Seagate Technology on Thursday introduced a 1.5 for the desktop, and two half-terabyte notebook drives.

The Barracuda 7200.11, the 11th generation of Seagate's flagship drive for desktop PCs, is targeted at mainstream computers, workstations, and gaming and high-end PCs. it achieves the high capacity through the use of what it calls which arranges the magnetic bits vertically on end on the surface of the disc to boost storage.

The 3.5-inch drive packs its on four platters and has a of 3 gigabits per second and a sustained data rate of up to 120 megabytes per second for faster times, application startup and access. The drive is also available in models between 160GB and 1TB.

For the faster growing notebook market, Seagate introduced the Momentus 7200.4 and the 5400.6. The former has a spin speed of 7,200 revolutions per minute and the latter a speed of 5,400 RPM . Both are 2.5 inches and a have a interface of 3Gb per second. The drives also have shock protection technology that parks the heads off the disc when it senses that the notebook is in free fall of as little as eight inches, Seagate said.

The three drives include a five-year warranty. The Barracuda 7200.11 is scheduled to ship in August. The Momentus notebook drives are expected to ship in the fourth quarter.

Seagate and rivals Hitachi and Samsung are rushing to produce the highest capacity devices for the PC to meet the rising demand for storage. Hitachi, for example, recently introduced a second-generation 1TB hard drive.

Much of the demand is driven by the increasing use of PCs to edit and store video, photos and music. All the major PC makers, such as and Hewlett-Packard, sell entertainment-focused computers.