The five largest hard-disk drive vendors have agreed to promote a new flash technology that promises to greatly improve PC performance.

Hitachi, Seagate, Fujitsu, Samsung, and Toshiba have formed the Hybrid Storage Alliance group to promote the technology, which is expected to come to market later in the first quarter.

Hybrid disks include flash memory that works like a buffer between the computer system and the disk. The memory will be used for short-term storage heading both to and from the disk and will mean an overall reduction in the amount of time the disk spins. That will reduce power consumption and a performance boost is also expected because reading and writing data from flash memory is significantly faster than from a disk.

"It takes advantage of the capacity of the hard-disk drive and the snappiness of solid-state technology," said Marc Noblitt, senior interface market development manager with Seagate. "When the PC comes out of hibernate it has the correct data in the flash to come out much quicker."

The technology has been developed by Microsoft and support is built into the new Vista operating system that goes on general sale on January 30. It's designed to eliminate the delay familiar to many computer users while the machine locates and loads a file from the hard disk. By anticipating the next required file and having it in flash memory the system can get it immediately.

The group will evangelise the technology to users and seeks to expand beyond its five members to companies such as chipset vendors and benchmark system makers, said Joni Clark, product marketing manager for notebooks at Seagate.

Several of the companies have already demonstrated prototype drives with built-in flash memory.

Last year Samsung demonstrated drives with 128 MB and 256 MB of embedded flash at the Windows Hardware Engineering Conference (WinHEC) in Seattle in May and followed up in July by announcing the development of a drive with 4 GB of flash memory. Both Seagate and Hitachi are planning drives.

Hybrid drives face competition from an Intel-backed technology called Robson, which seeks to achieve the same benefits by placing a flash memory cache in the computer. It has the advantage of working with any current hard-disk but requires a new interface card, said Noblitt.

"On boot performance and overall performance both should be comparable," said Noblitt. When it comes to battery performance he said he thought hybrid will have the edge. "We're storage companies and we know when best to get data so we think we'll have the advantage."

The Intel system is due in new laptops from the second quarter of this year.