MLC flash allows two or three bits of data to be written per cell. However, over the past year or so, vendors have come to recognize that by using special software in the drive controllers, they're able to boost the reliability and resiliency of their consumer-class MLC SSDs to the point where enterprises have embraced them for high-performance data center servers and storage arrays. SSD vendors have begun using the term eMLC (enterprise MLC) NAND flash to describe those SSDs.
Intel's X25-M line has never been designated an eMLC drive. It just organically gained popularity in data centers, Winslow said.
Yang said most enterprises that had been purchasing SLC-based SSDs over the past few years began switching over to MLC-based products in the third and fourth quarters of 2010, recognizing that they could achieve the performance boost NAND flash offered over enterprise-class hard drives while also maintaining a high level of resiliency.
According to Intel, of the first 1 million or so X25-M SSDs it sold, users reported a total 0.4% failure rate. "We're not satisfied with that," Winslow said. "We expect the 320 Series will have greater reliability than the X25-M, regardless of going down to the 25nm level."
Intel is putting its money where its mouth is. The company has already deployed 55,000 of its own SSDs in its data centers and in employee systems and expects that by the end of this year, all employees will have SSDs in their computers, Winslow said.
Later this year, Intel expects to release its first eMLC drive to replace the X25-E SSD line, he said. "That will provide the performance of an SLC drive and the endurance, but in a more cost-effective, higher-capacity MLC product," Winslow said.
"From a volume perspective, we do see there are really high-write-intensive, high-performance computing environments that may still need SLC, but that's in the top 10% of even the enterprise data center requirements," Winslow said.
Intel is feeding that upper 10% of the enterprise data center market through its joint venture with Hitachi Global Storage Technologies. Hitachi is producing the SSD400S line of Serial Attached SCSI SSDs, which has 6Gbit/sec. throughput -- twice that of its MLC-based SATA SSDs.
Last fall, Intel and Micron's joint venture company, IM Flash Technologies (IMFT), released a 3-bit-per-cell MLC SSD, also based on 25nm circuitry.
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