Flash Competitors Discuss Future Alternatives

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One of the most talked-about data storage alternatives to flash ROM is phase-change memory, which also appears to be one of the most promising

NAND and NOR flash get virtually all of the attention these days when the topic is solid-state memory and storage, but there are several other developments in this sector that have piqued the interest of future watchers.

One of the most talked-about alternatives is phase-change memory, which also appears to be one of the most promising. Ed Doller, CTO of Numonyx and a former Intel flash strategist, laid out the value proposition and product road map for Numonyx’s production of PCM chips on 11 August in a keynote at the fourth annual Flash Memory Summit at the Santa Clara Convention Center.

But there are several others that also bear watching, such as CMOx, a multilevel scRAM (storage-class RAM) chip; STT RAM (spin-transfer torque RAM); TAS-MRAM (thermally assisted switching magnetic RAM); and Hewlett-Packard’s memristor.

A panel discussion of these memory alternatives took center stage Aug. 13 on the final day of the summit.

Companies that are investing in this R&D are licking their chops at the prospect of replacing NAND flash, the reigning standard nonvolatile form of storage used in solid-state drives, iPods, cell phones, thumb drives, servers, storage arrays and other hardware.

While NAND and NOR flash have a long list of positive features, most analysts and industry veterans believe that the high-intensity/high-transaction Web-based applications that are coming into more common use may need an entirely new grade of SSD in the next few years to produce optimum results on a 24/7 basis.

Here’s a list of some of the competitors and brief descriptions of the attributes of their products. eWEEK will follow up with more detailed analysis on the progress of these technologies soon.

CMOx—Startup Unity Semiconductor is pushing CMOx, a multilayer flash chip that promises four times the density and five to 10 times the write speed of today’s high-end NAND flash.

Darrell Rinerson, co-founder and CEO of Unity, said the company has developed a 64GB CMOx (metal oxide) chip and describes it as a “passive rewritable cross-point memory array” with no transistors in the memory cell. CMOx is next-generation nonvolatile memory based on a proprietary switching effect that occurs in certain metal-oxide combinations. The 64GB chips are scheduled for pilot production in late 2010, with volume production set for 2011.

TAS-MRAM—This is being developed by startup Crocus Technology. As one of the most promising “spintronics” applications, MRAM combines the advantages of high writing and reading speed, limitless endurance and nonvolatility. The integration of MRAM in FPGA (field-programmable gate array) allows the logic circuit to rapidly configure the algorithm, the routing and logic functions, and easily realize the dynamical reconfiguration and multicontext configuration. It is nonvolatile, faster than SRAM (static RAM), potentially cheap, and features low power consumption and a high integration level.

Field-Induced MRAM (Toggle MRAM)—Historically, Field-Induced MRAM is hard to scale and has stability and retention problems. But Crocus, which is also working on this, aims to solve these problems using a thermally activated magnetic latch called Thermally Assisted Switching. This allows each flash cell to retain memory value. It also apparently scales well.

STT-RAM—Grandis, another chip startup, is championing this one. Grandis claims its proprietary Spin-Transfer Torque RAM technology has all the characteristics of an ideal “universal memory” and represents a breakthrough over first-generation, field-switched MRAM technology. Also known as SpinRAM, STT-RAM’s synthesis of nonvolatility, fast read and write speed, unlimited endurance, and extendibility beyond the 45-nanometer semiconductor node provides significant advantages over conventional memory technologies and allows system designers to develop new products with high performance, low power consumption and low cost, according to Grandis.

HP’s Memristor—HP Senior Fellow and Director of Quantum Science Research Stan Williams, speaking at the conference, described the technology this way: “This is sort of the missing element of the processor puzzle. It takes its place alongside the resistor, capacitor and inductor in the chip. An ideal memristor is a passive two-terminal electronic device that is built to express only the property of memristance (just as a resistor expresses resistance and an inductor expresses inductance).” In summary, let’s just say a memristor makes an SSD act as if it’s on steroids.

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