More than an interface: scsi vs. ata

This paper sets out to clear up a misconception prominent in the storage community today, that SCSI disc drives and IDE (ATA) disc drives are the same technology internally, and differ only in their external interface and in their suggested retail price. The two classes of drives represent two different product lines aimed at two different markets. In fact, both classes contain a range of products that address a variety of features and usage patterns beyond simply the interface used to talk to the device. The target market and final product specification are taken into account from the earliest design decision through the manufacturing and testing process. This paper attempts to clarify the differences by illuminating some of these design choices and their consequences on final device characteristics. This will hopefully allow the community to build better storage systems with better knowledge of the trade-offs being made and the performance characteristics that result.