摘要:
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. The address data and control data are selected by use of the identifying flags in the sector identifying portion ID and control field portion CF, and they are read, then the control data are reassembled in order by using the address data of the sector identifying portion ID.
摘要:
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. When the comparison shows that the number of data errors is greater than a predetermined reference value, the optical disk or the internal optical head is fouled to such an extent that the recording and reproducing function cannot be satisfactorily performed.
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:
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.
摘要:
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.
摘要:
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.
摘要:
A multi-layered optical disk comprising a plurality of recording layers accumulated in the thickness direction wherein a light bean 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.
摘要:
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.
摘要:
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.
摘要:
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.