New SSD File System From SanDisk

SanDisk has unveiled an advanced flash file system for solid-state drives (SSDs) that yields dramatic improvement in performance and reliability for computing applications. Called ExtremeFFS, this next-generation patented flash management system -“ which has the potential to accelerate random write speeds by up to 100 times over existing systems -“ will ship in SanDisk products during 2009.

Speaking in Los Angeles at WinHEC 2008, Rich Heye, senior vice president and general manager for SanDisk’s Solid-State Drive (SSD) Business Unit, presented ExtremeFFS along with two metrics -“ vRPM and LDE -“ that can help end-users evaluate SSDs. vRPM enables comparisons in performance between an SSD and a hard disk drive (HDD) or another SSD, and LDE calculates the lifespan of a solid-state drive.

For SSDs to perform optimally in Windows Vista, and thus replicate or surpass the functionality of hard disk drives, a new flash management technology is needed to accelerate SSD write speed and endurance, he said. “SSDs will revolutionize client storage, but we need new benchmarks that allow them to be treated differently than HDDs.”

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.

Since hard drive performance is measured in RPMs (revolutions per minute), SSDs need a simple performance metric for comparisons, he said. virtual RPM (vRPM) accurately and easily allows consumers to compare SSDs to HDDs and to each other when used in PCs, said Heye. “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?

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,” said Heye. Major PC OEMs and SSD competitors have reviewed and commented on SanDisk’s initial proposal, he added, and SanDisk has submitted a proposal and white paper to JEDEC, the leading developer of standards for the solid-state industry.