• Solid-state disk drives (SSDs). With SATA and SAS interfaces, SSDs can plug directly into most existing systems and will provide an immediate performance boost.
• Flash caches. Located very near the DRAM, Flash caches provide fast ways to back up DRAM data over wide memory buses with high bandwidth and low latency. AgigA Tech’s AGIGARAM and Denali’s FlashPoint controller are both aimed at this NAND subniche.
• Specialty storage devices based on non-disk interface standards. Disk interfaces including SATA and SAS were developed with built-in assumptions about the drives they support. Those assumptions include some temporal assumptions based on having rotating mechanical memory. Those assumptions don’t apply to NAND-based storage devices so it’s possible to use interfaces with more bandwidth, PCIe and Hypertransport for example, to connect such storage and get better performance. This is the sort of product available from Fusion-io.

Which finally brings us to the trigger for this blog entry. The MIT/Stanford Venture Lab (VLAB) held a panel discussion at Stanford University on Tuesday, November 17 and the evening’s topic was “SSDs: Game-Changing Technology for Better, Bigger, Faster Applications and Application Development” and the first speaker was David Flynn, President and CTO of Fusion-io. Flynn’s talk contained many interesting and worthwhile things for followers of NAND-related topics as they relate to computer system design.

Early in his presentation, Flynn projected a photo of Charlie Chaplin playing one of the last great roles of his life, “The Great Dictator.” However, Chaplin’s roundish face had been replaced with an inset photo of a hard-disk platter and the caption was: “Getting rid of nasty Disc-tators.” Flynn emphasized that Fusion-io’s PCIe-connected products are not solid-state disks and they deliver more performance than solid-state disks because they are connected to a data pipeline that delivers more performance than existing disk interfaces. They are I/O-memory devices that provide 10x the capacity of DRAM per dollar, 50x the capacity of DRAM per “module,” and 100x the capacity of DRAM per Watt. Using these metrics, Flynn is making it clear that he understands the figures of merit valued by his company’s prospects.

Flynn then compared NAND Flash memory to aircraft aluminum. When metallurgists developed aluminum alloys suitable for aircraft, the entire airframe had to be re-engineered because aeronautical engineers couldn’t use aluminum as a direct replacement for wooden struts and dope-covered fabric. Aluminum ushered in new types of airframes that rapidly evolved. Aircraft performance soared as a result.

The same is true of computer systems (and software) developed before and after the Flash Zone is filled with something, whether it’s SSDs, Flash caches, or I/O-attached storage. Assumptions must be rethought and systems and software need to be redesigned to fully exploit the advantages of a populated Flash Zone.