Author:
Tonya Comer, Product Marketing Manager
HP
Serial Attached SCSI (SAS) incorporates differential signaling, which reduces the effects of capacitance, inductance, and noise experienced by parallel SCSI at higher speeds. SAS links are full duplex (Figure 1); they send and receive information simultaneously, thereby reducing a major source of latency inherent in parallel SCSI. Unlike traditional parallel SCSI that shares the bandwidth of one bus with many devices, SAS is a point-to-point technology that provides maximum bandwidth to each device, greatly improving scalability and performance. All end devices (initiators and targets) have a connection point called a port. Expanders and HBAs have multiple ports. A port can contain one or more transceiver mechanisms, or phys. A narrow port has only one phy, while a wide port has more than one phy.
