These days, I think it's often true that ATA and SCSI drives are very similar internally. Some manufacturers have stated this fact, when producing two different interfaces for the same drive. I'm not sure what the current state of the technology is these days, but previously SCSI had a strong advantage in managing multiple storage devices simultaneously. Previously SCSI devices often had superior mechanical design/testing, and better predictive logic for multiple task management, seeking, and overall throughput. Since IDE has been using better DMA systems, and high speed serial transfer has come a long way in the past several years, I'm not sure how much of a difference there is any more. At least if one is using a single drive, I don't think there is much (any?) advantage in using SCSI. That wasn't really true 10 to 15 years ago, but IDE has definitely improved a lot. I have read that high priced SCSI drives are designed/tested to have much greater longevity and reliability for critical server applications, but who knows?
Is anyone here involved in storage design?
-Oli