Hardware User's Guide

Intel® SAS Controller RS25GB008 Hardware User’s Guide 1
1 Overview
The Intel
®
SAS Controller RS25GB008 is a high-performance, intelligent PCI Express*
2.0-compliant SAS/SATA II controller offers reliability and high performance. This is an
ideal solution for the large capacity storage needs of mid to low-end servers and
workstations for use by workgroups and departmental-sized organizations or individuals.
Intel
®
SAS Controller RS25GB008 offers a cost-effective way to attach physical drives to
a server for storage.
As the second generation PCI Express* storage adapters, the Intel
®
SAS Controller
RS25GB008 address the growing demand for increased data throughput and scalability
requirements across mid to low-end servers and workstations.
The SAS controller controls eight external 6-Gb/s SAS/SATA ports through two SFF-
8088x4 Mini SAS connectors and allows the use of expanders to connect upto 1024
devices. Note that all expander features will not be available at product launch. For more
information about the use of expanders, see the ANSI SAS Standard, version
2.0 specification.
SATA and SAS are serial, point-to-point, device interfaces that use simplified cabling,
smaller connectors, lower pin counts, and lower power requirements than parallel SCSI.
Benefits of SAS and SATA
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 than 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, connect to smaller devices, and do not
inhibit airflow. The point-to-point SATA architecture eliminates difficulties created by the
legacy ATA master-slave architecture, while maintaining compatibility with existing
ATA firmware.