[RndTbl] hard drive failure curve (John Donovan)

JD jd at wcgwave.ca
Fri Sep 5 15:55:37 CDT 2014

I am glad a visual was put, for the meaning of 'Bathtub Curve'. I am no
stats guy, but I can dig a Bell Curve, nine times out of ten, and I
groove to a good Fletcher-Munson Curve with regularity. The idea of a
Bathtub Curve makes me feel .. bubbly.

However, when it comes to interpreting Hard Disk Drive Mortality Rates,
I think there are some more factors to be considered. 

I've sold at least a thousand, and worked on almost as many more drives.
Mostly from the latter case, I have come to form some impressions,
having seen quite a lot of what most storage users would call 'very
private' information. So I end up having an opinion or two, for this.
Ok. Three. 

It's come up in meetings before, but bears repeating: 
Google released findings saying those common-off-the-shelf IDE drives
they'd been running (!droves of drives!) did NOT fail (any differently)
when their environs let them run rather hot. 

So, now, if the much dreaded Heat is not our bugbear, what gives with
hard drives dying without our permission?

We are not children, here, so let's skip past the usual physical
interferences, like shock, vibration, infra-Gaussian warbling, ball-pein
hammers and gamma particle storms. 

I believe the real answer is easily explained. 

Hard disk drives are marvels of precision machining, spartan firmware,
inspiring ASIC chippery and wildly fast signal processing when those
bits zing by under the 'flying' heads.

These drives are conceived in unusually clean rooms. Some say classy. I
say immaculate. And their nascence in mangers of such purity does not
prepare them for life on the streets. 

I choose to believe that most hard disk drives feel a bit excited when
they are first written with their very own system image: 
"Yes. I'll remember that for you. Yes. Yes." .. etc. 

At this stage, all is as intended.

Soon enough, our earnest little friends are further coddled into various
systems, for shipment worldwide. Away from their siblings, they are now
out on their own, and are still eager to remember & retrieve lots more
for us, in mere milliseconds! 

Then the box opens and it's up & onto the new owner's desktop!
Happyhappy! Joyjoy! 

But alas: As if it's not disappointing enough for them to finally learn
which operating system the majority of these drives have to host, add to
that, that a certain number of them will soon be asked to store untold
horrors; filth and crud which their owners call 'data'. Bad recipes.
Panda porn. Political opinions. Twittertwattwaddle. Fwd'd Fwds .. yucky
stuff. Blech. 

Think about it. (or maybe .. don't).

Marvel as we may, it is _us_ who kill them: 
Hard drives die of abject depression, chronic bewilderment, and

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