Abstract: Provided are a method and a device for permanently erasing data of an optical disk in an optical disk drive including an optical disk emulation. According to the method, an erase command of data recorded on an optical disk is received and it is determined whether the optical disk is a rewritable optical disk or not. Then, an output power of a laser to be projected is raised when the optical disk is the rewritable optical disk and then the data recorded on the optical disk are erased through an output power of the laser. Furthermore, the optical disk drive includes an optical disk storage unit, a contents memory unit, a disk type determination unit, a laser power adjustor, a pick-up unit, and a controller.

Abstract: A Maximum Likelihood Sequence Estimator comprises a signal receiver (401) which receives a first signal for decoding. An ISI processor (403) generates a compensation signal from the first signal. The compensation signal represents intersymbol interference outside a channel model window of a Maximum Likelihood Sequence Estimation (MLSE) but does not represent intersymbol interference within the channel model window of the MLSE. A compensation processor (405) generates a compensated signal by compensating the first signal by the compensation signal, e.g. by subtracting the compensation signal from the first signal. The compensated signal is fed to a MLSE decoder (407) which decodes data of the first signal by performing the MLSE on the compensated signal. The invention may provide reduced detection error rates and may in particular be suitable for optical disc reading systems.