> I suspect those URE numbers are made by the manufacturers figuring out they can be sure the disk will do 10^14, but they don't actually try to find the real number because 10^14 is good enough.
I am inclined to agree. However, I have one thought to the contrary. When a mechanical drive is failing, you tend to have debris inside the drive hitting the platters, causing damage that creates more debris, accelerating the drive’s eventual death, with read errors becoming increasingly common while it happens. When those are included in averages, the 10^14 might very well be accurate. I have not done any rigorous analysis to justify this thought and I do not have the data to be able to do that analysis. It is just something that occurs to me that might justify the 10^14 figure.
I am inclined to agree. However, I have one thought to the contrary. When a mechanical drive is failing, you tend to have debris inside the drive hitting the platters, causing damage that creates more debris, accelerating the drive’s eventual death, with read errors becoming increasingly common while it happens. When those are included in averages, the 10^14 might very well be accurate. I have not done any rigorous analysis to justify this thought and I do not have the data to be able to do that analysis. It is just something that occurs to me that might justify the 10^14 figure.