Abstract: A method and apparatus for modulating data modulates data having a length of m-bits to a variable length code having a basic code length of n-bits. A SYNC but insertion section adds a sync signal to a train of codes, after a minimum run. The sync signal has a pattern that breaks a maximum run.

Abstract: A multi-beam optical disc system is disclosed for recording on DVD or CD optical discs. Recorded data includes inner and outer error protection codes applied to data blocks having a predetermined size. Each block comprises several sectors. Multi-channel read-out provides in parallel a set of N sub-sequences, without restriction to the block or sub-block boundaries. Sector ID codes are detected within each channel to identify a series of sub-blocks forming a part of a data block and, even in the absence of data from the start of the block, outer error protection circuitry processes the sub-blocks to accumulate a partial error protection syndrome for the block. Upon reaching the end of the block, a syndrome for a next block within the subsequence is accumulated.

Abstract: Method and apparatus for detecting errors in data read from a data storage medium include an error correction step/device which receives at least one of (i) data and (ii) data with errors, from the data storage medium, and outputs an error sequence in a first order in the case where data with errors is received. A first CRC step/device receives the at least one of (i) data and (ii) data with errors from the data storage medium, and outputs a CRC checksum in a second order different from said first order. A second CRC step/device receives both the error sequence and the CRC checksum, and outputs another CRC checksum indicative of whether the correction device or step has generated a correct error sequence. Preferably, a first CRC is coupled parallel to a Reed-Soloman decoder, and a second CRC is coupled in series with the first CRC and so as to receive the output of the R-S decoder.

Abstract: Dynamically creating a communication path between first and second storage devices, includes creating a connection to a source volume on the first storage device and indicating that the source volume is not ready to transmit data on the communication path, after successfully creating the connection to the source volume, creating a connection to a destination volume on the second storage device and initially indicating that portions of one of: the destination volume and the source volume do not contain valid copies of data, where the destination volume accepts data from the source volume, and after successfully creating the connections to the source and destination volumes, indicating that the source volume is ready to transmit data on the communication path. Dynamically creating a communication path between first and second storage devices, may also include creating at least one of: the source volume and the destination volume.

Abstract: A method and apparatus for recording or reproducing data in which high performance encoding and a high efficiency decoding are realized to lower the decoding error rate. A magnetic recording and/or reproducing apparatus 50 includes, in a recording system, a modulation encoder 52 for modulation encoding input data in a predetermined fashion and an interleaver 53 for interleaving data supplied from the modulation encoder 52 to re-array the data sequence.

Abstract: An encoding/decoding system in an optical disk storage device for performing compact disc/digital video disk (CD/DVD) encoding/decoding of data. The encoding/decoding system includes address mappers for C1, C2, CD P/Q, and DVD inner/outer codes respectively and a shareable Reel-Solomon (RS) encoder/decoder. The shareable RS encoder/decoder is capable of selectively being coupled to either one of the address mappers. When the encoding/decoding system is encoding, the shareable RS encoder/decoder employs a generation polynomial of RS code to generate a parity code of 2T symbols and output a codeword of N symbols, wherein the values of N and 2T are associated with the selected address mapper.

Abstract: The present invention provides a method and system for audio data retrieval from an optical media. The method includes reading a sector of audio data from the optical media, the sector comprising a sector data and a sector sub-code; collecting the sector sub-code; correcting any errors in the sector data in a fixed time period; calculating a time offset between a time for the collecting of the sector sub-code and the fixed time period; and matching the corrected sector data to the sector sub-code based on the calculated time offset. A method and system for retrieving audio data from an optical media has been disclosed. The present invention uses a fixed time period for the sector data error correction process. By using a fixed correction time, the sector data and the sector sub-code can be automatically matched based upon an offset calculated from the fixed correction time.

Abstract: An encoder and method of encoding data words are provided, which map a block of at least one of the data words into an error correction code (ECC) code word. The ECC code word is defined by a plurality of multiple-bit ECC symbols which are separated by boundaries. Bit patterns are constrained from occurring in the ECC code word based on a relative location of the bit patterns to the boundaries.

Abstract: In a system for protecting encoded digital data, for example, on a digital audio compact disc (CD-DA), specific audio samples are altered to cause spikes which are audible as clicks if played. All of the codewords in the encoded data which contain those altered samples are then identified, and data in each codeword is changed such that on decoding, the codewords will be identified as uncorrectable. Thus, if the decoded data is played by an audio player, error flags are reliably set so that error concealment, such as interpolation, is invoked and the spikes are inaudible. However, a data reader will either pass the uncorrectable data unchanged or will attempt to correct it. Therefore if a copy of the audio data is made, the clicks will be audible on playback.

Abstract: Techniques for maintaining data consistency in a storage environment. In a HSM controlled storage environment, techniques are provided for automatically detecting and correcting inconsistencies after a file system or a portion thereof has been restored from backup. The file system may store data files, tag files, and/or repository files that have been restored from backup.

Abstract: A data buffer receives and temporarily stores data including a product code enabling error correction in first and second directions. An exclusive-OR operation circuit uses an error amount detected by error correction in the first direction and data stored in a storage element to calculate a first error check result. A PI direction error-checking circuit according to the first error check result performs error check after error correction in the first direction. A PO direction partial error-checking circuit and a PO direction aggregate error-checking circuit use an error amount detected in error correction in the second direction and calculate a second error check result. The first and second error check results are used to generate a final error check result by an exclusive-OR operation circuit.

Abstract: A method and apparatus are provided for implementing adaptive reordering of data recovery procedure (DRP) steps in a direct access storage device (DASD). An initial set of DRP steps is stored. A reorder table is stored during the operation of the DASD. The reorder table includes data recovery data for each data head of successful predefined DRP step numbers. When a DRP process is started, checking for a modified DRP step is performed using the reorder table. Responsive to not identifying the modified DRP step, file parameters for a DRP read operation are set based on the initial set of DRP steps. Responsive to identifying the modified DRP step, file parameters for a DRP read operation are set based on a reordered DRP step that is identified by using the stored successful predefined DRP step numbers in the reorder table. When a successful DRP read operation is identified, the data recovery data in the reorder table are updated.

Abstract: The present invention is a correcting system for correcting a linear block code generated by coding an original data via a data coding process when a predetermined correction portion of an original data is corrected by a variant correction data. The correcting system comprises a coding module and a correcting module. The coding module is used to code the variant correction data via the data coding process to generate a corresponding variant correction code. The correcting module is used to store the variant correction code and calculate the variant correction code and the linear block code to generate a substitute code to substitute the linear block code. Therefore, if the data is modified after an optical recording system has completed coding the data, the optical recording system could add the substitute code to generate the renewed linear block code, unnecessarily reprocessing the complicated data coding process.

Abstract: The present invention more efficiently retrieves and processes data stored on an optical disk in a DVD-ROM format. Generally, the retrieval and processing of data includes inner and outer code error correction for a Reed-Solomon product like code and an error detection process for evaluating an extent of errors in a sector of data. For this device, the sector of data is encoded within a plurality of inner codes and parts of plural sectors encoded within each outer code. The device calculates an initial and an intermediate error detection value for data within the sector. The target for the error detection value is non-zero because the data within the sector are scrambled. If there is a match between the initial or intermediate error detection value, the sector can be presumed to be free of errors.

Abstract: The present invention provides a method and system for error correction in optical media data processing. The method includes demodulating a data using a conversion table; marking errors which occur during the demodulation; utilizing estimated values for the marked errors; and performing error correction. The method and system marks errors which occur during demodulation. A logic array is used to obtain estimated values for the marked errors. The marking of errors and the use of values from the logic array for the marked errors increases the probability of the C1 and C2 correction processes being able to correct the errors. Fewer “not correctable” data results. This increases the integrity of the read data.

Abstract: A data storage system, such as RAID, upgraded dynamically including multiple stages, providing error checking data without taking the system off-line. Checksums are computed from the data and placed in block 63 of the same disk. The combination of parity bits across the parity disk, the remaining uncorrupted data in the data disks, and checksums within each disk includes sufficient information to enable restoration of corrupt data. The system is upgraded by reserving permanent checksum blocks, writing the checksums to a volume block number, and placing the checksums in permanently reserved checksum block locations after first moving data already there to unreserved blocks.

Abstract: A real-time recording system that decreases the load applied to a central processing unit, which controls recording. The recording system includes a memory for storing input data. An error correction circuit is connected to the memory for generating write data from the input data and storing the generated write data in the memory. A formatter circuit is connected to the memory and the error correction circuit for reading the write data stored in the memory and writing the read write data to the recording medium in real-time. The error correction and formatter circuits are controlled for the generation of the write data with the error correction circuit and the writing operation with the formatter circuit by a plurality of control signals. The control signals are transferred between the error correction circuit and the formatter circuit.

Abstract: Method and apparatus for preventing unauthorized replication of a digital data file. A plurality of second data set samples are substituted for a plurality of user data samples in a user data sequence to generate a combined data set. Error correction codes are calculated to correct errors in the combined data set. Uncorrectable errors are then intentionally written to the error correction codes corresponding to the second data set samples so that, during playback, the readback system conceals the corresponding second data set samples. An unauthorized copy of the digital data file will not include the uncorrectable errors; thus, the same readback system will output both the user data samples and the second data set samples, with the second data set samples interfering with the integrity of the user data samples.

Abstract: A method of and an apparatus for controlling a data storage system according to a temperature which thermally expands a write head pole tip of a write head includes supplying the write head with a predetermined warming current in a low temperature environment, so as to prevent a degradation of a writing characteristic of a signal in an initial writing stage. Therefore, errors due to a degradation of a signal level written in a sector of an initial writing mode do not occur by performing a warming write using the predetermined warming current so that data existing in a storage system before performing a writing mode is not erased, and by sufficiently thermally expanding the write head pole tip of the write head until a saturation state before writing starts.

Abstract: A recording apparatus is provided with a recording medium, an error correction circuit and an error processing circuit. The error correction circuit corrects errors in read data which are read from the recording medium. The error processing circuit inserts a data pattern in data which are output from the error correction circuit in a case where a missing error remains in the data. The data pattern indicates that the missing error remains.

Abstract: The invention discloses a signal decoding method for C3 decoding on a data storage medium. The data storage medium contains a lot of sectors, and each sector contains two C3 codes. Each C3 code contains a plurality of P codes and Q codes. The syndrome operation for an (N+1)th code and an error-correction for an N-th code are pipelined. An address for the (N+1)th code minus a predetermined value is an address for the N-th code.

Abstract: A method of reproducing data by performing error correction on data read from a recording medium. The method includes reading a sync pattern, checking if the sync pattern has been read, recovering data following the sync pattern when the sync pattern has not been read, and performing the error correction on the recovered data. The data following the sync pattern is recovered in the error correction, which makes it easier to lengthen the time width of a detection window setting signal for detecting the sync pattern.

Abstract: A data transfer device for successively storing data in a data storage unit or successively reading data from the data storage unit in data processing using an array of m rows×n columns, comprises a data storage unit for retaining data which have been stored in storage positions specified by row addresses indicating the positions in the row direction and column addresses indicating the positions in the column direction; a transfer address generation unit for generating transfer addresses comprising the row addresses and the column addresses so that the storage positions for transferred data are successively specified in each of storage blocks having a predetermined size and arranged in the row direction of the data storage unit; and a transfer control unit for controlling data transfer to the data storage unit by using the transfer addresses generated by the transfer address generation unit.

Abstract: A digital signal processing method and apparatus that provide a mechanism for controlling the output of digitally processed data in an optical disc player so as to reduce the probability of error and lost data during such output. In one aspect, an apparatus for processing information on an optical disc comprises a signal processor for processing a digital signal corresponding to an analog signal read from the optical disc to generate output data, a memory unit, operatively associated with the signal processor, for temporarily storing the output data in predetermined units under the control of the signal processor, and an output unit, operatively connected to the signal processor, for processing the output data based on the type of optical disc. The output unit generates a request signal that causes the signal processor to retrieve output data from the memory unit and transmit the retrieved output data to the output unit in parallel.

Abstract: An information storage medium includes a drive zone having a plurality of physical clusters or ECC blocks. When new drive data is recorded in the drive zone, the new drive data is recorded in a physical cluster or ECC block next to the physical cluster or ECC block containing the most recently recorded drive data. In the method of recording drive data, the drive data is recorded in a physical cluster or ECC block of the drive zone. When the drive zone is updated with the new drive data, the new drive data is recorded in the physical cluster or ECC block adjacent to physical cluster or ECC block containing the most recently drive data. The drive data recording method is applicable to a new format of information storage medium.

Abstract: An optical disk apparatus reads data written in an optical disk in units of code blocks arranged by joining a plurality of correcting codes. The optical disk apparatus includes a reading unit for reading the code block from the optical disk and an error correcting unit for combining first error correcting processing performed on the code block read by the reading unit with second error correcting processing performed by adding remove information to codes that cannot be corrected during at least the first error correcting processing.

Abstract: A code error correcting and detecting apparatus includes a controller that repetitively processes error correction and detection of encoded CD-ROM data, thereby relieving a control microprocessor of a CD-ROM system of the burden associated with such repetitive processing. The apparatus includes an error correction circuit that performs code error correction on digital data, such as digital data read from a CD, using an error-correcting code (ECC). An error detection circuit performs error detection on the error-corrected digital data using an error-detecting code (EDC) and determines whether there is an error. A control circuit causes the error-correction circuit to repeat its error-correction processing in accordance with the detection of an error by the error detection circuit.

Abstract: The present invention discloses an information processing method including the following steps: (1) a first step receiving an encoded information data series as input; (2) a second step selecting a candidate decoded data code series from a first candidate decoded data code series group, decoding the encoded information data series, and generating a first decoded data code series; (3) a third step detecting a position and contents of erroneous decoded data codes in the first decoded data code series that cannot exist in the information data code; (4) a fourth step correcting the erroneous decoded data code and generating a corrected data code; (5) a fifth step selecting a single decoded data code series out of a second candidate decoded data code series group, decoding the encoded information data code series again, and generating a second decoded data code series; (6) The second candidate decode data code series group includes candidate decoded data code series from the first candidate decoded data code

Abstract: Methods and device are provided for detecting and correcting errors in error correction coded (ECC) data sectors. The ECC data sectors are sequentially received as a data stream from a data storage medium. The device includes a buffer and an error detection and correction (EDAC) circuitry. The buffer is arranged to sequentially receive and store the ECC data sectors from the data storage medium. The EDAC circuitry is arranged to sequentially receive the ECC data sectors for sequentially generating a plurality of syndrome sets for the ECC data sectors with one syndrome set per ECC data sector. Each syndrome set includes a plurality of syndromes. The EDAC circuitry sequentially stores the syndrome sets into the buffer while accessing the stored syndrome sets sequentially to decode errors in the associated ECC data sectors. Preferably, erasure information containing one or more bad data byte locations is also generated and stored along with the syndromes for each ECC data sector.

Abstract: A method and an apparatus for accessing DVD data. In the apparatus for accessing the data of a DVD, a row data buffer and an error detection code file are added. The row data buffer stores the row data from the row data interface, and the error detection code file records the error detection code stored in the memory. When an error occurs in the error detection code, the error detection code in the error detection code file may be modified. In addition to the normal data access, the method of accessing DVD data only re-access for certain errors occurring during RSPC decoding.

Abstract: A method for recovering user data from a host device stored on a data storage medium where a said data may become corrupted during a read operation comprises: performing a read operation to read at least one encoded data fragment of said plurality of encoded data fragments from said data storage medium; storing status data indicating whether said at least one data fragment was correctly read; writing said read at least one data fragment to a buffer memory; attempting to decode said at least one encoded data fragment in said buffer memory wherein if said attempted decoding is unsuccessful then said method further comprises the steps of: re-reading incorrectly read encoded data fragments from said data storage medium; and attempting to decode said encoded data fragments located in said buffer memory.

Abstract: An encoding unit includes a separating section for separating a RLL code into a restricting portion corresponding to a basic code and a non-restricting portion corresponding to information bits, a first encoding section for adding an error correction code to the restricting portion and carrying out a RLL encoding, a second encoding section for adding an error correction code to the non-restricting portion, and an interleaving section for interleaving outputs of the first and second encoding means, and outputting encoded information.

Abstract: A digital data storage system in the form of a mass storage subsystem in which information is stored on one or more disk storage units, with a storage element constituting a track on a disk storage device and each track storing a plurality of records. Each track in each disk storage device of the digital data storage system is associated with a descriptor. When the control device retrieves the contents of a record, it can process the contents to generate a check value and compare the generated check value with the check value for the record as stored in the descriptor associated with the track. If they compare appropriately, the control device can determine that the record that was retrieved was, in fact, the record that was to be retrieved. On the other hand, if they do not compare appropriately, the control device can determine that the record that was retrieved was not the proper record.

Abstract: A disk drive is disclosed comprising a multiple-input sequence detector for detecting an estimated data sequence from a sequence of read signal sample values. The multiple-input sequence detector comprises a first iterative detector and a second iterative detector. An error correction code (ECC) decoder decodes the estimated data sequence into at least one decoded codeword comprising a plurality of bits which are used as reliability metrics for biasing at least one of the iterative detectors.

Abstract: A synchronizer circuit includes an input terminal, an output terminal, and a recovery circuit coupled to the input and output terminals. The input terminal receives an input signal that includes a sync mark, and the recovery circuit is operable to recover the sync mark from the input signal and to generate a synchronization signal on the output terminal in response to the recovered synchronization mark. For example, such a synchronizer circuit can recover the synchronization mark from a read signal and locate the beginning of a data stream for a Viterbi detector that is separate from the circuit. By performing the sync-recovery function in a separate circuit, one can reduce the complexity and increase the data-recovery speed of the Viterbi detector. Furthermore, the synchronizer circuit can recover the sync mark by executing state-transition routines in alignment with the input signal. For example, one can align the synchronizer circuit's state-transition routines to the preamble of the read signal.

Abstract: A system and method are disclosed for writing a multilevel data sequence to a storage medium so that a read signal generated by reading the multilevel data sequence from the storage medium will have reduced low frequency content is described. The method includes evaluating the effect of a plurality of candidate merge symbols on an RDS of the read signal. A preferred merge symbol is selected from among the plurality of candidate merge symbols based on the effect of the preferred merge symbol on an RDS of the read signal. The preferred merge symbol is added to the multilevel data sequence so that the RDS of the read signal is controlled.

Abstract: A data modulation method resistant to channel distortion and a method of correcting error in data coded by the modulation method. The data modulation method uses a run length limited (RLL) modulation code applied to write data to an optical storage medium, the RLL modulation code being expressed as RLL (d, k, m, n, s) with s=2 or greater, where d is minimum run length, k is maximum run length, m is a data bit length before modulation, n is a codeword bit length after modulation, and s is a space length between codewords. Further, the data modulation method provides run lengths expressed as in+1=in+s (n=1, 2, . . . ), where i1=d.

Abstract: Maximum Likelihood Sequence Estimation (MLSE) is performed on a received signal that is affected by non-linear distortion. In particular, a cleaned signal is produced by removing non-linear inter-symbol-interference (ISI) through a Volterra canceller which is a simplified structure with respect to a Volterra Equalizer. The latter only processes the non-linear distortion. Finally, a Viterbi Detector is used to process the cleaned signal in the manner of a linear signal, and to estimate appropriate metrics accordingly.

Abstract: The memory array of a server device organizes conventional desktop memory so as to be able to perform error correction. Each one of several Rambus Direct Random Access Memory (“RDRAM™”) devices transfers one group of bits of a data word across a corresponding channel. An additional RDRAM™ device transfers data used for performing error correction, including chip kill, for on the data stored in the RDRAM™ devices.

Abstract: A method for encoding data to meet a maximum run length limitation is disclosed. In one embodiment, the method comprises the steps of: (1) providing user data that includes a plurality of bits, wherein said bits have a value of 1 or 0; (2) performing an ECC computation on said plurality of user data bits to add ECC symbols in the form of a plurality of ECC bits; (3) randomizing the plurality of user data bits and said plurality of ECC bits; (4) analyzing said randomized user data bits and ECC bits to determine whether a number of consecutive bits have a common value; and, (5) inverting the value of a bit, when the number of consecutive bits having a common value exceeds the maximum run length limitation. Subsequently, representations of each of the randomized user bits and ECC bits, including any inverted bits, are stored onto a disk surface as magnetic-polarity transitions.

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.

Abstract: A method, computer program product, and data processing system for recovering corrupted data in a multi-track storage medium, such as magnetic tape, using a Reed-Solomon or other similar error correcting code system, is disclosed. A correction history keeping a tally of actual corrected instances of corruption in the storage medium is established. The “N” tracks requiring the greatest number of actual error corrections are designated as erasures. Any errors in the remaining tracks must be found on an individual basis before being corrected.

Abstract: An optical disc recording/reproducing method and apparatus employs a logical format that allows for long interleaving by a large block to thereby improve reliability of the recording/reproduction operation. Data is recorded/reproduced in accordance with a disc format in which an ECC block is formed by a first error correction code C1 interleaved with respect to the direction of data on the disc, and a second code C2 having a different data direction from that of the first error correction code. The ECC block is made up of one or more sectors, and an information word portion of the first error correction code in the ECC block encompasses the interleaved second code.

Abstract: The present invention relates to method and apparatus that records/reproduces data to/from an optical disk to rearrange user data such as video and/or audio data or to restore original data order by scanning each ECC block in a U-pattern. The present method arranges data in a data block in U-pattern scanning order on the block to randomize data sequence, and records the data block, of which data order has been randomized, sequentially along a track of a writable disk, whereby it is possible to recover individually a long burst error due to track-wise scratch, dust, fingerprint, or the like because an burst-error is scattered in a restored ECC block.

Abstract: In a disk array system of RAID (level 5) improving the system performance by distributing data, duplicated fields are allocated in a parity group in order to reduce an overhead of data write. In the data write process, write data is tentatively and duplicately written in the duplicate fields. At this time, a write completion is reported to CPU. The parity is generated later at a proper timing and written in a SCSI drive. Generating a parity and writing data can be efficiently scheduled.

Abstract: A method and apparatus for detecting and correcting errors and erasures in product-coded data arrays by iterative syndrome processing array data in row major order and column major order. A first dense map is formed for classifying each row containing location indicia of random errors, their correction patterns, and pointers to rows containing erasure errors. This map is used to effectuate row array random error corrections in place in memory. A second dense map is formed of location indicia and correction patterns for each pair adjacent position within a column containing erasure errors as indexed by a counterpart row pointer. The second map is used to effectuate column array erasure corrections and random error corrections in place in memory.

Abstract: Device and method of EEPR4 post processing in an EPR4 detection system to remove single bit errors by applying 1+D to the samples and comparing this to (1−D)(1+D)3 to the detected EPR4 bits.

Abstract: A parameter value is set in a register. A signal is read based on the parameter value. When an error is recognized from an MSE value calculated by a Viterbi decoder, the parameter value is changed and the signal is reread. A new parameter value is calculated based on a change value by which the parameter value is changed and the MSE value. The new parameter value is stored in the register. Thus, an error rate can be converged as a result of the retry.

Abstract: Data recording/reproduction is carried out in a disc format such that error correction codes interleaved with respect to the direction of data on a disc are collectively blocked into an error correction unit and that the input/output order of user data in an ECC block as an error correction unit is made coincident with the direction of processing of the error correction codes. Thus, coding can be started at the time when necessary data for generating one code is transmitted, without waiting for transmission of data for one ECC block. Also, transmission of user data can be started at the time when correction of one code is completed, without waiting for completion of correction operation for one ECC block. Also, since the direction of correction codes is the same as the direction of user data, no memory for rearrangement of data is required and the hardware structure can be minimized.

Abstract: A digital data recording channel which uses variable rate encoding. The encoder monitors an input bit stream for sequences associated with selected readback characteristics, and inserts one or more bits where desirable to improve the characteristics of the stored bit stream.