During the WinHEC 2008 conference in Los Angeles, California, SanDisk unveiled its proprietary technology that boosts write speed of solid state drives (SSDs) by up to 100 times, which will automatically accelerate overall performance dramatically. In addition, the supplier of flash products proposed the industry to implement new metrics that would measure SSD’s performance and reliability.
Speaking in Los Angeles at WinHEC 2008, Rich Heye, senior vice president and general manager for SanDisk’s SSD business unit, presented ExtremeFFS technology along with two metrics – virtual RPM (vRTM) and long-term data endurance LDE (LDE) – that can help end-users evaluate SSDs.
“SSDs will revolutionize client storage, but we need new benchmarks that allow them to be treated differently than HDDs,” said Mr. Heye.
ExtremeFFS Set to Accelerate Solid State Drives
For SSDs to perform optimally in Windows Vista, and thus replicate or surpass the functionality of hard disk drives (HDDs), a new flash management technology is needed to accelerate SSD write speed and endurance. When using an SSD under Windows Vista, the demands on the SSD require a large quantity of random writes, as opposed to sequential access.
“The mismatch to block size is significant,” explained Mr. Heye.
To maximize random write performance, SanDisk developed the ExtremeFFS flash file management system. This operates on a page-based algorithm, which means there is no fixed coupling between physical and logical location. When a sector of data is written, the SSD puts it where it is most convenient and efficient. The result is an improvement in random write performance – by up to 100 times – as well as in overall endurance.
ExtremeFFS incorporates a fully non-blocking architecture in which all of the NAND channels can behave independently, with some reading while others are writing and garbage collecting. Another key element of ExtremeFFS is usage-based content localization, which allows the advanced flash management system to “learn” user patterns and over time localize data to maximize the product’s performance and endurance.
“This feature might not show up in benchmarks, but we believe it is the right thing to do for end-users,” the head of SSD business unit said.
He also predicted that SSD net performance next year will be four times faster than the current generation of SSDs and nearly six times that of the latest 2.5” HDDs.
VirtualRPM Metrics Proposed
Since hard drive spindle-speed is measured in RPMs (rounds per minute), SSDs need a simple performance metric for comparisons between SSDs and HDDs, the company said. SanDisk offers to start using so-called virtual RPM (vRPM) metrics to make it easier for end-users to determine performance of such drives. The metric is hardly ideal to say at least since hard drives differ between each other with a lot more specifications than just spindle speed.
According to SanDisk, virtual RPM (vRPM) “accurately and easily” allows consumers to compare SSDs to HDDs and to each other when used in PCs.
“vRPM answers the question: How fast would you have to spin a virtual HDD to achieve the level of performance seen by an SSD in a client PC?” Mr. Heye asked.
“There has been a deluge of SSD products with varying levels of quality that have created undeserved hype and confusion for consumers and corporations. Industry support behind a common metric that clearly articulates the value proposition of an SSD on a like for like basis to a HDD will be instrumental in driving end-user understanding and subsequent adoption as prices continue to fall,” said Commenting on vRPM, Joseph Unsworth, research director at Gartner, said.
While there is definitely a need for certain standard performance measurement metric for both HDD and SSD, vRPM may not be the best option since performance of both is determined by much more specifics than spindle speed or read/write speed.
Long-Term Data Endurance to Determine Reliability of SSDs
Apart from vRPM, SanDisk is proposing Long-Term Data Endurance (LDE), which simplifies endurance as a useful number, as the first industry metric of long-term data endurance.
“This is a lot like measuring tread wear on a tire. Major PC OEMs and SSD competitors have reviewed and commented on SanDisk’s initial proposal and SanDisk has submitted a proposal and white paper to JEDEC. LDE represents the total amount of data writes allowed in the lifespan of an SSD. SanDisk will spec LDE on its future PC SSD products and “we strongly encourage others to follow SanDisk’s lead,” said Rich Heye.
“LDE allows OEMs a simple way to compare SSDs and determine, based on the applications usage patterns, which drives are suitable for a particular application. The beauty of LDE is that it captures endurance in one single, understandable figure. A common metric is necessary to facilitate SSD adoption moving forward,” said Greg Wong of Forward Insights said regarding LDE’s impact on SSD adoption