Abstract: An apparatus for controlling an electric motor is provided. A plurality of switches is provided for controlling a direction of current through motor coils of the electric motor. A brushless motor control circuit is connected to each of the plurality of switches. Responsive to a request to adjust one of an angular velocity and an angular acceleration of the electric motor, the plurality of switches are activated to place the motor coils in a predetermined configuration to maximize torque or reduce a total back electromotive force (BEMF) from the motor coils.

Abstract: In one embodiment, a tape read/write head supported by a lever is biased in a first position, using magnetic attraction between a magnet supported by the lever, and a return path structure of magnetically permeable material. In the illustrated embodiment, the magnet centers itself, in the absence of a coil generated magnetic field, in the middle of a gap of the magnetic return path structure. In one aspect, the mass of the read/write head and one side of the lever may be balanced by the mass of the magnet and the other side of the lever. The lever and hence the tape read/write head carried by the lever, may be pivoted by conducting current through a coil to generate a magnetic field which is conducted by the return path structure to interact with the magnetic field of the magnet. As a consequence, the lever pivots on a pivot axis as a function of the magnitude and direction of the current through the coil.

Abstract: A tape drive system which includes the ability to reliably reproduce LPOS information even if both of the servo channels of the tape drive system could not detect the LPOS information due to defects. The system recognizes that an LPOS sequence is sequentially incremented by one if a tape is moving in a forward direction and decremented by one if the tape is moving in a backward direction. This sequential property of the LPOS information lends itself to LPOS prediction, where the LPOS prediction is the previous LPOS value plus one if the tape is moving forward and the previous LPOS value minus one if the tape is moving backward. Even if the LPOS words from the two servo channels are both bad, but not all of the bits in the LPOS word are bad. The system uses the remaining good bits from the two servo channels to verify all of the bits of the LPOS prediction word.

Abstract: A method to decode linear position (“LPOS”) information encoded in a sequential information storage medium, by detecting each of one or a plurality of sequential first LPOS servo patterns encoded in a first servo band using a first servo sensor in communication with a first servo channel. While detecting that one or a plurality of first LPOS servo patterns, the method fails to detect (n) second LPOS servo patterns encoded in a second servo band. The method determines a value for (n), and then syncs the first servo channel with the second servo channel using that value of (n).

Abstract: An apparatus, system, and method are disclosed for a tape drive head. An upper servo element reads an upper servo track conforming to a specified format. A lower servo element reads a lower servo track conforming to the specified format. A mid servo element reads a mid servo track. The mid servo element is disposed between the upper servo element and the lower servo element. Sixteen legacy read elements are disposed between the upper server element and the lower servo element. The legacy read elements read legacy data tracks conforming to the specified format. At least eight incremental read elements are interleaved between the legacy read elements. One incremental read element is adjacent to each legacy read element on a side of the legacy read element away from the mid servo element.

Abstract: Dynamic calibration of a secondary velocity signal is provided in a tape drive. In one example, a reel motor is operated to drive a reel carrying a tape in a tape drive. The motion of the tape is measured to provide a measured primary velocity signal of the tape, and in addition, the operation of the reel motor is measured to provide an estimated secondary velocity signal of the tape as a function of motor parameters and the motor operation measurements. The estimated secondary velocity signal of the tape may be calibrated as the tape is driven, as a function of the tape motion measurements and the motor operation measurements. Other embodiments are described and claimed.

Abstract: In one embodiment, a tape read/write head supported by a lever is biased in a first position, using magnetic attraction between a magnet supported by the lever, and a return path structure of magnetically permeable material. In the illustrated embodiment, the magnet centers itself, in the absence of a coil generated magnetic field, in the middle of a gap of the magnetic return path structure. In one aspect, the mass of the read/write head and one side of the lever may be balanced by the mass of the magnet and the other side of the lever. The lever and hence the tape read/write head carried by the lever, may be pivoted by conducting current through a coil to generate a magnetic field which is conducted by the return path structure to interact with the magnetic field of the magnet. As a consequence, the lever pivots on a pivot axis as a function of the magnitude and direction of the current through the coil.

Abstract: In one embodiment, a tape movement constraint for a tape drive system, comprises a tiltable tape roller bearing having a grooved surface adapted to contact and engage a surface of the tape as the roller barrel rotates, and an actuator adapted to pivot the roller bearing surface when the actuator is actuated, to control the lateral position of a tape. In operation, in one embodiment, a roller barrel of the tiltable roller bearing is biased in a first position on a pivot axis, using magnetic attraction between a movable magnet and a return path structure of magnetically permeable material. The roller barrel is pivoted on the pivot axis by conducting current through a fixed coil to generate a magnetic field which is conducted by the return path structure to interact with the magnetic field of the magnet. At least a portion of any air bearing between the moving tape and the barrel surface is quenched using grooves formed in the barrel surface.

Abstract: An apparatus, system, and method are disclosed for dynamic tape stick and tape break detection. A first counter increments a first count and resets a second count in response to a sensor pulse from a first sensor of a first tape servo. A second counter increments the second count and resets the first count in response to a sensor pulse from a second sensor of a second tape servo. A detection module detects either the first count or the second count exceeding an error threshold.

Abstract: A tape drive system which includes the ability to reliably reproduce LPOS information even if both of the servo channels of the tape drive system could not detect the LPOS information due to defects. The system recognizes that an LPOS sequence is sequentially incremented by one if a tape is moving in a forward direction and decremented by one if the tape is moving in a backward direction. This sequential property of the LPOS information lends itself to LPOS prediction, where the LPOS prediction is the previous LPOS value plus one if the tape is moving forward and the previous LPOS value minus one if the tape is moving backward. Even if the LPOS words from the two servo channels are both bad, but not all of the bits in the LPOS word are bad. The system uses the remaining good bits from the two servo channels to verify all of the bits of the LPOS prediction word.

Abstract: A tape drive and a method of using a tape drive is provided. The tape drive includes a head assembly including at least a first and a second servo read element configured to detect transition stripes of a servo pattern on tape media. The first servo read element is configured to detect at least two transition stripes of an even servo band on the tape media at a first time. The servo detection logic is configured to detect a timing of at least two transition stripes of the even servo band on the tape media. The servo controller is configured to position the head assembly laterally with respect to the tape media in response to the timing of the at least two transition stripes of the even servo band on the tape media. The second servo read element is configured to detect at least two transition stripes of an odd servo band on the tape media at a second time, wherein the second time is a time delay after the first time corresponding to a distance D.

Abstract: An apparatus, system, and method are disclosed for formatting a timing-based servo pattern on a magnetic tape. A first write head concurrently writes a base number of stripes to a plurality of first stripe patterns with a first and third element and writes the base number of stripes to a plurality of second stripe patterns with a second and fourth element of a first write head in response to at least one first write signal. A second write head concurrently writes an incremental number of stripes to a specified first stripe pattern to form a first incremental stripe pattern with a fifth write element and writes the incremental number of stripes to a specified second stripe pattern to form a second incremental stripe pattern with a sixth write element.

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: Provided is a read channel, storage drive, and method to process signals read from a storage medium. At least one data channel including an interpolator and equalizer and a servo channel includes an interpolator. A timing recovery function processes a timing error from the interpolator in the servo channel to calculate interpolation timing information used by the interpolator to interpolate a servo channel signal. A path is coupled to the timing recovery function and the interpolator in the at least one data channel to communicate the interpolation timing information to the interpolator in the at least one data channel. The interpolator in the at least one data channel is configured to use the interpolation timing information to interpolate an asynchronous data channel signal.

Abstract: An apparatus, system, and method are disclosed for checking tape reel motion. A control module directs a leading servo to apply torque to a leading reel and a trailing servo to apply torque to a trailing reel, wherein the control module directs the leading servo to apply an initial positive torque in a tape motion direction and directs the trailing servo to apply an initial negative torque counter to the tape motion direction. If there is no change in an angular position of the leading and trailing reels, the control module incrementally sums a first incremental positive torque to the leading torque to increase the leading torque and a second incremental positive torque to the trailing torque until there is a change in the angular position of the leading and trailing reels and/or until the torques exceed torque limits.

Abstract: An apparatus, system, and method are disclosed for an “M” servo pattern. A servo pattern write module is included to simultaneously create a first servo mark, a second servo mark, a third servo mark, and a fourth servo mark in an “M” servo pattern on a magnetic tape. The magnetic tape is configured to store data. The first, second, third, and fourth servo marks are substantially linear and are substantially the same length. The first and third servo marks are positioned with a forward slope comprising first and third legs of the “M” pattern. The second and fourth servo marks are positioned with a backward slope comprising second and fourth legs of the “M” pattern. Distances between center points of the first and second servo marks, second and third servo marks, and third and fourth servo marks are substantially the same.

Abstract: A storage drive implements a method for a BEMF voltage reduction during a deceleration period of an electric motor of the storage drive. In operation, the electric motor is disconnected from a power supply during an entirety of the deceleration period of the electric motor to prevent any flow of a BEMF current into the power supply, and the electric motor is connected to a power return during a segment or an entirety of the deceleration period of the electric motor to dissipate any BEMF voltage within the electric motor.

Abstract: An apparatus, system, and method are disclosed for formatting a timing-based servo pattern on a magnetic tape. A first write head concurrently writes a base number of stripes to a plurality of first stripe patterns with a first and third element and writes the base number of stripes to a plurality of second stripe patterns with a second and fourth element of a first write head in response to at least one first write signal. A second write head concurrently writes an incremental number of stripes to a specified first stripe pattern to form a first incremental stripe pattern with a fifth write element and writes the incremental number of stripes to a specified second stripe pattern to form a second incremental stripe pattern with a sixth write element.

Abstract: Multiple servo sensors are laterally displaced over a distance less than the transverse width of timing based servo track laterally extending transitions. The servo sensors are configured to sense the transitions, and servo detection logic detects the relative timings of the laterally extending transitions sensed by the laterally displaced servo sensors as the magnetic tape is moved in the longitudinal direction. Logic is configured to determine from the relative timings of the sensed transitions for at least one known set of laterally extending transitions having differing slants, the lateral position of a servo sensor by employing the relative timing detected from one servo sensor and the relative timing detected from another servo sensor, or determine the longitudinal velocity of the magnetic tape by determining the difference between the relative timing detected from one servo sensor and the relative timing detected from another servo sensor.

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).