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Super SSD Technology

In an effort to infuse more life in my 1-year old Macbook Pro, I began researching SSD technology drives in the market and quite overwhelmed by the choice, I sauntered the Interwebs in an effort to make an educated decision that would skyrocket my productivity and in the process burn a proportionally deep hole in my pocket. During this process of research and analysis, I came across Israeli start-up Anobit Technologies Ltd. that has announced its first product, a multilevel cell (MLC) solid-state drive (SSD) that it claims is as reliable as today’s higher-end & higher-cost single-level cell (SLC) enterprise-class flash drives.

Ready for Relational Databases

Anobit said its Genesis SSDs extend standard MLC endurance from about 3,000 to more than 50,000 write/erase cycles, 20 times better than the average consumer-class drive today, making MLC technology suitable for high-duty cycle applications such as relational databases. The drives come in 200GB or 400GB capacities with Serial ATA interfaces. Through the use of an external bridge, they are capable of using the Serial-Attached SCSI (SAS) or Fibre Channel protocol. The drives have a sustained sequential read rate of 220MB/sec. and a sustained sequential write rate of 180MB/sec., according to Anobit.

The Genesis of Anobit

Anobit, founded in 2006 has raised more than US$40 million in venture capital and has created a special processor, called a Memory Signal Processor, that boosts MLC NAND flash memory reliability through a special error-correction algorithm. According to Gilad Engel, Anobit’s Business Development VP, the Memory Signal Processor adds an additional layer of error correction to the traditional error-correction code (ECC) that all SSD controllers have allowing the 200GB Genesis SSD to handle 2TB worth of data writes per day for five years. The 400GB SSD can sustain 4TB of writes per day. Both drives can achieve a write rate of 20,000 I/Os per second and a read rate of 30,000 IOPS, according to Engel. The drives have native support for 512-, 520- and 528-byte block sizes and have a nonvolatile cache memory that’s immune to power failures.

Competition Heats Up

Sandforce makes a processor that uses data compression and RAID architecture to get around the limitations of MLC. Sandforce uses “24-bit/512-byte ECC hard coding. However, the fundamental issue is that the signal quality is declining, and Anobit’s technology helps to get a ‘cleaner’ signal,” industry analysts say. The overhead for hardware-based signal decoding is relatively high, with some NAND flash vendors allocating up to 7.5% of the flash chip as spare area for ECC. Increasing the ECC hardware decoding capability not only increases the overhead further, but the effectiveness also declines with NAND’s decreasing signal-to-noise ratio.

Lithography Limitations

Manufacturers over time have been able to shrink the geometric size of the circuitry that makes up NAND flash technology from 90 nanometers a few years ago to 25nm to 34nm today. Intel recently announced it has begun using a 25nm process. The smaller the lithography process is, the more data can be fit on a single NAND flash chip. At 25nm, the cells in silicon are 3,000 times thinner than a strand of human hair. But as geometry shrinks, so too does the thickness of the walls that make up the cells that store bits of data. As the walls become thinner, more electrical interference, or “noise,” can pass between them, becoming a tougher obstacle to tackle as it creates more data errors. The amount of noise compared to the data that can be read by a NAND flash controller is known as the signal-to-noise ratio.

SSD for the Masses?

Anobit’s processor is able to continue to read data for a longer period of time compared with typical NAND flash with hard-coded ECC, which takes up flash capacity. It’s signal-processing technology, which uses software in the controller to increase the signal-to-noise ratio, making it possible to continue reading data even as electrical interference increases. Analysts at Objective Analysis, say Anobit’s proprietary technology would be able to offer dramatically lower prices than other SSD makers, because 70% of an SSDs manufacturing cost is in the creation of the NAND flash chips. Because MLC NAND can hold two to three times the capacity of SLC NAND in the same space, higher-capacity drives can be produced at a lower cost. Anobit’s MSP technology will enable manufacturers to use MLC more for higher-performance SSDs and thereby paving the way for lower-cost products in data centers. One can expect the cost of SSDs to drop considerably in the near future bringing faster computing at a lower power consumption to the masses hungry for the latest.