Hitachi Global Storage Technologies has announced a line of notebook hard drives which are designed to withstand rougher treatment than previous models.

Hitachi hopes the Travelstar 4K40's tougher specifications will help the company boost its fortunes in the booming market for laptop hard drives. The drives boast better shock-handling and failure-rate specifications than those of competitors, although it remains to be seen whether this will prove more attractive than features such as faster access to data.

Hitachi claims the drives, which spin at a rate of 4,200 revolutions per minute, can withstand a shock of 300 gravities (G) at two milliseconds (ms) while operating, or 1000G at 1ms when not in use. Higher gravities and milliseconds indicate greater shock resistance.

The company has also increased the load/unload cycle, the number of times the read/write head can move on and off the media without failure, to 600,000 times, which Hitachi says is twice the industry standard specification. The drives achieve their improved reliability partly because they use a single platter and use fewer chips and other components than previous models. They also use an improved actuating arm design to reduce the risk of contact between arm and disk.

"We've painstakingly manipulated every possible feature on the new Travelstar to boost reliability while maintaining the sweet spot at 40GB," said Bob Holleran, Hitachi GST's general manager for 2.5 and 1.8 inch hard disk drives. Hitachi and other companies make drives with capacities greater and less than 40GB, but that capacity is currently considered the most mainstream.

Hitachi is hoping that reliability will prove a unique selling point for its drives, by promising a nearly indestructible warehouse for customers' mobile data, while other manufacturers have focused on other benefits such as spin speed. For example, Seagate's Momentus notebook drives have a 5400 rpm spin speed, compared to the Hitachi's 4200 rpm, and so deliver information faster to the notebook's processor. The Momentus drives have an operating shock specification of 225G for 2ms and non-operating shock of 800G for 2ms.

By comparison, Seagate's Savvio 2.5 inch enterprise drives spin at 10,000 rpm and have much lower shock ratings, at 20G (2ms) for operating shock and 275G (2ms) for non-operating shock.

Fujitsu and Toshiba produce drives for their own notebook computers. The Fujitsu 2.5-inch MHT2040AT drive, comparable to Hitachi's 4K40 with 40GB capacity at 4200 rpm, has an operating shock measure of 225G (2ms) and an non-operating shock of 900G (1ms). Neither Maxtor nor Western Digital produce drives in this area.

There is no measured direct relationship between a notebook drive's internal reliability and its ruggedness and performance in the field, but the two are thought to be linked. The Hitachi drives are aimed at third-party notebook makers.

The new HGST drives are available in 20, 30 and 40GB capacities. Hitachi sells higher notebook drive capacities in its 80GN and 4K80 lines.