Abstract: To provide a technique for optimizing the processing order of recall requests in which the average latency time of a host apparatus is minimized. A storage manager accepts a request of the host apparatus for the recalling data from a tape library, and stores the request in a queue table. In response to storage of the request, the storage manager calculates the latency time for each request in all the conceivable execution orders for all the requests stored in the queue table. The storage manager determines the execution order which minimizes the total calculated latency time for all the requests including the active request.

Abstract: A method according to one embodiment includes generating track following controller state information based on a positional signal of a head relative to a medium. One or more portions of the state information corresponding to particular frequencies are used to determine at least one of: lateral tape movement, tape skew, vibration operation conditions, and roller performance.

Abstract: Controlling the position of a head within a tape transport system. A track-follow control system (TFCS) includes a controller device for generating a control signal as a function of a position error signal (PES), wherein the PES indicates a difference between the actual and target positions of the head relative to the tape, and an actuator for changing the actual position. The TFCS is adapted to select a controller device configuration from a plurality of configurations dependent on an operating tape speed. The configurations are predetermined depending on a vibration frequency domain profile indicative of environmental vibrations induced to the head and tape to determine the control signal for adjusting an actuator output signal relative to a lateral tape motion signal. The TFCS is also adapted to feed-back a signal depending on a difference of the actuator output signal and the lateral tape motion signal to generate the PES.

Abstract: A method according to one embodiment includes generating track following controller state information based on a positional signal of a head relative to a medium. One or more portions of the state information corresponding to particular frequencies are used to determine at least one of: lateral tape movement, tape skew, vibration operation conditions, and roller performance.

Abstract: A maximum velocity is dynamically determined during a tape drive operation to obtain a statistical standard deviation of a position error signal (PES) that yields an amount of stopwrite (SW) operations that avoids backhitching. The tape velocity is adjusted to the maximum velocity.

Abstract: According to one general embodiment, a method includes determining an offset between first and second arrays of transducers on a magnetic head in a direction perpendicular to an intended direction of media travel when the magnetic head is positioned at a first position, tilting the magnetic head to a second position, and delaying writing by at least some of the write transducers to provide magnetic transitions on a magnetic medium as if the longitudinal axis of the array was aligned in the direction perpendicular to the intended direction of media travel. At least one of the arrays of transducers includes write transducers. Moreover, the arrays of transducers have longitudinal axes aligned at the second position greater or less than 0 degrees from the longitudinal axes of the arrays of transducers aligned at the first position.

Abstract: To provide a technique for optimizing the processing order of recall requests in which the average latency time of a host apparatus is minimized. A storage manager accepts a request of the host apparatus for the recalling data from a tape library, and stores the request in a queue table. In response to storage of the request, the storage manager calculates the latency time for each request in all the conceivable execution orders for all the requests stored in the queue table. The storage manager determines the execution order which minimizes the total calculated latency time for all the requests including the active request, and rearranges the requests in the queue table.

Abstract: Controlling the position of a head within a tape transport system. A track-follow control system (TFCS) includes a controller device for generating a control signal as a function of a position error signal (PES), wherein the PES indicates a difference between the actual and target positions of the head relative to the tape, and an actuator for changing the actual position. The TFCS is adapted to select a controller device configuration from a plurality of configurations dependent on an operating tape speed. The configurations are predetermined depending on a vibration frequency domain profile indicative of environmental vibrations induced to the head and tape to determine the control signal for adjusting an actuator output signal relative to a lateral tape motion signal. The TFCS is also adapted to feed-back a signal depending on a difference of the actuator output signal and the lateral tape motion signal to generate the PES.

Abstract: A method according to one embodiment includes generating or receiving a value representative of a lateral position of a tape. The value is used to adjust a position of a coarse actuator in response to determining that the value is in a first range relative to a first threshold. An integrator center value is used to adjust the position of the coarse actuator in response to determining that the value is in a second range relative to the first threshold.

Abstract: Various embodiments described herein include processing of a lateral tape motion signal, caused primarily by a tape supply reel (e.g., depending on direction of tape movement). The resulting data may be used, at least in part, to determine placement of a coarse actuator. In one general embodiment, a method includes receiving a signal representative of a lateral position of a magnetic head, and integrating portions of the signal representative of a lateral position of a magnetic head, the portions corresponding to fractions of one or more revolutions of a supply reel for generating first data. The first data is averaged over a value or values corresponding to one or more revolutions of the supply reel for generating second data.

Abstract: Provided are a computer program product, system, and method for determining a skew error signal (SES) offset used to determine an SES to adjust heads in a drive unit. A determination is made of a first difference in a first orientation with respect to a direction of movement of the recordable storage media based on first and second position information read by first and second servo read elements on a first head. A determination is made of a second difference in a second orientation with respect to the direction of movement of the recordable storage media based on third and fourth position information read by the first servo read element and a third servo read element on a second head. An offset, calculated based on the determined first and second difference, is used to generate an error signal to adjust the first and second heads.

Abstract: Various embodiments include positioning a coarse actuator based, at least in part on lateral motion of a magnetic tape. In one general embodiment, a method includes receiving a value (IntegRevAve) representative of a lateral position of a tape, comparing the value to a first threshold, using the value to adjust a position of a coarse actuator when the value is in a first range relative to the first threshold, and selectively using an integrator center value (IntegCtr) to adjust the position of the coarse actuator when the value is in a second range relative to the first threshold.

Abstract: In one embodiment, a method includes determining a stopwrite threshold based on a standard deviation or a variance at a current position error signal sample, and determining whether the current position error signal sample exceeds the stopwrite threshold. Writing is disabled in response to determining that the current position error signal sample exceeds the stopwrite threshold. Writing is enabled in response to determining that the current position error signal sample does not exceed the stopwrite threshold.

Abstract: In one embodiment, a method includes updating a standard deviation or a variance based on a current position error signal sample, where a smoothing factor applied to a subsequent calculation of the standard deviation or variance is dynamically altered based at least in part on whether a current value of the standard deviation or the variance is above or below a specified value. A determination is made as to whether the standard deviation or the variance exceeds a predetermined threshold. A stopwrite threshold is determined based on the standard deviation or the variance when the standard deviation or the variance exceeds the predetermined threshold. A determination is made as to whether the current position error signal sample exceeds the stopwrite threshold. Writing is disabled when the current position error signal sample exceeds the stopwrite threshold. Writing is enabled when the current position error signal sample does not exceed the stopwrite threshold.

Abstract: Controlling the position of a head within a tape transport system. A track-follow control system (TFCS) includes a controller device for generating a control signal as a function of a position error signal (PES), wherein the PES indicates a difference between the actual and target positions of the head relative to the tape, and an actuator for changing the actual position. The TFCS is adapted to select a controller device configuration from a plurality of configurations dependent on an operating tape speed. The configurations are predetermined depending on a vibration frequency domain profile indicative of environmental vibrations induced to the head and tape to determine the control signal for adjusting an actuator output signal relative to a lateral tape motion signal. The TFCS is also adapted to feed-back a signal depending on a difference of the actuator output signal and the lateral tape motion signal to generate the PES.

Abstract: A maximum velocity is dynamically determined during a tape drive operation to obtain a statistical standard deviation of a position error signal (PES) that yields an amount of stopwrite (SW) operations that avoids backhitching. The tape velocity is adjusted to the maximum velocity.

Abstract: Provided are a computer program product, system, and method for determining a skew error signal (SES) offset used to determine an SES to adjust heads in a drive unit. A determination is made of a first difference in a first orientation with respect to a direction of movement of the recordable storage media based on first and second position information read by first and second servo read elements on a first head. A determination is made of a second difference in a second orientation with respect to the direction of movement of the recordable storage media based on third and fourth position information read by the first servo read element and a third servo read element on a second head. An offset, calculated based on the determined first and second difference, is used to generate an error signal to adjust the first and second heads.

Abstract: To provide a technique for optimizing the processing order of recall requests in which the average latency time of a host apparatus is minimized. A storage manager accepts a request of the host apparatus for the recalling data from a tape library, and stores the request in a queue table. In response to storage of the request, the storage manager calculates the latency time for each request in all the conceivable execution orders for all the requests stored in the queue table. The storage manager determines the execution order which minimizes the total calculated latency time for all the requests including the active request, and rearranges the requests in the queue table.

Abstract: In one embodiment, a method includes updating a standard deviation or a variance based on a current position error signal sample, where a smoothing factor applied to a subsequent calculation of the standard deviation or variance is dynamically altered based at least in part on whether a current value of the standard deviation or the variance is above or below a specified value. A determination is made as to whether the standard deviation or the variance exceeds a predetermined threshold. A stopwrite threshold is determined based on the standard deviation or the variance when the standard deviation or the variance exceeds the predetermined threshold. A determination is made as to whether the current position error signal sample exceeds the stopwrite threshold. Writing is disabled when the current position error signal sample exceeds the stopwrite threshold. Writing is enabled when the current position error signal sample does not exceed the stopwrite threshold.

Abstract: In a controller of a tape drive, a CM input-output unit recognizes a tape format; a tape variable acquisition unit acquires tape variables; a setting variable acquisition unit acquires setting variables; and a minimum number calculator calculates a minimum number m of sub datasets, which are to be written to a tape to secure resistance to burst error, by using the tape variables and setting variables. When a command processor receives a synchronization command, the buffer manager generates n sub datasets for storing data in the buffer. If n is smaller than m, m sub datasets are padded out and set as write data. If n is m or more, the n sub datasets are set as write data. Then, the channel input-output unit writes the write data to the tape.