Hitachi Ltd's hard disk drive unit said on Sunday that it will invest approximately $200 million in its Thailand factory to double disk drive output of its 1-inch, 4-gigabyte disk drives that are found in the iPod Mini.

The investment will reportedly boost production of Hitachi's Microdrive to about 2 million units per quarter by the end of the year, up from 200,000 per month in the first quarter of this year, John Osterhout, who manages Hitachi GST's Microdrive program, told Reuters.

In March, Cupertino, California-based Apple Computer said it would delay global sales of the iPod Mini because it couldn't get enough of the hard drives to meet U.S. demand, which had then surpassed supply through June. The company now plans to sell iPod outside the United States starting in July.

Hitachi GST said that the Thailand Board of Investment had approved the expansion of the plant's capacity to 60 million units annually from 30 million. In addition to the Microdrive, the Thailand plant also produces Hitachi GST's 2.4-inch Travelstar drives used in laptops and its 3.5-inch Deskstar drives used in desktop PCs and personal video recorders.

Bill Healy, Hitachi senior vice president, said in Bangkok today that the company would add about 4,000 workers to its staff of 12,000 employees and contract workers to boost production.

Healy said the expansion will raise to $1 billion the total investment made by his firm in Thailand since 1997. He said many components of Hitachi's hard disk drives produced in Thailand came from its computer parts factories in Futian and Shenzhen in China.

As a result of these measures, the current six-week waiting list to get an iPod Mini digital music player from Apple is likely to get shorter by the end of 2004.