Serial Attached SCSI gains momentum

Alan Earls lists future product plans for SAS, explains why many see momentum building for SAS and where this technology is headed.

Early this month a list of "Who's Who of storage players camped out on the campus of the University of New Hampshire. They weren't there to sample late winter New England skiing. They were there for another major Serial Attached SCSI (SAS) plugfest. And while organizers and participants are staying mum about the results, vendors see momentum building for SAS.

On paper, at least SAS looks appealing. It supports both SCSI and ATA and it can use three transport protocols: Serial SCSI protocol (SSP), Serial ATA Tunneling Protocol (STP), and Serial Management Protocol (SMP). The SCSI Trade Association (STA) positions SAS in the middle ground between desktop/ATA applications -- in servers and DAS applications -- and top-end FC-oriented applications. And, late in January, STA and the InterNational Committee for Information Technology Standards (INCITS) announced that the SAS standard had been approved by the American National Standards Institute (ANSI).

The same day, Hitachi Global Storage Technologies announced successful testing of 3Gb/s SAS disk drive interoperability with LSI Logic silicon. Shortly thereafter, Maxtor Corporation announced verification of full-speed, 3Gb/s, operation between an LSI Logic Serial Attached SCSI (SAS) controller and an in-form-factor prototype Maxtor SAS disk drive with dual active ports.

Hitachi spokesperson Jim Pascoe says, SAS will continue to build upon the established SCSI technologies that are typically used in RAID and other enterprise environments. Its advantages include "serial point-to-point interconnections, dual porting, increased addressability and full duplex operation," says Pascoe. SAS will also ease the design process for system builders because it uses simplified cable routing and shares similar physical attributes and interface transfer rates with Serial ATA, he says.

According to Pascoe, Hitachi has been working with its customers for more than a year to prepare them for the eventual transition to SAS and small form factor drives. He says the company is on track to deliver SAS and SFF enterprise HDDs into our product portfolio this year.

"Parallel buses are getting more and more difficult to implement so this was the next step for SCSI," says Marty Czekalski, interface architect at Maxtor. Czekalski says the industry is in the process of exchanging prototypes. "By the end of the year we expect industry wide there will be HBAs and drives shipping or getting ready to ship," he adds.

Finally, Harry Mason, director of industry marketing at LSI Logic and president of STA notes that the timeline for development and introduction of SAS was laid out some two and a half years ago. "We are pretty much on schedule," he adds.

For more information:

Tip: Seagate touts SAS drives as faster alternative to SATA

Tip: where SAS will play out

Tip: Hitachi announces biggest ever SCSI drive

About the author: Alan Earls is a freelance writer in Franklin, MA.

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