Interesting:
http://www.computerworld.com/hardwaretopics/storage/story/0,10801,78946,00.html
Analysts and storage vendors said one of the key benefits of the serial SCSI interface technology that's due to start being built into disk drives this year is its compatibility with the Serial Advanced Technology Attachment (ATA) interface used in low-end drives.
That will enable the development of hybrid storage arrays that let users mix and match high-performance SCSI drives for use in transaction processing applications with lower-cost Serial ATA devices for data backup and recovery procedures. The two disk-drive technologies could also be plugged into a single backplane within servers, according to drive vendors.
http://www.computerworld.com/hardwaretopics/storage/story/0,10801,78946,00.html