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SanDisk Technical Expertise and Metrics

SanDisk?s Know-How Strengthens the SSD Industry

With an eye to benefiting the end user, SanDisk® has taken proactive steps to provide the technology and measuring tools primed to hasten the adoption of solid state drives (SSDs) in PCs. ExtremeFFS?, SanDisk?s new flash management technology, is specially tuned with the potential to accelerate the performance and extend the endurance of SanDisk SSDs inside PCs that use full-featured operating systems. SanDisk?s newly introduced industry metrics, LDE (Long-term Data Endurance) and vRPM (virtual Revolutions Per Minute), give users benchmarks to evaluate the endurance of SSDs and their performance vs. hard disk drives (HDDs) and other SSDs.

ExtremeFFS (Extreme Flash File System)

ExtremeFFS has the potential to greatly extend endurance and accelerate SSD random write speeds by as much as 100 times compared with existing systems. Based on SanDisk?s TrueFFS? flash management system that was introduced in 1994 and incorporated into Windows 95 as the leading flash file system for major mobile handset vendors, ExtremeFFS applies a novel approach to flash management based on design elements such as:

Page-based algorithm: Customized for popular operating systems such as Vista, ExtremeFFS uses a page-based algorithm with no fixed coupling between physical and logical location. This gives SanDisk SSD the freedom to store a sector of written data where it is most convenient and efficient.
Fully non-blocking architecture: NAND channels operate independently as required by user activities, with some reading while others are writing and garbage collecting.
User pattern learning: ExtremeFFS can learn user patterns to store data used with higher frequency in quickly accessible locations.
LDE (Long-term Data Endurance)

LDE is the first industry metric that expresses how long data can be reliably stored in SSDs in a measurable number. LDE was proposed by SanDisk as a benchmark to enable users to compare the data endurance of SSDs from various manufacturers. Based on typical end-user activity, LDE provides the total number of data writes, expressed in Terabytes, that can be performed over the SSD lifespan. SanDisk offers a methodology that enables accelerated testing.

vRPM (virtual Revolutions Per Minute)

This is a new metric to enable users to compare SSD performance in client PCs with the HDD and with other SSDs. The beauty of vRPM is its simplicity. SanDisk chose to use RPM since it is a language that users understand, a defacto standard in the hard disk drive (HDD) world. However, since the SSD has no revolving parts, which cause the HDD to incur latency penalties, SanDisk modified RPM to vRPM. vRPM essentially 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?? SanDisk?s new vRPM metric results indicate that SSDs are faster than HDDs when performing random read and write operations.