> I am becoming more and more convinced that hard drive reliability is linked to the batch more than to the individual drive models themselves.
Worked in a component test role for many years. It's all of the above. We definitely saw significant differences in AFR across various models, even within the same product line, which were not specific to a batch. Sometimes simply having more or less platters can be enough to skew the failure rate. We didn't do in depth forensics models with higher AFRs as we'd just disqualify them and move on, but I always assumed it probably had something to do with electrical, mechanical (vibration/harmonics) or thermal differences.
Worked in a component test role for many years. It's all of the above. We definitely saw significant differences in AFR across various models, even within the same product line, which were not specific to a batch. Sometimes simply having more or less platters can be enough to skew the failure rate. We didn't do in depth forensics models with higher AFRs as we'd just disqualify them and move on, but I always assumed it probably had something to do with electrical, mechanical (vibration/harmonics) or thermal differences.