[wtallis]

The endurance figures for hard drives are probably derived from the rated number of seek operations for the heads, which is why it doesn't matter whether the operations are for reading or writing data. But that bakes in some assumptions about the mix of random vs sequential IO. And of course the figures are subject to de-rating when the company doesn't want the warranty to cover anything close to the real expected lifespan, especially for products further down the lineup.