Verifying data by controlling the gain of an amplifying means according

Abstract

In a disc drive device upon recording, the writing of data is executed and thereafter the reading of data is executed to verify, i.e., make a check as to whether the written data can be properly read out. In this case, the gain of a gain control amplifier for amplifying a reproduced signal is set so as to be lower than usual and a window width of a window comparator is set so as to be greater than usual. An error rate in a bubble shaped region in which the amplitude of the reproduced signal is small, is rendered high. Thus, verify can be taken as NG when recording power falls within the bubble region. Verify is determined based on RESYNC bytes added every predetermined data intervals, i.e., detected information about patterns for data having the minimum and maximum inversion intervals as well as on error information. As a result, verify can be reliably taken as NG even when the recording power is placed in a region between the bubble shaped region and a normal region. Thus, the accuracy of verify can be enhanced.