Tape Bias from the Technician's Perspective (a little technical)

From a technician's perspective, how recording tape bias works. Note: I might not of been clear about the relationship of a tape's coercivity and hysteresis to the bias. The optimal amount of bias for any given tape material is directly proportional to the tape material's coercivity and hysteresis. i.e.: the higher a tape's coercivity and hysteresis is, the higher the bias value must be for optimal tape performance!