SAS
Serial Attached SCSI (SAS) is a data transfer technology designed to move data to and from computer storage devices such as hard drives and tape drives.
A typical Serial Attached SCSI system consists of the following basic components:
1. An Initiator is a device that originates device service and task management requests to be processed by a target device and receives responses for the same requests from other target devices. Initiators may be provided as an on-board component on the motherboard (as is the case with many server-oriented motherboards) or as an add-on host bus adapter.
2. A Target is a device containing logical units and target ports that receives device service and task management requests for processing and sends responses for the same requests to initiator devices. A target device could be a hard disk or a disk array system.
3. A Service Delivery Subsystem is the part of an I/O system that transmits information between an initiator and a target. Typically cables connecting an initiator and target with or without expanders and backplanes constitute a service delivery subsystem.
4. Expanders are devices that are part of a service delivery subsystem and facilitate communication between SAS devices. It facilitates connection of multiple SAS End devices to a single initiator port.
