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: An information recording and reproducing apparatus has a plurality of optical disk drives including a data optical disk drive for storing data, a work or backup optical disk drive for temporarily storing the data and, preferably, a disk cache memory. The optical disk drives are coupled to a host device such as a central processing unit (CPU) through an optical disk control unit for controlling recording and reproduction of the data. The optical disk control unit writes commands and data transmitted from the host device into the work optical disk drive and the disk cache memory and, if required, writes the data of the disk cache memory into the data optical disk drive.

Abstract: A multi-layered optical disk comprising a plurality of recording layers accumulated in the thickness direction wherein a light beam is focused on one of tracks of one of the layers thereby to record and reproduce data, the optical disk being characterized in that recording layers each have an identification section storing an address of the recording layer which the identification section belongs to.

Abstract: An information recording and reproducing apparatus includes a rewritable optical disc having a plurality of sectors on which data can be rewritten. The rewritable optical disc is divided into an additionally recordable region in which the data are additionally recorded and a rewritable disc control region in which an address of a latest recorded sector in the additionally recordable region is recorded. The optical disc is used as an additionally recordable optical disc in which recording is permitted only one time and reproduction can be performed plural times. The information recording and reproducing apparatus further includes a control circuit for recording data on unrecorded sectors in the additionally recordable region and for reading the data from recorded sectors. This control circuit can rewrite and reproduce data in the disc control region.

Abstract: A disk shaped information recording medium has a virtual ROM area where data sectors, and parity sectors are recorded, and a disk definition area where management data of a virtual ROM area is recorded in a rewritable user area information recording and reproducing apparatus fabricates the information recording medium. Also, the information recording and reproducing apparatus prohibits a data recording operation with respect to the virtual ROM area and recovers a data of the defective sector detected in the virtual ROM area using a parity sector.

Abstract: The apparatus includes optical recording media each of which includes a single plate substrate with recording layers and spiral grooves formed on both sides of the substrate and which are available for recording and reproduction or for recording, erasing and reproduction via irradiation with laser beams. Both surfaces of the recording media are available for simultaneous access, and a plurality of thin floating-type optical heads are provided to irradiate laser beams onto the recording media. The optical heads are respectively provided at each side of the recording media and float, responsive to rotation of the recording media, above the respective surfaces of the recording media at a distance of at most hundreds of microns. The combination of these optical recording media and optical heads makes it possible to stack plural pairs thereof within an ultra-thin space, thus greatly improving the on-line capacity of the optical recording apparatus.

Abstract: A double-sided optical disc player which comprises first and second optical heads for radiating laser beams to tracks on respective sides of a double-sided optical disc; first and second ID read-out units for reading respective sector addresses out from associated sector identifiers; an ID offset detecting unit for calculating, in response to outputs from the ID read-out unit, the ID offset value descriptive of an angular displacement in sector position between the opposite sides of the optical disc traced by the associated optical heads; an ID offset retaining unit for retaining the ID offset value; a first sector recording and/or production control unit for detecting a target sector when an sector address output from the first ID read-out unit coincide with the target sector and for activating a recording or reproduction of information; an adder for adding the ID offset value to an output from the second ID read-out unit; a second sector recording and/or reproduction control unit for detecting a target obje

Abstract: An optical disk recording and/or reproducing apparatus realizes a high ability to transmit data by operating a plurality of optical disk drives in parallel. By actuating the data recording or reproducing operation in parallel after these optical disk drives all have completed seeking the target track, deviation in synchronism between these drives can be suppressed below a one track maximum, resulting in the parallel operation of a plurality of optical disk drives using a a small capacity memory. In addition, by transmitting data via a high speed FIFO memory connected to each drive interface and a host interface to a RAM, speedy data transmission using the parallel operation of the plurality of drives is made possible.

Abstract: In data recording medium used with the apparatus of the present invention, there are allocated a sequential access zone consisting of a data area for recording real time data such as sounds or video images, a C list area for recording a C defect list managing defective sectors detected in the formatting process, and a G list area for recording a G defect list managing defective sectors detected in the recording process of data, and a random access zone consisting of a data area for recording random access data such as code data, a spare area for replacing defective sectors detected in the recording process, and an R list area for recording an R defect list managing the relation between defective sectors and corresponding spare sectors. In the recording process of data in the sequential access zone, data is recorded while defective sectors registered in the C defect list and G defect list are skipped, thereby achieving recording of both the random access data and the real time data.

Abstract: The present invention provides a large-capacity stack type optical disk unit capable of information recording and reproducing operation at a high speed and an optical information recording and reproducing apparatus for recording/reproducing information onto/from the stack type optical disk unit. The optical information recording and reproducing apparatus comprises a stack type optical disk unit having N recording faces, the sector starting position on the respective recording faces are displaced by a sector as unit from one face to another, one stationary optical units including a laser light source, a collimator, a reflector and a detector for a reflected beam from the recording faces, N sets of focusing units each for focusing a collimated beam onto respective recording faces, a beam distribution unit for distributing the collimated beam to the focusing units, and a servo unit for focussing outputs from the focusing units onto tracks of the recording faces and for performing tracking.

Abstract: A data reproducing system is provided wherein data stored in an optical disk can be read and, in accordance with a coded error detection and correction code, can have an error pointer defined in synchronization with a modulated data of one symbol. This information can be transmitted, through a time division multiplexing circuit, at a faster clock speed than a demodulating clock with which the timing of a data demodulating will be controlled.

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: 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: In an information recording method in repeatedly and alternately performing a write operation and a verifying operation on an information recording medium having a spiral track, the data processing sector unit amount is set in advance to be less by the latency necessary for the inter-track jump. Also, the processing data for the data recording operation and the verifying operation are set to an appropriate length, so that a desired processing time is obtained from the time after termination of the data reading out operation of the verifying operation to the time of commencement of the data recording operation in the write operation. It is thus possible to minimize the latency from the writing operation to the verifying operation and the latency from the verifying operation to the next writing operation.

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: 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: The method of determining the last sector containing recorded information or the last recorded sector, of a writer-once and read-many optical disc, comprises dividing tracks of a write-once and read-many optical disc into a plurality of sectors, where each sector has a data part for recording data and a sector ID part in which ID information for identifying the sector is recorded in advance. The ID information of a sector is attached to the data part of the sector and is recorded in the data part of the sector. The ID information reproduced from the data part of the sector is then compared with the ID information reproduced from the sector ID part of the sector, and when the ID information from the ID part and the data part coincide, the sector is determined to be the last recorded sector.

Abstract: In an optical disc recording-reproducing apparatus using a standard optical disc enclosed in a cartridge, and optical plate for correcting various aberrations generated by a focusing lens is comprised therein in order to allow use of a double recording optical disc enclosed in the standard cartridge of the same size, the optical plate is placed in front of a focusing lens when the double recording optical disc is used, and is removed from the front of the focusing lens when the standard optical disc is used.

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.