Patent application number | Description | Published |
20080259484 | READ CHANNEL APPARATUS FOR ASYNCHRONOUS SAMPLING AND SYNCHRONOUS EQUALIZATION - 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. | 10-23-2008 |
20080259785 | Link Adaptation - The present invention discloses an apparatus and method for adapting a transmission parameter in a transmitting node of a data communication system to the current link quality of a data communication channel. The adapted transmission parameter is selected by the transmitting node from a set of transmission parameters in dependence on a number of successful transmissions. The number of successful transmissions is compared in the transmitting node against one of a first threshold value corresponding to a first state of the transmitting node and a second threshold value corresponding to a second state of the transmitting node. The method comprises in the transmitting node the steps of (a) counting the number of successful transmissions; (b) selecting the adapted transmission parameter (b | 10-23-2008 |
20080297937 | USING A MEASURED ERROR TO DETERMINE COEFFICIENTS TO PROVIDE TO AN EQUALIZER TO USE TO EQUALIZE AN INPUT SIGNAL - Provided are a read channel, storage drive and method using a measured error to determine coefficients to provide to an equalizer to use to equalize an input signal. A read channel is incorporated in a storage device to process signals read from a storage medium. An equalizer uses coefficients to equalize input read signals to produce equalizer output signals. A detector processes adjusted equalizer output signals to determine output values comprising data represented by the input read signals. An equalizer adaptor is enabled to provide a reference measured error and coefficients used to produce the adjusted equalizer signals that are associated with the reference measured error. The equalizer adaptor computes new equalizer coefficients to use to equalize input read signals that result in a new measured error from the detector and computes a new measured error for the new equalizer coefficients. The equalizer adaptor determines whether the new measured error is degraded with respect to the reference measured error and saves the new equalizer coefficients and the new measured error in response to determining that the new measured error is not degraded with respect to the reference measured error. The equalizer adaptor provides the equalizer coefficients associated with the reference measured error to the equalizer to use to equalize input read signals in response to determining that the new measured error is degraded with respect to the reference measured error. | 12-04-2008 |
20090097535 | MULTI-CHANNEL DATA DETECTION PHASE LOCKED LOOP ERROR COMBINATION LOGIC - Phase-error combination for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving phase error information with respect to each channel; combination logic configured to combine the received phase error information and generate a combined phase error; and a phase-error output configured to apply the combined phase error to at least one channel phase locked loop. Additionally, error signal combination comprises receiving error information of a signal relevant to a phase locked loop with respect to each channel; combination logic configured to combine the received error signal information and generate a combined error signal, weighting the received error signal information from each channel, for example with reliability information. An error compensation output is configured to apply the combined, weighted error signal to at least one channel phase locked loop. | 04-16-2009 |
20090097536 | MULTI-CHANNEL DATA DETECTION PHASE LOCKED LOOP FREQUENCY ERROR COMBINATION LOGIC - Frequency error combination for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving frequency error information with respect to each channel; combination logic configured to combine the received frequency error information and generate a combined phase error, weighting the received frequency error information from each channel; and a frequency error output configured to apply the combined frequency error to at least one channel phase locked loop. | 04-16-2009 |
20090097603 | COMMON STATE-SPACE MULTI-CHANNEL DIGITAL SAMPLE TIMING PHASE CONTROL OF MULTIPLE READ CHANNELS FOR CORRELATED SIGNALS - Common sample timing control for sample timing of multiple read channels, wherein the signal clocking of the signals received by the multiple read channels are correlated, for example from parallel tracks of magnetic tape that have been written simultaneously. In one embodiment, a common sample timing control comprises multiple phase error inputs, each indicating phase error of one of the read channels. Logic responsive to the multiple phase error inputs is configured to weight and crosscouple the phase error indication of each phase error input with the phase error indication of each other phase error input, and to apply gain related to the variance of noise of the phase error indications. Feedback logic is responsive to the crosscoupling and is configured to provide a sample timing phase estimate for each read channel. | 04-16-2009 |
20090097604 | METHODS FOR MULTI-CHANNEL DATA DETECTION PHASE LOCKED LOOP ERROR COMBINATION - Phase-error combination methods for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving phase error information with respect to each channel; combining the received phase error information and generating a combined phase error; and applying the combined phase error to at least one channel phase locked loop. Error signal combination comprises receiving error information of a signal relevant to a phase locked loop with respect to each channel; combining the received error signal information and generating a combined error signal, weighting the received error signal information from each channel, for example with reliability information. The combined, weighted error signal is applied to at least one channel phase locked loop. | 04-16-2009 |
20090097606 | METHODS FOR MULTI-CHANNEL DATA DETECTION PHASE LOCKED LOOP FREQUENCY ERROR COMBINATION - Frequency error combination for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving frequency error information of a signal relevant to a phase locked loop with respect to each channel; combining the received error signal information and generating a combined error signal, weighting the received error signal information from each channel, for example with reliability information. The combined frequency error signal is applied to at least one channel phase locked loop. | 04-16-2009 |
20090174964 | SERVO CHANNEL FOR TAPE DRIVE SYSTEMS - Provided are techniques for synchronous servo channel for a data tape drive. A servo reader is configured to read servo bursts from a data tape. An anti-aliasing filter is operable to output a bandlimited signal and is coupled to receive a servo channel signal comprising servo bursts from the servo reader. An analog-to-digital converter (ADC) is operable to output signal samples and is coupled to receive the bandlimited signal from the anti-aliasing filter. An interpolation and control unit is operable to output interpolated signal samples and control signals, has a first input coupled to receive the signal samples from the ADC, and has a second input coupled to receive the correlation signal samples from the dibit correlator. A dibit correlator is operable to output correlation signal samples and is coupled to receive the interpolated signal samples and control signals from the interpolation and control unit. | 07-09-2009 |
20090279202 | HEAD DESIGN FOR WRITING SERVO PATTERNS ON MAGNETIC TAPE - A servo write head is provided and is configured to simultaneously write at least two servo patterns in respective servo bands on linear magnetic tape. Centerlines of the servo patterns are substantially uniformly spaced in the lateral direction. In addition, the servo patterns of all adjacent respective servo bands are displaced relative to each other in a longitudinal direction by an amount that is related to a length of a servo frame and a type of the servo patterns. | 11-12-2009 |
20090323510 | Modulation and demodulation of OFDM signals - The invention relates to a method for modulating sub-carrier symbols to an intermediate-frequency OFDM signal having even and odd samples, including following steps:
| 12-31-2009 |
20100073800 | RECOVERING SERVO INFORMATION FROM A SYNCHRONOUS SERVO CHANNEL - Provided are a method, servo channel, and tape drive for recovering servo information from a synchronous servo channel. An interpolator reads samples of a servo signal obtained from a servo reader at a rate of one servo sample per clock interval, to produce up to M interpolated servo samples per clock interval. A first buffer buffers interpolation time instants at which the interpolator generates interpolated servo samples. The interpolated servo samples are buffered in a second buffer and the interpolated servo samples are outputted from the second buffer to a correlator to produce correlation signal samples. | 03-25-2010 |
20100226037 | COMBINING INFORMATION FROM PARALLEL SERVO CHANNELS - A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module servo module comprises two servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted metric and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. A first multiplying node receives a first unweighted metric and a first weight signal and is operable to output a first weighted metric. A second multiplying node receives a second unweighted metric and a second weight signal and outputs a second weighted metric. A summing node receives the first and second weighted metrics and outputs a combined weighted metric to an LPOS word decoder. | 09-09-2010 |
20100226039 | COMBINING INFORMATION FROM PARALLEL SERVO CHANNELS - A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module comprises two synchronous servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted parameter estimate and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. An offset computation module provides first and second offset terms which are summed with the unweighted parameter estimates. Multiplying nodes receive the unweighted parameter estimates and the weight signals and outputs offset weighted parameter estimates. A summing node receives the offset weighted parameter estimates and outputs a combined offset weighted parameter estimate to a servomechanism. | 09-09-2010 |
20100328803 | COMBINING INFORMATION FROM PARALLEL SERVO CHANNELS - A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module comprises two synchronous servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted parameter estimate and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. An offset computation module provides first and second offset terms which are summed with the unweighted parameter estimates. Multiplying nodes receive the unweighted parameter estimates and the weight signals and outputs offset weighted parameter estimates. A summing node receives the offset weighted parameter estimates and outputs a combined offset weighted parameter estimate to a servomechanism. | 12-30-2010 |
20110007418 | COMBINING INFORMATION FROM PARALLEL SERVO CHANNELS - A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module comprises two synchronous servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted parameter estimate and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. An offset computation module provides first and second offset terms which are summed with the unweighted parameter estimates. Multiplying nodes receive the unweighted parameter estimates and the weight signals and outputs offset weighted parameter estimates. A summing node receives the offset weighted parameter estimates and outputs a combined offset weighted parameter estimate to a servomechanism. | 01-13-2011 |
20110043945 | SERVOMECHANISM WITH ADJUSTABLE PREDICTOR FILTER - A digital control system, and in particular a tape drive system having a track-following servomechanism with a predictor (also referred to herein as a predictor filter), is described. In certain embodiments, the servomechanism includes an actuator, a servo channel, and a predictor coupled to the servo channel. The predictor receives from the servo channel a lateral position estimate signal and determines a modified lateral position estimate signal that reduces a difference, introduced by a tape velocity-dependent delay, e.g., introduced by the servo channel, between the modified lateral position estimate signal and an actual lateral position. The modified lateral position estimate may be used to modify a control signal sent to the actuator. | 02-24-2011 |
20110102927 | MULTILEVEL PULSE POSITION MODULATION FOR EFFICIENT ENCODING OF INFORMATION INTO SERVO PATTERNS - A storage medium on which servo patterns are encoded to provide lateral and longitudinal position (LPOS) information is provided. Each of the servo patterns includes a servo frame, including first through fourth bursts, which are each independently modulated with multi-level pulse position modulation (PPM) to encode at least one independent bit per burst. | 05-05-2011 |
20110102934 | CANCELLATION OF TIME-VARYING PERIODIC DISTURBANCES IN SERVO CONTROL SYSTEMS - Various embodiments for addressing time-varying periodic disturbances in a servo control system are provided. Each of a plurality of coefficients is updated based on an estimation of at least one disturbance frequency. The updated plurality of coefficients is provided to at least one peak filter modifying an input signal of the servo control system. The peak filter is operable in view of the updated plurality of coefficients to cancel at least one of the time-varying periodic disturbances. | 05-05-2011 |
20110134562 | OPERATING A REEL-TO-REEL SYSTEM - A method for operating a reel-to-reel system of a storage device with a first reel, a second reel, a first motor and a second motor, the first motor drives the first reel and the second motor drives the second reel. The system transports a tape supplied by one of the two reels and taken up by the other reel. A tape velocity and tape tension between the first and reels, and a longitudinal displacement are determined. An estimated state vector depends on the tape velocity, tape tension and longitudinal displacement. A reference state vector depends on a predetermined reference tape velocity and a predetermined reference tape tension. A first control signal and a second control signal are generated dependent on the estimated state vector and the reference state vector. The first motor is controlled by the first control signal and the second motor is controlled by the second control signal. | 06-09-2011 |
20110205657 | SYNCHRONIZATION OF SYMMETRIC TIMING BASED SERVO BURSTS - Timing based servo bursts of servo frames, in which the frames are arranged to be symmetric with the same number of servo stripes in each burst of a frame, are synchronized by shifting selected bits. For example, servo frames are arranged with four servo bursts with an equal number of servo stripes in each burst, the servo frames comprising two symmetric sub-frames, each sub-frame comprising two bursts of servo stripes that are parallel to each other within a burst, and the bursts are non-parallel with respect to each other; each servo burst is arranged to comprise at least one reference servo stripe; and each servo burst is arranged to comprise at least one shifted servo stripe, wherein the shift is in the same longitudinal direction with respect to at least one reference servo stripe for each burst of a frame and the opposite longitudinal direction for bursts of sequentially adjacent frames. | 08-25-2011 |
20110216434 | TIMING ALTERNATIVE INTERVALS WITHIN A TIMING BASED SERVO BAND - An alternative time interval is taken of a timing based servo band to determine lateral position of a servo read head. The servo band is arranged in a sequence bursts with non-parallel servo stripes in sequentially adjacent sub-frames of a linear tape. The timing intervals comprise at least a first time interval (A) between a first pair of non-parallel servo stripes of a sub-frame; and an alternative time interval (C) between a pair of non-parallel servo stripes intermediate the first time intervals (A), the alternative interval servo stripes of sequentially adjacent sub-frames comprising a second servo stripe of the first pair, and a first servo stripe of a sequentially succeeding first pair. Position signals are ratios involving the first and second time intervals. | 09-08-2011 |
20110267717 | LINEAR RECORDING TAPE WITH A REDUCED SERVO BAND WIDTH, AND SYSTEM AND METHOD FOR USING THE SAME - In one embodiment, a linear magnetic recording tape includes at least one servo band having a servo pattern readable by a servo reader of a magnetic head for positioning thereof, wherein the servo pattern is adapted to substantially fill a width b of the servo band, the servo band width h is less than or equal to about 1.2 B/N, N is an integer greater than or equal to 2, and b corresponds to a distance between data read/write transducers of the magnetic head in a direction transverse to a longitudinal length of the tape. In another embodiment, a method includes providing the linear magnetic recording tape, formatting the tape, and positioning the magnetic head within a first lateral tape region. Other linear magnetic tapes, systems, and methods are described according to other embodiments. | 11-03-2011 |
20120014010 | DETERMINING A REFERENCE WAVEFORM USED BY A CORRELATOR IN A SERVO CHANNEL - Provided are a method, servo channel, and tape drive for determining a reference waveform used by a correlator in a servo channel. Sequences of servo signal samples are provided from read servo signals read from a servo pattern on a recording medium. A determination is made of a reference waveform based on the sequences of servo signal samples and the reference waveform is forwarded. Interpolated servo signals are generated. The interpolated servo signal samples and the forwarded reference waveform are received to generate correlation output samples. Position and velocity information are calculated from the correlation output samples. | 01-19-2012 |
20120212852 | DETERMINING A REFERENCE WAVEFORM USED BY A CORRELATOR IN A SERVO CHANNEL - Provided are a method, servo channel, and tape drive for determining a reference waveform used by a correlator in a servo channel. Sequences of servo signal samples are provided from read servo signals read from a servo pattern on a recording medium. A determination is made of a reference waveform based on the sequences of servo signal samples and the reference waveform is forwarded. Interpolated servo signals are generated. The interpolated servo signal samples and the forwarded reference waveform are received to generate correlation output samples. Position and velocity information are calculated from the correlation output samples. | 08-23-2012 |
20120268842 | METHOD AND APPARATUS FOR OPERATING A STORAGE DEVICE - Method for operating a storage device with a tape and a head which is operable to read and/or write data from and respectively to the tape. The tape is moveable in a predetermined longitudinal direction. At least two consecutive current lateral tape positions of the tape with respect to a predetermined reference point are determined at a predetermined longitudinal capture position. A tape skew of the tape is determined dependent on the at least two determined lateral positions. The tape skew represents an angle between a current tape motion direction of the tape and the longitudinal direction. A skew control signal is determined dependent on the determined tape skew. A rotational head position of the head is controlled dependent on the skew control signal to align the head to the current tape motion direction in such a way that the head is operable to read and/or write data. | 10-25-2012 |
20120293889 | METHOD AND APPARATUS FOR OPERATING A STORAGE DEVICE - Method for operating a storage device with a tape and a head wherein the head comprises a first and a second read element. Each read element is operable to detect servo-pattern of a particular servo band. The first and the second read element are arranged such that the tape at first passes one of both read elements and subsequently passes the other of both read elements when the tape moves in a predetermined longitudinal direction. A tape transport direction of the tape along the longitudinal direction is determined. The first read element is selected dependent on the determined tape transport direction, when the determined tape transport direction represents a direction where the tape at first passes the first read element and subsequently the second read element. Otherwise the second read element is selected. A position error signal is determined dependent on the selected read element. | 11-22-2012 |
20130088794 | ROBUST METRIC COMPUTATION OF LONGITUDINAL POSITION (LPOS) DATA SYMBOL DETECTION - In one embodiment, a tape drive system includes a magnetic head having a servo sensor for sensing a defined servo track of a magnetic tape and configured to read servo pulses from servo bursts of the servo track while the magnetic tape is moving past the magnetic head with the servo bursts representing an encoded data symbol, an analog-to-digital converter configured to provide a sequence of samples of the readback servo signal, a digital correlator configured to compute a correlation signal between the sequence and a reference waveform, a timing reference module configured to provide a reference timing model having interpolation instants to the digital correlator, a correlation interpolator configured to interpolate the correlation signal at the interpolation instants and compute a longitudinal position (LPOS) detection metric, and an LPOS detector configured to decode the encoded data symbol of the servo bursts using the computed LPOS detection metric. | 04-11-2013 |
20130132663 | READING FILES STORED ON A STORAGE SYSTEM - A system and method for reading files stored on a storage system is disclosed. The method includes communicatively coupling one or more remote systems for reading files stored in storage with a first set of files according to a predetermined data format and in a cache memory with a second set of files, the second set of files being a subset of the first set of files. Next one or more remote systems are received at least one read request for reading a sequence of files. A determination is made, among the files of the sequence of files, whether one or more cached files are already stored in the cache memory and whether one or more remaining files are not already stored in the cache memory. Creating, within the one or more remaining files, an order according to which the remaining files should be read on the storage system. | 05-23-2013 |
20130321949 | SERVO CONTROL - A tape head includes a set of one or more segments, wherein each segment of the set is individually movable with respect to a frame; each segment of the set comprising at least one of a write element configured to write data to a tape and a read element configured to read data from the tape; and each segment of the set comprising a further read element having a width transverse to a motion direction of the tape being at least a width of the write element of the segment or, in the event that no write element is comprised in the segment, of a write element of a different segment. | 12-05-2013 |
20130335857 | VIBRATION DISTURBANCE ESTIMATION AND CONTROL - A tape drive configured to accurately position a head actuator in the presence of physical disturbances is disclosed. The tape drive includes a track-follow controller to position a head actuator over data tracks on magnetic tape. The tape drive further includes a disturbance observer configured to estimate a vibration disturbance and output a compensation signal to assist the track-follow controller to accurately position the head actuator over the data tracks in the presence of vibration. When estimating the vibration disturbance, the disturbance observer takes into account vibration frequency characteristics, such as frequency characteristics derived from a vibration specification associated with the tape drive, or frequency characteristics derived from known vibration disturbances experienced by the tape drive. A corresponding method is also disclosed. | 12-19-2013 |
20140029130 | METHOD AND APPARATUS FOR OPERATING A TAPE STORAGE DEVICE - In a method for operating a tape storage device comprising a tape head for reading and/or writing data from/to a tape in the tape storage device, a first tape skew value concerning a skew of the tape is determined and the first tape skew value is converted into a first skew control signal by means of a skew feedback controller. A second tape skew value concerning the skew of the tape is determined, and the second tape skew value is converted into a second skew control signal by means of feed-forward controller. At least one compensation signal for the second skew control signal is determined, and at least one of a rotational orientation of the tape head and a tape motion direction of the tape is controlled dependent on the second skew control signal and the compensation signal in case the first skew control signal fails. | 01-30-2014 |
20140036382 | ROBUST METRIC COMPUTATION OF LONGITUDINAL POSITION (LPOS) DATA SYMBOL DETECTION - An apparatus according to one embodiment includes a digital correlator configured to compute a correlation signal between a sequence of samples of a readback servo signal and a reference waveform. A timing reference module is configured to provide a reference timing model comprising one or more interpolation instants to the digital correlator, wherein the correlation signal determined at each interpolation instant yields a detection metric for one data symbol. A correlation interpolator is configured to interpolate the correlation signal at the interpolation instants and compute a longitudinal position (LPOS) detection metric according to the interpolated correlation signal samples. | 02-06-2014 |
20140204483 | SERVO CONTROL - In a method for operating a tape storage system, while a tape is being moved in a tape drive across a tape head for one or more of reading and writing user data from/to a data track of the tape, a read element of the tape head, which read element is assigned to the data track, is moved transverse to a moving direction of the tape for a distance of more than a width of the data track. A transverse position of one or more of the following elements is subject to a signal supplied by the read element during its transverse move: The read element; another read element assigned to the data track; and a write element assigned to the data track. | 07-24-2014 |
20140312154 | CONTROLLING THE TRANSPORT OF A TAPE WITHIN A TAPE TRANSPORT SYSTEM - A control device for controlling the transport of a tape within a tape transport system, the tape transport system having a head being operable to read data from and/or write data to the tape, an outboard reel and an inboard reel, wherein the tape is moveable from the outboard reel to the inboard reel in forward direction or from the inboard reel to the outboard reel in reverse direction, wherein the control device is adapted to generate control signals to control the velocity of the outboard reel and the velocity of the inboard reel as a function of a primary velocity of the tape at the head and a secondary velocity of the tape at the inboard reel and/or a secondary velocity of the tape at the outboard reel. | 10-23-2014 |
20140330817 | TAPE DRIVE SYSTEM SERVER - A tape drive system server includes a non-volatile memory used as a cache memory for storing data files, at least part of the cache memory comprising a first region managed using a First In First Out policy management and a second region managed using a Least Recently Used policy management; a file system interface for interacting with data files stored on a tape drive system; an interface for allowing one or more remote systems reading and writing data stored on the cache memory; the server configured to: receive from the one or more remote systems one or more write requests for writing one or more data files; interpret attributes associated to data files instructed to be written by the one or more remote systems; and store data files instructed to be written by the remote systems according to the interpreted attributes. | 11-06-2014 |
20140358871 | DEDUPLICATION FOR A STORAGE SYSTEM - A method and system for deduplication of data to be stored on a storage system. A deduplication system performs a method that includes the steps of: segmenting a storage object into a plurality of data segments; generating a content similarity key indicative of a content of a data segment as well as associating a physical position on the storage medium for the data segment with the generated content similarity key; storing the association in deduplication index information; and using the stored associations for optimizing the deduplication. | 12-04-2014 |
20140363699 | CURRENT-PERPENDICULAR-TO-PLANE MAGNETORESISTIVE READ SENSOR - A current-perpendicular-to-plane magnetoresistive read sensor includes a stack of layers extending along a stacking direction, and an edge surface parallel to the stacking direction that forms at least part of a bearing surface of the read sensor, the bearing surface designed to face a recording medium. The stack of layers includes a first contact layer, a ferromagnetic free layer whose magnetic orientation varies according to an applied magnetic field, above the first contact layer, a non-magnetic layer above the ferromagnetic layer, a ferromagnetic spin injection layer above the non-magnetic layer, and a second contact layer above the spin injection layer, such that a current can flow between the second contact layer and the first contact layer along a current-perpendicular-to-plane direction, parallel to the stacking direction. The stack of layers further includes a series of structures extending along a direction parallel to the bearing surface and perpendicular to the stacking direction. | 12-11-2014 |
20150062740 | TAPE STORAGE SYSTEM - A tape storage medium includes a tape head for reading/writing data from/to a tape storage medium. At least one servo band along a longitudinal extension of the tape storage medium determines positional information. The servo band includes a set of servo tracks having a width extending along the longitudinal extension and arranged next to each other. A total of two different servo patterns are contained in the set of servo tracks. The tape head includes two servo readers. A width of each servo reader orthogonal to the longitudinal extension of the tape storage medium is at least half the width of a servo track. The two servo readers are offset from each other orthogonal to the longitudinal extension by d*wST+n*wST with wST being the width of the servo track, with 003-05-2015 | |
20150062744 | CONTROLLING THE TRANSPORT OF A TAPE WITHIN A TAPE TRANSPORT SYSTEM - A control device for controlling tape transport within a tape transport system is disclosed. The control device includes a determination unit, which includes at least a first servo channel and a second servo channel for determining a first lateral position of a tape relative to the head, and for determining a difference between the first and second lateral positions. A computing unit computes a number of unsupported wraps of the tape as a function of the lateral position difference, wherein the number of unsupported wraps corresponds to the number of layers of the tape around the take-up reel having air layers in-between, and computes a spring constant of the tape as a function of the number of unsupported wraps, a radius of the take-up reel and a nominal tape path length. A calibration unit calibrates at least one unit of the tape transport system dependent on the spring constant. | 03-05-2015 |
20150067331 | REMOTE DATA STORAGE - A computer-implemented method for performing remote data storage includes providing, by at least one client, files to be stored on a remote server, evaluating popularity of the files, and storing the files on the server in a form that depends on the popularity of the files. Files with a first level of popularity are stored in a deduplicated form and files with a second level of popularity are stored in an encrypted form, the first level of popularity being higher than the second level of popularity. | 03-05-2015 |