The present invention relates to a method and apparatus for performing communications by adjusting a resource unit. For each sub-pixel shift, an overall energy is calculated and is based on a plurality of gradients that represent changes in a channel value among the shifted first pixels and the mapped second pixels. A solid-state laser is attached to or incorporated into the slider or head and is positioned to direct thermal energy through a waveguide and onto a track of a readwrite surface to lower the coercivity of the recording medium to facilitate the write process. Further, a switching mechanism including switches for selectively connecting the fuel cells to the power generation circuit or selectively disconnecting the fuel cells from the power generation circuit is provided.