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Photo by MatteX / CC0

I noticed this with an older laptop a few years ago… it was working fine. As in, there was no application on it that was significantly slow that made me wish for a new one. That wasn’t always the case with this laptop. Before, it would be slugging, noisy, unreliable.

What changed everything was switching to a solid state drive. I fell in love with SSDs shortly after they came out because moving from a standard hard drive to an SSD is night and day difference. Beyond just speed of data transfer, the reliability of SSDs means they can last for orders of magnitude longer than their rotating counterparts.

A disk that boasts 7200 RPM subjects the edges to huge accelerations. Assuming 2.5 in drive (radius), let’s do some back of the napkin calculations.

The velocity on the edge is…

Rotations per second = 7200 / 60 = 120

Circumference = C = 2 * π * R = 2 * π * 0.0635 m = 0.399 m

So speed = 120 rotation / s * 0.399 m / rotation= 47.9 m / s

Acceleration around a circle is a = V²/R = (47.9 m/s)² / 0.0635 m = 36,100 m/s²

Even a small amount of mass over type can warp the drive and cause it to spin out of alignment. Mechanical things eventually break. Solid things are subject to heat stresses, but those can be controlled more easily.

The result of switching is now a laptop, five years on, can operate nearly as well as it did the day it was used. It makes me think of how much landfill space was saved as a result of an update to hard drives.

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