Intel SRCSAS18E User Guide - Page 22

SAS/SATA Device SAS/SATA Device SAS/SATA Device SAS/SATA Device SAS/SATA Device SAS/SATA Device SAS/SATA Device SAS/SATA Device Port 0 Port 1 Port 2 Port 3 Port 4 Port 5 Port 6 Port 7 32-bit Memory Address/Data Bus PCI Express* RAID Controller I2C Interface Flash ROM/ PSBRAM/ NVSRAM I2C PCI Express Interface Figure 1. Example Direct-Connect Application Benefits of SAS SAS is a serial, point-to-point, enterprise-level device interface that leverages the proven SCSI protocol set. SAS is a convergence of the advantages of SATA, SCSI, and FC, and is the future mainstay of the enterprise and high-end workstation storage markets. SAS offers a higher bandwidth per pin than parallel SCSI, and improves signal and data integrity. The SAS interface uses the proven SCSI command set to ensure reliable data transfers, while providing the connectivity and flexibility of point-to-point serial data transfers. The serial transmission of SCSI commands eliminates clock skew challenges. The SAS interface provides improved performance, simplified cabling, smaller connectors, lower pin count, and lower power requirements when compared to parallel SCSI. SAS controllers leverage a common electrical and physical connection interface that is compatible with Serial ATA technology. The SAS and SATA protocols use a thin, 7-wire connector instead of the 68-wire SCSI cable or 40-wire ATA cable. The SAS/SATA connector and cable are easier to manipulate, allow connections to smaller devices, and do not inhibit airflow. The point-to-point SATA architecture eliminates inherent difficulties created by the legacy ATA master-slave architecture, while maintaining compatibility with existing ATA firmware. 3 Intel® RAID Controller SRCSAS18E User's Guide