Rich Freeman on 13 Apr 2016 11:41:14 -0700

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Re: [PLUG] Desktop Support ?

On Wed, Apr 13, 2016 at 1:35 PM, Keith C. Perry
<> wrote:
> Things aren't quite that clean- once electrical systems go out of spec (e.g.
> under or overvoltage how that is caused... e.g. source, parasitic, cascading
> events creates a dynamic failure) all bets are off since it is impossible to
> detect and trap multi-system faults unless you have external supervisory
> circuitry in place.

Is there any kind of study on this?  That is certainly not my
expectation for a hard drive, and (not being an EE) I'd think that you
could design a circuit that stopped writing when the voltage supply
dropped.  The drive already has the ability to retract the heads after
a power failure, so it has some kind of capacitor/etc for such things.
If the drive is retracting the heads on a power failure that would
also preclude it from writing anything while those heads aren't over
the drive.

It sounds like somebody just needs to boot a rescue disk and fsck the
filesystem and see what is going on.  If it looks serious I'd probably
clone the drive before attempting repairs.

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