STA

Author: Linus Wong, Director Strategic Marketing
Adaptec

One of the key considerations in developing a new technology is interoperability. As witnessed by the early issues with Fibre Channel solutions, market acceptance of a new technology, no matter what performance gains or cost reductions it provides, will be slowed by interoperability doubts.

As a result, interoperability has been a focal point throughout the development of the Serial Attached SCSI (SAS) technology standard and products. SCSI Trade Association and its members are committed to providing fully interoperable products, and in 2004, three plugfests at the University of New Hampshire InterOperability Laboratory tested for both SAS and Serial ATA (SATA) compatibility and multi-vendor interoperability. Components tested for interoperability included disk drives, controllers, test equipment, cables, connectors and systems. The fourth SAS plugfest, held April 25-29, 2005, continued this commitment.

This electrical level interoperability testing provides peace of mind that products can be connected to other products from multiple vendors and integrated into existing environments. However, creating SAS solutions, particularly early in the adoption process, requires more than hardware interoperability.

Stephen Schaeffer, Manager of University of New Hampshire InterOperability Laboratory (UNH-IOL) iSCSI, Fibre Channel, SAS and SATA consortiums, interviewed Mike Fitzpatrick of Fujitsu Computer Products of America, to learn how the company approaches testing Serial Attached SCSI (SAS) hard disk drives. Fitzpatrick was interviewed during a recent SAS interoperability plugfest held at UNH-IOL that drew 17 companies. Fujitsu and UNH-IOL are members of the SCSI Trade Association (STA).

Author: Chris Croteau
Intel Corporation

SCSI is undergoing an exciting serial transformation, one that goes far beyond a mere parallel-to-serial conversion to deliver significantly increased capabilities. Serial Attached SCSI (SAS) is the next evolution of SCSI technology following Ultra320 SCSI, utilizing a speedy serial point-to-point architecture to eliminate the bus overhead of today’s parallel SCSI technology. Dual-ported devices are also a standard feature for Serial Attached SCSI, enabling multiple signal paths for each disk drive. In addition, Serial Attached SCSI will have the ability to scale to over 16,000 physical devices in a single domain through the use of expanders. And SAS leverages existing SCSI protocols, thus ensuring backward compatibility with legacy SCSI drivers and enterprise application software.

In addition to compatibility with existing SCSI drivers and software, Serial Attached SCSI offers interoperability with Serial ATA devices. This is an unprecedented development in storage technologies. The inclusion of the Serial ATA Tunneling Protocol (STP) allows Serial Attached SCSI environments to host Serial ATA devices. This will not only allow flexibility in system deployment, but also offers end users more choices based upon economics and workloads for specific applications.