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.

Serial ATA drives are mainly used in desktop systems now but are finding their way into disk arrays that store fixed data or provide nearline storage capabilities. With the advent of serial SCSI, a company could configure arrays to store transactional data on disks equipped with that interface while putting check images or financial documents on Serial ATA drives, said John Joseph, vice president of marketing for the server products group at Maxtor Corp. in Milpitas, Calif.

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scsi drives are expensive. (hows that for a comment?)