Toshiba has begun shipping the MK4007GAL – what it claims is the world's first perpendicular hard disk drive. Perpendicular recording increases disk capacity by aligning the millions of magnetic domains at 90° to the disk's surface rather than parallel to it. The drive is a 1.8in unit and provides 40GB of storage on a single platter. It is 5mm thick and weighs 51g.

That will allow the likes of Apple to offer either slimmer, lighter music players or use the space freed up by the slimmer HDD to increase the size and capacity of the battery. Apple already uses Toshiba's 1.8in HDD family in the iPod.
Toshiba said that a two-platter, 80GB version should be available later this year. Both drives spin at 4200rpmm, and provide a parallel ATA-100 interface. Perpendicular technology is being pursued by a number of HDD manufacturers, with Seagate expected to release a 2.5in, 160GB perpendicular HDD for notebooks later this year.