Abstract: An optical disk according to the present invention includes a first track having a spiral shape and a second track having a spiral shape, the first track and the second track adjoining each other, and information being recorded on or reproduced from the first track and the second track. The optical disk further includes an address region including: a first address block formed so as to be on both the first track and the second track adjoining the first track on an inner periphery side; and a second address block formed so as to be on both the first track and the second track adjoining the first track on an outer periphery side.

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 optical disk according to the present invention includes a first track having a spiral shape and a second track having a spiral shape, the first track and the second track adjoining each other, and information being recorded on or reproduced from the first track and the second track. The optical disk further includes an address region including: a first address block formed so as to be on both the first track and the second track adjoining the first track on an inner periphery side; and a second address block formed so as to be on both the first track and the second track adjoining the first track on an outer periphery side.

Abstract: An optical disk is provided which includes a rewritable first recording area and a read-only second recording area. The first recording area includes groove tracks and land tracks divided into first sectors. Each first sector has a header region with identification data and a data region for recording user data. The second recording area includes tracks formed with physical bit rows, the tracks being divided into second sectors. Each second sector includes a header region and a data region having read-only data recorded as the bit rows. The header regions in the first sectors include pits the width of groove tracks and wobbled from a center line of the groove track. The header regions in the second sectors include pits having a width smaller than the groove tracks and formed along the center line of a track.

Abstract: An optical disc using a single-spiral land and groove track format and an address signal enabling simple sector address management and format compatibility with read-only optical disc media is disclosed. Four physical address areas PID1-PID4 are recorded to a header area such that PID1 and PID2 are offset one-half track pitch toward the outside circumference of the disc from the groove track center, and PID3 and PID4 are offset one-half track pitch toward the inside circumference of the disc from the groove track center, and the header area is shared by groove track sectors and land track sectors. A groove track sector address is written to PID3 and PID4, and the sector address of the land track sector adjacent on the outside circumference side of that groove sector is written to PID1 and PID2. The address of each sector increases 1 in the same sequence as the sectors are formed in the recording spiral.

Abstract: A dc-stabilized power circuit which has a PNP-type output transistor that is connected between input and output terminals, a base-driving circuit for controlling the driving current of the base of the output transistor in response to the difference between a voltage obtained by voltage-dividing the output voltage from the output terminal and a reference voltage that has been preliminarily determined, and a driving-current suppressing circuit for detecting a voltage between the input and output terminals and for suppressing a driving current released by the driving-current supplying means based upon the result of the detection. The greater the input-output voltage, the further the driving-current suppressing circuit suppresses the driving current from the base-driving circuit to the output transistor, thereby suppressing the output current.

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: In an optical disk comprising a recording plane having a spiral first track and a spiral second track, information being to be recorded into and/or reproduced from the first and second tracks, the first track is formed into a groove-like shape, the second track is formed between adjacent the first tracks and into a land-like shape, and the first and second tracks record informations in different modulation methods.

Abstract: An information device which ensures fast data transfer between a RAM and an I/O channel, between an I/O channel and another I/O channel, or between a RAM and another RAM: comprises address decoder circuit which allows the CPU to gain simultaneous access to both the RAM and the I/O channel when the CPU accesses a data transfer area mapped for data transfer, and an inverter which assures that both the RAM and the I/O channel operate in a mutually opposite manner, either in one mode in which the RAM works in a read operation with the I/O channel in a write operation or vice versa in response to the access request of read/write from the CPU. By assuring that both the RAM and the I/O channel operate in a mutually opposite manner, in response to an access from the CPU, data transfer between the RAM and the I/O channel is completed in a single access from the CPU; thus, fast data transfer is achieved.

Abstract: Optical information recording and reproducing apparatus and method of the invention perform the recording and reproducing for various types of information recording media each having a converged laser spot size different from the spot sizes of the other types. The optical information recording and reproducing apparatus includes a spot size recognizing circuit for recognizing a spot size suitable for an information recording medium to be loaded, and performs erasing, recording, and reproducing to the information recording medium by defocusing or by off-tracking based on the spot size recognized by the spot size recognizing circuit.

Abstract: A reproduction type optical disk having same sector structure as that of a recordable optical disk, can reproduce data even if a plurality of sectors are disabled from correction. The disk has data sectors for recording data, parity sectors obtained by a new error correction coding between a plurality of data sectors, wherein the error correction coding between the data sectors is performed by arranging a plurality of data sectors into a matrix and by coding them in directions of row and column doubly to make a product code.

Abstract: An inspection sector area is disposed on each data sector area of the recording area of an optical disc, and predetermined reference inspection data is recorded in the inspection sector area of a new optical disc before use. The recorded inspection data is reproduced and the number (Ej) of data errors which initially occur in the optical disc is detected by comparing the reproduced inspection data with the inspection data during recording and is memorized in the optical disc. During operation, the recorded inspection data is reproduced and compared with the reference data, and the number (Em) of data errors is issued, thereby producing the number of data errors due to particulate contamination as given by a difference between the numbers (Ej) and (Em).

Abstract: A method and apparatus for recording/reproducing information on an optical disk using the UNIX operating system. The optical disk has a plurality of partitions. An open table is provided to prevent the removal of the optical disk when the optical disk device is in use. The open table manages the use situation of the plurality of partitions. The optical disk is prohibited from being removed from the optical disk device when one partition is opened earlier than the other partitions. The removal prohibition of the optical disk is released when the final partition is closed.

Abstract: In an information recording medium, wherein data are reproduced in a sector unit, a file area for recording the file systems of a plurality of operating systems and a discrimination area for recording the position data on the file systems in the file area are provided. Then, the same data recorded in the recording medium can be managed by the operating systems of different file management systems. In a recording apparatus for reproducing data from the information recording medium, the position data are reproduced from the discrimination area and the data recorded in the information recording medium can be read by converting the position data to an actual sector address in the information recording medium. Thus, a file can by reproduced from the recording medium with either of the operating systems.

Abstract: A write/read device includes two optical heads for writing data on an optical disk. The two heads are moved simultaneously after data is written in a track, the written data is read and checked for writing errors. This write verify is performed by the two optical heads in parallel, and data can be written on an optical disk at a fast rate.

Abstract: Proposed is an aqueous coating composition based on a polyvinyl alcohol suitable for use to provide a protective film on various electronic materials. The composition comprises, as dissolved in water, a partially saponified polyvinyl alcohol having a specified average degree of polymerization and a specified degree of saponification, a fluorine-containing surface active agent and, optionally, a quaternary ammonium hydroxide. The liquid coating composition is preferably freed from sodium ions as an impurity by an ion-exchange treatment.

Abstract: The present invention relates to an information retrieval apparatus for retrieving large quantities of the document files stored in the information recording medium by the successive matched comparison between the character string of a target and the character string in the coded document. When the retrieving result of the document file retrieved in the past is stored within the information recording medium together with the retrieving conditions and the document file is retrieved again with the same retrieving conditions, the information retrieval apparatus of the present invention makes it unnecessary to retrieve the document file itself by the reuse of the past retrieving results if the latest retrieved date and time are newer than the recording date and time of the document file so as to shorten the retrieving time.

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 optical disk apparatus for an optical disk having two sides for which data can be simultaneously recorded. Each of the two sides includes a spare area for alternative recording. In the optical disk apparatus, a series of data to be recorded is distributed into first data for the first one of the two sides and second data for the second one of the two sides. The apparatus of this invention detects any defective sector into which data cannot be recorded which occurs in either one or both sides during the simultaneous recording. If there is a defective sector in one side, an alternative recording process is performed for alternatively recording data that was to be recorded into the detected defective sector, and data to be recorded into a sector in the other side corresponding to the defective sector, into alternative sectors in the spare areas of the two sides, respectively. Also, defect information relating to the defective sector is recorded into a predetermined area of the optical disk.

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.