SAN JOSE, Calif. SanDisk Corp. is announcing a new flash-file format for solid-state drives it will release in its 2009 products, claiming it bolsters performance 100-fold on some operations. The company is also releasing details about two metrics for comparing the performance of SSDs.
SanDisk (Milpitas, Calif.) has no plans to license the ExtremeFFS file system so far, despite the fact the earlier TrueFFS format from MSystems which SanDisk acquired in 2006 was widely licensed. It is however working to make its new measures for SSD performance and endurance broadly accepted.
ExtremeFFS aims to improve sequential write performance by providing a direct route to writing individual pages of data. Rather than requiring a system to update and move an entire block at a time, Extreme FFS can simply write a new page to a new block and invalidate the old page.
The file system handles garbage collection simultaneously with reads and writes in multiple non-blocking channels. It can also learn which data structures are most and least often accessed and optimize the placement of the data sets.
The sequential write issues were relatively small for digital cameras and other devices that have used NAND flash cards to date. But Windows PCs typically require many sequential random write operations that can raise significant performance issues for SSDs.
ExtremeFFS should not only improve performance on random read and write operations but lower power consumption and optimize flash endurance as well, said Don Barnetson, senior director of marketing for SanDisk's SSD group.
"Most of our competitors don't like to talk about what's going on inside their drive, but we are trying to be more open about it," said Barnetson.
The earlier generation TrueFFS format was used for PCMCIA flash cards in Microsoft Windows 95 and became widely licensed by flash-card makers. SanDisk had royalty revenues of $450 million's in 2007 based on licenses companies took for its range of patents including those on TrueFFS.
While SanDisk currently has not plan to license ExtremeFFS, it is encouraging the industry to adopt two new SSD metrics to communicate performance characteristics to end users.
Virtual RPM is a method for calculating the performance of an SSD in the equivalent of rotation figures used to measure hard drives today. The equation takes into account the very different read and write performance characteristics of flash as well as the typical mix of reads and writes in average PC applications.
"vRPM answers the question: How fast would you have to spin a virtual hard drive to achieve the level of performance seen by an SSD in a client PC?" said Rich Heye, general manager of SanDisk's SSD group in a press statement.
The company has posted details about the vRPM approach at its Web site.
"There are so many axis of performance that it's difficult to measure the relative performance of SSDs today," said Barnetson. "Our goals are to get the industry to adopt this metric and to be transparent about how it works," he added.
"There has been a deluge of SSD products with varying levels of quality that have created undeserved hype and confusion," said Joseph Unsworth, research director at market watcher Gartner Inc. (Stamford, Conn.) in a press statement. "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" of SSDs, he added.
A second metric announced earlier this year offers a way to measure endurance of SSDs, an important aspect of the devices. Unlike hard disks media which does not degrade significantly over typical product life spans, the flash cells in SSDs can wear out before a product reaches its end of life.
SanDisk has written a white paper on its so-called Long-term Data Endurance metric. It submitted the paper recently to the Jedec 64.8 working group that is developing standards for SSDs.