
is something insulating, like fluff.

Laptop type HD will get rid of heat better and thus tolerate allegedly
higher temperatures, because the MAXIMUM distance from any point in
the disk to the outside is about 4mm, as opposed to 10mm or more for a
full size disk, thin stuff dumps heat better than blocks.

I'll say it again, I have NEVER had a heat death on one of my own hard
disks on stuff I build for myself, because I ALWAYS have forced air
cooling on both sides of the HD on everything I build.
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