Digital BW, The Print

The theory behind 'not turning devices off' comes primarily from the
heat induced expansion/contraction of cards/chips in sockets
eventually working their way partially out of the socket, causing
failure or erroneous operating.
Due to the nature of a HDD having many moving parts which can wear out
(bearings, motor, solenoids) over time, I suggest this negates the
benefits to the controller pcb (and it's components) of being
constantly powered on.

You'll find "compelling" opinions on both sides of this argument.  
It's good to not overheat the drives, but spinning up is also a stress
on the drive motor.  Personally I let the drives spindown after an
hour -- when I'm actually using my computer this almost never happens,
but it lets the drives spindown and cool off overnight or if I'm gone.
  I also set the drives this way on all the systems I help folks with
-- and have outstanding reliability with those systems.

Hard data is difficult to come by.  What you CAN find if you look at
the detailed specifications for any drive are rated start/stop cycles
(usually around 50,000 minimum), service life (typically 5 years), and
sometimes a very impressive (but misleading) MTBF specification.   The
most important specification in terms of this discussion is the rated
start/stop cycles.   For example, I just looked up a WD 500GB Caviar
(SE16 SATA-II) -- it's rated for a minimum of 50,000 start/stop
cycles.   Note that if it spun up once an hour it would be about 6
years before it got to this number!!  (and that's a minimum).   And a
drive set to spin down after an hour is unlikely to spin down more
than a couple of times a day -- I'd guess mine spins down 1 or 2 times
during the day and at night; to be safe I'll say 6 spinups a day -- so
I'll reach the minimum rated number in about 24 years !!   I suspect
I'll replace my drives before then :-)   And wear from other factors
-- heat generation, power-on hours of the spindle motor, etc. will be
much lower than it would be if the drive was constantly on.

By the way, notebook drives are designed for far more start/stop
cycles than desktop drives, since they are likely to spinup/spindown
much more.   Some IBM notebook drives have head load/unload cycle
ratings (they use a slightly different technology to store the heads,
so this spec is functionally equivalent to start/stop cycles) of
300,000 cycles !!

As far as power-related issues with PC's, I think the two most
important things you can do are (a) ensure the system has adequate
power with plenty of "headroom"; and (b) be sure the system has a UPS
==> systems that are never exposed to unplanned, sudden power outages
have FAR fewer problems than those that are.   Doing this will
probably have a far greater impact on your hard drives' life than
whether or not you set them to spindown.

Best
Howard



--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Dan Girellini
<drg@...> wrote:
>
> ginnylady33 wrote:
> 
> >2-They are mainly in sleep mode or whatever it is called. They are not
> >spinning all day long.
> >  
> >
> 
> Actually, starting and stopping is rougher on the drive.  Keeping them
> spinning all the time will increase their life (at the expense of noise
> and power).
> 
> I strongly agree with another poster's suggestion to switch brands or
> otherwise figure out what's wrong.  You're failure rate is way to high.
> 
> Dan.
>