US Patent 7474491 Adaptive write unsafe thresholds for self servo writing

An apparatus and associated method is provided for observing a positional misplacement of a control object at a first commanded position, defining a fault threshold as a function of the observed positional misplacement, and signaling a write unsafe command to the control object in relation to comparing an instantaneous positional misplacement of the control object to the defined fault threshold during self servo writing with the control object.