A complex objective lens composed of a hologram and an objective lens, capable of realizing stable and high-precision compatible reproducingrecording of a BD with a base thickness of about 0. One method, which can be performed by each node in a cluster, involves associating a current sequence number with each of several write operations included in a set of independent write operations. The phase of the reference waveform depends on a previous modulated bit, and a difference in phase between the reference waveform and the data waveform pair depend on the current bit. The first ends of the first and second sidewalls extend from the base surface. The position-based attribute of the object is then determined with respect to the plurality of electrodes from the electrical effects. The mining machine also includes a first disc cutter adapted to engage the material to be mined and mounted on a first disc cutter assembly for eccentrically driving the first disc cutter, the first disc cutter assembly being mounted within the substantial weight.