"The best use of solid-state disk is direct-attached, not in a shared network array," Workman says. "The reason for that is the latencies for solid-state disk are so low that putting it on a network to get at it actually makes the latency of the solid-state disk much worse than it could be."

Pillar doesn't sell flash today, but designed its Axiom storage system so that flash can be easily embedded when it becomes more cost-effective. Sun Microsystems has gone the direct-attached route, saying it plans to embed flash storage in nearly all of its servers by year-end. 

Turning point for flash

Solid-state disks and flash drives are nothing new. Texas Memory Systems, for example, has been selling solid-state disks for three decades, notes Woody Hutsell, the vendor's executive vice president. Texas Memory specialized in RAM-based solid state drives, which are used for the most latency-sensitive applications because it's even faster than flash, he says. The downside is RAM requires backup batteries, because data can be lost if the power goes out. That's not a problem with flash, but Texas Memory Systems resisted the urge to sell a flash product until January of this year.

"Every other year, we'd look at flash and say 'is it time?'" Hutsell recalls. "For the longest time, the answer was no."

Only recently have manufacturers begun making flash chips with higher densities and at a lower price point than RAM, he says. Texas Memory made its RamSan product available with flash in January.

Hutsell credits the consumer electronics market and EMC's decision to sell flash as the turning points.

"What's happened over the last two years is that due to rapid adoption of flash in the consumer electronics market, the price of flash chips dropped dramatically," Hutsell says. "The real effect of EMC entering the solid-state market is adding credibility to the message we've been delivering for 30 years, which is that there are applications that are slowed down by hard disk drives."

EMC in January unveiled its plans to sell 73- and 146-gigabyte solid-state drives using flash memory, and made a bold prediction last month: Flash storage technology will be nearly as inexpensive as high-end disk drives within two years.

EMC, which uses flash chips built by manufacturer STEC, is counting on its own bulk buying power to drive prices down. Currently, flash chips are about 20 times more expensive than high-performance Fibre Channel drives on a per-gigabyte basis, EMC's Wambach says. By 2010, flash will only be double or triple the cost of those high-end drives, making it cost-effective enough to hit the mainstream, he says.