Seagate Technology has begun shipping a 160GB hard drive for laptops.

The drive, which is the highest-capacity 2.5-inch drive on the market according to the company, was promised last year and is Seagate's first laptop drive to use perpendicular data recording. This involves standing the magnetic fields that represent data bits upright. In most current drives these fields lay flat on the disk surface. Standing them upright means they take less space, enabling more to be packed on the disk and the storage capacity to be increased.

Seagate first announced this drive last year and said it would ship in the first quarter of 2006. By the end of this year, the company expects nearly all of its products will use perpendicular recording. The same technology is also being fast adopted by other disk makers.

The Momentus 5400.3 drive is, as its name suggests, a 5,400 rpm (revolutions per minute) drive designed for notebooks. The version shipping now has an Ultra ATA/100 interface and a second version with a faster Serial ATA interface will be available later this year, said Seagate. No price was given for either drive.