Hitachi Global Storage Technologies (HGST) is planning capacity increases for its 2.5in hard-disk drives over the next 12 months, the company said on Wednesday.

The company's 2.5in line, which is typically used in laptop computers and some consumer products, currently tops out at 160GB for the 5,400rpm (revolutions per minute) drives and 100GB for the faster 7,200rpm models, but that is set to change.

In the first half of 2007, HGST anticipates a 200GB 7,200rpm drive and in the latter half of the year a 5,400rpm drive with a capacity of around 250GB, said Larry Swezey, director of the mobile product strategy at HGST, in a telephone interview. The faster drive will have a lower capacity than the slower drive because the complexity of storing and reading back data rises with the drive's speed.

The drives will employ perpendicular recording to achieve their higher capacity. The technology is fast becoming common in hard disk drives because it allows for considerably more data to be stored per square inch than the longitudinal recording method that has been most common.

In longitudinal recording, the north and south poles of the magnetic particles used to store data run parallel to the disk, but in the new method they are arranged perpendicular to the disk. The result of this new arrangement is that each particle occupies a smaller area of the disk's surface and so more particles can be crammed onto the disk.

Hitachi has been mass producing disk drives that use perpendicular recording for about six months and has recently made its millionth drive. It expects to produce four million drives using the technology by the end of this year.

The new drives coming next year won't just offer more capacity. Both will be available in versions with embedded flash memory and hardware data encryption.

The embedded flash memory will act as a temporary buffer reducing the number of times the drive needs to read and write data from the drive. This will speed up performance and also cut down on power consumption - both important for battery-powered laptop computers.

Hardware data encryption employs a custom chip in the disk drive to encrypt and decrypt data on the fly. The system should help keep data secure if a laptop is misplaced or stolen and will be promoted to companies who have employees that store personal information about customers and staff on their hard-disk drives.