Disk drive having double heads and method for controlling head switching

Abstract

A disk drive constructed according to an exemplary embodiment of the present invention includes a disk having a plurality of tracks formed concentrically along a first surface of the disk for storing data. The tracks are divided into first and second data storage regions positioned between an innermost circumferential region and an outermost circumferential region of the disk. First and second heads write and read data to and from the first surface of the disk. The first head is positioned to access the first data storage region while the second head is positioned to access the second data storage region, and the first head being positioned to access the second data storage region while the second head is positioned to access the first data storage region. First and second arm assemblies are respectively connected to the first and second heads. The first arm assembly extends the first head over a first radius of the disk, and the second arm assembly extends the second head over a second radius of the disk. An actuator shifts the first and second heads among the tracks by driving the first and second arm assemblies. A control unit enables selection of the one of the first and second heads that is closer to a target position on the first surface of the disk so that the closer head can access the data at the target track.