DATA RECORDING AND REPRODUCING DEVICE

PURPOSE:To effectively use a storage area without unnecessarily recognizing a defective sector by setting an error byte reference value for recognizing a defective sector at the initializing time and at the normal time respectively and the max. number of error correctable bytes to satisfy a prescribed relationship. CONSTITUTION:At the read time, error correcting information is read out together with data from a specified sector of a disk 3, and the read data is checked to recognize whether this sector is a defective sector incapable of correcting an error by an error correcting block 5 of an optical disk controller 7 in accordance with a command of an MPU 1. For this recognition, the max. number M of error correctable bytes, the initializing time error byte reference value N1 and the normal time error byte reference value N2 are used to satisfy the condition of an expression of M>N2>>M1, and an unnecessary defective sector is not recognized by this setting in response to a phenomenon of a strong probability that a defect at the initializing time is increased and expanded in accordance with hereafter recording and reproducing, and hence the storage area can effectively be used.