[RndTbl] hard drive failure curve

[Trevor Cordes]

OK, so you know how many (most?) computer components' failure rates
follow the "bathtub curve":

http://users.ece.cmu.edu/~koopman/des_s99/sw_reliability/Image1.gif

They either die quickly due to egregious manufacturing faults, or live
a long time (near 0% failure rate), and then all start dying as they get
really old.

The bathtub curve occurs in tons of places, like with a simple light
bulb.

As per my experience (probably dealing with over 1000 drives
personally), and google's studies, as well as anecdotal information,
hard drives are different.  The failure rate seems to be bathtub-ish.
The initial failure rate is fairly bathtub.  But the useful-life period
is at a much higher level and seems to grow slightly, meaning instead
of dropping to near-zero failures during useful life, they drop to
around 15% failure rate each year, mostly independent of age.  Then,
in the old-age phase they seem to ramp up much slower towards death.
It's not a hockey-stick right edge, it's more a constant gentle hill
slope.  We all have seen many drives that are still running after 8,
10, 20 years.  In fact, it seems more of a survival of the fittest
system (maybe like turtles?), where once they live to a certain age,
many go on to live far beyond the average.

Anyhow, my question is, what else in the non-computer world has a
failure graph like hard drives?  Something easy for a neophyte to grasp.
Normal bathtubs have lightbulbs.  What analogy can be used for hard
drives?  I haven't been able to think of any!

Surely there must be one??