Suffice to say IDE is not a protocal like SCSI it is a
DEVICE
interface and is somewhat uncooked at that.
That's a fairly disingenuous claim. Both SCSI and IDE have a "device
interface" (physical layer) and a "protocol" (interpretation of bytes
in various registers and phases).
IDE in fact has two different protocols, ATA and ATAPI; ATAPI protocol
is by design very similar to SCSI protocol.
As of SCSI 3, there are *many* different SCSI physical layers and
several different protocols.