Abstract: An automated data storage library accesses data stored on storage media contained in cartridges in response to commands from an external host. The cartridges may include cartridge memory and a component in the library may include a cartridge memory interface for reading data from and/or writing data to the cartridge memory. When a cartridge is to be stored in the library, the library modifies the contents of the cartridge memory, or the contents of the storage media such that the data stored on the cartridge becomes inaccessible, thereby preventing access to the data outside of the library. To perform an authorized access, the library restores the contents of the cartridge memory or the storage media. Alternatively, the library provides a correction or correction algorithm to the drive to allow access to the data stored on the storage media without removing the access protection of the storage media.

Abstract: A read channel and method using that read channel are disclosed. The read channel comprises an analog to digital converter which asynchronously samples at a fixed rate an analog signal formed by reading a data track, where that data track was written to a data storage medium at a symbol rate and an interpolator interconnected with the analog to digital converter. The read channel further comprises a fractionally-spaced equalizer, where the interpolator provides an interpolated signal to the fractionally-spaced equalizer at an interpolation rate, where that interpolation rate is greater than the symbol rate. The fractionally-spaced equalizer forms a synchronous equalized signal. The read channel further comprises a gain control module interconnected with the fractionally-spaced equalizer, and a sequence detector interconnected with the gain control module.

Abstract: A method and apparatus for providing error correction capability to longitudinal position data are disclosed. Initially, data are encoded via a set of even LPOS words and a set of odd LPOS words. The encoded data are then decoded by generating a set of syndrome bits for each of the LPOS words. A determination is then made as to whether or not there is an error within one of the LPOS words based on its corresponding syndrome bits.

Abstract: An automated data storage library accesses data stored on storage media contained in cartridges in response to commands from an external host. The cartridges include cartridge memory and a component in the library includes a cartridge memory interface for reading data from and/or writing data to the cartridge memory. When a cartridge is to be stored in the library, the library modifies the contents of the cartridge memory such that the data stored on the cartridge becomes inaccessible, thereby preventing access to the data outside of the library. To perform an authorized access, the library restores the contents of the cartridge memory or provides a correction or correction algorithm to allow access to the data without removing the access protection of the storage media. The cartridge memory may also or alternatively include an identifier which permits access to the data only by the identified physical and/or logical library(s).

Abstract: Methods, apparatus and computer program products are provided to monitor and report performance data of a device such as a data storage drive. A plurality of quantitative values are obtained from feedback and measurement mechanisms in a data storage device of a first model during operation of the storage device. The plurality of quantitative values are normalized. Then, one or more qualitative values are generated from one or more normalized quantitative values and evaluated against corresponding baseline performance values established for the first model.

Abstract: Searching data string matches, e.g. data stored on magnetic tape cartridges, and is searched by magnetic tape drives. String comparison engines are configured to search data and to indicate matches to search terms, and an identification engine is configured to identify patterns of the matches indicated by selected string comparison engines.

Abstract: A magnetic tape cartridge, a recording system, and a magnetic tape drive are configured to, for example, guard against tampering with a write once overwrite protection pointer which allows a rewritable magnetic tape to be treated as write once. In one embodiment, the magnetic tape cartridge comprises a magnetic tape and a cartridge memory. The magnetic tape is configured to provide at least one overwrite protection pointer, the overwrite protection pointer identifying data to be protected from being overwritten; and the cartridge memory is configured to provide the at least one overwrite protection pointer, the overwrite protection pointer identifying magnetic tape data to be protected from being overwritten.

Abstract: A method to read (N) sequential files written to an information storage medium, and then skip the next (M) sequential files. The method initially identifies the (M) files to be skipped. After identifying the (M) files to be skipped, the method reads the (N) files.

Abstract: An apparatus, system, and method are disclosed for asymmetric maximum likelihood detection. An initialization module initializes a plurality of branch metrics and a plurality of path memories. A coefficient module calculates a plurality of coefficients. A computation module calculates a first and second specified likelihood function. A selection module calculates a third specified branch metric as the maximum of the first and second specified likelihood functions. A path metrics module calculates a third specified path memory from a first and second specified path memory. A results module identifies a data output value from one or more path memories.

Abstract: Provided are a method, system, and program for writing data in a tape medium having wraps. A layout of the tape is provided including at least one segment within a full available length of a first set of wraps for writing user data and at least one segment within a full length of a second set of wraps for writing a work copy of the user data. User data is received to write to the tape medium and detecting is performed as to whether the data being written is occurring in a specified write mode. If the data writing is not occurring in the specified write mode, then writing the received user data to one segment in the first set of wraps. If the data writing is occurring in the specified write mode, then writing a work copy to available full length wraps not having user data.

Abstract: A read channel equalizer of a magnetic tape drive which equalizes digitally sampled magnetic signals detected by a read head is dynamically adapted. A detector of equalizer dynamic adaptation logic compares equalizer output signals to desired values that are based on the decoding scheme (such as +2, 0 and ?2 for PR4) to sense equalizer output signals that are offset from at least one desired value, and signals the fact of each offset and its polarity as amplitude independent error signals. The signaled sensed amplitude independent error signals are fed back to adjustable taps of the equalizer. The simplified error signals thus avoid complex calculations of waveform errors, such as least mean square calculations. The error signals may be weighted and may be adjusted to align synchronously provided error signals with asynchronous taps of the equalizer.

Abstract: Magnetic tape read channel signal values are developed employing intermediate bits of the path memory of a PRML Viterbi detector. Identification logic identifies a most likely path memory state of the PRML Viterbi detector from the path metrics of the PRML Viterbi detector. An intermediate bit sequence of the identified most likely path memory state is obtained, the intermediate bit sequence extending from an initiation point of the path memory which is intermediate the output and the input of the PRML Viterbi detector. A sample value is determined which corresponds to the obtained intermediate bit sequence.

Abstract: An apparatus, system, and method are disclosed for mitigating signal asymmetry. An analog to digital converter samples an analog signal from a read head and converts the sample to a digital input signal. The digital input signal addresses a look-up module, and the look-up module outputs a modified digital signal. The modified digital signal value is a specified function of the digital input signal value, wherein the specified function is configured to mitigate the asymmetry of the digital input signal. The modified digital signal value may be periodically recalculated to adjust for read head wear.

Abstract: An error correction code system, e.g. of a magnetic tape drive, applies error correction redundancy to data, separates it, or interleaves it, and records it into separate groups. An error correction encoder applies an outer error correction code to one of the separate groups of information, forming one set of rows of information and outer ECC information. An error correction encoder applies an outer error correction code to another separate group of information, forming another set of rows of information and outer ECC information. A data organizer interleaves the one set of rows of information and outer ECC information with the another set of rows of information and outer ECC information for recording on tracks of a recording media in an interleaved pattern of one set of rows of information and outer ECC information with another set of rows of information and outer ECC information.

Abstract: A method to read information from a tape storage medium, where that tape includes a calibration region and a data region. The method uses a read channel having a first detection mode and a second detection mode. The method initializes the first detection mode and forms a calibration waveform comprising information read from the calibration region using the first detection mode. The method then defines a plurality of bit cell boundaries, initializes the second detection mode, and reads information from the data region using the second detection mode.

Abstract: A cartridge handling system and method initialize a data storage cartridge having rewritable media for tamper resistant write once recording. A write once flag is written to a lockable section of a cartridge memory; the lockable section is locked to read-only; and a write once flag is written to a required data set of the rewritable media. Thus, write once flags are provided both at the locked read-only section of the cartridge memory, and at the required data set of the rewritable media.

Abstract: A recording system of a magnetic tape drive is operated to cause one separate set of write heads to write data discontinuously to magnetic tape as received, and to save the data, and, during the same operation, to cause another separate set of write heads to rewrite data to magnetic tape in a continuous arrangement. The writing may be in parallel and simultaneous. Thus, during the same operation, and at the same time, the separate sets of the plurality of write heads, temporarily write the received data to magnetic tape so that the sender can erase its copy, and rewrite the saved data to the magnetic tape in a permanent arrangement, without waiting to complete first writing received data, to complete subsequently rewriting the data, and repeating.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.