There is provided an actuator for a disk drive. During a read access of one of the memory cells, the sense amplifier connected to the memory cell to be read out evaluates a cell voltage of the memory cell to be read out and generates a data item with a logical Low or High level depending on the level of the cell voltage at a data terminal. With this technology, data can be searched conveniently without manipulating keys many times. A secondary table also includes raceway assemblies connected to a secondary winding circuit.