A Tried, True, And Trusted Friend Just Got Better — Serial Attached SCSI (SAS)

By Dell Inc.

Serial Attached SCSI (SAS) has been added to EqualLogic storage products as a method of connecting high performance disk drives to a PS Series storage array controller delivering significant data rate improvement to an already solid platform. While the name SAS may sound new, the base technology uses SCSI as its foundation. A well established interconnect and protocol standard that has been around for over 25 years. SCSI is not new. It just keeps getting better.

SCSI or Small Computer System Interface has been around a long time. At 25 years of existence, this data transport technology was developed in the 1980's as a way of connecting several storage devices to a controller using a shared bus architecture. To date, over 1 billion SCSI connections have been made between controllers and storage devices. In fact, the SCSI protocol is used over multiple transports including USB, 1394, Parallel SCSI, Fibre Channel, iSCSI and now SAS. All of the SCSI "middleware" remains the same and represents a robust and mature base for essentially all storage infrastructures.

SAS delivers the latest electrical connection technology to a long standing SCSI protocol. Storage devices use the same SCSI language to speak to each other, but over far more robust electrical lines. This new standard essentially uses a point to point switching technology to overcome design limitations experienced with SCSI and sets a framework to grow with tomorrow's advancements in storage products.