Abstract: A method of recording and reproducing data on and from a rewritable optical disk used for recording/reproduction of data on a sector by sector basis. A dummy block or a parity subject to error detection and correction coding is additionally recorded at the rear of a data block on a sector. A defect caused by deterioration due to reiterative operation at the trail of the sector can be prevented from reaching the data block and data can be reproduced with high reliability.

Abstract: In recording data on a disk-shaped information recording medium having formed thereon a plurality of concentric or spiral tracks each being divided into a plurality of sectors each having an ID field and a data field, a data mark is selected from a plurality of distinct data marks according to an address of a target sector such that the selected data mark is different from a data mark recorded in an adjacent sector which is contained in an adjacent track. The selected data mark is recorded at the start position of the data field of the target sector. In reproducing the recorded data, a data mark is selected from the plurality of distinct data marks according to an address of a target sector, and is compared with a data mark reproduced from the target sector to detect whether the reproduced data mark coincides with the selected data mark. Sector data in the target sector is reproduced only when the reproduced data mark coincides with the selected data mark.

Abstract: This invention provides an erasable optical disk, on which information is recorded and reproduced repeatedly through the irradiation of laser beams, and an optical information recording/reproduction apparatus which records and reproduces information on the erasable optical disk. In erasing and then recording information on the erasable optical disk by using an erasing laser beam and a recording/reproduction laser beam, respectively, the tracking of both laser beams on the same track is detected so as to prevent erroneous erasing. The apparatus uses the optical disk having a mark signal disposed between a sector identifier and a data field, which mark signal is capable of determining the presence of the erasing laser beam on an adjacent track on the erasable optical disk, and the apparatus reproduces and detects the mark signal by using the erasing laser beam.

Abstract: A composite read-only and rewritable type optical disc, and a disc drive apparatus for reading/writing data into the disc. The optical disc has a plurality of sectors forming a data read-only area and a write/read area. The disc includes a recording film formed over its entire surface by which data can be recorded on the disc. Each area has track sectors each having a sector identifier portion in which address information is recorded and a data field portion to record data. Data-field identification flags indicative of the read-only area and the write/read area are recorded in the respective identifier portions. On reading or writing this optical disc, the data field identification flag is detected to identify the kind of related area, i.e., whether it is a read-only area or a write/read area. Thus, it is possible to avoid erroneous recording of data into the read-only area. Upon executing a reading operation, waveform equalization and binary-clipping level of reproduction signals can be well controlled.

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: Directory data relating to user data are recorded in sectors of a checkerboard pattern or in sectors on every other track in a directory data area on an optical disk. The sectors which store the directory data are always flanked by adjacent virgin sectors in a direction normal to the tracks. Therefore, the latest directory data can be detected highly reliably without crosstalk noise from adjacent tracks. Alternatively, old directory data except the latest directory data are deleted or old directory data except the latest directory data and directory data in a predetermined number of sectors before the latest directory data are deleted, and the latest directory data can be detected highly reliably by detecting the deletion of the directory data.

Abstract: In the reproduction of data from one of N-frame sectors of an optical disk, data marks representing the front ends of the respective frames of a desired sector are detected and counted. When the number of the data marks is more than a predetermined value M (1<M.ltoreq.N), the reproduced data is accepted. Hence, the data accuracy can be ensured and the operating reliability of a data reproducing apparatus can be improved.

Abstract: A deinterleaving and error correction system which is advantageously utilized in a playback system of an optical recording disk apparatus. As each block of sector data, encoded for example with the Reed-Solomon error correction code with block interleaving, is read from the disk, the positions within the data block at which drop-out of the playback signal occurs are respectively stored in a memory in which the data symbols are also stored, with these drop-out positions being stored as error position data. Error correction processing is executed using the error position data in conjunction with the code words, enabling the maximum number of correctable errors for each sector to be substantially increased using a simple system configuration.

Abstract: A read only type optical disc, and disc drive apparatus for reading/additionally writing data into the disc. The disc has a recording material formed in all of the tracks by which data can be additionally recorded on the disc. This optical disc has a plurality of sectors forming a data read-only area and a write/read area. Each area has track sectors each having a sector identifier portion in which address information is recorded and a data field portion to record data. Data-field identification flags indicativ of the read-only area and the write/read area are recorded in the respective identifier portions. On reading or writing this optical disc, the data field identification flag is detected to identify the kind of related area i.e., rea-only area or write/read area. Thus, it is possible to avoid erroneous recording of data into the read-only area. Upon reading operation, waveform equalization and binary-clipping level of reproduction signals can be well controlled.

Abstract: An information recording and reproducing apparatus for recording and reproducing information on and from a disk type information recording medium, wherein the information recording medium is used in which normal sectors (S1, Sn) each having an address formatted on an address area 12 in a sector ID field 9 and an alternative sector R1 having an address not yet recorded thereon are included on a same track. When a defective sector S3 is detected, first, the address of the defective sector is disabled to be reproduced by recording a delete signal 109 on the address area 12 of the defective sector S3, and at the same time, the address of the defective sector is recorded on an address area 13 in the unused alternative sector R1 located on the same track as the defective sector S3, and then, the data to be recorded on the defective sector is recorded within the alternative sector R1.

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.

Abstract: This invention provides an erasable optical disk, on which information is recorded and reproduced repeatedly through the irradiation of laser beams, and an optical information recording/reproduction apparatus which records and reproduces information on the erasable optical disk. In erasing and then recording information on the erasable optical disk by using an erasing laser beam and a recording/reproduction laser beam, respectively, the tracking of both laser beams on the same track is detected so as to prevent erroneous erasing. The apparatus uses the optical disk having a mark signal disposed between a sector identifier and a data field, which mark signal is capable of determining the presence of the erasing laser beam on an adjacent track on the erasable optical disk, and the apparatus reproduces and detects the mark signal by using the erasing laser beam.

Abstract: An information recording and reproducing apparatus for recording and reproducing information on and from a disk type information recording medium, wherein the information recording medium is used in which normal sectors (s1, Sn) each having an address formatted on an address area 12 in a sector ID field 9 and an alternative sector R1 having an address not yet recorded thereon are included on a same track. When a defective sector S3 is detected, first, the address of the defective sector is disabled to be reproduced by recording a delete signal 109 on the address area 12 of the defective sector S3, and at the same time, the address of the defective sector is recorded on an address area 13 in the unused alternative sector R1 located on the same track as the defective sector S3, and then, the data to be recorded on the defective sector is recorded within the alternative sector R1.

Abstract: In an optical disk system of the type including an optical disk for performing the recording and reproduction of data by use of a semiconductor laser and an optical disk recording and reproducing apparatus, an optical disk, optical disk recording and reproducing apparatus and copy preventive method for optical disks capable of preventing copying of the stored data from one optical disk on another. Irrespective of the kinds of optical disks, such as, read only-type optical disk, DRAW-type optical disk and erasable optical disk, each of the optical disks is provided in common with sectors from which data can be reproduced but not recorded on, i.e., data record-protected sectors and at least part of the stored data is stored in the record-protected sectors of the optical disk, thereby protecting the stored data from being recorded on the same address sectors of another recordable optical disk forming a part of the optical disk system.

Abstract: Disclosed is an information recording/reproducing apparatus which uses a rewritable recording medium having a sector structure, and in which a data writing gate signal and a data erasing gate signal are reproduced on the basis of an ID detection signal of a target sector, while a data reading gate signal and a marking gate signal are produced on the basis of the ID detection signal of the target sector or on the basis of an ID detection signal of a sector located N sectors before the target one, so that when data is to be renewed in a specific sector from which no ID detection signal can be obtained, marking is performed in the specific sector on the basis of an ID detection signal of a sector located N sectors before the specific sector and new data are rewritten into a substitutive sector, whereby it is possible to perform data erasing and data recording in a target sector with high reliability and high positional accuracy and it is possible to shorten gaps respectively in front and rear of a data field to

Abstract: An optical disk duplicating apparatus comprises reproducing means for reproducing user's data recorded on a first optical disk, adding means for adding sector data identification information indicative of the state of using sectors in recording tracks on the first optical disk to the reproduced user's data, recording means for recording the user's data on a second optical disk, and transfer means for transferring the user's data and the sector data identification information to the recording means.

Abstract: An information recording and reproducing apparatus detects deterioration in a recording medium. Structure is provided for recording information including an error correction code. A signal indicative of recorded information is received, and an error signal indicative of a number of errors that are detected is produced. This error signal is based on verification of the error correction code. The error correction code is verified using a strict clipping level, which is a level stricter than a usual level recognized as a particular signal level. This strict clipping level is compared with the signal indicative of reading areas, and error signals are produced thereby. When the error signal indicates a number of errors greater than a predetermined number, each sector is checked to determine if it is a bad sector. Each bad sector is recorded with a mark signal that indicates a bad sector.

Abstract: An information recording and reproducing apparatus records and reproduces information on and from an optical recording disk having a sector recording format of frame structure in which data in each sector are divided into a plurality of frames, and a data head identification mark is affixed to the head of each of the frames, so as to prevent propagation of a demodulation error due to failure of word synchronization attributable to pull-out of a PLL during data reproduction. In the apparatus, one frame pulse is generated for each of the frames on the basis of a sector identifier detection signal and a frame data demodulation start signal, and, according to the result of counting the frame pulses, the frame numbers of frame data demodulated and stored in a sector buffer memory are accurately detected.