Abstract: A tape drive-implemented method, according to one embodiment, includes: using information read from one or more servo bands on a magnetic tape to position a magnetic tape head relative to the magnetic tape. An array of data transducers is positioned along the magnetic tape head, the array extending perpendicular to a direction of travel of the magnetic tape. Moreover, a group of servo readers is positioned at each end of the array of data transducers. A distance between each of the immediately adjacent servo readers in each of the groups of servo readers is less than or equal to one third of a prespecified width of each of the servo bands. Furthermore, the distance between each of the servo readers in each of the groups and the prespecified width are both measured in a direction perpendicular to the direction of travel of the magnetic tape.

Abstract: The present invention is notably directed to a computer-implemented method of accessing data by an application. The method comprises detecting an application that is accessing an initial file stored in a storage system; fetching an application model of the detected application, the application model comprising an association between access patterns of the detected application when accessing first files with first metadata information of the said first files; identifying one or more second files stored in the storage system, the identified one or more second files having second metadata information that are similar to the first metadata information; and prefetching the identified one or more second files.

Abstract: A tape drive-implemented method, according to one embodiment, includes: using information read from one or more servo bands on a magnetic tape to position a magnetic tape head relative to the magnetic tape. An array of data transducers is positioned along the magnetic tape head, the array extending perpendicular to a direction of travel of the magnetic tape. Moreover, a group of servo readers is positioned at each end of the array of data transducers. A distance between each of the immediately adjacent servo readers in each of the groups of servo readers is less than or equal to one third of a prespecified width of each of the servo bands. Furthermore, the distance between each of the servo readers in each of the groups and the prespecified width are both measured in a direction perpendicular to the direction of travel of the magnetic tape.

Abstract: The invention is notably directed to computer-implemented methods and systems for managing datasets in a storage system. In such systems, it is assumed that a (typically small) subset of datasets are labeled with respect to their relevance, so as to be associated with respective relevance values. Essentially, the present methods determine, for each unlabeled dataset of the datasets, a respective probability distribution over a set of relevance values. From this probability distribution, a corresponding relevance value can be obtained. This probability distribution is computed based on distances (or similarities), in terms of metadata values, between said each unlabeled dataset and the labeled datasets. Based on their associated relevance values, datasets can then be efficiently managed in a storage system.

Abstract: Embodiments of the present invention provide a tape transport control system with enhanced regulation of tape tension and velocity over the entire length of the tape. The tape transport control system comprises of circuitry adapted to output and circuitry adapted to receive one or more signals representing a tape velocity, at least one radius of either the first tape reel or the second tape reel, and a tape tension, and based on the received signals, generate at least one control signal to control at least one of the first reel motor or the second reel motor so as to reduce a tension disturbance at a minimum, one frequency corresponding to a time-varying reel-rotation frequency, based on controller parameters that depend on the tape velocity and on the at least one radius of either the first tape reel or the second tape reel.

Abstract: A tape drive-implemented method, according to one embodiment, includes: using information read from one or more servo bands on a magnetic tape to position a magnetic tape head relative to the magnetic tape. An array of data transducers is positioned along the magnetic tape head, the array extending perpendicular to a direction of travel of the magnetic tape. Moreover, a group of servo readers is positioned at each end of the array of data transducers. A distance between each of the immediately adjacent servo readers in each of the groups of servo readers is less than or equal to one third of a prespecified width of each of the servo bands. Furthermore, the distance between each of the servo readers in each of the groups and the prespecified width are both measured in a direction perpendicular to the direction of travel of the magnetic tape.

Abstract: The present invention is directed to methods and apparatuses for beamforming signals or compute beamformed signals. The present approach is to determine a series of beams from or for a set of devices configured for receiving signals from and/or transmitting signals to one or more regions of interest in an n-dimensional space, with n=2 or 3. Each of the devices has a known position pi within said n-dimensional space. Signals are to be respectively transmitted or received non-uniformly in this space, i.e., according to the particular regions of interest. During a first phase, operations are performed in order to successively obtain a spatial filter function {circumflex over (?)}(r), a beamforming function ?(p), and beamforming weights ?(pi). The spatial filter function {circumflex over (?)}(r) matches projections of the regions of interest onto an n?1-dimensional sphere centered on said set of devices.

Abstract: A sensor device comprising a computational memory and electronic circuitry. The sensor device is configured to receive an input signal, to compress the input signal into a compressed signal and to compute a reconstructed signal from the compressed signal. The electronic circuitry is configured to perform a reconstruction algorithm to compute the reconstructed signal. The computational memory is configured to compute the compressed signal and partial results of the reconstruction algorithm. A related method and a related design structure may be provided.

Abstract: A method for timing recovery for a high-speed data transmission system may be provided. The method comprises receiving an analog input signal at an ADC and passing processed digital signal samples to a Viterbi detector. The method also comprises receiving at least one processed signal sample and at least two sets of at least one candidate symbol each from the Viterbi detector and/or the processed signal samples by timing error detectors and forwarding output digital signals of the timing error detectors via loop filters to related multiplexers. Furthermore, the method comprises selecting one digital signal from each of the multiplexers using a select signal generated by the Viterbi detector, and deriving a control signal controlling a sampling clock of the analog-to-digital converter by at least one of the selected digital signals from the multiplexers.

Abstract: A tape transport control system with enhanced regulation of tape tension and velocity over the entire length of the tape. For example, a closed-loop control system for controlling a tape transport includes circuitry adapted to output a signal representing a tape velocity at a tape head, circuitry adapted to output a signal representing a tape velocity at the first tape reel and a signal representing a tape velocity at the second tape reel, circuitry adapted to output a signal representing a tape tension, and circuitry adapted to, based on the received signals, generate control signals to control the tape velocity at least at one of the tape head, the first tape reel, the second tape reel, and the tension of the tape, using controller gains that depend on a longitudinal position of the tape, and to implement a system transfer function that is approximately independent of the longitudinal position.

Abstract: A computing system having a computational memory and a method configured to perform computations using an approximate message passing process. The system exploits memcomputing which is a prominent non-von Neumann computational approach expected to significantly improve an energy efficiency of computing systems. The computational memory includes at least one memristive array comprising a plurality of memristive devices arranged in a crossbar topology and the computing system may further comprise digital combinational control circuitry adapted to perform read and write operations on the at least one memristive array and to store at least one state variable of the approximate message passing process. An output of the at least one memristive array represents a result of a computation of the approximate message passing process. The control circuitry may comprise circuitry to iteratively perform computations that may not require high precision.

Abstract: Sequence detectors and detection methods are provided for detecting symbol values corresponding to a sequence of input samples obtained from an ISI channel. The sequence detector comprises a branch metric unit (BMU) and a path metric unit (PMU). The BMU, which comprises an initial set of pipeline stages, is adapted to calculate, for each input sample, branch metrics for respective possible transitions between states of a trellis. To calculate these branch metrics, the BMU selects hypothesized input values, each dependent on a possible symbol value for the input sample and L>0 previous symbol values corresponding to possible transitions between states of the trellis. The BMU then calculates differences between the input sample and each hypothesized input value. The BMU compares these differences and selects, as the branch metric for each possible transition, an optimum difference in dependence on a predetermined state in a survivor path through the trellis.

Abstract: Predictively selecting a subset of disks of a storage system to be spun-up, including providing metadata of data entities stored in the disks of the storage system, estimating the data entity access probabilities for a prediction time window based on said metadata, each data entity access probability being indicative for the probability of access to a certain data entity within said prediction time window, calculating disk access probabilities for a prediction time window based on the estimated probability of access of data entities, each disk access probability being indicative for the probability of access to a certain disk within said prediction time window, estimating the number of disks to be spun-up in a certain prediction time window, dynamically adapting the data entity threshold value and/or the disk access threshold value, selecting a subset of disks to be spun-up in the following prediction time window.

Abstract: The present invention is notably directed to a computer-implemented method for image reconstruction. The method comprises: accessing elements that respectively correspond to measurement values, which can be respectively mapped to measurement nodes; and performing message passing estimator operations to obtain estimates of random variables associated with variable nodes, according to a message passing method in a bipartite factor graph. In this message passing method: the measurement values are, each, expressed as a term that comprises linear combinations of the random variables; each message exchanged between any of the measurement nodes and any of the variable nodes is parameterized by parameters of a distribution of the random variables; and performing the message passing estimator operations further comprises randomly mapping measurement values to the measurement nodes, at one or more iterations of the message passing method.

Abstract: A tape drive-implemented method, according to one embodiment, includes: causing a servo reader to move in a first direction over a high-density servo pattern which includes a plurality of high-density servo tracks. Each of the servo tracks includes at least two patterns written at different frequencies to produce different periodic waveforms during readback. Moreover, a readback signal is received from the servo reader as the servo reader moves in the first direction. The readback signal is used to set a gain parameter for each of the respective periodic waveforms. Other systems, methods, and computer program products are described in additional embodiments.

Abstract: A tape drive-implemented method, according to one embodiment, includes: determining a length of a window of a servo pattern to use for calculating a lateral position estimate, and determining a number of the windows of the servo pattern to use for calculating a lateral position value. A lateral position estimate is calculated for each of the number of the windows of the servo pattern. Moreover, the lateral position value is calculated by using the lateral position estimates. The lateral position value is used to control a tape head actuator. Other systems, methods, and computer program products are described in additional embodiments.

Abstract: A tape drive-implemented method, according to one embodiment, includes: determining a length of a window of a servo pattern to use for calculating a lateral position estimate, and determining a number of the windows of the servo pattern to use for calculating a lateral position value. A lateral position estimate is calculated for each of the number of the windows of the servo pattern using signals which correspond to each of the number of the windows. Moreover, the lateral position value is calculated by using the lateral position estimates. The lateral position value is used to control a tape head actuator. Other systems, methods, and computer program products are described in additional embodiments.

Abstract: Sequence detectors and detection methods are provided for detecting symbol values corresponding to a sequence of input samples obtained from an ISI channel. The sequence detector comprises a branch metric unit (BMU) and a path metric unit (PMU). The BMU, which comprises an initial set of pipeline stages, is adapted to calculate, for each input sample, branch metrics for respective possible transitions between states of a trellis. To calculate these branch metrics, the BMU selects hypothesized input values, each dependent on a possible symbol value for the input sample and L>0 previous symbol values corresponding to possible transitions between states of the trellis. The BMU then calculates differences between the input sample and each hypothesized input value. The BMU compares these differences and selects, as the branch metric for each possible transition, an optimum difference in dependence on a predetermined state in a survivor path through the trellis.

Abstract: The invention is notably directed to computer-implemented methods and systems for managing datasets in a storage system. In such systems, it is assumed that a (typically small) subset of datasets are labeled with respect to their relevance, so as to be associated with respective relevance values. Essentially, the present methods determine, for each unlabeled dataset of the datasets, a respective probability distribution over a set of relevance values. From this probability distribution, a corresponding relevance value can be obtained. This probability distribution is computed based on distances (or similarities), in terms of metadata values, between said each unlabeled dataset and the labeled datasets. Based on their associated relevance values, datasets can then be efficiently managed in a storage system.

Abstract: A sequence detector is provided for detecting symbol values corresponding to a sequence of input samples obtained from a transmission channel. The sequence detector comprises a branch metric unit (BMU), a path metric unit (PMU) and a survivor memory unit. The branch metric unit calculates branch metrics for respective possible transitions between states of a trellis. The path metric unit accumulates branch metrics provided by the branch metric unit in order to establish path metrics. The survivor memory unit selects a survivor path based on the path metrics and outputs a survivor sequence of the detected symbols corresponding to the survivor path. The sequence detector is configured such that the synchronization length is different than the survivor path memory length.