Lucas Mearian

Solid state disks find home with Google, Apple

May 13, 2008 5:00 PM EDT
Google plans to roll out solid state disk (SSD) drives from Intel in servers located in its North American headquarters and Apple will be replacing the 64GB SSD drive offered in the MacBook Air laptop with a higher-density, less costly 100GB+ SSD drive, according to published reports and industry sources.

Both roll outs, which neither company would confirm, point to growing interest in SSD technology in the commercial and retail sectors, according to Avi Cohen, a head of research at Avian Securities LLC, in Boston.

Cohen cited channel sources who have told him Apple is looking to use multi-layer cell (MLC) SSD drives from STEC Inc. in the MacBook Air. MLC-based SSD drives offer greater density at a lower cost compared to the single-layer cell (SLC) memory that Apple currently uses in the popular laptop.

An STEC spokeswoman said the company can't comment on unannounced partnerships, "and we haven't announced a partnership with Apple yet." She did, however, confirm STEC has been receiving many inquiries about a possible deal. An Apple spokesman said the company was not willing to comment on future products.

Cohen has also been told that Google is planning to swap out a number of traditional spinning hard disk drives in its headquarter's servers for SSDs in order to serve up faster random reads to bandwidth-hungry applications and lower energy consumption.

Google was mum when asked about the hardware change-out. "We don't disclose specifics about our infrastructure or hardware," said Eitan Bencuya, with Google corporate communications.

While the number of SSDs being deployed at both Apple and Google is likely small in comparison to the market for hard disk drives in general, it does send a strong message about the validation of the technology in the data center in terms of energy savings, as well as an important endorsement of the Intel-Micron NAND memory, Cohen said.

To date, SSD adoption has not met analysts' expectations, he said.

"Higher performance requirements and therefore higher price tolerance of data center applications were hoped to kick start the market for SSDs and progress on that front should be positive for all the NAND players," Cohen wrote in a research note Monday.

Intel Corp. and Apple are also working to produce an MLC SSD drive that is expected to be unveiled late this quarter and that they plan to market together (see also "Intel, Micron unveil high-speed NAND technology").

While SSDs often don't offer any significant performance boost in terms of sequential reads and writes over traditional spinning hard disk drives, they do offer a tremendous boost in terms of random reads, according to Cohen and other experts such as Intel fellow Rich Coulson. That allows enterprise IT managers to consider them for customizing network performance. For example, relational databases that perform many random reads would be able to take advantage of SSD's faster speeds.

However, a major issue facing the adoption of SSDs is longevity. There are only so many times an application can rewrite data to the cells in NAND memory before they wear out and become unreliable.

There are two major types of solid state memory: SLC NAND memory, which writes one bit per cell, and MLC NAND memory, which writes two or more bits per cell. MLC offers greater density and lower cost, but because it writes multiple bits per cell, it also tends to wear out faster, according to Cohen and other experts. One fix for addressing the wear level of memory is larger SSD drives that offer more area on which to write data, but with more capacity comes greater cost, Cohen said. Another way of addressing memory life is something called "wear leveling," or the use of software to distribute data more evenly across the silicon so as to not wear out one area faster than another, and thereby prolonging the life of erasable computer storage memory. But wear-leveling software is still in its infancy.

Yet another issue facing SSD adoption is error correction, or the ability to fix errors caused by noise or other impairments during data transmission, which is more difficult to perform on more cost-effective MLC memory.

"We're at the proof-of-concept stage for all of these new solid state drives. True MLC drives are just starting to filter out there," Cohen said. "We need to see these things operate over a year or two and see true failure rates and get a better sense of where and how they would work as replacement drives."

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