Abstract: In one general embodiment, a method for selecting parameters of an error recovery procedure includes detecting an error during performance of a data operation on a data storage medium by an apparatus. In response to detecting the error, parameters of an error recovery procedure are selected based at least in part on: (a) first information about previous interactions between the apparatus and multiple data storage media, and (b) second information about previous interactions between the data storage medium and other apparatuses.

Abstract: A tape may be mounted into a tape drive. Mounting the tape into the tape drive may include loading the tape from a storage slot. The tape drive may request a first record of the tape from a tape storage subsystem. The tape drive may determine whether the first record of the tape exists in the tape storage subsystem. The tape drive may load the first record of the tape in random access memory (RAM) of the tape drive. The first record may include one or more data entries. The tape drive may append a new data entry to the first record. The first record may be transitioned to a second record upon being appended with the new data entry. The tape may be unmounted from 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: A tape may be mounted into a tape drive. Mounting the tape into the tape drive may include loading the tape from a storage slot. The tape drive may request a first record of the tape from a tape storage subsystem. The tape drive may determine whether the first record of the tape exists in the tape storage subsystem. The tape drive may load the first record of the tape in random access memory (RAM) of the tape drive. The first record may include one or more data entries. The tape drive may append a new data entry to the first record. The first record may be transitioned to a second record upon being appended with the new data entry. The tape may be unmounted from the tape drive.

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: An apparatus, system, and method are provided for developing failure prediction software for a storage system. The present invention allows a user to edit and revise a failure prediction algorithm that includes fuzzy logic rules. The failure prediction algorithm is generated in a human readable format and uses terms and operators familiar to experts in the field of storage systems. In addition, the present invention generates the machine-readable code necessary to implement or test a draft failure prediction algorithm. If the results of the failure prediction algorithm are unsatisfactory, the user may revise the failure prediction algorithm and re-run the tests until the results correspond to expected results. In addition, the present invention includes a performance monitor, processor, and determination module. The performance monitor gathers performance data for a storage system. The processor executes the failure prediction algorithm on the performance data to produce a result.

Abstract: Selection of servo signals for peak detection of timing based servo tracks of magnetic tape for lateral positioning of heads relative to the magnetic tape. Servo signals from magneto-resistive servo read head(s) reading a magnetic tape are digitized by analog to digital converter(s); digital peak measurement apparatus is configured to sense the digital converter(s), and provide positive peak values and negative peak values of the digitized servo signals; and control apparatus is configured to determine the greater of the provided positive peak values or negative peak values, and select servo signals having the greater values for a servo channel. Servo apparatus is configured to respond to the selected servo signals to control the lateral positioning of the servo read head(s).

Abstract: Selection of servo signals for peak detection of timing based servo tracks of magnetic tape for lateral positioning of heads relative to the magnetic tape. Servo signals from magneto-resistive servo read head(s) reading a magnetic tape are digitized by analog to digital converter(s); digital peak measurement apparatus is configured to sense the digital converter(s), and provide positive peak values and negative peak values of the digitized servo signals; and control apparatus is configured to determine the greater of the provided positive peak values or negative peak values, and select servo signals having the greater values for a servo channel. Servo apparatus is configured to respond to the selected servo signals to control the lateral positioning of the servo read head(s).

Abstract: Selection of servo signals for peak detection of timing based servo tracks of magnetic tape for lateral positioning of heads relative to the magnetic tape. Servo signals from magneto-resistive servo read head(s) reading a magnetic tape are digitized by analog to digital converter(s); digital peak measurement apparatus is configured to sense the digital converter(s), and provide positive peak values and negative peak values of the digitized servo signals; and control apparatus is configured to determine the greater of the provided positive peak values or negative peak values, and select servo signals having the greater values for a servo channel. Servo apparatus is configured to respond to the selected servo signals to control the lateral positioning of the servo read head(s).

Abstract: Mitigation of distortion of read signals from magneto-resistive read head(s) are provided in various embodiments of the present invention. In one embodiment, the read signals provided to a read channel having an analog to digital converter and digital equalizer. Digital peak measurement apparatus is configured to sense the output of the digital equalizer, and provide average positive peak values and average negative peak values of the output. Control apparatus is configured to respond to the peak values, to iteratively determine asymmetry of the peak values and estimate the cancellation slope of the asymmetry and cancellation term relationship; from the measured asymmetry and estimated cancellation slope, to iteratively estimate the convergence cancellation term; and to feed back the convergence cancellation term to modify the digital read signals for the input of the digital equalizer to iteratively converge the asymmetry to substantially zero.

Abstract: A system, method and an article of manufacture to provide more accurate magnetic tape servo operation are disclosed. Accurate measurements of the width of the servo pattern written on the magnetic tape are accomplished in the presence of relatively large motion of the magnetic tape. The accurate measurements of the width of the servo pattern are used to produce a corrected position error signal that provides improved servo track following to maintain the tape head at an optimal alignment for writing and reading data tracks on the tape.

Abstract: Width of a write track for a magnetic tape head is measured by writing a foreground magnetic track signal on a magnetic tape having a dissimilar background signal. A magnetic tape read head is moved from beyond one edge, laterally across, and beyond the opposite edge of the foreground track signal. Logic detects the read head encountering the one edge and the opposite edge of the foreground track signal; and determines, from an independent position sensor, the width of the foreground track signal as the lateral distance between the lateral position of the read head at one edge, and at the opposite edge of the foreground track signal.

Abstract: A control system compensates for web tension variation caused by a first spool, (A) determines rotational frequency of the first spool; (B) determines variation in rotational velocity at the second spool which occurs at the (A) first spool frequency; (C) determines the rotational position at the first spool corresponding to the (B) variation in rotational velocity at the second spool; (D) calculates a drive motor profile for the first spool which tends to cancel the (B) variation in rotational velocity at the second spool; and (E) superimposes the (D) drive motor profile on a first spool drive motor at the (C) determined rotational position of the first spool.

Abstract: A system, method and an article of manufacture to provide more accurate magnetic tape servo operation are disclosed. Accurate measurements of the width of the servo pattern written on the magnetic tape are accomplished in the presence of relatively large motion of the magnetic tape. The accurate measurements of the width of the servo pattern are used to produce a corrected position error signal that provides improved servo track following to maintain the tape head at an optimal alignment for writing and reading data tracks on the tape.

Abstract: Initially, from an off-track position at a known side of, and displaced from, a servo track pattern of a tape subject to lateral movement, servo loop logic slews a tape head servo sensor laterally toward the pattern at a rate greater than the maximum rate of lateral movement of the tape. Upon detecting sensed servo signals, the logic decelerates the slewing rate. Upon detecting that the sensed servo signals are within a lock window tolerance, the logic locks a servo loop to a position error signal representing the current lateral position of the servo sensor, thereby acquiring the servo pattern.

Abstract: Calibration of magnetic tape servo index positions, which are laterally offset from edges and measured by ratios of dissimilar servo signals. A defined signal is injected into the track following servo to modulate the lateral position of the servo sensor, which is detected by an independent position sensor. Logic converts the detected lateral positions and servo signals to frequency components; selects injected signal frequency components; converts the selected frequency components to lateral positions and servo signals, and fits a curve to the converted lateral positions with respect to the converted servo signals to calibrate the index positions.

Abstract: Width of a write track for a magnetic tape head is measured by writing a foreground magnetic track signal on a magnetic tape having a dissimilar background signal. A magnetic tape read head is moved from beyond one edge, laterally across, and beyond the opposite edge of the foreground track signal. Logic detects the read head encountering the one edge and the opposite edge of the foreground track signal; and determines, from an independent position sensor, the width of the foreground track signal as the lateral distance between the lateral position of the read head at one edge, and at the opposite edge of the foreground track signal.

Abstract: A control system compensates for web tension variation caused by a first spool, (A) determines rotational frequency of the first spool; (B) determines variation in rotational velocity at the second spool which occurs at the (A) first spool frequency; (C) determines the rotational position at the first spool corresponding to the (B) variation in rotational velocity at the second spool; (D) calculates a drive motor profile for the first spool which tends to cancel the (B) variation in rotational velocity at the second spool; and (E) superimposes the (D) drive motor profile on a first spool drive motor at the (C) determined rotational position of the first spool.

Abstract: Initially, from an off-track position at a known side of, and displaced from, a servo track pattern of a tape subject to lateral movement, servo loop logic slews a tape head servo sensor laterally toward the pattern at a rate greater than the maximum rate of lateral movement of the tape. Upon detecting sensed servo signals, the logic decelerates the slewing rate. Upon detecting that the sensed servo signals are within a lock window tolerance, the logic locks a servo loop to a position error signal representing the current lateral position of the servo sensor, thereby acquiring the servo pattern.