Micron preps 256GB solid-state drive

Micron Technology announced Tuesday that it will ship a series of solid-state drives next quarter ranging up to 256 gigabytes in capacity, but at one-third the price per gigabyte of existing drives.

Micron's RealSSD-branded products are targeted at both the corporate enterprise and laptop markets--the latter drives priced significantly lower. The Boise, Idaho-based memory chip manufacturer's entry into the high-capacity SSD market presages Intel's launch of a line of SSDs later this year. Intel and Micron have a partnership to jointly manufacture flash memory.

SSDs generally are faster and more power efficient than hard disk drives, though there is an ongoing debate about the degree to which SSDs exceed hard disk drives in power efficiency.

The P200 enterprise drives use single-level cell (SLC) technology, while the less expensive C200 consumer drives are based on multi-level cell (MLC). MLC allows drive makers to build larger capacity drives at lower cost but is not as fast as SLC nor inherently as reliable. Though SLC solid-state drives are used currently in laptops such as the Apple MacBook Air and ThinkPad X300, in most cases they will be replaced by MLC drives in future laptop models.

RealSSD C200 drives based on MLC technology will be available in 2.5- and 1.8-inch form factors. The former ranging in capacity up to 256GB, rivaling the capacities now seen in mainstream notebook hard disk drives. The 1.8-inch C200 will range in density from 32GB to 128GB, Micron said.

Typical laptops today use 2.5-inch hard disk drives, while ultra-portables such as the MacBook Air use 1.8-inch drives.

In a departure from many SSDs to date, the C200 is spec'd with a high-speed 3-gigabit-per-second Serial ATA (SATA) interface. A number of SSDs on the market today use a slower PATA (Parallel ATA) interface. The C200 products provide a read speed of up to 250 MB/s and a write speed of up to 100 MB/s, Micron said.

C200 laptop drives will be about one-third the price of enterprise drives, Micron said. "Today on the open spot (market) a gigabyte of MLC NAND (flash memory) is about one-third the price of a gigabyte of SLC NAND. Therefore a 64GB C200 (laptop drive) will be about one-third the price of a 64GB P200 (enterprise drive)," Micron said in a statement. The company is not yet revealing specific pricing information yet.

Initially, analysts see adoption of laptop drives at the extremes of the market. "We are convinced that on the very low end and on the very high end SSD will penetrate the NoteBook/Netbook markets but the mainstream notebook will remain HDD for the foreseeable future," said Avi Cohen, managing partner at Avian Securities. "Progress in general on SSD adoption has been slower then we would of all preferred or predicted. And the truth is wider adoption for SSD will probably take a bit longer."

Micron, Intel, Samsung, and others must also continue to assure users that SSDs are just as reliable as hard disk drives. "SSDs age gracefully. They degrade gracefully. We can predict (this) based on your usage model how much longer that drive will last," said Dean Klein, vice president of memory system development at Micron.

"Typical raw NAND write endurance is ten thousand cycles for MLC. While, SLC is typically a hundred thousand cycles," Klein said. "The typical notebook user only writes two to four gigabytes per day. Even if you look at 40 or 60 gigabytes a day, you still don't need the 10,000 cycles of MLC in five years," Klein said.

SSD manufacturers have been on a learning curve, Klein said. "One of the things that SSD manufacturers have been slow to learn (is that) you can't just take a compact flash controller, throw some NAND on there and call it an SSD," Klein said. The controller manages the reading and writing of data on an SSD. "The application of storing data on a notebook--and certainly on the enterprise--is far different than that controller was designed to support," he said.

Klein claims Micron's SSD overcomes this with an intelligent processor and plenty of DRAM memory (64MB). "We've got a lot of processing power in this controller. We've got a very large DRAM buffer attached to this controller. So having that DRAM buffer both allows us to increase the performance of the drive...in addition to minimizing the wear."

Micron's P200 enterprise drives "achieves sub-millisecond latency while a typical enterprise hard disk drive has an average latency of approximately eight milliseconds," the company said. The P200 consumes about one-tenth the power of a typical data center hard drive, operating at 2.5 watts in active mode and under at 0.3 watts in idle. The P200 requires almost zero cooling, keeping power consumption low, Micron added.