SandForce's revolutionary SSD controller

Endurance

The DuraClass technology of the SF-1000 is claimed to offer its longer endurance (compared to, say, Mtron and Phison notebook SSD controllers), up to 100 times more reliability than other SSDs and better power efficiency with 5,000 IOPS/watt (compared to a stated less than 20 IOPS/watt for hard drives) without using either a DRAM cache, over-provisioning the flash or requiring a stated or de facto daily write limitation to achieve endurance goals.

SandForce says users will experience five years of MLC SSD life with no daily usage restrictions. It reckons that both Intel M-class SSDs and Fusion-io ioDrives have effective write limitations.

Reliability is aided by its own error correction logic and by using RAISE, a Redundant Array of Silicon Elements, which is said to be single drive RAID-like but more efficient. (Having a 'redundant' array does suggest some kind of over-provisioning). Data written through the SF-1000 controller is automatically encrypted by the chip's hardware.

SandForce provides a 3Gbit/s SATA interface to the SF-1000 although a SAS interface is available from partners supplying a SATA-SAS bridge. It also has a SMART interface for diagnostics. The company says that, because it has a single chip controller, it can be used, uniquely, by OEMS to build a 1.8-inch format 512GB SSD, 512GB being the maximum capacity the controller supports.

Its roadmap extends to shrinking NAND geometries, 3 and 4-bit MLC technologies, adding a 6Gbit/s SATA interface plus PCI Express, USB 3.0 and other interfaces.

OEMs

SandForce says it is engaged with multiple tier one SSD OEMs and its SF-1000 product will be shipped later this year.

Perhaps it's significant that Mike Desens, IBM Systems and Technology Group VP for system design, is quoted in SandForce's release: "The SF-1000 SSD Processor Family promises to address key NAND flash issues allowing MLC flash technologies to be reliably used in broad-based, mission-critical storage environments. These innovations can be truly disruptive and will accelerate the adoption of Solid State technologies across the data center."

Desens has been heavily involved in IBM's Big Green eco-friendly initiative and has been quoted with reference to IBM's million IOPS project Quicksilver which used 4TB of Fusion-io SSD. Fusion-io seems confident in its IBM relationship so perhaps IBM will use SandForce-controlled SSDs somewhere else in its product range, but in a data centre environment. Could SSDs, which first appeared in mainframes in 1978 (StorageTek 4305), be about to return to them?

There are two other potential SSD OEM connections visible at SandForce. Dr. Chong Park is a SandForce board director and also a board director at Seagate, which has publicly said it will enter the enterprise SSD market this year but has no known SSD technology relationships except with LSI.

Before joining SandForce, Kent Smith, SandForce's senior product marketing director, was the product management director at SATA multiplexer chip maker SiliconStor, which he and the management team sold to LSI in February 2007. Michael Vorhis, Sandforce's applications engineering director, also worked at SiliconStor in the period leading up to the LSI acquisition.

Advanced claims

It appears that Intel, Fusion-io, Texas Memory Systems, STEC, and Violin Memory have a potentially substantial new enterprise SSD competitor, with existing storage OEM relationships about to bear fruit. SandForce appears well-funded and well-staffed, with credible storage OEM relationships. Its claimed capabilities regarding MLC flash - both read-write speed and symmetry, prolonged endurance, and data integrity - are far in advance of any other enterprise SSD supplier and are, it says, equally applicable to notebook use.

This means that, as MLC flash cheapens the cost per GB of SSD storage, SandForce's controller technology could help make it applicable to many more use cases currently best-served by hard disk drives. The company and its technology is now out of stealth, giving people a chance to see how both stack up and whether or not SandForce will be the actual force in the enterprise and mobile SSD markets it claims to be. ®