Multiplexer brings dual-ported interface to SATA drives


New SS1300 Device Based on AAMUX™ Technology Enhances SATA Drives for Enterprise Storage Connectivity on Par with Fibre Channel and SAS

Fremont, Calif.— SiliconStor, Inc., provider of innovative silicon solutions for enterprise storage, today announced availability of its third-generation active-active multiplexer device, a critical enabling component of new enterprise storage systems to be introduced beginning later in 2005. Based on the SiliconStor patent-pending AAMUX technology, the new SS1300 device enables storage system manufacturers to build cost-effective and reliable enterprise storage systems with low cost, high capacity Serial ATA (SATA) hard drives. SS1300 has been delivered to major OEMs in pre-production volumes for final qualification of new storage systems based on Serial-Attached SCSI (SAS) that will feature SATA drives connected using the AAMUX technology.

“SATA drives are rapidly moving into enterprise applications such as backup, restore and active archiving. But even for these applications SATA drives need to be enhanced in order to meet the basic standards that we have come to expect for enterprise connectivity,” said Arun Taneja of Taneja Group. “SiliconStor’s AAMUX technology does precisely that by augmenting SATA drives with essential enterprise-class features such as dual-porting and signal conditioning comparable to SAS and Fibre Channel drives.”

SS1300 Lowers Cost, Improves Reliability of Connecting SATA Drives in SAS Systems
The SS1300 includes all the key features of SiliconStor’s second generation SS1200 device, which was introduced in November 2004 and is currently shipping to major system OEMs. Both SS1200 and SS1300 include support for 3G SATA I/O and Native Command Queuing (NCQ) and are completely backward compatible with 1.5G SATA I/O. The SS1300 features an integrated voltage regulator and optimized packaging for lowering cost and reducing component count on existing interposer/dongle implementations. To further minimize cost of SAS storage systems, the SS1300 also offers increased pin spacing and optimal pin-out for alternative deployment directly onto high-density multi-layer SAS mid-planes enabling direct connection of SATA drives without an interposer/dongle card.

In addition, the SS1300 improves system flexibility and reliability with its enhanced signal conditioning and retiming as well as granular tuning of transmit amplitude and pre-emphasis settings at each port. SS1300 has been comprehensively tested for robust interoperability with SAS storage infrastructure components and new enterprise-capable SATA hard drives being offered by multiple vendors.

“The escalating demand for enterprise-class SATA hard drives for a broad range of storage applications is evident in the enterprise as well as SMB markets. Industry analysts are forecasting that by 2008 over two-thirds of all enterprise hard drives will ship with either SATA or SAS interfaces,” said Joel Warford, vice president of marketing and business development for SiliconStor. “Our new SS1300 device is specifically tailored for the new generation of SAS-based storage systems that are designed to accommodate both SATA and SAS drives.”

AAMUX Technology Reduces Complexity with Active-Active Mux Approach
The SiliconStor AAMUX technology enables single-ported SATA drives to connect like active, dual-ported drives for use in enterprise storage systems using SAS expanders supporting the SATA tunneling protocol (SAS-STP). Unlike the SiliconStor AAMUX solution which is an active-active approach, first generation solutions used an active-passive or port selector approach, where only one host port is actually connected to the device port, while the other host port remains on hold in case of a single failover. This active-passive mechanism results in increased complexity to the system software and reduced system performance due to latency associated with failover switching.

While others claim to support an active-active like approach, only the SS1300 with AAMUX technology enables the implementation of true active-active dual ported SATA drives, making both ports simultaneously available, much like dual-ported Fibre Channel or SAS drives. Because failover is no longer required, this true active-active approach greatly simplifies system software complexity and manageability.

Pricing and Availability
SS1300 customer samples are available now in quantities of 1000’s with general production availability in Q4 2005. OEM pricing for the SS1300 will range from $5-$6. SiliconStor also offers full design services and complete interposer card assemblies based on SS1300 depending on the needs of its OEM customers

As serial ATA (SATA) technology quickly penetrates many types of enterprise storage applications, SiliconStor has developed a device that transforms a single-ported SATA drive into a dual-ported active-active drive.

Its SS1300 active-active multiplexer (AAMUX) device boosts the performance of SATA drives, which are single-ported in nature, delivering enterprise storage connectivity that is on par with Fibre Channel and SAS using two SAS expanders that establish two paths.

The SS1300 is designed to provide seemless integration of SATA drives into Fibre Channel and SAS-based storage systems.

“There's a big trend that we’re following here— the need for SATA technology in enterprise storage applications,” said Joel Warford, vice president of marketing and business development at SiliconStor. “What's driving it is the need for capacity in secondary storage applications like archiving, lifecycle management, tiered storage, compliance and requirements where you need a lot of capacity, but don't need to access that capacity on a 24/7 basis.”

OEMs are choosing SATA because it offers more capacity at lower cost, Warford said, citing an 8 to 10X improvement in cost/capacity. For example, an 80-Gbyte Fibre Channel drive costs approximately $700 vs. a 400-Gbyte SATA drive for $300, he said.

Its SS1300 AAMUX device provides an active-active or dual-ported interface for enterprise systems. Prior to this technology, storage OEMs were using a port selector or an active-passive approach with two paths to the hard drive that were active one at a time. If there was an event of pass failure upstream somewhere in the system, they had to invoke a failover mechanism and switch that path over and move all the data onto the other path.

The SS1300 AAMUX allows both paths to remain active at all times, providing two independent paths to a single-ported hard drive.

“The real benefit to the system guys is we reduce their development, qualification and support costs of their system software,” Warford said. “Since both sides are always active, there's no need for any failover software, and no need for any switching mechanism, which can cause performance and latency issues. It behaves just like a Fibre Channel drive.”

SiliconStor's device also provides optimum signal conditioning capabilities. The device can retime and regenerate the signal at the port level and drive it at the same signal strength as Fibre Channel would drive it. And it could also drive a range of voltage amplitudes.

To enable the SATA drive to communicate to the system and drive the signal over a long cable, the SS1300 is designed with a active-active load balancing scheme to the hard drive, helping to achieve higher performance levels, he said.

The AAMUX device also offers pre-emphasis at each port, which drives the signal a little higher than the specification and at various levels. The company is offering that feature as option.

“You don't want to overdrive the signal because it creates more power. You want to optimize it. Users are not tuning it all the time; they just tune it the first time before they ship the system based on where that drive fits into the system,” Warford said.

SiliconStor's previous generation device, the 1200, has a maximum-voltage amplitude of 850 millivolts. Its latest device, the 1300, can transmit voltages at 1200 millivolts, which meets the requirement for the SAS specification. It offers 60 settings for voltage amplitude.

To further reduce costs, the device features an integrated voltage regulator and offers an easier interposer design and layout with BGA packaging, pin spacing and pin out. As a result, the device can be applied directly onto high-density, multi-layer SAS mid-planes for direct connection of SATA drives without an interposer or dongle card.

The SS1300 AAMUX device is sampling now in quantities of 1,000 with production availability scheduled for this quarter. OEM pricing will range from $5 to $6 each. The company is also offering interposer card assemblies for approximately $40.

SiliconStor Inc., 1-510-490-7750,

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