摘要:
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., one extending circumferentially and radially) is present on the disk, there is no case in which two or more information sectors associated with the check sector cannot be subjected to error correction. Also, as a result of having one track including (2.sup.m -1) information sectors and one check sector which has overall parities of the information sectors recorded therein, it becomes possible to record in the check sector and in each of the information sectors, respectively, an address, which is peculiar to each sector, to thereby, realize the reproduction of data with high reliability.
摘要:
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.
摘要:
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.
摘要:
An optical recording and reproducing apparatus for recording and reproducing data in an optical disk is disclosed. The optical disk has a plurality of erase test sectors in tracks, in one of which the accumulated number of tests together with test data is written. The data read from the erase test sector is compared with the recorded data to effect an erase function diagnosis. If data comparison shows an non-coincidence or the accumulated number of tests exceeds a predetermined value, a new erase test sector is used. The fatigue of the recording medium caused by a defect of the medium or reduced erasing efficiency due to an increased number of erasures of the recording medium is checked by controlling the accumulated number, completely separately from the fault of erase function of the apparatus, thus improving the reliability of the erase function self-diagnosis. Upon detection of an error in the read data or when the accumulated number of tests exceeds a predetermined value, a marking signal is written in the data field of a defective sector, and the apparatus shift to a new erase test sector not yet marked for subsequent erase function self-diagnosis, thereby making possible erase function self-diagnosis without being affected by the fatigue of the recording medium.
摘要:
An optical information recording and reproducing apparatus for recording and reproducing information on and from an optical recording disk having an optically detectable guide track divided into a plurality of sectors is disclosed. When a sector to or from which a data is to be recorded or reproduced is a defective sector or a non-use sector because of updating, a special pattern signal is recorded on the defective sector or the non-use sector, and if the recorded special pattern signal is detected in the reproduction cycle, that sector is determined as a defective or non-use sector and recording or reproducing on or from that sector is inhibited.
摘要:
An optical information recording and reproducing apparatus for recording and reproducing information from an optical recording disc including an optically detectable guide track preliminarily divided into a plurality of sectors. In the case of an unerasable disc, if an uncorrectable error exists in any sector after data has been recorded and reproduced from the sector, it is necessary to process this sector so as to prevent further reproduction an again record the data in another sector. Also, when updating a part of the data or erasing the file, it is desirable to take a measure so that reproduction of the data in any unwanted sector is prevented. Also, in the case of any unrecorded sector involving such dropout that the recording of data is presumed to cause an uncorrectable error, it is desirable to handle it as a defective sector and process it so as to prevent the recording of data therein. In such a case, it is desirable to effect the similar process also in the case of an erasable disc. A conceivable method of making such defective or unwanted sector distinguishable at a later time is to write in its information recording area a signal having a special pattern indicative of the defective or unwanted sector. In accordance with the invention, the reliability of special signal detection is increased by writing the special signal again when it is impossible to detect the special signal due to the occurrence of a track jump prior to or during the writing of the special signal, due to the occurrence of dropouts or the like.
摘要:
An optical and reversible recording and reproducing apparatus providing a practical apparatus in which information signals can be recorded, reproduced and erased by irradiating a laser beam and the like on the substrate to be optically recorded. More practically, there is provided such an apparatus wherein two light sources such as lasers having different wavelengths are used, and a first almost circular micro-lightspot is produced by one light source, while a second elliptic light spot having a longitudinal diameter in the tangential direction of a guide track on a disc is produced by the other light source. These first and second light spots are closely irradiated on one and the same guide track of an optical recording disc. The recording and reproducing of the signals are performed using the first light spot while the erasure of the recorded signals can be made by using the second light spot or using both first and second light spots in combination.
摘要:
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. The gain of the servo loop can be switched. The track searching operation can be stably performed. The reading and writing of data with respect to the data write/read area can be improved.
摘要:
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
摘要:
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.