Serial-Attached Scsi Device Interface; Serial Ata Ii Features - Lenovo ThinkServer RD240 Software User's Manual

1.2

Serial-attached SCSI Device Interface

1.3

Serial ATA II Features

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 II, SCSI, and Fibre Channel, 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 it
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 II protocols use a thin, 7-wire connector instead of the 68-wire
SCSI cable or 26-wire ATA cable. The SAS/SATA II connector and cable
are easier to manipulate, allow connections to smaller devices, and do
not inhibit airflow. The point-to-point SATA II architecture eliminates
inherent difficulties created by the legacy ATA master-slave architecture,
while maintaining compatibility with existing ATA firmware.
The SATA bus is a high-speed, internal bus that provides a low pin count,
low voltage level bus for device connections between a host controller
and a SATA device.
The following list describes the SATA II features of the RAID controllers:
•
Supports SATA II data transfers of 3.0 Gbits/s
•
Supports STP data transfers of 3.0 Gbits/s
•
Provides a serial, point-to-point storage interface
•
Simplifies cabling between devices
Serial-attached SCSI Device Interface 1-3