Samsung Electronics yesterday unveiled what it claims to be the first commercial prototype of a hybrid hard disk (HHD), a next-generation drive for notebooks and PCs that integrates Nand Flash memory with traditional rotating magnetic storage.

The HHD will initially be available with two cache densities: 128MB and 256MB.

The high densities of magnetic storage technology are preserved but augmented by the exceptionally low power, high reliability and fast read/write access of advanced Nand Flash technology "at minimal additional cost".

Samsung claimed that the system boots or resumes twice as fast as conventional hard disk drives, lasts 20-30 minutes longer when running on battery power and is up to five times more reliable.

The HHD eliminates the need for the hard disk to spin constantly whenever a computer is operating on battery power, and is less susceptible to damage from jarring or being dropped since it is idle most of the time.

Every time the cache is filled, the rotating drive spins to "flush out" or transfer data from the cache, spinning only a few seconds every 10-20 minutes.

The HHD saves between eight and 25 seconds of boot-up time and extends laptop battery life by up to 10 per cent depending on the model of computer.

Samsung will test the device with customers in the next quarter, and intends to ship the HHD in large quantities by January in conjunction with the Windows Vista rollout.

"HHDs and Windows ReadyDrive are integrated advancements that improve the performance and reliability of computers using Vista, especially notebook computers," said Mike Sievert, corporate vice president of Windows client marketing at Microsoft.