SAN FRANCISCO — The landscape is shifting in the emerging market for solid-state storage drives (SSDs). Micron Technology last week entered the fray, and Toshiba stands poised to join the rapidly crowding field, whose proponents promise to propel the technology into the mainstream PC market at the expense of the lowly hard drive.

Based on standard NAND flash, SSDs constitute a new class of rugged, low-power systems that could threaten power-hungry hard disk drives (HDDs), whose mechanical parts make them susceptible to failures in the field. But analysts differ on when flash-based storage might make headway in mainstream PCs, since OEMs face cost and design barriers, including the lack of NAND controllers optimized for drive applications and the write-cycle limitations of multilevel-cell NAND flash.

In some cases, today's SSDs provide less performance and are up to 45 times more expensive than rival hard drives in PC, industrial and related storage applications. Meanwhile, thanks to perpendicular recording technology and other futuristic schemes, workhorse hard drives are expected to continue to scale for several years, possibly pushing out the need for SSDs to the next decade.

SSDs must make dramatic improvements in both cost and design before the PC community will consider widespread adoption, said analyst Joseph Unsworth at Gartner Inc. (Stamford, Conn.). He foresees a long "education process" before OEMs and end users understand the benefits of SSDs for notebooks, desktops and server farms.

Unsworth puts the tipping point for SSDs at 2009, though other analysts do not expect widespread adoption until 2011 or 2012.

Most SSDs today are niche-oriented products sold into "nontraditional" drive markets such as the industrial and military sectors, said Jeffrey Janukowicz, an analyst at International Data Corp. (IDC; Framingham, Mass.). PC OEMs like Dell and Hewlett-Packard offer SSDs as an option for their systems, but the solutions are often expensive and are not widely advertised on the vendors' Web sites. A 32-Gbyte SSD sells for some $350, while a 160-Gbyte hard drive goes for less than $100, Janukowicz noted.

Alan Niebel, chief executive of Web-Feet Research Inc. (Monterey, Calif.) put the average cost per gigabyte at $10 for SSDs and 30 cents for hard drives. "If you want to see big adoption of SSDs, they must hit $1 per gigabyte," Niebel said. He doesn't expect that magic price point to arrive before 2011--and by that time, hard drives are expected to cost a mere 10 cents, and perhaps as little as 3 or 4 cents, per gigabyte of storage.

At present, the SSD market is dominated by smaller players, such as BiT Micro Networks, Mtron, Super Talent and Stec. These vendors do not have fabs and must procure NAND parts from outside suppliers. And only a few of the SSD vendors develop their own controller technologies.

But the potential for PC market adoption of solid-state drives is changing the SSD landscape. Some 40 vendors are already chasing a total SSD market that IDC expects to grow from $373 million in 2006 to $5.4 billion by 2011. Intel, SanDisk and Samsung have recently rolled out SSD products. Now Micron has tossed its hat in the ring, and Toshiba may be next.

This week, Micron rolled out the RealSSD family of drives for PC, embedded and related applications. Based on Micron's own NAND flash devices, the new solid-state drives vary in density from 1 to 64 Gbytes.

A spokeswoman for Toshiba, meanwhile, confirmed that the NAND giant expects to field a drive early next year.

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For Intel, Micron and Toshiba, SSDs represent a new NAND growth driver and an avenue to sell their internal capacity. Even the disk drive community is seeing the SSD light, with Seagate and others expected to enter the fray in 2008. Most of the chip and drive giants are developing their own controllers.

The eventual winners in the marketplace? It's too early to tell, but some see a shakeout on the horizon.

"Obviously, the fabs guys have a cost advantage," said Niebel of WebFeet. "But you will still need to have the critical intellectual property and controller technology" to succeed.

As the larger players take the field, averaging selling prices for solid-state drives are expected to fall. Some even foresee a price war, especially with Samsung's thrust and the eventual entry of Toshiba.