2019-12-31

<p>
I had a SATA HD which, after 11.5 years of continuous service, failed to
restart after a power failure. I could hear the motor spin, the head make a
clicking sound, and then the motor spin down; this repeated for a few times
before reporting an error. No luck changing the orientation of the drive,
or gentle or less gentle shaking, or various folklore remedies such as a
journey in the freezer.

<p>
Eventually I realized that the head is moved using a coil and a strong
magnet, and so perhaps a bit of perturbation the magnetic field could
influence the movement of the head in some magical way.

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<img src="hd-magnet.jpg" style="float:right; max-width:50%;">
So I took a moderately strong magnet (the small tray in the picture,
$1.50), and moved it around on the case of the drive.
In some positions the head did not move, in some others it kept clicking,
but somewhere in between I could hear the joyful noise of the head moving
properly during the probe phase thus letting the drive spin up.

<p>
At that point, I could "dd" the content to a new drive and recover the system.

<p>
No data loss, apparently.

<p>
Best $1.50 ever spent!