A main pole layer of a magnetic head includes a first portion disposed at a distance from a medium facing surface, and a second portion that is smaller in thickness than the first portion and disposed between the first portion and the medium facing surface. When a mode signal included in a test signal input from an external connection terminal indicates a \u201cnormal operation mode\u201d, a test circuit provided on a logic chip allows a logic circuit to use an access path to a memory circuit. The transfer link is a selectively compliant beam having a first rigid section and a second rigid section connected to each other via a flexible area. A spindle end arranged in the first space is displaceable in its longitudinal direction and rotatably mounted. The parameter is output power, a resistance of the load, an output current, an output voltage, or functions thereof in various embodiments.