Abstract: The present invention relates to a method for operating an optical drive system capable of reproducing/recording information from/to an optical carrier (30), wherein a position error and a speed error of a radiation spot (12, 53) on the carrier has been created due to an unreliable error signal which has been generated due to a surface defect (52). The method includes the steps of registering values of e.g. servo signals, determining the occurrence of a defect using a defect detector DEFO (22), generating a first and a second compensation signal and applying these compensation signals to the control system (10) of the optical drive system. The first compensation signal is capable of reducing the speed error and the second compensation signal is capable of reducing the position error. Thus, the application of the compensation signals immediately after the unreliable error signals reduces the position error and the speed error of the focussed radiation spot (12, 53).

Abstract: A method for detecting a mechanical shock affecting on optical disc drive based on using the Focus Error (FE) and/or the Tracking Error (TE) servo-loop signals. An shock detection signal is generated as weighted time-integral of the servo loop signal, for example by using the integral signal of the PID controller of the servo loop, or a low pass filter, or digital integration by a Digital Signal Processor (DSP). A shock is considered to be detected if the shock detection signal exceeds a threshold value. A method for recording data onto an optical disc and the corresponding optical disc drive are also disclosed. The shock signal is monitored real time and the recording is interrupted if a shock is detected. The recording is resumed by linking from the last recorded area when the shock signal becomes low again.

Abstract: The present invention relates to a method for operating an optical drive system capable of reproducing/recording information from/to an optical carrier (30), wherein a position error and a speed error of a radiation spot (12, 53) on the carrier has been created due to an unreliable error signal which has been generated due to a surface defect (52). The method includes the steps of registering values of e.g. servo signals, determining the occurrence of a defect using a defect detector DEFO (22), generating a first and a second compensation signal and applying these compensation signals to the control system (10) of the optical drive system. The first compensation signal is capable of reducing the speed error and the second compensation signal is capable of reducing the position error. Thus, the application of the compensation signals immediately after the unreliable error signals reduces the position error and the speed error of the focussed radiation spot (12, 53).