Introduction

With the advent of serial transfer technology for the hard disk market, we have finally seen improved transfer speeds when it comes to hard disks. NCQ and 300MB/s data transfer speeds now allow for desktop hard disks to perform faster and more reliably than the older parallel ATA solutions. While this may bode well for the desktop, the server market has still had to deal with parallel technology. SCSI has been the long favourite because of its faster interface speeds along with the ability to daisy chain up to 32 drives per channel. And with SCSI controllers having three or four channels, it was clear that SCSI had its benefits. However, parallel interfacing has gone out the window and we now have a new technology to replace it; this called Serial Attached SCSI or SAS.

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.