A drive unit drives a wafer stage in a Y-axis direction based on a measurement value of an encoder that measures position information of the wafer stage in the Y-axis direction and based on information on the flatness of a scale that is measured by the encoder. During standby andor a read operation of the SRAM cell, one of the fifth primary current path and the sixth primary current path is conductive. The controller is configured so that the application programs can concurrently access the random access storage device as a sequential access tape storage device.