Last time we began to look at why vendors are moving us off the parallel SCSI interface and onto Serial Attached SCSI, or SAS - identifying benefits such as thinner cables and increased signal integrity over longer distances. Today let's look at some of the other benefits vendors expect to see.
Even those of us who avoided accounting classes like the plague understand that, generally speaking, corporate profitability results from making more money than you spend. Not unexpectedly, in order to ensure robust profit margins for their products, vendors always try to squeeze as much cost out of their offerings as they can.
When it comes to hardware, cost reductions result from either the commoditization of parts (the more that are made, the cheaper the individual components become) or the introduction of new and more efficient technologies. Make either of these easy for vendors to build into their equipment and they are likely to go away happy.
These are going to be good days indeed for vendors, because serial SCSI offers them a terrific opportunity to take advantage of both of these efficiency enablers, commoditized parts and innovative technology. This occurs because SAS and serial ATA devices use identical command sets (SATA uses a subset of the SCSI commands) and both types of devices can plug into the SAS connector. This means that when vendors design a backplane for SAS devices, they are at the same time designing an environment that will also work with SATA. Savings number one then, results from the fact that when they design a backplane or midplane, they get a "two-fer," a design that can be implemented in products that address high-performance (SAS) and low-priced (SATA) market segments.
SAS-SATA compatibility results from some cooperation between the SAS and ATA communities, and from the SATA group's settling on the well-proven SCSI command set.
What made this a relatively safe bet for both groups as they moved to the new serial implementations of their products is that serial connectivity is in every sense an evolutionary change rather than an abrupt shift in their product roadmaps. Thus, both groups get to execute on their new strategies while taking on relatively little risk.
As more of these boxes are built to the SAS specification, the use of the cheaper SATA drives very likely will begin to drive the vendors' costs down, increasing their profitability. Whether this will translate into savings for IT buyers of course will be answered by whatever competitive pressures are driving the market at the time.
We still should look at what values the IT buyer can expect from this and, in connection with that, we should look at what SAS will deliver when compared to Fibre Channel. More on that next time.