Techniques are provided for performing file operations. The underfilm is a Group III nitride including at least 50 atomic percent of elemental Al for each of the Group III elements of the underfilm Group III nitride. This amplitude and phase information is sent to an overshoot current generator to generate an overshoot current that is responsive to the dynamic impedance properties of a magnetic write head during operation. The elevator device includes a ladder attachment assembly to affix the device to a ladder or ladders, a lateral travel section, and a roof top mounting device.