Abstract: According to one embodiment, an information recording apparatus comprises a recording unit which records information in blocks in a rewritable medium, a buffer which stores recording information of blocks while performing update, and stops the update of information when the write error is detected, an identifying unit configured to play back recording information of the information recording medium corresponding to the blocks when the write error is detected, and to identify a block including a write error occurring position based on whether a playback of the recording information has succeeded or not, and a re-recording unit configured to re-record the block identified by the identifying unit.

Abstract: An optical disk drive includes an optical pickup which emits a light beam onto an optical disk, and receiving a reflection light to output a signal in accordance with the reflection light, a PRML processing unit which carries out signal processing with respect to the signal output from the optical pickup using a partial response and maximum likelihood (PRML) technique, a focus offset setting unit which sets a focus offset value used for focusing the optical pickup based on a difference value between a signal processed by the PRML processing unit and the signal output from the optical pickup, and a focus control unit which controls a focus of the optical pickup in accordance with focus offset set by the focus offset setting unit.

Abstract: An optical disk apparatus includes an error arithmetic circuit which detects the relative position between the position of an LPP portion and data which is being recorded, switching units which switch a reference clock source to change the frequency of a correction clock output from a PLL unit to generate a data recording clock for a predetermined time on the basis of the direction and magnitude of a shift in the relative position between the data being recorded and the position of the LPP portion, which is detected by the error arithmetic circuit, and a control device which changes the frequency of the correction clock for a predetermined time.

Abstract: An optical disk apparatus includes rotating mechanisms which rotate an optical disk, recording functions which irradiate the optical disk with a laser beam to perform recording processing, a measuring circuit which measures a focus error signal FE caused by the irradiation with the laser beam, and a rotational speed setting circuit which controls speed of the optical disk on the basis of a value of the focus error signal so as to properly decrease the speed of the optical disk. The rotational speed is decreased corresponding to distortion of the optical disk, so that a servo can follow the distortion and the stable recording processing can be performed.

Abstract: When the header portion of an optical disk is read, a recording pulse width for the optical disk is corrected. The recording pulse width is determined by the delay time of a voltage control type delay element, and the recording pulse width is corrected by controlling the delay element. An internal oscillator having an oscillation frequency is determined by the delay time of the delay element, a comparison circuit for comparing the phase of a pulse output signal from the internal oscillator with the phase of an external reference pulse signal, and an integrator for integrating a phase difference obtained from the comparison circuit are arranged, and an output voltage from the integrator controls the delay time of the voltage control type delay element. Therefore, the delay time of the delay element is kept at a high accuracy in accordance with the external reference pulse signal during reading of the header portion.