[OT] Life expectancy of powered down hard drives....

[Roland Smith]

On Tue, Sep 06, 2005 at 11:36:52PM +1000, Norberto Meijome wrote:

> I read somewhere (sorry, cant remember where) that hard drives fail if 
> not powered up every so often (not sure of time frames, but the 
> discussion was about tapes still being better for backups than hard 
> drives if planning for long term storage). It was also mentioned a 
> "knock on the centre of the drive" to bring it back to life (??).
> 
> How much truth is in this? I have EIDE drives that I havent used in 
> years and I just tested them and they work fine...but again, I've had an 
> instance of a new drive, used twice to backup some info and then left 
> untouched for 10 months, and it wouldn't even spin up...

When a disk spins down, the heads move to the landing zone, stop
floating on an air-cushion that forms when the platters are spinning and
come in contact with the platters.

So the disk platters are lubricated to prevent wear and tear during
stops/starts. Now in the past these lubricants used to become sticky
over time, preventing the drive from starting up. I'm not sure if it is
still a problem these days; my workstation is on 24/7.

> Does this affect SCSI drives? I suppose it would be more likely to 
> affect desktop-quality IDE / SATA drives...

The difference between SCSI and IDE is in the controller. The underlying
technology is the same. SCSI drives might be built to higher
specifications though.

The only real solution to the parking problem that I'm aware of is IBM's
load/unload technology. See
http://www.pcguide.com/ref/hdd/perf/qual/featuresHead-c.html

Roland
-- 
R.F.Smith (http://www.xs4all.nl/~rsmith/) Please send e-mail as plain text.
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