Evolution In Hard Disk Drive Technology: SAS And SATA

Two new serial interfaces to disk drives are replacing two venerable parallel interfaces. The advanced technology attachment (ATA) interface will be succeeded by serial ATA (SATA), and the small computer system interface (SCSI) will be replaced by serial attached SCSI (SAS). These new point-to-point technologies provide greater dedicated bandwidth and smaller connectors, and SAS technology supports both SAS and SATA disk drives. While Fibre Channel interface technology will continue to be leveraged in the enterprise storage marketplace (specifically storage area networks), IDC believes that SAS technology also will find its place in this market. SAS and SATA disk drives will appear in the storage middle market, and SATA disk drives will become a wholesale replacement for any ATA drive that is used in PCs, workstations, and low-end servers.

Continuing growth in the demand for storage capacity and performance is driving the need for faster point-to-point disk drive interfaces, as opposed to shared bus topologies. In addition to traditional categories of data, such as transactional data, reference data has emerged as a new class. Unlike transactional data, which is constantly changing and updated regularly, reference data remains unchanged after it is written. Among the many examples of reference data are corporate email, multimedia presentations, digital voicemail, and digital images.

Storage systems for reference data need high-capacity disk drives, low cost per gigabyte, and only modest storage system performance. Using new SAS and SATA disk drives, OEMs can design storage systems that mix higher-performance, higher-cost SAS drives with higher-capacity, lower-cost SATA drives. These next-generation storage products will support both performance-intensive and capacity-intensive enterprise storage needs.

While IDC believes that OEMs and customers will find next-generation storage products based on SAS and SATA valuable, some challenges lie ahead. First, the multiple suppliers of SAS and SATA products must meet their objectives for interoperability and their road maps for improved performance. Second, OEMs must accept and trust the new technology, and the products that drive vendors ship using SAS and SATA must meet customer expectations for cost, performance, and ease of use. Finally, SAS and SATA must find their place alongside an incumbent disk interface and storage interconnect technology: Fibre Channel.

IDC encourages storage OEMs and storage system users to evaluate the deployment of new SAS and SATA technologies. These successor interfaces to SCSI and ATA will be important players in the storage market over the months ahead.