Hitachi’s hard disk drive unit said Sunday that it will spend about $200 million to double the disk drive output of its Thailand factory, including the 1-inch, 4GB disk drives that are found in the iPod Mini. Production of Hitachi Global Storage Technologies’ Microdrive will rise to about 2 million units per quarter by the end of the year, from 200,000 in the first three months of this year, said John Osterhout, who manages Hitachi GST’s Microdrive program.