Abstract: The present disclosure includes systems and methods for reducing rewrite overhead in a sequential access storage system. The method may comprise writing a data set to a sequential access medium using a magnetic head, wherein the data set comprises a plurality of encoded data blocks, classifying each of the plurality of encoded data blocks on the sequential access medium into one of at least three classes of write quality, and rewriting the encoded data blocks in a rewrite area of the sequential access medium based at least in part on the write quality class. In some embodiments, the at least three classes of write quality may comprise a hard rewrite class for which rewrites are necessary to prevent data loss, a soft rewrite class for which rewrites are desirable but not necessary, and a no rewrite class for which no rewrite is needed or desired.

Abstract: In an approach to adaptive tape calibration criteria based on the number of dead tracks, the number of rewrite occurrences for each dead track on a tape drive is determined. Responsive to detecting that a head is in a dead track state, the number of dead tracks is stored on the tape drive. A calibration threshold is determined, where the calibration threshold includes the number of dead track rewrites and the calibration reference value for a specific tape drive type. Responsive to the number of rewrite occurrences exceeding the calibration threshold while writing a data set, a calibration of the tape drive.

Abstract: In an approach to adaptive tape calibration criteria based on the number of dead tracks, the number of rewrite occurrences for each dead track on a tape drive is determined. Responsive to detecting that a head is in a dead track state, the number of dead tracks is stored on the tape drive. A calibration threshold is determined, where the calibration threshold includes the number of dead track rewrites and the calibration reference value for a specific tape drive type. Responsive to the number of rewrite occurrences exceeding the calibration threshold while writing a data set, a calibration of the tape drive.

Abstract: Provided are a tape drive, tape drive controller, and method for measuring amplitudes of written tracks to determine errors in read and write elements. The write element writes a data pattern and erase pattern to the tape medium to provide the data pattern and the erase pattern on sides of the data pattern. The read element is positioned to measure amplitudes at offsets in the data pattern. The offsets and the amplitudes at the offsets are processed to estimate a maximum amplitude read while the read element is estimated to be positioned entirely in the data pattern and estimate an offset at which the read element reads a fixed percentage of the maximum amplitude. A width of the read element is estimated based on the estimated offset. The estimated width of the read element is outputted to determine whether the estimated width of the read element is acceptable.

Abstract: In an approach to adaptive tape calibration criteria based on the number of stop writes, the number of rewrite occurrences caused by a stop write is determined for each specific tape drive type. Responsive to detecting a stop write during a write operation, the total number of stop writes is stored on the tape drive. A rewrite calibration threshold is determined, where the rewrite calibration threshold includes the total number of stop writes on the tape drive and a calibration reference value for the specific tape drive type. Responsive to the number of rewrite occurrences caused by the stop write exceeding the rewrite calibration threshold while writing a data set on the tape drive, a calibration of the tape drive is performed.

Abstract: A method includes determining whether a tunneling magnetoresistance (TMR) sensor is corroded using resistance, amplitude and signal to noise ratio (SNR) measurements of the sensor. A method to determine whether a TMR sensor is corroded includes determining an expected initial resistance value, RTMRoUse and measuring a resistance value, RTMR, of the sensor. The method includes calculating a ratio of the RTMR value and the expected initial resistance value, RTMRoUse and determining whether the ratio is in a predefined range for the TMR sensor. In response to determining that the ratio of the sensor is within the predefined range, the method includes outputting an indication that the TMR sensor is corroded. In response to determining that the ratio of the sensor is outside the predefined range, the method includes outputting an indication that the TMR sensor is not corroded.

Abstract: A method includes determining whether a tunneling magnetoresistance (TMR) sensor is corroded using resistance, amplitude and signal to noise ratio (SNR) measurements of the sensor. A method to determine whether a TMR sensor is corroded includes determining an expected initial resistance value, RTMRoUse and measuring a resistance value, RTMR, of the sensor. The method includes calculating a ratio of the RTMR value and the expected initial resistance value, RTMRoUse and determining whether the ratio is in a predefined range for the TMR sensor. In response to determining that the ratio of the sensor is within the predefined range, the method includes outputting an indication that the TMR sensor is corroded. In response to determining that the ratio of the sensor is outside the predefined range, the method includes outputting an indication that the TMR sensor is not corroded.

Abstract: Tape media life is increased by dynamically controlling a turn around point (TAP) on the tape media for either an end of a tape wrap or a directional change from a first longitudinal position tape section to a second longitudinal position tape section for reducing damage to the tape media caused by debris by monitoring the TAP for all tape media motion and adjusting tape deceleration for maintaining the TAP to be located at the second longitudinal position tape section.

Abstract: Magnetoresistive (MR) bias is dynamically controlled in a tape drive using a processor device. Upon determining head amplitude is below a threshold value, the MR bias is adjusted for increasing the head amplitude and extending the useful life span of the tape drive.

Abstract: Tape media life is increased by dynamically controlling a turn around point (TAP) on the tape media for either an end of a tape wrap or a directional change from a first longitudinal position tape section to a second longitudinal position tape section for reducing damage to the tape media caused by debris by monitoring the TAP for all tape media motion and adjusting tape deceleration for maintaining the TAP to be located at the second longitudinal position tape section.

Abstract: Magnetoresistive (MR) bias is dynamically controlled in a tape drive using a processor device. Upon determining head amplitude is below a threshold value, the MR bias is adjusted for increasing the head amplitude and extending the useful life span of the tape drive.

Abstract: A method for selecting which tap coefficients of a programmable finite-impulse-response (FIR) equalizer to fix is disclosed. In one embodiment, such a method includes performing an initial calibration to determine an initial value for each tap coefficient of a FIR equalizer. These initial values may be used to produce a first waveform. The method then performs an operation on the first waveform to produce a second waveform comprising multiple lobes. The second waveform is then analyzed to determine one or more lobes of the second waveform that have the largest area. The method then fixes coefficients of one or more taps that are closest to the lobe or lobes having the largest area. A corresponding apparatus and computer program product are also disclosed.

Abstract: A method for selecting which tap coefficients of a programmable finite-impulse-response (FIR) equalizer to fix includes performing an initial calibration to determine an initial value for each tap coefficient of a FIR equalizer. Using these initial values, a “total” FIR equalizer is determined which sets the tap coefficients to their initial values. The method further determines multiple sets of tap coefficients that may potentially be fixed in the FIR equalizer. For each set of tap coefficients that may potentially be fixed, the method determines a “fixed” FIR equalizer that sets the tap coefficients in the set to their initial values and other tap coefficients to zero. The method then determines a phase-difference energy between the “total” FIR equalizer and the “fixed” FIR equalizer for each set of tap coefficients that may potentially be fixed. The set of tap coefficients associated with the lowest phase-difference energy are then fixed.

Abstract: A method according to one embodiment includes monitoring a data transfer operation for detecting temporary errors; determining whether an error burst has occurred based on the monitoring; if an error burst has occurred, altering a condition of the data transfer operation; monitoring the data transfer operation having the altered condition for detecting temporary errors; determining whether another error burst has occurred based on the monitoring of the data transfer operation having the altered condition; and if another error burst has occurred, altering another condition of the data transfer operation. Additional systems and methods are also presented.

Abstract: A method according to one embodiment includes monitoring a data transfer operation for detecting temporary errors; determining whether an error burst has occurred based on the monitoring; if an error burst has occurred, altering a condition of the data transfer operation; monitoring the data transfer operation having the altered condition for detecting temporary errors; determining whether another error burst has occurred based on the monitoring of the data transfer operation having the altered condition; and if another error burst has occurred, altering another condition of the data transfer operation. Additional systems and methods are also presented.

Abstract: A method according to one embodiment includes monitoring a data transfer operation for detecting temporary errors; determining whether an error burst has occurred based on the monitoring; if an error burst has occurred, altering a condition of the data transfer operation; monitoring the data transfer operation having the altered condition for detecting temporary errors; determining whether another error burst has occurred based on the monitoring of the data transfer operation having the altered condition; and if another error burst has occurred; altering another condition of the data transfer operation. Additional systems and methods are also presented.

Abstract: As the result of a tape stick condition of magnetic tape with respect to a tape head, the supply reel and the take-up reel apply a base tension to the magnetic tape therebetween of substantially less than a full tension that occurs when the tape is running, and one reel varies the applied tension greater than and less than the base tension by an amount less than the base tension. The variation of the applied tension comprises first applying the greater tension and in succession, second, applying the less tension, comprising a whip effect. The whip effect may be in accordance with a sine wave. The varied tension is less than the base tension to maintain positive tension.

Abstract: A method in one embodiment includes detecting an identifier of a drive that has written data to a data storage medium; performing a data transfer operation to read the data from the data storage medium; monitoring the data transfer operation for detecting temporary errors; determining whether an error burst has occurred based on the monitoring; and if an error burst has occurred, altering a condition of the data transfer operation, the alteration being selected based on the identifier of the drive that wrote the data to the data storage medium. Additional methods and systems are also disclosed.

Abstract: A method in one embodiment includes detecting an identifier of a drive that has written data to a data storage medium; performing a data transfer operation to read the data from the data storage medium; monitoring the data transfer operation for detecting temporary errors; determining whether an error burst has occurred based on the monitoring; and if an error burst has occurred, altering a condition of the data transfer operation, the alteration being selected based on the identifier of the drive that wrote the data to the data storage medium. Additional methods and systems are also disclosed.

Abstract: A method according to one embodiment includes monitoring a data transfer operation for detecting temporary errors; determining whether art error burst has occurred based on the monitoring; if an error burst has occurred, altering a condition of the data transfer operation; monitoring the data transfer operation having the altered condition for detecting temporary errors; determining whether another error burst has occurred based on the monitoring of the data transfer operation having the altered condition; and if another error burst has occurred; altering another condition of the data transfer operation. Additional systems and methods are also presented.