摘要:
A method for decoding encoded data comprising integrated data and header protection is disclosed herein. In one embodiment, such a method includes receiving an extended data array. The extended data array includes a data array organized into rows and columns, headers appended to the rows of the data array, column ECC parity protecting the columns of the data array, and row ECC parity protecting the rows and headers combined. The method then decodes the extended data array. Among other operations, this decoding step includes checking the header associated with each row to determine whether the header is legal. If the header is legal, the method determines the contribution of the header to the corresponding row ECC parity. The method then reverses the contribution of the header to the corresponding row ECC parity. A corresponding apparatus (i.e., a tape drive configured to implement the above-described method) is also disclosed herein.
摘要:
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.
摘要:
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.
摘要:
A method for physically laying out data on tape is disclosed herein. In one embodiment, such a method includes receiving a data set, wherein the data set includes S sub data sets (SDSs) of fixed size and each SDS includes N codeword interleaves (CWIs). The method further distributes the CWIs for the S SDSs across T tracks on a physical tape medium such that the distances between CWIs of the same SDS are substantially maximized on the physical tape medium. To maximize the distances, the method periodically rotates the tracks within the data set by a track rotation value R, wherein the number of tracks T is equal to 2k, and the track rotation value R is equal to 2k−1−1. A corresponding apparatus is also disclosed herein.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
An apparatus, system, and method are disclosed for detecting a periodic sequence. A value detector module detects a plurality of values of a periodic sequence. In one embodiment, a transformation module transforms the plurality of values into transformed values. A confinement module confines the values to a limited set of confined values. A correlation module correlates the confined values with a plurality of instances of the periodic sequence. In addition, a selection module selects an instance of the periodic sequence with the highest correlation to the confined values as an observed periodic sequence.
摘要:
Methods and apparatus for interleaving data in a multitrack tape drive and for writing data on a multitrack tape in the tape drive. One method includes: partitioning the data into m(2n+k) data blocks, where each data block has a logical array of rows and columns of data bytes; error-correction coding a row and a column of the logical array to produce an encoded block; assigning the coded row to a respective location in a logical interleave array having L rows and 2n+k columns of locations; and writing a sequence of assigned coded rows simultaneously in respective data tracks on the multitrack tape. The coded row is assigned such that the minimum Euclidean distance on the multitrack tape between the coded rows is maximized. The apparatus includes units for performing the methods and the computer program product includes a program code means for causing a computer to perform the methods.
摘要:
A method and apparatus are provided for implementing soft-input soft-output iterative detectors/decoders. Soft-input information is added directly to incoming channel samples. Input signals comprising the received incoming channel samples with the added soft-input information are detected using a detector trellis. Branch metric terms are transformed to shift all time varying terms with the added soft-input information and some constant terms after an add compare select (ACS) unit. The shifted time varying terms with the added soft-input information and the shifted constant terms are added directly to state metric terms. The soft-input information is added directly to incoming channel samples and the computation of branch metrics is not affected. This allows optimization of a dual-max detector and soft-input soft-output Viterbi detector architectures to minimize hardware complexity and power consumption.