may be made of a magneto resistive mr material the transducer 16 may be integrated into the slider 20 the slider 20 may be constructed to create an air bearing between the transducer 16 and the disk surface 18 the slider 20 may be incorporated into the hga 22 the hga 22 may be attached to the actuator arm 24 which has a voice coil 26 the voice coil 26 may be located adjacent to a magnet assembly 28 to define a vcm 30 a current applied to the voice coil 26 generates a torque for rotating the actuator arm 24 about a bearing assembly 32 rotation of the actuator arm 24 moves the transducer 16 across the disk surface 18 information is typically stored in circular tracks 34 of the magnetic disk 12 in general each track 34 is divided into a plurality of sectors each sector may include a data field and an identification field the identification field may contain gray code information which identifies the sector and track cylinder the transducer 16 is moved across the magnetic surface 18 to write or read information stored in another track the movement of the transducer between different tracks is generally referred to as a seek routine as shown in fig2 a disk drive according to the present invention includes a disk 12 a transducer 16 a pre amplifier 210 a read write r w channel 220 a buffer 230 a controller 240 a rom 250 a a ram 250 b a host interface 260 a vcm driving unit 270 and a voltage detection unit 280 the rom.