Abstract: A system effecting a data reproducing method for a plurality of devices, for sending and receiving data by authenticating the plurality of devices with each other, said data reproducing method including: selecting, from a plurality of descrambling methods, a descrambling method corresponding to a type of said data, executing authentication by an authenticating method corresponding to the selected descrambling method, where the authenticating method is selected from a plurality of authenticating methods, and reproducing said data.

Abstract: A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.

Abstract: There is provided a method of calculating the degradation over time of the quality of data recorded on an optical disk in a short time. In the method, when user data is recorded on a data area, a test signal including a component in which the signal level is smaller than a reference value, is recorded on a test area. Then, the test signal is reproduced from the test area when a predetermined time has passed, to calculate the quality degradation of the user data from the evaluation result. Alternatively, every time when the user data is recorded/reproduced on/from the data area, the test signal is recorded/reproduced repeatedly on/from the test area. Then, the test signal is reproduced from the test area at a predetermined timing, to calculate the quality degradation of the user data from the evaluation result.

Abstract: A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.

Abstract: A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.

Abstract: A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.

Abstract: A system effecting a data reproducing method for a plurality of devices, for sending and receiving data by authenticating the plurality of devices with each other, said data reproducing method including: selecting, from a plurality of descrambling methods, a descrambling method corresponding to a type of said data, executing authentication by an authenticating method corresponding to the selected descrambling method, where the authenticating method is selected from a plurality of authenticating methods, and reproducing said data.

Abstract: Even when recording data which is continuously inputted at a high speed, it is possible to correct a recording error and reproduce preferable AV data without a noise upon reproduction. A recording error detection circuit (14) detects an error generation upon recording according to the fluctuation of amplitude of a tracking error signal or a focus error signal. A recording signal processing circuit (6) again records (performs skip recording) the same data in a region subsequently adjacent to a region where a recording error has occurred. When performing the skip recording, address information contained in the recording data is rewritten into address information on a new recording region. Moreover, an identifier (skip mark) indicating that a recording error has occurred is added to the pattern of the link region of the recording data.

Abstract: A data reproducing method for a plurality of devices, for sending and receiving data by authenticating the plurality of devices with each other, said data reproducing method including: selecting, from a plurality of descrambling methods, a scrambling method corresponding to a type of said data, executing authentication by an authenticating method corresponding to the selected descrambling method, where the authenticating method is selected from a plurality of authenticating methods, and reproducing said data.

Abstract: A watermark information detection process prevents prolonging of time required for setup process when no watermark information can be detected from an optical disc where watermark information has been recorded. During a setup, the number of retrials is limited. Weighting of the retrial is changed so that detection of watermark information is performed when it is confirmed that watermark information is recorded. This enables detection of information for copyright protection in an appropriate processing time.

Abstract: A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.

Abstract: If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations is restricted. To solve the above problems, the present invention records data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

Abstract: If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations is restricted. To solve the above problems, the present invention records data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

Abstract: If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations is restricted. To solve the above problems, the present invention records data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

Abstract: If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations which can be performed is restricted. To solve the above problems, the present invention can record data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

Abstract: If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations which can be performed is restricted. To solve the above problems, the present invention can record data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

Abstract: If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations which can be performed is restricted. To solve the above problems, the present invention can record data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

Abstract: A recording/reproducing apparatus capable of encrypting bus data to a host has a bus encryption circuit and controls the access to a memory. Encryption of data between the recording/reproducing apparatus and the host can be achieved to assure protection of data and contents recorded on an optical disc.

Abstract: To update the program, the file is updated by verifying according to a digital signature attached to the file having the program converted whether the file is not dishonestly falsified. To verify the digital signature, a time for verifying the signature can be shortened by verifying not the entire file but only a particularly important part, and an area for temporarily storing the file can be made small. Thus, the control can be performed to update only when the file is valid.

Abstract: If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations which can be performed is restricted. To solve the above problems, the present invention can record data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.