A magnetic head according to one embodiment includes a reader and a thermal sensor for detecting a thermal effect thereon from a magnetic medium passing by the thermal sensor. A tape drive system according to one embodiment includes a magnetic head for reading data from a magnetic tape, a thermal sensor for detecting a thermal effect thereon from the magnetic tape passing by the thermal sensor, a drive mechanism for passing the tape over the head, and a processor for causing alteration of a readback signal from the magnetic head based on an output of the thermal sensor.