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NAND Flash +DRAM Improves Memory Sys

Fusion io's blog discusses their collaboration with computer scientists at Princeton University

"  Volatile DRAM is faster—but much more expensive at high densities—than flash. NAND flash has much greater density than DRAM, and requires substantially less power to do its job. The Extended Memory library transparently tiers data between available DRAM in the system and the persistent NAND flash tier, making it much more affordable for organizations to greatly expand the size of their in-memory data sets without re-writing their applications."

See more about this partnership below:

Intel's approach regarding  PC memory organization is discussed in How SSDs conquered mobile devices and modern OSes

Other approaches for internal PC memory organizations were covered in a May blog -

Apple NAND Storage in Upcoming MacBook Pros

"There is a room for an overall personal computer hierarchy reorganization. Maybe Apple could lead here.
Currently in PC/ Mac we have a microprocessor (with some fast DRAM memory) connected to long term storage in flash SSD or HDD.
There would be many benefits to adding a small flash NAND between the microprocessor and the long term storage. Such computer hierarchy would benefit from the faster operation of the small flash NAND storage and its long term non volatile storage. It will also reduce power consumption.
The NAND memory could support the microprocessor operations or be used for storage of the operating system."


Princeton Scientists Partner On DRAM Innovation

By Adrian Bridgwater, July 11, 2012

Fusion-io technology now extends memory from DRAM to NAND flash

A collaboration between computer scientists at Princeton University and Fusion-io has led to the development of a new Extended Memory subsystem to be made available as part of the firm's own brand SDK.

The Extended Memory subsystem works to extend system memory from DRAM onto flash, providing what has been described as "much more high-performance memory capacity" than currently possible with DRAM alone.

The firm's message to software programmers is that this is an extended memory option for developers who chose to customize applications to leverage ioMemory technology. Applications can then extend their in-memory data from DRAM onto ioMemory, which — generally speaking — should also save money as DRAM is argued to be cost-prohibitive, not persistent, and limited in capacity.

Will this garner interest from developers attracted to the benefits of storing all data in-memory, especially to meet the needs of web-scale, cloud, and big data computing? It is an attractive sounding option for sure, but success here will be based on whether this Extended Memory's ability to intelligently tier data between available DRAM in the system and the persistent NAND flash tier works as well as described.

"The Fusion ioMemory architecture is uniquely suited to innovation like the Extended Memory subsystem," said Chris Mason, Fusion-io director of kernel engineering and principal author of the Btrfs filesystem for Linux. "Since Fusion ioMemory has moved beyond legacy disk-era protocols, we can integrate new features like the Extended Memory subsystem to truly advance application performance for enterprise computing in ways that are simply not possible with traditional SSDs."

The Extended Memory subsystem dynamically moves frequently accessed data pages into memory on-demand while migrating rarely accessed data pages from DRAM into ioMemory. This says Fusion-io allows developers to simplify application design by assuming that entire datasets are in-memory, without the costs associated with DRAM purchase and operation.

Application developers are able to further tune performance through software development kit tools that lock selected pages into DRAM, giving access to NAND flash as memory, instead of treating it as an extension of disk storage. This allows legacy applications to scale up with flash memory, instead of scaling out, boosting performance and reducing total cost of ownership.