Abstract: An information recording/reproducing apparatus is suitable for writing on and reading from a rewritable optical disk signals having a time-based continuity attribute such as video signals and audio signals. The optical disk has a plurality of tracks each divided into sectors. The apparatus has a RAM for storing data externally supplied, and first and second address counters for generating addresses for writing into and reading from the RAM, respectively. The apparatus also has a track-jump detector circuit for detecting the occurrence of a track jump of an optical head while the head is writing on the disk. When a track jump is detected, a laser driving circuit stops actuating the head such that the writing operation is halted, and a track-jump address latch circuit stores an address of a track-jump occurring sector. Based on the address stored in the track-jump address latch circuit and a track address where the head is actually is, the head is returned to the sector where the track jump occurred.

Abstract: In a plurality of sectors in a track of an optical disc, when defect sectors having defect are a lesser number than a predetermined number, a substitution sector in a first substitution area of the optical disc is substituted for the defect sector, and when the number of the defect sector is the predetermined number or more, the sectors of a substitution track in a second substitution area is substituted for entire sectors in the track, then a map data including the address of the track and the address of the substitution track are recorded in a map sector of a map sector area.

Abstract: An information recording-reproducing apparatus for optimizing data transfer between a host computer and an information recording medium. The apparatus has a transfer mode control device which selects the optimal data transfer operation mode for transferring data between the host computer and the information recording medium. The transfer mode control device determines which one of a duration of a modulation-demodulation operation, data transfer from the apparatus to the information recording medium, and a duration of a data transfer operation, transfer of data from the apparatus to the host computer, is longer. The transfer mode control device selects a parallel mode in which the modulation-demodulation operation and the data transfer operation are performed in parallel when a duration of the modulation-demodulation operation is longer than the data transfer operation.

Abstract: A bit error measuring apparatus in which bit errors in a rewritable information recording medium are measured by reproducing data after the data have been repeatedly recorded on the medium, in which position of recording data used in random number data generated in a memory is periodically shifted every time recording is performed such that not only different recording data can be repeatedly recorded at a predetermined area of the medium at high speed but bit errors can be detected at identical bit locations of the medium by reproducing data from the predetermined area only when the identical recording data have been recorded.

Abstract: In a disk-shaped information recording medium using an MCAV format, a plurality of tracks are divided in a radial direction of the disk to form plural zones, at the boundary of which a dummy track area is formed by dummy tracks on which a discrimination signal is recorded. By this provision, the erroneous data recording and reproducing operation in the tracks positioned at both ends of the zone due to crosstalk is prevented. In an information recording and reproducing apparatus, by providing a circuit for correcting the seek distance based on the number of the dummy tracks located between a current track and a target track, correct seek operation is executed. Also, by providing a detector for detecting the discrimination signal and a mechanism to move the head on the dummy track into the zone, erroneous recording and reproducing operation of the data in the dummy track is prevented.

Abstract: A read only optical disk is provided which includes (1) information sectors having recorded therein first encoded data obtained by encoding data by a first error detection/correction code to perform error detection and correction of the data and (2) check sectors each having recorded therein second encoded data obtained by encoding data among the first encoded data recorded in a plurality of selected information sectors by a second error detection/correction code. The second encoding by the second error detection/correction code is performed with respect to the data of the plurality of selected information sectors which are selected from respective tracks and are arranged sequentially at predetermined intervals in the circumferential direction on the tracks. As a result, in this read only optical disk, even when a two-dimensional defect (i.e.

Abstract: An optical information recording and reproducing apparatus irradiates a laser beam to an optical disk for repeatedly recording and reproducing data on and from data sectors of the optical disk. The optical disk comprises a plurality of track blocks each comprising data sectors for recording data thereon, alternate sectors for substituting defective ones of the data sectors, and at least one mapping sector for recording mapping data representing the address correspondence between the defective sectors and the alternate sectors substituting the defective sectors.

Abstract: The apparatus includes a one-chip microcontroller, an error flag counter and an error comparison circuit to detect whether or not an optical disk or an internal optical head of the apparatus is fouled. Test data is recorded on a self-diagnostic area of the optical disk when the optical disk loaded in the apparatus is new and has not yet been used, and initial error information detected in the test data reproduced from the self-diagnostic area is registered on an error managing area of the optical disk. When an optical disk which has already been used is loaded, error information detected in the test data recorded on and reproduced from the self-diagnostic area of the optical disk is compared with the initial error information registered in the error managing area of the optical disk.

Abstract: The present invention relates to an optical disk having a control track. The control track is divided into sectors in a manner similarly to a data track to record data and comprises a plurality of sectors. Each sector is composed of a sector identifying portion ID in which address information is recorded and a control field portion CF in which control data is recorded. The control field portion CF has the same format as the sector identifying portion ID. The control data is divided into recording data units in the control field portion CF and recorded. An identification flag is provided for each of the sector identifying portion ID and control field portion CF. The control track is searched by the address information in the sector identifying portion ID.

Abstract: In a read only type optical disk and a write type optical disk each thereof having a data recording area and a spare area, first encoded data for error detection and correction are recorded in the data recording area. In the case of the read only type optical disk, the spare area is used as a check sector in which second encoded data are recorded. When error correction by first error control means becomes impossible while sectors in the data recording area are reproduced, second error control means performs error correction by using the check sector corresponding to an associated error sector. In the case of the write type optical disk, the spare area is used as an alternate sector. A defective sector detected by defective sector detecting means is alternately recorded by being replaced by the alternate sector through sector alternating means.