"How SAS works is very similar to SATA; it uses the same seven wires to connect the drive to the host controller. However, instead of sending ATA packets, SCSI data bits are sent along the controller cable to the controller which then decodes them. This means that the drive has no interface chip; similar to parallel SCSI; it’s all handled on the controller card itself.
Today we have HighPoints Value series SAS controller card, aimed at the mid-range workstation or desktop with high data demands. The RocketRAID 2640X4 today makes its appearance here at TweakTown."