Abstract: According to one embodiment, a system for selecting an optimum tape layout to store data on a tape medium includes a processor and logic integrated with and/or executable by the processor, the logic being configured to compute a set of all minimum distances corresponding to a plurality of data set layouts, wherein each minimum distance is computed between a location of a first codeword interleave (CWI) and locations of all other CWIs in a common sub data set (SDS), and calculate a first performance metric associated with each possible set of parameters using the set of all minimum distances for the plurality of data set layouts, the parameters being associated with at least a tape drive and the tape medium. More systems, methods, and computer program products for selecting optimum tape layouts to store data on tape media are described in accordance with other embodiments.

Abstract: In one embodiment, a method includes passing a signal through an adaptive noise whitening filter, wherein one or more noise whitening coefficients used in the noise whitening filter are updated using a noise whitening filter coefficient updater, wherein the noise whitening filter is configured to process the signal according to a transfer polynomial: W(D)=1?(p1D+ . . . +p??D??), where p1 . . . p?? are noise whitening coefficients, where a tape channel is characterized by a transfer polynomial F(D)=1+f1D+ . . . +fLDL where D is delay corresponding to bit duration, with 2L being a number of states of the tape channel, wherein a soft detector has a total of 2L+? states, the noise whitening filter comprises 2?? states, ?? is greater than ?, L represents a memory length of the tape channel, and ? represents a memory length of the noise whitening filter.

Abstract: In one embodiment, a computer program product for iterative read channel operation has program instructions embodied therewith that are executable by a controller to cause the controller to: in an iterative process until a maximum number of iterations has been reached or a valid codeword is produced: execute one or more digital front-end (DFE) functions on a plurality of signal samples employing the set of decisions provided by a decoder; execute a detection algorithm on the signal samples using a detector employing the set of decisions provided by the decoder to regenerate the set of decisions provided by a detector; execute a decoding algorithm of an error correcting code (ECC) using the set of decisions provided by the detector to regenerate the set of decisions provided by the decoder; and output decoding information relating to the signal samples when the decoding algorithm produces a valid codeword.

Abstract: In accordance with one embodiment, a computer program product includes a computer readable storage medium having computer readable program code that is readable and/or executable by a processor to: receive a signal including precoded data read from a magnetic tape medium and pass the signal through a soft detector to calculator first soft information about each bit of the signal and to provide adaptive compensation for the precoded data, send the first soft information to a soft decoder, pass the signal through the soft decoder to calculate second soft information about each bit the signal, and send the second soft information to the soft detector, wherein the precoded data is passed through at least one precoder prior to being written to the magnetic tape medium via a precoder that applies 1/(1?D2) to bits of data, where D is delay corresponding to bit duration

Abstract: In one embodiment, a method includes passing a signal through a noise whitening filter, passing the signal through a soft detector to calculate first soft information, passing the signal through the soft decoder to calculate second soft information based on the first soft information, and sending the second soft information to the soft detector, wherein the noise whitening filter is configured to process the signal according to the following transfer polynomial: W(D)=1?(p1D+ . . . p1D?), where p1 . . . p? are noise whitening coefficients, D is delay corresponding to bit duration, and a transfer polynomial of the tape channel is F(D)=1+f1D+ . . . +fLDL, wherein L represents a memory length of the tape channel, and wherein ? represents a memory length of the noise whitening filter. Other methods, systems, and computer program products are described in more embodiments.

Abstract: According to one embodiment, a computer program product for dropout detection in a read channel includes a computer readable storage medium having program code embodied therewith, the embedded program code being readable and/or executable by a processor to execute dropout detection on a block of signal samples to detect one or more dropout events employing a set of decisions provided by a detector executing a detection algorithm, determine an approximate location for each of the one or more detected dropout events, statistically characterize the one or more detected dropout events to calculate one or more dropout profiles, and selectively filter the block of signal samples during a duration of each of the detected dropout events. Other computer program products, systems, and methods for detecting dropouts are presented in more embodiments.

Abstract: According to one embodiment, a system for selecting an optimum tape layout to store data on a tape medium may include a processor and logic integrated with and/or executable by the processor, the logic being configured to: select a family of data set layouts based on parameters associated with at least a tape drive and the tape medium, compute a set of all minimum distances for the selected family of data set layouts, calculate a first performance metric associated with each possible set of parameters, select a best first performance metric from all calculated first performance metrics and store a set of parameters associated with the best first performance metric, and select a data set layout algorithm which utilizes the set of parameters associated with the best first performance metric, wherein the data set layout algorithm and a rewrite layout algorithm combine to form an optimum tape layout.

Abstract: In one embodiment, a system for integrating data and header protection includes a processor and logic integrated with and/or executable by the processor, the logic being configured to receive a data array organized in rows and columns, each row of the data array comprising two or more interleaved C1 codewords (CWI), and modify one or more rows of the data array to include a header and error correction code (ECC) parity to form one or more modified rows, wherein each modified row includes two or more interleaved codewords, at least one codeword being a C1? codeword which includes ECC parity, wherein each header comprises a CWI Designation (CWID) which indicates a location of the CWI within the data array, and wherein none of the CWIDs are split across multiple C1? codewords in a single modified row. Other systems, methods, and computer program products are presented in additional embodiments.

Abstract: In one embodiment, a method for iterative read channel operation includes executing digital front-end (DFE) functions on signal samples employing decisions provided by a detector executing a detection algorithm, executing an error correcting code (ECC) decoding algorithm on the signal samples using a decoder employing the decisions provided by the detector to generate decisions provided by the decoder, storing the signal samples and the decisions provided by the detector and the decoder, and in an iterative process: executing the DFE functions on the signal samples employing the decisions provided by the decoder, executing the detection algorithm on the signal samples using the detector employing the decisions provided by the decoder to regenerate the decisions provided by the detector, executing the decoding algorithm using the decisions provided by the detector to regenerate the decisions provided by the decoder, and outputting decoding information when the decoding algorithm produces a valid codeword.

Abstract: In one embodiment, a system for providing header protection in magnetic tape recording is adapted to write a codeword interleave (CWI) set on a magnetic tape including a plurality of CWIs equal to a number of tracks, wherein a data set includes a plurality of CWI sets, provide a CWI set header for the CWI set, the CWI set header including a CWI header for each CWI in the CWI set, each CWI header including at least a CWI Designation (CWID) which indicates a location of the CWI within the data set, calculate or obtain CWID parity for all CWIDs in the CWI set header, the CWID parity including error correction coding (ECC) parity, and store the CWID parity to one or more fields which are repeated for each CWI header in the CWI set header without using reserved bits in the CWI set header to store the CWID parity.

Abstract: According to one embodiment, a magnetic medium's readback signal samples are processed iteratively to provide dropout mitigation for a read channel by feeding the decoder output decisions back to the read channel front end where they are used to drive the decision-aided digital signal processing functions and control loops. Since data decisions provided by the decoder are typically more reliable than those provided by the detector, a significant performance improvement is obtained. A more reliable operation of the digital front-end signal processing functions in turn allows improvements to the reliability of the decoded data. Usage of Error Correcting Code (ECC) schemes that are soft decodable makes the read channel technique, described according to various embodiments herein, particularly efficient.

Abstract: In one embodiment, a system for combination error and erasure decoding for product codes includes a processor and logic integrated with and/or executable by the processor, the logic being configured to receive captured data, generate erasure flags for the captured data and provide the erasure flags to a C2 decoder, set a stop parameter to be equal to a length of C1 codewords in a codeword interleave used to encode the captured data, and selectively perform, in an iterative process, error or erasure C1 decoding followed by error or erasure C2 decoding until decoding is successful or unsuccessful. In more embodiments, a method and/or a computer program product may be used for combination error and erasure decoding for product codes.

Abstract: According to one embodiment, a system for processing data includes an equalizer configured to use servo coefficients for processing servo data and data coefficients for processing non-servo data, wherein the equalizer includes a finite impulse response (FIR) filter configured to process data read with a magnetic tape channel using the servo coefficients to generate equalized data, one or more low-pass filters with aggressive frequency characteristics configured to filter the equalized data to output filtered data, the one or more low-pass filters with aggressive frequency characteristics being configured to remove high frequency noise from the equalized data, a peak detector configured to process peaks in a waveform of the filtered data, and at least one servo pattern detector configured to detect a servo pattern in the filtered data. Other systems and methods for processing data are described in more embodiments.

Abstract: According to one embodiment, a system for selecting an optimum tape layout to store data on a tape medium may include a processor and logic integrated with and/or executable by the processor, the logic being configured to: select a family of data set layouts based on parameters associated with at least a tape drive and the tape medium, compute a set of all minimum distances for the selected family of data set layouts, calculate a first performance metric associated with each possible set of parameters, select a best first performance metric from all calculated first performance metrics and store a set of parameters associated with the best first performance metric, and select a data set layout algorithm which utilizes the set of parameters associated with the best first performance metric, wherein the data set layout algorithm and a rewrite layout algorithm combine to form an optimum tape layout.

Abstract: In one embodiment, a system for integrating data and header protection in tape recording includes a processor and logic adapted to: provide a data array organized in rows and columns, each row of the data array including four interleaved C1 codewords (CWI-4), add a header to each row of the data array, each header including a CWI-4 Designation (CWID) which indicates a location of the CWI-4 within the data array, calculate ECC parity for at least one C1 codeword in each of the headerized rows, and modify the headerized rows to include the ECC parity, wherein each modified row includes four interleaved codewords, at least one codeword being a C1? codeword which includes ECC parity for a data portion of a C1 codeword and a portion of a header, wherein none of the CWIDs are split across multiple C1? codewords in a single modified row.

Abstract: A method for decoding a headerized sub data set (SDS) according to one embodiment includes decoding a header from a headerized SDS to obtain a SDS. C1 and C2 decoding are performed on the SDS in a number of iterations based on a number of interleaves in each row of the SDS. A number of columns of the SDS are overwritten with successfully decoded C2 codewords. A number of rows of the SDS are overwritten with successfully decoded C1 codewords. A number of C1 and/or C2 codewords of the SDS are erased. Remaining rows and/or columns of the SDS are maintained as uncorrected. The SDS is output when all rows of the SDS include only C1 codewords and all columns of the SDS include only C2 codewords.

Abstract: In one embodiment, a system for encoding data includes logic adapted for receiving data having one or more sub data sets, a C1 encoder module adapted for generating a plurality of C1 codewords during C1 ECC encoding of the one or more sub data sets, logic adapted for interleaving the plurality of C1 codewords into C1 codeword interleaves (CWIs), each CWI having a predetermined number of C1 codewords interleaved therein, a C2 encoder module adapted for generating a plurality of C2 codewords during C2 ECC encoding of the one or more sub data sets, wherein each C2 codeword has at most one symbol from each C1 codeword in each CWI, and wherein each C2 codeword has one symbol from at least two different C1 codewords in each CWI, and logic adapted for writing the one or more encoded sub data sets to a storage medium.

Abstract: According to one embodiment, a magnetic medium's readback signal samples are processed iteratively to provide dropout mitigation for a read channel by feeding the decoder output decisions back to the read channel front end where they are used to drive the decision-aided digital signal processing functions and control loops. Since data decisions provided by the decoder are typically more reliable than those provided by the detector, a significant performance improvement is obtained. A more reliable operation of the digital front-end signal processing functions in turn allows improvements to the reliability of the decoded data. Usage of Error Correcting Code (ECC) schemes that are soft decodable makes the read channel technique, described according to various embodiments herein, particularly efficient.

Abstract: In one embodiment, a system for integrating data and header protection in tape recording includes a processor and logic adapted to: provide a data array organized in rows and columns, each row of the data array including four interleaved C1 codewords (CWI-4), add a header to each row of the data array, each header including a CWI-4 Designation (CWID) which indicates a location of the CWI-4 within the data array, calculate ECC parity for at least one C1 codeword in each of the headerized rows, and modify the headerized rows to include the ECC parity, wherein each modified row includes four interleaved codewords, at least one codeword being a C1? codeword which includes ECC parity for a data portion of a C1 codeword and a portion of a header, wherein none of the CWIDs are split across multiple C1? codewords in a single modified row.

Abstract: In one embodiment, a method for iterative read channel operation includes executing digital front-end (DFE) functions on signal samples employing decisions provided by a detector executing a detection algorithm, executing an error correcting code (ECC) decoding algorithm on the signal samples using a decoder employing the decisions provided by the detector to generate decisions provided by the decoder, storing the signal samples and the decisions provided by the detector and the decoder, and in an iterative process: executing the DFE functions on the signal samples employing the decisions provided by the decoder, executing the detection algorithm on the signal samples using the detector employing the decisions provided by the decoder to regenerate the decisions provided by the detector, executing the decoding algorithm using the decisions provided by the detector to regenerate the decisions provided by the decoder, and outputting decoding information when the decoding algorithm produces a valid codeword.