Abstract: In accordance with one embodiment, a data storage system includes a tape channel for reading precoded data from a magnetic tape medium to produce a signal, a soft detector adapted for calculating first soft information about each bit of the signal and sending the first soft information to a soft decoder, and the soft decoder positioned subsequent to the soft detector, the soft decoder being adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft detector, wherein the precoded data includes a characteristic of being passed through at least one precoder prior to being written to the magnetic tape medium, and wherein the soft detector provides automatic compensation for the precoded data. Other systems, methods, and computer program products for reading data using an adaptive soft-output detector are described according to more embodiments.

Abstract: In one embodiment, a data storage system includes a tape channel for reading data from a tape to produce a signal, an adaptive noise whitening filter adapted for receiving the signal, the noise whitening filter being adapted for minimizing variance of noise affecting the signal output from the noise whitening filter, a soft DMAX detector adapted for receiving the signal from the noise whitening filter, the soft detector adapted for calculating first soft information about each bit of the signal and sending the first soft information to a soft decoder, and the soft decoder positioned subsequent to the soft detector, the soft decoder being adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft DMAX detector, wherein one or more noise whitening coefficients used in the noise whitening filter are updated using a noise whitening filter coefficient updater.

Abstract: In one embodiment, a system includes a tape channel for reading data from a magnetic tape medium to produce a signal, a bank of noise whitening filters positioned subsequent to the tape channel adapted for receiving the signal, the bank of noise whitening filters being adapted for minimizing variance of noise affecting the signal at an output of the bank of noise whitening filters, wherein each noise whitening filter in the bank of noise whitening filters is dependent on a different possible data pattern, a soft DMAX detector adapted for calculating first soft information, dependent on the different possible data patterns, about each bit of the signal from the bank of noise whitening filters, and sending the first soft information to a soft decoder adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft DMAX detector.

Abstract: In one embodiment, a data storage system includes a write channel for writing data to a storage medium, the write channel configured to utilize a partial reverse concatenated modulation code. The write channel includes logic adapted for encoding data sets using a C2 encoding scheme, logic adapted for adding a header to each subunit of the data sets, logic adapted for encoding the headers of the data sets with a first modulation encoding scheme, logic adapted for encoding data portions of the data sets with a second modulation encoding scheme, logic adapted for encoding portions of the one or more C2-encoded data sets using a C1 encoding scheme, logic adapted for combining the C1-encoded portions with the modulation-encoded headers of the C2-encoded data sets using a multiplexer, and logic adapted for writing the one or more combined C1- and C2-encoded data sets to data tracks.

Abstract: In one embodiment, a method includes writing data to a storage medium of a data storage system using a partial reverse concatenated modulation code by encoding data sets using a C2 encoding scheme, adding a header to each subunit of the data sets, encoding the headers of the data sets with a first modulation encoding scheme, encoding data portions of the data sets with a second modulation encoding scheme, encoding portions of the one or more C2-encoded data sets using a C1 encoding scheme, combining the C1-encoded portions with the modulation-encoded headers of the C2-encoded data sets using a multiplexer, and writing the one or more combined C1- and C2-encoded data sets to data tracks of the storage medium. Other methods for writing data to a storage medium of a data storage system using a partial reverse concatenated modulation code are presented according to more embodiments.

Abstract: In one embodiment, a tape drive system includes a write channel for writing data to a magnetic tape, the write channel utilizing a rate-(232/234) reverse concatenated modulation code. The write channel includes logic adapted for receiving a data stream comprising one or more data sets, logic adapted for separating each data set into a plurality of sub data sets, logic adapted for encoding each sub data set with a C2 encoding, logic adapted for encoding each C2-encoded sub data set with a modulation code, logic adapted for encoding each modulated sub data set with a C1 encoding, and logic adapted for simultaneously writing the encoded modulated sub data sets to data tracks of the magnetic tape. Other systems for writing data to a magnetic tape utilizing a rate-(232/234) reverse concatenated modulation code are described according to various other embodiments.

Abstract: Methods and apparatus are provided for recording input data in q-level cells of solid-state memory (2), where q>2. Input data words are encoded as respective codewords, each having a plurality of symbols. The coding scheme is such that each symbol can take one of q values corresponding to respective predetermined levels of the q-level cells, and each of the possible input data words is encoded as a codeword with a unique sequence of relative symbol values. The symbols of each codeword are then recorded in respective cells of the solid-state memory by setting each cell to the level corresponding to the recorded symbol value. Input data is thus effectively encoded in the relative positions of cell levels, providing resistance to certain effects of drift noise.

Abstract: In one embodiment, a method includes executing a first forward loop of a detection algorithm on a block of signal samples during a first time interval, executing a first reverse loop of the detection algorithm on the block during a second time interval to produce first soft information, executing a decoding algorithm on the block during a third time interval using the first soft information to produce second soft information, executing a second forward loop of the detection algorithm on the block during a fourth time interval using the second soft information, executing a second reverse loop of the detection algorithm on the block during a fifth time interval to produce third soft information, executing the decoding algorithm on the block during a sixth time interval using the third soft information to produce a decoded block of signal samples, and outputting the decoded block of signal samples.

Abstract: In one embodiment, a tape drive system includes a soft detector for executing a first forward loop of a detection algorithm on a first block of signal samples during a first time interval; and logic for executing forward and reverse loops during several time intervals; and logic adapted for outputting a first decoded block of signal samples based on the executing the decoding algorithm on the first block during a sixth time interval, wherein a sum of second, third, fourth, fifth, and sixth time intervals are about equal in duration to the first time interval.

Abstract: A method for efficiently rewriting data to tape is disclosed herein. In one embodiment, such a method includes writing a data set to tape, the data set comprising S sub data sets of fixed size, each sub data set comprising N code word interleaves (CWIs). The method further includes reading the data set while writing it to the tape to identify faulty CWIs. While reading the data set, the method buffers the faulty CWIs (such as by storing, identifying, and/or marking the faulty CWIs) for later retrieval. When the end of the data set is reached, the method writes corrected versions of the faulty CWIs to the end of the data set. A corresponding apparatus is also disclosed and claimed herein.

Abstract: Provided are a computer program product, system, and method for generating a code alphabet for use by a deployed program to determine codewords for words. A first code alphabet is generated having a first number of symbols that provide variable length codings of the words. The symbols in the first code alphabet are merged into a second number of groups of the symbols in the first code alphabet, where the second number is less than the first number. A second code alphabet is generated having the second number of symbols, wherein a second average codeword length of the codewords produced using the symbols in the second code alphabet is smaller than the codeword length (b) of the words, and wherein the second code alphabet comprises the code alphabet used by the deployed program.

Abstract: A method for integrating data and header protection in tape drives includes receiving an array of data organized into rows and columns. The array is extended to include one or more headers for each row of data in the array. The method provides two dimensions of error correction code (ECC) protection for the data in the array and a single dimension of ECC protection for the headers in the array. A corresponding apparatus is also disclosed herein.

Abstract: Selecting bins in a memory by receiving a target cost for performing writes at an analog memory that is capable of storing a range of values. Possible bins that may be created in the range of values and a cost associated with each possible bin are determined. Each possible bin includes one or more of the values. A group of bins are identified, the group of bins are among the possible bins with associated costs that are within a threshold of the target cost. A maximum number of bins are selected from the group of bins that have non-overlapping values. The selected bins are stored along with the values of the selected bins utilized to encode and decode contents of the analog memory.

Abstract: A method for randomizing data to mitigate false VFO detection is described. In one embodiment, such a method includes simultaneously receiving multiple input data streams. Each input data stream is associated with a different track on a magnetic tape medium. The input data streams are simultaneously scrambled to produce multiple randomized data streams. The input data streams are scrambled such that different bit patterns are produced in the randomized data streams even where corresponding bit patterns in the input data streams are identical. The randomized data streams are simultaneously written to their associated data tracks on the magnetic tape medium.

Abstract: A phase-change memory (PCM) includes a matrix of storage cells, including at least a first group with at least one cell. Each cell includes a phase change material having at least a first resistance value and a second resistance value, such that the first group can have an identical message encoded therein in at least a first way and a second way. The memory also includes a controller configured to encode the identical message in the at least first group the first or second way, based on which way causes the least amount of writing cost, given current levels of the group. Another embodiment of memory includes a matrix of storage cells. Each of the storage cells has at least two levels, such that each of the storage cells can have an identical message encoded therein in at least a first way and a second way.

Abstract: A method for randomizing data to mitigate false VFO detection is described. In one embodiment, such a method includes simultaneously receiving multiple input data streams. Each input data stream is associated with a different track on a magnetic tape medium. The input data streams are simultaneously scrambled to produce multiple randomized data streams. The input data streams are scrambled such that different bit patterns are produced in the randomized data streams even where corresponding bit patterns in the input data streams are identical. The randomized data streams are simultaneously written to their associated data tracks on the magnetic tape medium. A corresponding apparatus is also described.

Abstract: A phase-change memory (PCM) includes a matrix of storage cells, including at least a first group with at least one cell. Each cell includes a phase change material having at least a first resistance value and a second resistance value, such that the first group can have an identical message encoded therein in at least a first way and a second way. The memory also includes a controller configured to encode the identical message in the at least first group the first or second way, based on which way causes the least amount of writing cost, given current levels of the group. Another embodiment of memory includes a matrix of storage cells, including at least a first group with at least one cell. Each of the storage cells has at least two levels, such that each of the storage cells can have an identical message encoded therein in at least a first way and a second way (the cells can be PCM or another technology).

Abstract: An apparatus, system, and method are disclosed for read back verification of stored data. A file CRC module calculates a first file CRC for a data file. A segmentation module segments the data file into a plurality of data blocks that comprise a copy of the data file. A block CRC module calculates a data block CRC for each data block. An aggregated CRC module calculates a second file CRC from the data block CRCs. In addition, the aggregated CRC module verifies copy of the data file if the second file CRC is substantially equivalent to the first file CRC.

Abstract: Methods and apparatus are provided for encoding input data for recording in s-level storage of a solid state storage device, where s f 2. Input data words are encoded in groups of M input data words in accordance with first and second BCH codes to produce, for each group, a set of M first codewords of the first BCH code. The set of M first codewords is produced such that at least one predetermined linear combination of the M first codewords produces a second codeword of the second BCH code, this second BCH code being a sub-code of the first BCH code. The sets of M first codewords are then recorded in the s-level storage. If each of the first and second codewords comprises N q-ary symbols where q=pk, k is a positive integer and p is a prime number, the q-ary code alphabet can be matched to the s-ary storage by ensuring that q and s are uth and vth powers respectively of a common base r, where u and v are positive integers and k f u, whereby p(k/u)v=s.

Abstract: A method for encoding a data word for writing an encoded data word in N cells of a solid state memory. Each of the N cells can be programmed in one of q nominal levels. The method includes encoding the data word as a codeword of a first codeword type having q symbol values or as a codeword of a second codeword type having (q-d) symbol values, d ? [1, . . . , q-1], depending on a state of the N cells.