The feature, called ReadyDrive, could also reduce the incidence of hard disk crashes due to shocks" the most common hardware failure in notebooks" by decreasing the amount of time the disk needs to be spinn

Notebooks will be the first systems to leverage the technology, but its potential is much broader, said Ruston Panabaker, an architect in Microsoft Corp.'s Windows hardware innovation group. "We fully expect to see it show up in desktops and perhaps even in specific server applications," he said.

ReadyDrive has spawned a new category of flash-assisted hard drives. Both Samsung Semiconductor Inc. and Seagate Technology have announced hybrid drives that integrate a 1.5-in. magnetic hard disk with up to 256MB of onboard flash. Both are expected to be available early next year. A competing technology from Intel Corp., code-named Robson, places the cache on the motherboard, along with a controller chip. Robson will launch with Intel's Santa Rosa notebook platforms in the first quarter of 2007.

"The interface to flash chips has been doubling in read and write performance every single year," Panabaker said. This year market research company IDC predicted that flash prices would drop by 55 percent. Halfway through 2006 prices have already exceeded projections. Current prices have dropped into the $17.50 per GB range, and the trend is expected to continue.

Because disk I/O speeds haven't kept up with CPU horsepower gains, it was just a matter of time before storage vendors turned to flash. "Vista was certainly the catalyst," said IDC analyst John Rydning, but the use of hybrid drives could well expand beyond Windows systems.