Serial Attached SCSI (SAS)

Serial Attached SCSI (SAS) , is a computer bus technology primarily designed for transfer of data to and from devices like hard drives, CD-ROM drives and so on. SAS is a serial communication protocol for direct attached storage (DAS) devices. It is designed for the corporate and enterprise market as a replacement for parallel SCSI, allowing for much higher speed data transfers than previously available, and is backwards-compatible with SATA drives. Though SAS uses serial communication instead of the parallel method found in traditional SCSI devices, it still uses SCSI commands for interacting with SAS End devices.

The SAS protocol is developed and maintained by the T10 committee. Serial Attached SCSI is comprised of three transport protocols: Serial SCSI Protocol (SSP) - Supporting SAS disk drives; Serial ATA Tunneling Protocol (STP) - Supporting SATA disks; Serial Management Protocol (SMP) - for managing SAS Expanders