A command user interface with via mask programmability includes a decoder with transistors selectively coupleable to one of an input or its complement. In addition, use as a write or read region a specified region of the recording medium which is greater than or equal to a unitary data size being handled during error correction processing to be performed when writing or reading image information on or out of said recording medium. A curvature radius of a surface of the second lens on the object side is positive. The request may indicate that the channel quality indication is to be based on measurement of the reference signal. A tri-layer indium gallium nitride active region is employed.