Tracy R Reed wrote:
I have heard for years that SCSI drives get the platters and drive heads that QA'd higher or some such thing. I have always wondered if that was true. I am skeptical.
It is true that SCSI drives get QA'd better at the high end. I don't know about SCSI drives at the lower end (ie. 7200 RPM).
Besides, it really isn't normally the platter that gives out on a drive. It is generally the motors or head. Heat causes the motors to burn out or the semicondtors in the head to fail.
However, a platter failure is an amazing thing to see. 15000 RPM's of angular momentum turned into linear kinetic energy used to do an *amazing* amount of damage to the casing. It may no longer be quite so spectacular now that they use glass platters.
The main reason for stronger QA on SCSI drive is that they push the thermal envelope *much* harder with 15K RPM drives. Aerodynamic drag is proportional to v^2. At 15000 RPM, aerodynamic drag (the primary cause of platter heat) is 4X what it is at 7200RPM. The motor has to be 4X as strong. And, for SCSI, things are generally qualified for continuous usage duty cycles.
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