One more thing to watch out for at data centers - fire drills

Stephen Satchell list at
Sun Sep 18 13:45:51 UTC 2016

On 09/17/2016 02:43 PM, Larry Sheldon wrote:
> My experiences were back in the days of washing-machine class disc
> drives and they were a 4-hour fire-wall away, but I don't remember them
> being impacted. (I can't believe that I was allowed to conduct a test
> with them running, but I don't remember shutting them down.)
> I wonder if orientation mattered--mine were all platters parallel to the
> floor, I wonder if the damaged ones were parallel to the wave front.

If you watched the video of the guy who screamed at his disk drives to 
cause temporary faults, the JBOD had its platters horizontal to the floor.

One of the reason the washing-machine-sized CDC Storage Module Drives 
weren't affected by high noise level is the sheer beefy mass of the head 
assembly and the voice coil.  Also, the track spacing on the platters of 
those drives was far less dense, so any noise-induced mis-tracking would 
be minuscule, and easily handled by said voice-coil's position-error 
system.  The heads were larger, as well as the head arms.  In this 
situation, mass is your friend.

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