The higher the areal density, the more data an HDD can store. Fujitsu's MHS Series 2.5-inch HDD only needs two platters for a total capacity of 60Gbytes. IBM's Travelstar 60GH has four platters and an areal density of only 28 G bpsi, and Toshiba's MK6021GAS has two platters but an areal density of only 48.8G bpsi.
The 2.5-inch HDDs are used for mobile devices such as notebook PCs and portable HDD subsystems. Fujitsu expects expects its products to be used in digital audio players and consumer electronic products.