SIGNAL PROCESSING DEVICE, MAGNETIC TAPE DRIVE, MAGNETIC TAPE, MAGNETIC TAPE CARTRIDGE, SIGNAL PROCESSING METHOD, MAGNETIC TAPE MANUFACTURING METHOD, AND PROGRAM

A processor acquires a first signal based on a first result of reading a servo pattern via a first servo reading element while a first servo reading element is positioned on a reference region of a magnetic tape, acquires a second signal based on a second result of reading a servo pattern via a second servo reading element while a second servo reading element is positioned on the reference region, and executes, based on a servo band interval signal corresponding to a servo band interval according to the first signal and the second signal, processing of skewing a magnetic head according to the servo band interval.

BACKGROUND

1. Technical Field

The technology of the present disclosure relates to a signal processing device, a magnetic tape drive, a magnetic tape, a magnetic tape cartridge, a signal processing method, a magnetic tape manufacturing method, and a program.

2. Related Art

JP2020-170582A discloses a magnetic tape cartridge comprising: a magnetic tape including a plurality of servo bands on which servo patterns are recorded and a data band that is provided between the servo bands and on which data is recorded; and a recording medium on which servo band interval-related information is recorded, the servo band interval-related information including an interval in a direction corresponding to a width direction of the magnetic tape between adjacent servo recording elements in a plurality of servo recording elements for recording the servo patterns on each of the plurality of servo bands.

JP2021-039814A discloses a recording and reproducing apparatus comprising: a magnetic head which is used in a magnetic tape, in which a servo band on which a servo pattern is recorded and a data band having a plurality of data tracks on which data is recorded are alternately arranged along a width direction, and which includes a recording and reproducing element which records or reproduces data with respect to the data track and at least two servo reproducing elements which read servo patterns adjacent to each other in the width direction of the magnetic tape, respectively; a selection unit which selects one or two servo reproducing elements from the servo reproducing elements of the magnetic head according to a position of the data track, as a target of recording or reproducing of data in the data band, along the width direction; and a controller which controls positioning of the magnetic head along the width direction by using a result of reading of the servo patterns by the servo reproducing element selected by the selection unit.

SUMMARY

One embodiment according to the technology of the present disclosure provides a signal processing device, a magnetic tape drive, a magnetic tape, a magnetic tape cartridge, a program, a signal processing method, and a magnetic tape manufacturing method that implement skew control taking into consideration a servo band interval between servo bands adjacent to each other in a width direction of a magnetic tape.

According to a first aspect according to the technology of the present disclosure, there is provided a signal processing device comprising: a processor that acquires and processes data read by a magnetic head from a magnetic tape on which a plurality of servo bands are formed, in which the plurality of servo bands are disposed at intervals in a width direction of the magnetic tape, a plurality of servo patterns are formed in each of the plurality of servo bands along a longitudinal direction of the magnetic tape, the magnetic head has a pair of servo reading elements corresponding to a pair of servo bands adjacent to each other in the width direction among the plurality of servo bands, a first servo reading element included in the pair of servo reading elements reads the servo pattern included in a first servo band included in the pair of servo bands, a second servo reading element included in the pair of servo reading elements reads the servo pattern included in a second servo band included in the pair of servo bands, and the processor acquires a first signal based on a first result of reading the servo pattern in the first servo band via the first servo reading element while the first servo reading element is positioned on a reference region of the magnetic tape, acquires a second signal based on a second result of reading the servo pattern in the second servo band via the second servo reading element while the second servo reading element is positioned on the reference region, and executes skew processing for a skew mechanism that skews the magnetic head based on a servo band interval signal corresponding to a servo band interval according to the first signal and the second signal, the skew processing being processing of skewing the magnetic head according to the servo band interval.

A second aspect according to the technology of the present disclosure provides the signal processing device according to the first aspect, in which the servo band interval is used in common for a plurality of division areas obtained by dividing a data band in the width direction of the magnetic tape, and is a representative interval between a first servo pattern, which is the servo pattern in the first servo band of the pair of servo bands adjacent to each other via the data band, and a second servo pattern, which is the servo pattern in the second servo band of the pair of servo bands.

A third aspect according to the technology of the present disclosure provides the signal processing device according to the second aspect, in which the representative interval is obtained by statistically processing results of measuring an interval between the first servo pattern and the second servo pattern for each of the division areas in a case where the magnetic tape is run.

A fourth aspect according to the technology of the present disclosure provides the signal processing device according to the second or third aspect, in which the representative interval is obtained by statistically processing results of measuring an interval between the first servo pattern and the second servo pattern in a partial section of the division areas along a running direction of the magnetic tape for each of the division areas in a case where the magnetic tape is run.

A fifth aspect according to the technology of the present disclosure provides the signal processing device according to the second or third aspect, in which the representative interval is obtained by statistically processing results of measuring an interval between the first servo pattern and the second servo pattern in an entire section of the division areas along a running direction of the magnetic tape for each of the division areas in a case where the magnetic tape is run.

A sixth aspect according to the technology of the present disclosure provides the signal processing device according to any one of the second to fifth aspects, in which the representative interval is an average value of results of measuring an interval between the first servo pattern and the second servo pattern for each of the division areas in a case where the magnetic tape is run.

A seventh aspect according to the technology of the present disclosure provides the signal processing device according to any one of the first to sixth aspects, in which the reference region is a BOT region.

An eighth aspect according to the technology of the present disclosure provides the signal processing device according to any one of the first to seventh aspects, in which the processor stores the servo band interval signal in a storage medium.

A ninth aspect according to the technology of the present disclosure provides the signal processing device according to the eighth aspect, in which the magnetic tape is accommodated in a magnetic tape cartridge, the magnetic tape cartridge is provided with a noncontact storage medium that is able to perform communication in a noncontact manner, and the storage medium includes the noncontact storage medium.

A tenth aspect according to the technology of the present disclosure provides the signal processing device according to the eighth or ninth aspect, in which the storage medium includes a partial region of the magnetic tape.

According to an eleventh aspect according to the technology of the present disclosure, there is provided a magnetic tape drive in which skew processing is performed by the signal processing device according to any one of the first to tenth aspects.

According to a twelfth aspect according to the technology of the present disclosure, there is provided a magnetic tape comprising: a plurality of servo bands formed thereon, in which the plurality of servo bands are disposed at intervals in a width direction of the magnetic tape, a plurality of servo patterns are formed in each of the plurality of servo bands along a longitudinal direction of the magnetic tape, and a servo band interval between a pair of servo bands adjacent to each other in the width direction among the plurality of servo bands corresponds to the servo band interval signal obtained from the signal processing device according to any one of first to tenth aspects.

A thirteenth aspect according to the technology of the present disclosure provides the magnetic tape according to the twelfth aspect, in which the servo band interval signal is stored in a partial region of the magnetic tape.

A fourteenth aspect according to the technology of the present disclosure provides the magnetic tape according to the thirteenth aspect, in which the partial region is a BOT region and/or an EOT region.

According to a fifteenth aspect according to the technology of the present disclosure, there is provided a magnetic tape cartridge comprising: the magnetic tape according to any one of the twelfth to fourteenth aspects accommodated therein.

According to a sixteenth aspect according to the technology of the present disclosure, there is provided a magnetic tape cartridge comprising: a noncontact storage medium that is able to perform communication in a noncontact manner, in which the servo band interval signal obtained from the signal processing device according to any one of the first to tenth aspects is stored in the noncontact storage medium.

According to a seventeenth aspect according to the technology of the present disclosure, there is provided a signal processing method comprising: acquiring and processing data read by a magnetic head from a magnetic tape on which a plurality of servo bands are formed, in which the plurality of servo bands are disposed at intervals in a width direction of the magnetic tape, a plurality of servo patterns are formed in each of the plurality of servo bands along a longitudinal direction of the magnetic tape, the magnetic head has a pair of servo reading elements corresponding to a pair of servo bands adjacent to each other in the width direction among the plurality of servo bands, a first servo reading element included in the pair of servo reading elements reads the servo pattern included in a first servo band included in the pair of servo bands, a second servo reading element included in the pair of servo reading elements reads the servo pattern included in a second servo band included in the pair of servo bands, and the signal processing method includes acquiring a first signal based on a first result of reading the servo pattern in the first servo band via the first servo reading element while the first servo reading element is positioned on a reference region of the magnetic tape, acquiring a second signal based on a second result of reading the servo pattern in the second servo band via the second servo reading element while the second servo reading element is positioned on the reference region, and executing skew processing for a skew mechanism that skews the magnetic head based on a servo band interval signal corresponding to a servo band interval according to the first signal and the second signal, the skew processing being processing of skewing the magnetic head according to the servo band interval.

According to an eighteenth aspect according to the technology of the present disclosure, there is provided a magnetic tape manufacturing method comprising: recording the servo pattern in accordance with the servo band interval signal obtained from the signal processing device according to any one of the first to tenth aspects.

According to a nineteenth aspect according to the technology of the present disclosure, there is provided a magnetic tape on which the servo pattern is recorded in accordance with the servo band interval signal obtained by using the signal processing method according to the seventeenth aspect.

According to a twentieth aspect according to the technology of the present disclosure, there is provided a magnetic tape manufacturing method comprising: recording the servo pattern on a magnetic tape in accordance with the servo band interval signal obtained by using the signal processing method according to the seventeenth aspect.

According to a twenty-first aspect according to the technology of the present disclosure, there is provided a program for causing a computer to execute signal processing comprising: acquiring and processing data read by a magnetic head from a magnetic tape on which a plurality of servo bands are formed, in which the plurality of servo bands are disposed at intervals in a width direction of the magnetic tape, a plurality of servo patterns are formed in each of the plurality of servo bands along a longitudinal direction of the magnetic tape, the magnetic head has a pair of servo reading elements corresponding to a pair of servo bands adjacent to each other in the width direction among the plurality of servo bands, a first servo reading element included in the pair of servo reading elements reads the servo pattern included in a first servo band included in the pair of servo bands, a second servo reading element included in the pair of servo reading elements reads the servo pattern included in a second servo band included in the pair of servo bands, and the signal processing includes acquiring a first signal based on a first result of reading the servo pattern in the first servo band via the first servo reading element while the first servo reading element is positioned on a reference region of the magnetic tape, acquiring a second signal based on a second result of reading the servo pattern in the second servo band via the second servo reading element while the second servo reading element is positioned on the reference region, and executing skew processing for a skew mechanism that skews the magnetic head based on a servo band interval signal corresponding to a servo band interval according to the first signal and the second signal, the skew processing being processing of skewing the magnetic head according to the servo band interval.

DETAILED DESCRIPTION

Hereinafter, examples of embodiments of a signal processing device, a magnetic tape drive, a magnetic tape, a magnetic tape cartridge, a program, a signal processing method, and a magnetic tape manufacturing method according to the technology of the present disclosure will be described with reference to the accompanying drawings.

First, the terms used in the following description will be described.

CPU is an abbreviation for “central processing unit”. NVM is an abbreviation for “non-volatile memory”. RAM is an abbreviation for “random access memory”. EEPROM is an abbreviation for “electrically erasable and programmable read only memory”. SSD is an abbreviation for “solid state drive”. HDD is an abbreviation for “hard disk drive”. ASIC is an abbreviation for “application specific integrated circuit”. FPGA is an abbreviation for “field-programmable gate array”. PLC is an abbreviation for “programmable logic controller”. SoC is an abbreviation for “system-on-a-chip”. IC is an abbreviation for “integrated circuit”. RFID is an abbreviation for “radio frequency identifier”. BOT is an abbreviation of “beginning of tape”. EOT is an abbreviation for “end of tape”. UI is an abbreviation for “user interface”. WAN is an abbreviation for “wide area network”. LAN is an abbreviation for “local area network”. PES is an abbreviation for “position error signal”. In addition, in the following description, geometrical characteristics refer to generally recognized geometrical characteristics such as a length, a shape, an orientation, and/or a position.

As shown inFIG.1as an example, a magnetic tape system10comprises a magnetic tape cartridge12and a magnetic tape drive14. The magnetic tape drive14is loaded with the magnetic tape cartridge12. The magnetic tape cartridge12accommodates a magnetic tape MT. The magnetic tape drive14extracts the magnetic tape MT from the loaded magnetic tape cartridge12, and records data onto the magnetic tape MT or reads data from the magnetic tape MT while the extracted magnetic tape MT is running.

In the present embodiment, the magnetic tape MT is an example of a “magnetic tape” according to the technology of the present disclosure. In addition, in the present embodiment, the magnetic tape drive14is an example of a “magnetic tape drive” according to the technology of the present disclosure. In addition, in the present embodiment, the magnetic tape cartridge12is an example of a “magnetic tape cartridge” according to the technology of the present disclosure.

Next, an example of a configuration of the magnetic tape cartridge12will be described with reference toFIGS.2to4. In the following description, for convenience of description, inFIGS.2to4, a direction of loading the magnetic tape cartridge12into the magnetic tape drive14is indicated by an arrow A, a direction of the arrow A is defined as a front direction of the magnetic tape cartridge12, and a side of the magnetic tape cartridge12in the front direction is defined as a front side of the magnetic tape cartridge12. In the description of the structure to be shown below, “front” indicates the front side of the magnetic tape cartridge12.

In addition, in the following description, for convenience of description, inFIGS.2to4, a direction of an arrow B that is perpendicular to the direction of the arrow A is defined as a right direction, and a side of the magnetic tape cartridge12in the right direction is defined as a right side of the magnetic tape cartridge12. In the description of the structure to be shown below, “right” indicates the right side of the magnetic tape cartridge12.

In addition, in the following description, for convenience of description, inFIGS.2to4, a direction opposite to the direction of the arrow B is defined as a left direction, and a side of the magnetic tape cartridge12in the left direction is defined as a left side of the magnetic tape cartridge12. In the description of the structure to be shown below, “left” indicates the left side of the magnetic tape cartridge12.

In addition, in the following description, for convenience of description, inFIGS.2to4, a direction perpendicular to the direction of the arrow A and to the direction of the arrow B is indicated by an arrow C, a direction of the arrow C is defined as an upper direction of the magnetic tape cartridge12, and a side of the magnetic tape cartridge12in the upper direction is defined as an upper side of the magnetic tape cartridge12. In the description of the structure to be shown below, “upper” indicates the upper side of the magnetic tape cartridge12.

In addition, in the following description, for convenience of description, inFIGS.2to4, a direction opposite to the front direction of the magnetic tape cartridge12is defined as a rear direction of the magnetic tape cartridge12, and a side of the magnetic tape cartridge12in the rear direction is defined as a rear side of the magnetic tape cartridge12. In the description of the structure to be shown below, “rear” indicates the rear side of the magnetic tape cartridge12.

In addition, in the following description, for convenience of description, inFIGS.2to4, a direction opposite to the upper direction of the magnetic tape cartridge12is defined as a lower direction of the magnetic tape cartridge12, and a side of the magnetic tape cartridge12in the lower direction is defined as a lower side of the magnetic tape cartridge12. In the description of the structure to be shown below, “lower” indicates the lower side of the magnetic tape cartridge12.

As shown inFIG.2as an example, the magnetic tape cartridge12has a substantially rectangular shape in a plan view and comprises a box-like case16. The magnetic tape MT is accommodated in the case16. The case16is made of resin such as polycarbonate and comprises an upper case18and a lower case20. The upper case18and the lower case20are bonded by welding (for example, ultrasound welding) and screwing in a state in which a lower peripheral edge surface of the upper case18and an upper peripheral edge surface of the lower case20are brought into contact with each other. The bonding method is not limited to welding and screwing, and other bonding methods may be used.

A feeding reel22is rotatably accommodated inside the case16. The feeding reel22comprises a reel hub22A, an upper flange22B1, and a lower flange22B2. The reel hub22A is formed in a cylindrical shape. The reel hub22A is an axial center portion of the feeding reel22, has an axial center direction along an up-down direction of the case16, and is disposed in a center portion of the case16. Each of the upper flange22B1and the lower flange22B2is formed in an annular shape. A center portion of the upper flange22B1in a plan view is fixed to an upper end portion of the reel hub22A, and a center portion of the lower flange22B2in a plan view is fixed to a lower end portion of the reel hub22A. The reel hub22A and the lower flange22B2may be integrally molded.

The magnetic tape MT is wound around an outer peripheral surface of the reel hub22A, and an end portion of the magnetic tape MT in a width direction is held by the upper flange22B1and the lower flange22B2.

An opening16B is formed on a front side of a right wall16A of the case16. The magnetic tape MT is extracted from the opening16B.

A cartridge memory24is provided in the lower case20. Specifically, the cartridge memory24is accommodated in a right rear end portion of the lower case20. The cartridge memory24is a memory that can perform communication in a noncontact manner. An IC chip having an NVM is mounted in the cartridge memory24. In the present embodiment, a so-called passive RFID tag is adopted as the cartridge memory24, and various pieces of information are read and written with respect to the cartridge memory24in a noncontact manner. In the present embodiment, the form example has been described in which the cartridge memory24is provided in the lower case20, but the technology of the present disclosure is not limited to this, and the cartridge memory24need only be provided in the case16at a position at which various pieces of information can be read and written in a noncontact manner.

The cartridge memory24stores management information13for managing the magnetic tape cartridge12. The management information13includes, for example, information about the cartridge memory24(for example, information for specifying the magnetic tape cartridge12), information about the magnetic tape MT, and information about the magnetic tape drive14(for example, information that indicates specifications of the magnetic tape drive14and a signal used in the magnetic tape drive14). The information about the magnetic tape MT includes specification information13A. The specification information13A is information for specifying the specifications of the magnetic tape MT. In addition, the information about the magnetic tape MT also includes information that indicates an outline of the data recorded on the magnetic tape MT, information that indicates an item of the data recorded on the magnetic tape MT, information that indicates a recording format of the data recorded on the magnetic tape MT, and the like. In the present embodiment, the cartridge memory24is an example of a “storage medium” and a “noncontact storage medium” according to the technology of the present disclosure.

As shown inFIG.3as an example, the magnetic tape drive14comprises a controller25, a transport device26, a magnetic head28, a UI system device34, and a communication interface35. The controller25comprises a control device30and a storage32. In the present embodiment, the magnetic head28is an example of a “magnetic head” according to the technology of the present disclosure, and the controller25is an example of a “signal processing device”. In addition, the control device30is an example of a “processor” according to the technology of the present disclosure.

The magnetic tape cartridge12is loaded into the magnetic tape drive14along the direction of the arrow A. In the magnetic tape drive14, the magnetic tape MT is used by being extracted from the magnetic tape cartridge12. The controller25controls the entire magnetic tape drive14(for example, the magnetic head28) by using the management information13and the like stored in the cartridge memory24.

The magnetic tape MT has a magnetic layer29A, a base film29B, and a back coating layer29C. The magnetic layer29A is formed on one surface side of the base film29B, and the back coating layer29C is formed on the other surface side of the base film29B. The data is recorded in the magnetic layer29A. The magnetic layer29A contains a ferromagnetic powder. As the ferromagnetic powder, for example, a ferromagnetic powder generally used in the magnetic layers of various magnetic recording media is used. Preferable specific examples of the ferromagnetic powder include a hexagonal ferrite powder. Examples of the hexagonal ferrite powder include a hexagonal strontium ferrite powder and a hexagonal barium ferrite powder. The back coating layer29C is a layer containing a non-magnetic powder such as carbon black. The base film29B is also referred to as a support, and is made of, for example, polyethylene terephthalate, polyethylene naphthalate, or polyamide. A non-magnetic layer may be formed between the base film29B and the magnetic layer29A. In the magnetic tape MT, a surface on which the magnetic layer29A is formed is a front surface31of the magnetic tape MT, and a surface on which the back coating layer29C is formed is a back surface33of the magnetic tape MT.

The magnetic tape drive14performs magnetic processing on the surface31of the magnetic tape MT by using the magnetic head28in a state in which the magnetic tape MT is running. Here, the magnetic processing refers to recording the data (that is, writing the data) on the front surface31of the magnetic tape MT and reading the data (that is, reproducing the data) from the front surface31of the magnetic tape MT. In the present embodiment, the magnetic tape drive14selectively performs the recording of the data on the front surface31of the magnetic tape MT and the reading of the data from the front surface31of the magnetic tape MT by using the magnetic head28. That is, the magnetic tape drive14extracts the magnetic tape MT from the magnetic tape cartridge12, and records the data on the front surface31of the extracted magnetic tape MT by using the magnetic head28or reads the data from the front surface31of the extracted magnetic tape MT by using the magnetic head28.

The control device30controls the entire magnetic tape drive14. In the present embodiment, although the control device30is implemented by an ASIC, the technology of the present disclosure is not limited to this. For example, the control device30may be implemented by an FPGA and/or a PLC. In addition, the control device30may be implemented by the computer including a CPU, a flash memory (for example, an EEPROM and/or an SSD), and a RAM. In addition, the control device30may be implemented by combining two or more of an ASIC, an FPGA, a PLC, and a computer. That is, the control device30may be implemented by a combination of a hardware configuration and a software configuration.

The storage32is connected to the control device30, and the control device30writes various pieces of information to the storage32and reads out various pieces of information from the storage32. Examples of the storage32include a flash memory and/or an HDD. The flash memory and the HDD are merely examples, and any memory may be used as long as the memory is a non-volatile memory that can be mounted in the magnetic tape drive14.

The UI system device34is a device having a reception function of receiving an instruction signal indicating an instruction from a user and a presentation function of presenting the information to the user. The reception function is implemented by a touch panel, a hard key (for example, a keyboard), and/or a mouse, for example. The presentation function is implemented by a display, a printer, and/or a speaker, for example. The UI system device34is connected to the control device30. The control device30acquires the instruction signal received by the UI system device34. The UI system device34presents various pieces of information to the user under the control of the control device30.

The communication interface35is connected to the control device30. In addition, the communication interface35is connected to an external device37via a communication network (not shown) such as a WAN and/or a LAN. The communication interface35controls the exchange of various pieces of information (for example, data to be recorded on the magnetic tape MT, data read from the magnetic tape MT, and/or an instruction signal given to the control device30) between the control device30and the external device37. Examples of the external device37include a personal computer and a mainframe.

The transport device26is a device that selectively transports the magnetic tape MT along a predetermined path in a forward direction and a backward direction, and comprises a feeding motor36, a winding reel38, a winding motor40, and a plurality of guide rollers GR. Here, the forward direction indicates a feeding direction of the magnetic tape MT, and the backward direction indicates a rewinding direction of the magnetic tape MT.

The feeding motor36rotates the feeding reel22in the magnetic tape cartridge12under the control of the control device30. The control device30controls the feeding motor36to control a rotation direction, a rotation speed, a rotation torque, and the like of the feeding reel22.

The winding motor40rotates the winding reel38under the control of the control device30. The control device30controls the winding motor40to control a rotation direction, a rotation speed, a rotation torque, and the like of the winding reel38.

In a case where the magnetic tape MT is wound by the winding reel38, the control device30rotates the feeding motor36and the winding motor40such that the magnetic tape MT runs along the predetermined path in the forward direction. The rotation speed, the rotation torque, and the like of the feeding motor36and the winding motor40are adjusted in accordance with a speed at which the magnetic tape MT is wound around the winding reel38. In addition, the rotation speed, the rotation torque, and the like of each of the feeding motor36and the winding motor40are adjusted by the control device30, thereby applying the tension to the magnetic tape MT. In addition, the tension applied to the magnetic tape MT is controlled by adjusting the rotation speed, the rotation torque, and the like of each of the feeding motor36and the winding motor40via the control device30.

In a case where the magnetic tape MT is rewound to the feeding reel22, the control device30rotates the feeding motor36and the winding motor40such that the magnetic tape MT runs along the predetermined path in the backward direction.

In the present embodiment, the tension applied to the magnetic tape MT is controlled by controlling the rotation speed, the rotation torque, and the like of the feeding motor36and the winding motor40, but the technology of the present disclosure is not limited to this. For example, the tension applied to the magnetic tape MT may be controlled by using a dancer roller, or may be controlled by drawing the magnetic tape MT into a vacuum chamber.

Each of the plurality of guide rollers GR is a roller that guides the magnetic tape MT. The predetermined path, that is, a running path of the magnetic tape MT is determined by separately disposing the plurality of guide rollers GR at positions straddling the magnetic head28between the magnetic tape cartridge12and the winding reel38.

The magnetic head28comprises a magnetic element unit42and a holder44. The magnetic element unit42is held by the holder44so as to come into contact with the running magnetic tape MT. The magnetic element unit42includes a plurality of magnetic elements.

The magnetic element unit42records data on the magnetic tape MT transported by the transport device26, and reads data from the magnetic tape MT transported by the transport device26. Here, the data refers to, for example, a servo pattern52(seeFIG.6) and data other than the servo pattern52, that is, data recorded in a data band DB (seeFIG.6). The data referred to here is an example of “data” according to the technology of the present disclosure.

The magnetic tape drive14comprises a noncontact read/write device46. The noncontact read/write device46is disposed to face a back surface24A of the cartridge memory24on the lower side of the magnetic tape cartridge12in a state in which the magnetic tape cartridge12is loaded, and reads and writes the information with respect to the cartridge memory24in a noncontact manner.

As shown inFIG.4as an example, the noncontact read/write device46releases a magnetic field MF from the lower side of the magnetic tape cartridge12toward the cartridge memory24. The magnetic field MF passes through the cartridge memory24.

The noncontact read/write device46is connected to the control device30. The control device30outputs a memory control signal to the noncontact read/write device46. The memory control signal is a signal for controlling the cartridge memory24. The noncontact read/write device46generates the magnetic field MF in response to the memory control signal input from the control device30, and releases the generated magnetic field MF toward the cartridge memory24.

The noncontact read/write device46performs processing on the cartridge memory24in response to the memory control signal by performing noncontact communication with the cartridge memory24via the magnetic field MF. For example, under the control of the control device30, the noncontact read/write device46selectively performs processing of reading the information from the cartridge memory24and processing of storing the information in the cartridge memory24(that is, processing of writing the information to the cartridge memory24). In other words, the control device30reads the information from the cartridge memory24and stores the information in the cartridge memory24by performing communication with the cartridge memory24in a noncontact manner via the noncontact read/write device46.

As shown inFIG.5as an example, the magnetic tape drive14comprises a moving mechanism48. The moving mechanism48includes a movement actuator48A. Examples of the movement actuator48A include a voice coil motor and/or a piezo actuator. The movement actuator48A is connected to the control device30, and the control device30controls the movement actuator48A. The movement actuator48A generates power under the control of the control device30. The moving mechanism48moves the magnetic head28in a width direction WD (seeFIG.6) of the magnetic tape MT by receiving the power generated by the movement actuator48A.

The magnetic tape drive14comprises an inclination mechanism49. The inclination mechanism49is an example of a “skew mechanism” according to the technology of the present disclosure. The inclination mechanism49includes an inclination actuator49A. Examples of the inclination actuator49A include a voice coil motor and/or a piezo actuator. The inclination actuator49A is connected to the control device30, and the control device30controls the inclination actuator49A. The inclination actuator49A generates power under the control of the control device30. The inclination mechanism49inclines the magnetic head28to a longitudinal direction LD side of the magnetic tape MT with respect to the width direction WD of the magnetic tape MT by receiving the power generated by the inclination actuator49A (seeFIG.10). That is, the magnetic head28is skewed on the magnetic tape MT by the application of the power from the inclination mechanism49under the control of the control device30.

As shown inFIG.6as an example, on the front surface31of the magnetic tape MT, servo bands SB1, SB2, and SB3and data bands DB1and DB2are formed. In the following, for convenience of description, in a case where the distinction is not specifically needed, the servo bands SB1to SB3are referred to as a servo band SB, and the data bands DB1and DB2are referred to as a data band DB. The servo bands SB1to SB3are examples of a “servo band” according to the technology of the present disclosure.

The servo bands SB1to SB3and the data bands DB1and DB2are formed along the longitudinal direction LD (that is, an overall length direction) of the magnetic tape MT. Here, the overall length direction of the magnetic tape MT refers to, in other words, the running direction of the magnetic tape MT. The running direction of the magnetic tape MT is defined in two directions of the forward direction which is a direction in which the magnetic tape MT runs from the feeding reel22side to the winding reel38side (hereinafter, also simply referred to as a “forward direction”), and the backward direction which is a direction in which the magnetic tape MT runs from the winding reel38side to the feeding reel22side (hereinafter, also simply referred to as a “backward direction”).

The servo bands SB1to SB3are arranged at positions spaced in the width direction WD of the magnetic tape MT (hereinafter, also simply referred to as a “width direction WD”). For example, the servo bands SB1to SB3are arranged at equal intervals along the width direction WD. In the present embodiment, the term “equal intervals” refers to equal intervals in the sense of including, in addition to a completely equal interval, an error that is generally acceptable in the technical field to which the technology of the present disclosure belongs, and that does not contradict the purpose of the technology of the present disclosure.

The data band DB1is disposed between the servo band SB1and the servo band SB2, and the data band DB2is disposed between the servo band SB2and the servo band SB3. That is, the servo bands SB and the data bands DB are arranged alternately along the width direction WD.

In the example shown inFIG.6, for convenience of description, three servo bands SB and two data bands DB are shown, but these are merely examples, and two servo bands SB and one data band DB may be used, and the technology of the present disclosure is established even in a case where four or more servo bands SB and three or more data bands DB are used.

A plurality of servo patterns52are formed in the servo band SB along the longitudinal direction LD of the magnetic tape MT. The servo pattern52is an example of a “servo pattern” according to the technology of the present disclosure. The servo patterns52are classified into a servo pattern52A and a servo pattern52B. The plurality of servo patterns52are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT. In the present embodiment, the term “regular” refers to the regularity in the sense of including, in addition to the exact regularity, an error that is generally acceptable in the technical field to which the technology of the present disclosure belongs, and that does not contradict the purpose of the technology of the present disclosure.

The servo band SB is divided by a plurality of frames50along the longitudinal direction LD of the magnetic tape MT. The frame50is defined by a set of servo patterns52. In the example shown inFIG.6, the servo patterns52A and52B are shown as an example of the set of servo patterns52. The servo patterns52A and52B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern52A is positioned on an upstream side in the forward direction and the servo pattern52B is positioned on a downstream side in the forward direction in the frame50.

The servo pattern52consists of linear magnetization region pairs54. The linear magnetization region pair54is classified into a linear magnetization region pair54A and a linear magnetization region pair54B.

The servo pattern52A consists of the linear magnetization region pair54A. In the example shown inFIG.6, a pair of linear magnetization regions54A1and54A2is shown as an example of the linear magnetization region pair54A. Each of the linear magnetization regions54A1and54A2is a linearly magnetized region.

The linear magnetization regions54A1and54A2are inclined in opposite directions with respect to an imaginary straight line C1which is an imaginary straight line along the width direction WD. In the example shown inFIG.6, the linear magnetization regions54A1and54A2are inclined line-symmetrically with respect to the imaginary straight line C1. More specifically, the linear magnetization regions54A1and54A2are formed in a state of being not parallel to each other and being inclined at a predetermined angle (for example, 5 degrees) in opposite directions on the longitudinal direction LD side of the magnetic tape MT with the imaginary straight line C1as a symmetry axis.

The linear magnetization region54A1is a set of magnetization straight lines54A1a, which are five magnetized straight lines. The linear magnetization region54A2is a set of magnetization straight lines54A2a, which are five magnetized straight lines. The set of the magnetization straight lines54A1aand the set of the magnetization straight lines54A2aare examples of a “set of a plurality of magnetization straight lines” according to the technology of the present disclosure.

The servo pattern52B consists of the linear magnetization region pair54B. In the example shown inFIG.6, a pair of linear magnetization regions54B1and54B2is shown as an example of the linear magnetization region pair54B. Each of the linear magnetization regions54B1and54B2is a linearly magnetized region.

The linear magnetization regions54B1and54B2are inclined in opposite directions with respect to an imaginary straight line C2which is an imaginary straight line along the width direction WD. In the example shown inFIG.6, the linear magnetization regions54B1and54B2are inclined line-symmetrically with respect to the imaginary straight line C2. More specifically, the linear magnetization regions54B1and54B2are formed in a state of being not parallel to each other and being inclined at a predetermined angle (for example, 5 degrees) in opposite directions on the longitudinal direction LD side of the magnetic tape MT with the imaginary straight line C2as a symmetry axis.

The linear magnetization region54B1is a set of magnetization straight lines54B1a, which are four magnetized straight lines. The linear magnetization region54B2is a set of magnetization straight lines54B2a, which are four magnetized straight lines.

The magnetic head28is disposed on the front surface31side of the magnetic tape MT configured as described above. The holder44is formed in a rectangular parallelepiped shape, and is disposed to cross the front surface31of the magnetic tape MT along the width direction WD. The plurality of magnetic elements of the magnetic element unit42are arranged linearly along the longitudinal direction of the holder44. The magnetic element unit42includes a pair of servo reading elements SR and a plurality of data read/write elements DRW as the plurality of magnetic elements. In the present embodiment, the pair of servo reading elements SR is an example of a “pair of servo reading elements” according to the technology of the present disclosure.

A length of the holder44in the longitudinal direction is sufficiently long with respect to the width of the magnetic tape MT. For example, the length of the holder44in the longitudinal direction is set to a length exceeding the width of the magnetic tape MT even in a case where the magnetic element unit42is disposed at any position on the magnetic tape MT.

The pair of servo reading elements SR is mounted on the magnetic head28. In the magnetic head28, a relative positional relationship between the holder44and the pair of servo reading elements SR is fixed. The pair of servo reading elements SR consists of servo reading elements SR1and SR2. The servo reading element SR1is disposed at one end of the magnetic element unit42, and the servo reading element SR2is disposed at the other end of the magnetic element unit42. In the example shown inFIG.6, the servo reading element SR1is provided at a position corresponding to the servo band SB2, and the servo reading element SR2is provided at a position corresponding to the servo band SB3. In the present embodiment, the servo reading element SR1is an example of a “first servo reading element” according to the technology of the present disclosure, and the servo reading element SR2is an example of a “second servo reading element” according to the technology of the present disclosure. In addition, the servo band SB2is an example of a “first servo band” according to the technology of the present disclosure, and the servo band SB3is an example of a “second servo band” according to the technology of the present disclosure.

The plurality of data read/write elements DRW are disposed linearly between the servo reading element SR1and the servo reading element SR2. The plurality of data read/write elements DRW are disposed at intervals along the longitudinal direction of the magnetic head28(for example, are disposed at equal intervals along the longitudinal direction of the magnetic head28). In the example shown inFIG.6, the plurality of data read/write elements DRW are provided at positions corresponding to the data band DB2.

The control device30acquires a servo pattern signal which is a result of reading the servo pattern52via the servo reading element SR, and performs tracking control (also referred to as “servo control”) in response to the acquired servo pattern signal. Here, the tracking control refers to control (that is, control of adjusting the position of the magnetic head28such that on-track occurs) of positioning the magnetic head28to a designated portion by moving the magnetic head28in the width direction WD of the magnetic tape MT via the moving mechanism48in accordance with the servo pattern52read by the servo reading element SR.

By performing the tracking control, the plurality of data read/write elements DRW are positioned on a designated region in the data band DB, and in this state, the magnetic processing is performed on the designated region in the data band DB. In the example shown inFIG.6, the plurality of data read/write elements DRW perform the magnetic processing on the designated region in the data band DB2.

In addition, in a case where the data band DB of which the data is to be read by the magnetic element unit42is changed (in the example shown inFIG.6, in a case where the data band DB of which the data is to be read by the magnetic element unit42is changed from the data band DB2to the data band DB1), the moving mechanism48moves the magnetic head28in the width direction WD to change the position of the pair of servo reading elements SR under the control of the control device30. That is, by moving the magnetic head28in the width direction WD, the moving mechanism48moves the servo reading element SR1to a position corresponding to the servo band SB1and moves the servo reading element SR2to the position corresponding to the servo band SB2. As a result, the positions of the plurality of data read/write elements DRW are changed from on the data band DB2to on the data band DB1, and the plurality of data read/write elements DRW perform the magnetic processing on the data band DB1.

As shown inFIG.7as an example, in the data band DB2, as a plurality of division areas obtained by dividing the data band DB2in the width direction WD, data tracks DT1, DT2, DT3, DT4, DT5, DT6, DT7, and DT8are formed from the servo band SB2side to the servo band SB3side.

The magnetic head28includes, as the plurality of data read/write elements DRW, data read/write elements DRW1, DRW2, DRW3, DRW4, DRW5, DRW6, DRW7, and DRW8between the servo reading element SR1and the servo reading element SR2along the width direction WD. The data read/write elements DRW1to DRW8have a one-to-one correspondence with the data tracks DT1to DT8, and can read (that is, reproduce) data from the data tracks DT1to DT8and record (that is, write) the data on the data tracks DT1to DT8.

In addition, although not shown, a plurality of data tracks DT corresponding to the data tracks DT1, DT2, DT3, DT4, DT5, DT6, DT7, and DT8are also formed in the data band DB1(seeFIG.6).

Hereinafter, in a case where the distinction is not specifically needed, the data tracks DT1, DT2, DT3, DT4, DT5, DT6, DT7, and DT8are referred to as a “data track DT”. In addition, in the following, in a case where the distinction is not specifically needed, the data read/write elements DRW1, DRW2, DRW3, DRW4, DRW5, DRW6, DRW7, and DRW8are referred to as a “data read/write element DRW”.

As shown inFIG.8as an example, the data track DT includes a division data track group DTG. The data tracks DT1to DT8correspond to division data track groups DTG1to DTG8. In the following, in a case where the distinction is not specifically needed, the division data track groups DTG1to DTG8are referred to as a “division data track group DTG”.

The division data track group DTG1is a set of a plurality of division data tracks obtained by dividing the data track DT in the width direction WD. In the example shown inFIG.8, as an example of the division data track group DTG1, division data tracks DT1_1, DT1_2, DT1_3, DT1_4, . . . , DT1_11, and DT1_12obtained by dividing the data track DT into 12 equal parts in the width direction WD are shown. In the present embodiment, the division data track is an example of a “division area” according to the technology of the present disclosure.

The data read/write element DRW1is responsible for the magnetic processing on the division data track group DTG1. That is, the data read/write element DRW1is responsible for recording data on the division data tracks DT1_1, DT1_2, DT1_3, DT1_4, . . . , DT1_11, and DT1_12and for reading data from the division data tracks DT1_1, DT1_2, DT1_3, DT1_4, . . . , DT1_11, and DT1_12.

Each of the data read/write elements DRW2to DRW8is also responsible for the magnetic processing on the division data track group DTG of the data track DT corresponding to each data read/write element DRW, similarly to the data read/write element DRW1.

The data read/write element DRW is moved to a position corresponding to designated one data track DT among the plurality of data tracks DT with the movement of the magnetic head28in the width direction WD via the moving mechanism48(seeFIG.6). The data read/write element DRW is fixed at a position corresponding to the designated one data track DT by the tracking control using the servo pattern52(seeFIGS.6and7).

Incidentally, in recent years, research on a technology of reducing the influence of transverse dimensional stability (TDS) has been advanced. It has been known that the TDS is affected by a temperature, humidity, a pressure at which the magnetic tape is wound around the reel, temporal deterioration, or the like, the TDS is increased in a case where no measures are taken, and off-track (that is, misregistration of the data read/write element DRW with respect to the track in the data band DB) occurs in a scene in which the magnetic processing is performed on the data band DB.

In the example shown inFIG.9, an aspect is shown in which the width of the magnetic tape MT contracts with the elapse of time. In this case, the off-track occurs. The off-track refers to a state in which the data read/write element DRW is not positioned on the designated division data track among the division data tracks DT1_1, DT1_2, DT1_3, DT1_4, . . . , DT1_11, and DT1_12included in the division data track group DTG (that is, a state in which the position of the designated division data track and the position of the data read/write element DRW deviate from each other in the width direction WD).

In some cases, the width of the magnetic tape MT expands, and the off-track occurs in this case as well. That is, in a case where the width of the magnetic tape MT contracts or expands with the elapse of time, the position of the servo reading element SR with respect to the servo pattern52diverges in the width direction WD from a predetermined position (that is, a predetermined position determined in design with respect to each of the linear magnetization regions54A1,54A2,54B1, and54B2) determined in design. In a case where the position of the servo reading element SR with respect to the servo pattern52diverges in the width direction WD from the predetermined position determined in design, the accuracy of the tracking control is deteriorated, and the position of the track (for example, the designated division data track among the division data tracks DT1_1, DT1_2, DT1_3, DT1_4, . . . , DT1_11, and DT1_12) in the data band DB and the position of the data read/write element DRW deviate from each other. Then, an originally planned track will not be subjected to the magnetic processing.

As a method of reducing the influence of the TDS, a method of adjusting the width of the magnetic tape MT by adjusting the tension applied to the magnetic tape MT is considered. However, in a case where an amount of deformation of the magnetic tape MT in the width direction WD is too large, the off-track may not be eliminated even in a case where the tension applied to the magnetic tape MT is adjusted. In addition, in a case where the tension applied to the magnetic tape MT is increased, the load applied to the magnetic tape MT is also increased, which may lead to shortening the life of the magnetic tape MT. Further, in a case where the tension applied to the magnetic tape MT is too weak, the contact state between the magnetic head28and the magnetic tape MT is unstable, and it is difficult for the magnetic head28to perform the magnetic processing on the magnetic tape MT. As a method of reducing the influence of the TDS other than the method of adjusting the tension applied to the magnetic tape MT, as shown inFIG.10as an example, a method of holding the position of the servo reading element SR with respect to the servo pattern52at the predetermined position determined in design by skewing the magnetic head28on the magnetic tape MT is known.

The magnetic head28comprises a rotation axis RA. The rotation axis RA is provided at a position corresponding to a center portion of the magnetic element unit42provided in the magnetic head28in a plan view. The magnetic head28is rotatably held by the inclination mechanism49via the rotation axis RA. In the present embodiment, the operation of inclining the magnetic head28with respect to the width direction WD by rotating the magnetic head28on the front surface31with the rotation axis RA as a central axis along the front surface31is referred to as “skew”.

An imaginary straight line C3which is an imaginary center line is provided in the magnetic head28. The imaginary straight line C3is a straight line that passes through the rotation axis RA and that extends in the longitudinal direction of the magnetic head28in a plan view (that is, the direction in which the plurality of data read/write elements DRW are arranged). The magnetic head28is disposed in an inclined posture with respect to the width direction WD along the front surface31(in other words, a posture in which the imaginary straight line C3is inclined with respect to an imaginary straight line C4along the front surface31). In the example shown inFIG.10, the magnetic head28is held by the inclination mechanism49to have a posture in which the imaginary straight line C3is inclined to the longitudinal direction LD side of the magnetic tape MT with respect to the imaginary straight line C4which is an imaginary straight line along the width direction WD. In the example shown inFIG.10, the magnetic head28is held by the inclination mechanism49in a posture in which the imaginary straight line C3is inclined to the feeding reel22side with respect to the imaginary straight line C4(that is, a posture inclined counterclockwise as viewed from a paper surface side ofFIG.10). An angle formed by the imaginary straight line C3and the imaginary straight line C4corresponds to an angle at which the magnetic head28is inclined with respect to the width direction WD by rotating the magnetic head28on the front surface31with the rotation axis RA as a central axis along the front surface31. In the following, the angle formed by the imaginary straight line C3and the imaginary straight line C4is also referred to as a “skew angle” or a “skew angle of the magnetic head28”. The skew angle is an angle defined such that the counterclockwise direction as viewed from the paper surface side ofFIG.10is positive, and the clockwise direction as viewed from the paper surface side ofFIG.10is negative.

The inclination mechanism49receives power from the inclination actuator49A (seeFIG.5) to rotate the magnetic head28around the rotation axis RA on the front surface31of the magnetic tape MT. Under the control of the control device30, the inclination mechanism49rotates the magnetic head28around the rotation axis RA on the front surface31of the magnetic tape MT, thereby changing the direction of the inclination (that is, azimuth) and the inclined angle of the imaginary straight line C3with respect to the imaginary straight line C4. The change the direction of the inclination and the inclined angle of the imaginary straight line C3with respect to the imaginary straight line C4is implemented by changing an angle at which the magnetic head28is inclined with respect to the width direction WD along the front surface31, that is, the skew angle of the magnetic head28. In the present embodiment, the direction of the inclination and the inclined angle of the imaginary straight line C3with respect to the imaginary straight line C4are expressed by the skew angle of the magnetic head28.

By changing the direction of the inclination and the inclined angle of the imaginary straight line C3with respect to the imaginary straight line C4, that is, the skew angle in accordance with the temperature, the humidity, the pressure at which the magnetic tape MT is wound around the reel, the temporal deterioration, and the like, or expansion and contraction of the magnetic tape MT in the width direction WD due to these, the position of the servo reading element SR with respect to the servo pattern52is held at the predetermined position determined in design. In this case, the on-track occurs. The on-track refers to a state in which the data read/write element DRW is positioned on the designated division data track among the division data tracks DT1_1, DT1_2, DT1_3, DT1_4, . . . , DT1_11, and DT1_12included in the division data track group DTG (that is, a state in which the position of the designated division data track and the position of the data read/write element DRW match each other in the width direction WD).

The servo reading element SR reads the servo pattern52and outputs the servo pattern signal indicating a read result. The servo reading element SR is formed linearly along the imaginary straight line C3. Therefore, in a case where the servo pattern52A is read by the servo reading element SR, an angle formed by the linear magnetization region54A1and the servo reading element SR and an angle formed by the linear magnetization region54A2and the servo reading element SR are different in the linear magnetization region pair54A. In a case where the angles are different in this way, a variation due to an azimuth loss (for example, a variation in signal level and waveform distortion) occurs between the servo pattern signal derived from the linear magnetization region54A1(that is, the servo pattern signal obtained by reading the linear magnetization region54A1via the servo reading element SR) and the servo pattern signal derived from the linear magnetization region54A2(that is, the servo pattern signal obtained by reading the linear magnetization region54A2via the servo reading element SR).

In the example shown inFIG.10, since the angle formed by the servo reading element SR and the linear magnetization region54A1is larger than the angle formed by the servo reading element SR and the linear magnetization region54A2, the output of the servo pattern signal is small, and the waveform also spreads, so that a variation occurs in the servo pattern signal obtained by being read by the servo reading element SR across the servo band SB in a state in which the magnetic tape MT runs. In addition, also in a case where the servo pattern52B is read by the servo reading element SR, the variation due to the azimuth loss occurs between the servo pattern signal derived from the linear magnetization region54B1and the servo pattern signal derived from the linear magnetization region54B2.

As will be described in detail below, in the present embodiment, as a method of detecting the servo pattern signal in which the variation occurs due to the azimuth loss as described above, a method of detecting the servo pattern signal using an autocorrelation coefficient is used (seeFIG.15).

Next, an example of contents of specific processing performed by the control device30will be described with reference toFIGS.11to17.

As shown inFIG.11as an example, the controller25comprises a position detection device30B in addition to the control device30. In the example shown inFIG.11, the position detection device30B is separate from the control device30, but this is merely an example, and the position detection device30B may be integrated with the control device30by being incorporated into the control device30.

The position detection device30B includes a first position detection device30B1and a second position detection device30B2. The position detection device30B acquires a servo band signal that is a result of reading the servo band SB via the servo reading element SR, and detects the position of the magnetic head28on the magnetic tape MT based on the acquired servo band signal. The servo band signal includes a signal (for example, noise) unnecessary for the tracking control in addition to the servo pattern signal that is the result of reading the servo pattern52.

The position detection device30B acquires the servo band signal from the magnetic head28. The servo band signal is classified into a first servo band signal S1and a second servo band signal S2. The first servo band signal S1is a signal indicating the result of reading the servo pattern52in the servo band SB via the servo reading element SR1. The second servo band signal S2is a signal indicating the result of reading the servo pattern52in the servo band SB via the servo reading element SR2. The first servo band signal S1is an example of a “first result of reading the servo pattern via the first servo reading element” according to the technology of the present disclosure, and the second servo band signal S2is an example of a “second result of reading the servo pattern via the second servo reading element” according to the technology of the present disclosure.

The result of reading the servo pattern52in the servo band SB via the servo reading element SR1refers to, for example, a result of reading the linear magnetization regions54A1,54A2,54B1, and54B2included in one servo pattern52via the servo reading element SR1. Five magnetization straight lines54A1aare included in the linear magnetization region54A1. In addition, five magnetization straight lines54A2aare included in the linear magnetization region54A2. In addition, four magnetization straight lines54B1aare included in the linear magnetization region54B1. In addition, four magnetization straight lines54B2aare included in the linear magnetization region54B2. Therefore, the result of reading the servo pattern52via the servo reading element SR1is obtained as a pulse signal group (hereinafter, also referred to as a “first pulse signal group”) consisting of 18 pulse signals corresponding to the linear magnetization regions54A1,54A2,54B1, and54B2.

In the example shown inFIG.11, the first pulse signal group is a set of time-series pulse signals corresponding to the linear magnetization regions54A1,54A2,54B1, and54B2in the servo band SB2. In addition, in the present embodiment, the first pulse signal group is the first servo band signal S1.

Here, as the first pulse signal group, a set of time-series pulse signals corresponding to the linear magnetization regions54A1,54A2,54B1and54B2in the servo band SB2has been described, but this is merely an example. For example, the first pulse signal group may be a set of time-series pulse signals corresponding to the linear magnetization regions54A1and54A2in the servo band SB2or a set of time-series pulse signals corresponding to the linear magnetization regions54B1and54B2in the servo band SB2.

The result of reading the servo pattern52in the servo band SB via the servo reading element SR2refers to, for example, a result of reading the linear magnetization regions54A1,54A2,54B1, and54B2included in one servo pattern52via the servo reading element SR2. Therefore, the result of reading the servo pattern52via the servo reading element SR2is obtained as a pulse signal group (hereinafter, also referred to as a “second pulse signal group”) consisting of 18 pulse signals corresponding to the linear magnetization regions54A1,54A2,54B1, and54B2.

In the example shown inFIG.11, the second pulse signal group is a set of time-series pulse signals corresponding to the linear magnetization regions54A1,54A2,54B1, and54B2in the servo band SB3. In addition, in the present embodiment, the second pulse signal group is the second servo band signal S2.

Here, as the second pulse signal group, a set of time-series pulse signals corresponding to the linear magnetization regions54A1,54A2,54B1, and54B2in the servo band SB3has been described, but this is merely an example. For example, the second pulse signal group may be a set of time-series pulse signals corresponding to the linear magnetization regions54A1and54A2in the servo band SB3or a set of time-series pulse signals corresponding to the linear magnetization regions54B1and54B2in the servo band SB3.

The first position detection device30B1acquires the first servo band signal S1, and the second position detection device30B2acquires the second servo band signal S2. In the example shown inFIG.11, the signal obtained by reading the servo band SB2via the servo reading element SR1is shown as an example of the first servo band signal S1, and the signal obtained by reading the servo band SB3via the servo reading element SR2is shown as an example of the second servo band signal S2. In the present embodiment, for convenience of description, in a case where the distinction is not specifically needed, the first servo band signal S1and the second servo band signal S2will be referred to as a “servo band signal” without being denoted by reference numerals.

Incidentally, in the magnetic tape drive14, the tracking control and off-track suppression control (hereinafter, also referred to as “various controls”) are performed. The off-track suppression control is control of suppressing the occurrence of the off-track. Examples of the off-track suppression control include skew control of skewing the magnetic head28. The skew control is an example of “skew processing” according to the technology of the present disclosure. In addition, as the off-track suppression control, tension control of controlling the tension applied to the magnetic tape MT may be performed in addition to the skew control.

The off-track suppression control is control performed based on a servo band interval SBP. Here, the servo band interval SBP refers to a distance along the width direction WD of the magnetic tape MT between a predetermined position in a certain servo band (for example, an upper end of the servo band as viewed from the paper surface side ofFIG.11) and a predetermined position in an adjacent servo band (for example, an upper end of the servo band as viewed from the paper surface side ofFIG.11). The servo band interval SBP is calculated based on the first servo band signal S1and the second servo band signal S2. Therefore, in a case where the servo band interval SBP varies for each individual magnetic tape MT, the calculation of the servo band interval SBP is affected by at least the variation in the servo band interval SBP, and the accuracy of various types of control (for example, the skew control) is also reduced accordingly.

The servo pattern52is recorded by a servo writer. Various servo writers are used for recording the servo pattern52, and there is a manufacturing error and/or an attachment error between the servo writers. The manufacturing error and/or the attachment error between the servo writers appear as a difference (for example, a tolerance) in the servo band interval SBP for each adjacent servo band (for example, the servo band SB2and the servo band SB3). As long as the servo band interval SBP can be determined for each adjacent servo band, it becomes possible to perform various types of control taking into consideration the differences in the servo band interval SBP.

Therefore, in view of such circumstances, in the magnetic tape system10, as shown inFIG.12as an example, the servo band signal is acquired on a BOT region31A of the magnetic tape MT. The BOT region31A is an example of a “reference region” according to the technology of the present disclosure. The example shown inFIG.12shows a state in which the magnetic head28is skewed on the BOT region31A of the magnetic tape MT around the rotation axis RA such that the imaginary straight line C3is inclined with respect to the imaginary straight line C1to the upstream side in the forward direction at an angle β (that is, an angle β counterclockwise as viewed from the paper surface side ofFIG.12). The angle β is an angle corresponding to an interval D (seeFIG.12) and is determined in advance as the skew angle on the BOT region31A. For example, the angle β is included in the management information13(seeFIG.2) and is acquired by the control device30. The control device30operates the inclination mechanism49(seeFIGS.5and10) to skew the magnetic head28on the BOT region31A such that the skew angle is the angle β. In a state in which the skew angle that is the angle β is maintained, the control device30acquires the first servo band signal S1from the servo reading element SR1and acquires the second servo band signal S2from the servo reading element SR2.

As shown inFIG.13as an example, the first position detection device30B1includes a first detection circuit39A and a second detection circuit39B. The first detection circuit39A and the second detection circuit39B are connected in parallel, and comprise an input terminal30B1aand an output terminal30B1bthat are common to each other. In the example shown inFIG.13, an aspect example is shown in which the first servo band signal S1is input to the input terminal30B1a. The first servo band signal S1includes a first linear magnetization region signal S1aand a second linear magnetization region signal S1b. The first linear magnetization region signal S1aand the second linear magnetization region signal S1bare servo pattern signals (that is, analog servo pattern signals) indicating the results of the reading via the servo reading element SR1(seeFIG.11). The same can be said about the second servo band signal S2(seeFIG.11) as about the first servo band signal S1. That is, the servo pattern signal includes the first linear magnetization region signal S1aand the second linear magnetization region signal S1b.

One ideal waveform signal66is stored in advance in the storage32, for each frame50. For example, the ideal waveform signal66is individually associated with each of all the frames50from the beginning to the end of the magnetic tape MT. In a case where the servo pattern52included in each frame50is read by the servo reading element SR from the beginning to the end of the magnetic tape MT, the first position detection device30B1acquires the ideal waveform signal66corresponding to each frame50from the storage32for each time the servo pattern52included in each frame50is read by the servo reading element SR (for example, in synchronization with a timing at which reading of the servo pattern52via the servo reading element SR is started), and uses the acquired ideal waveform signal66for comparison with the first servo band signal S1.

The ideal waveform signal66is a signal indicating an ideal waveform of a servo pattern signal (that is, an analog servo pattern signal) indicating the result of reading the servo pattern52(seeFIG.11) recorded in the servo band SB of the magnetic tape MT via the servo reading element SR. The ideal waveform signal66can be said to be a sample signal to be compared with the first servo band signal S1.

The ideal waveform signal66is classified into a first ideal waveform signal66A and a second ideal waveform signal66B. The first ideal waveform signal66A corresponds to a signal derived from the linear magnetization region54A2or54B2, that is, the second linear magnetization region signal S1b, and is a signal indicating an ideal waveform of the second linear magnetization region signal S1b. The second ideal waveform signal66B corresponds to a signal derived from the linear magnetization region54A1or54B1, that is, the first linear magnetization region signal S1a, and is a signal indicating an ideal waveform of the first linear magnetization region signal S1a.

More specifically, for example, the first ideal waveform signal66A is a signal indicating a single ideal waveform (that is, for one wavelength) included in the second linear magnetization region signal S1b(for example, an ideal signal that is a result of reading one of ideal magnetization straight lines included in the servo pattern52via the servo reading element SR). In addition, for example, the second ideal waveform signal66B is a signal indicating a single ideal waveform (that is, for one wavelength) included in the first linear magnetization region signal S1a(for example, an ideal signal that is a result of reading one of ideal magnetization straight lines included in the servo pattern52via the servo reading element SR).

The ideal waveform indicated by the first ideal waveform signal66A is a waveform determined in accordance with an orientation of the magnetic head28on the magnetic tape MT. A relative positional relationship between the holder44(seeFIG.10) of the magnetic head28and the servo reading element SR is fixed. Therefore, the ideal waveform indicated by the first ideal waveform signal66A can be said to be a waveform determined in accordance with the orientation of the servo reading element SR on the magnetic tape MT. For example, the ideal waveform indicated by the first ideal waveform signal66A is a waveform determined in accordance with the geometrical characteristics of the linear magnetization region54A2of the servo pattern52A (for example, the geometrical characteristics of the magnetization straight line54A2a) and the orientation of the magnetic head28on the magnetic tape MT.

As described above, since the relative positional relationship between the holder44(seeFIG.10) of the magnetic head28and the servo reading element SR is fixed, the ideal waveform indicated by the first ideal waveform signal66A can be said to be a waveform determined in accordance with the geometrical characteristics of the linear magnetization region54A2of the servo pattern52A (for example, the geometrical characteristics of the magnetization straight line54A2a) and the orientation of the servo reading element SR on the magnetic tape MT. Here, the orientation of the magnetic head28on the magnetic tape MT refers to, for example, an angle formed by the linear magnetization region54A2and the magnetic head28on the magnetic tape MT. In addition, the orientation of the servo reading element SR on the magnetic tape MT refers to, for example, an angle formed by the linear magnetization region54A2and the servo reading element SR on the magnetic tape MT.

The ideal waveform indicated by the first ideal waveform signal66A may be determined taking into account, in addition to the elements described above, the characteristics of the servo reading element SR itself (material, size, shape, and/or use history), the characteristics of the magnetic tape MT (material and/or use history), and/or the use environment of the magnetic head28.

Similarly to the ideal waveform indicated by the first ideal waveform signal66A, the ideal waveform indicated by the second ideal waveform signal66B is also a waveform determined in accordance with the orientation of the magnetic head28on the magnetic tape MT, that is, a waveform determined in accordance with the orientation of the servo reading element SR on the magnetic tape MT. For example, the ideal waveform indicated by the second ideal waveform signal66B is a waveform determined in accordance with the geometrical characteristics of the linear magnetization region54A1of the servo pattern52A (for example, the geometrical characteristics of the magnetization straight line54A1a) and the orientation of the magnetic head28on the magnetic tape MT, that is, a waveform determined in accordance with the geometrical characteristics of the linear magnetization region54A1of the servo pattern52A (for example, the geometrical characteristics of the magnetization straight line54A1a) and the orientation of the servo reading element SR on the magnetic tape MT. Here, the orientation of the magnetic head28on the magnetic tape MT refers to, for example, an angle formed by the linear magnetization region54A1and the magnetic head28on the magnetic tape MT. In addition, the orientation of the servo reading element SR on the magnetic tape MT refers to, for example, an angle formed by the linear magnetization region54A1and the servo reading element SR on the magnetic tape MT.

Similarly to the ideal waveform indicated by the first ideal waveform signal66A, the ideal waveform indicated by the second ideal waveform signal66B may also be determined taking into account, in addition to the elements described above, the characteristics of the servo reading element SR itself (material, size, shape, and/or use history), the characteristics of the magnetic tape MT (material and/or use history), and/or the use environment of the magnetic head28.

The first position detection device30B1acquires the first servo band signal S1, and compares the acquired first servo band signal S1with the ideal waveform signal66to detect a servo pattern signal S1A. In the example shown inFIG.12, the first position detection device30B1detects the servo pattern signal S1A by using the first detection circuit39A and the second detection circuit39B.

The first servo band signal S1is input to the first detection circuit39A via the input terminal30B1a. The first detection circuit39A detects the second linear magnetization region signal S1bfrom the input first servo band signal S1by using an autocorrelation coefficient.

The autocorrelation coefficient used by the first detection circuit39A is a coefficient indicating a degree of correlation between the first servo band signal S1and the first ideal waveform signal66A. The first detection circuit39A acquires the first ideal waveform signal66A from the storage32and compares the acquired first ideal waveform signal66A with the first servo band signal S1. Moreover, the first detection circuit39A calculates the autocorrelation coefficient based on the comparison result. The first detection circuit39A detects a position at which the correlation between the first servo band signal S1and the first ideal waveform signal66A is high (for example, a position at which the first servo band signal S1and the first ideal waveform signal66A match each other) on the servo band SB (for example, the servo band SB2shown inFIG.9) in accordance with the autocorrelation coefficient.

On the other hand, the first servo band signal S1is also input to the second detection circuit39B via the input terminal30B1a. The second detection circuit39B detects the first linear magnetization region signal S1afrom the input first servo band signal S1by using the autocorrelation coefficient.

The autocorrelation coefficient used by the second detection circuit39B is a coefficient indicating a degree of correlation between the first servo band signal S1and the second ideal waveform signal66B. The second detection circuit39B acquires the second ideal waveform signal66B from the storage32and compares the acquired second ideal waveform signal66B with the first servo band signal S1. Moreover, the second detection circuit39B calculates the autocorrelation coefficient based on the comparison result. The second detection circuit39B detects a position at which the correlation between the first servo band signal S1and the second ideal waveform signal66B is high (for example, a position at which the first servo band signal S1and the second ideal waveform signal66B match each other) on the servo band SB (for example, the servo band SB2shown inFIG.9) in accordance with the autocorrelation coefficient.

The first position detection device30B1detects the servo pattern signal S1A based on the detection result by the first detection circuit39A and the detection result by the second detection circuit39B. The first position detection device30B1outputs the servo pattern signal S1A from the output terminal30B1bto the control device30. The servo pattern signal S1A is a signal (for example, a digital signal) indicating a logical sum of the second linear magnetization region signal S1bdetected by the first detection circuit39A and the first linear magnetization region signal S1adetected by the second detection circuit39B.

In the example shown inFIG.13, the form example has been described in which the first position detection device30B1detects the servo pattern signal S1A by comparing the first servo band signal S1with the ideal waveform signal66, similarly, the second position detection device30B2also detects the servo pattern signal S2A by comparing the second servo band signal S2with the ideal waveform signal66, and outputs the detected servo pattern signal S2A to the control device30.

As shown inFIG.14as an example, the control device30executes PES calculation processing. In the PES calculation processing, the control device30calculates a PES based on the servo pattern signals S1A and S2A acquired from the position detection device30B. For example, the control device30calculates a first PES based on the first servo pattern signal S1A input from the first position detection device30B1. In addition, the control device30calculates a second PES based on the second servo pattern signal S2A input from the second position detection device30B2.

In the example shown inFIG.14, the first PES refers to a PES that is a signal indicating a position in the width direction WD in the servo pattern52on the servo band SB2where the servo reading element SR1is positioned. The second PES refers to a PES that is a signal indicating a position in the width direction WD in the servo pattern52on the servo band SB3where the servo reading element SR2is positioned. Hereinafter, in cases where the distinction is not specifically needed, the first PES and the second PES are referred to as a “PES”. The first PES is an example of a “first signal” according to the technology of the present disclosure, and the second PES is an example of a “second signal” according to the technology of the present disclosure.

The PES is calculated using Expression (1).

Here,α1 is an angle determined in advance as an angle formed by the imaginary straight line C1and the linear magnetization region54A1,α2 is an angle determined in advance as an angle formed by the imaginary straight line C1and the linear magnetization region54A2,d is a distance determined in advance as a distance in the longitudinal direction LD between the linear magnetization region54A1and the linear magnetization region54B1,Aiis a second distance, andBiis a first distance.

In Expression (1), “α1” is an angle determined in advance as an angle formed by the imaginary straight line C1and the linear magnetization region54A1. In Expression (1), “α2” is an angle determined in advance as an angle formed by the imaginary straight line C1and the linear magnetization region54A2. In the present embodiment, since the linear magnetization regions54A1and54A2are inclined line-symmetrically with respect to the imaginary straight line C1, “α1” and “α2” are equivalent.

In Expression (1), “i” is a natural number from 1 to 4. The maximum value of “i” (here, 4) is the number of the magnetization straight lines54A1aused for the measurement of the PES. In Expression (1), the second distance “Ai” refers to a distance between the magnetization straight line54A1aand the magnetization straight line54A2aat positions that correspond to each other in a case where the servo reading element SR crosses the servo pattern52A along the longitudinal direction LD. Here, the phrase “the magnetization straight line54A1aand the magnetization straight line54A2aat positions that correspond to each other” refers to first to fourth magnetization straight line pairs. The first magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54A2athat are positioned on the most upstream side in the running direction of the magnetic tape MT in the linear magnetization regions54A1and54A2. The second magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54A2athat are positioned second from the most upstream side to the downstream side in the running direction of the magnetic tape MT in the linear magnetization regions54A1and54A2. The third magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54A2athat are positioned third from the most upstream side to the downstream side in the running direction of the magnetic tape MT in the linear magnetization regions54A1and54A2. The fourth magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54A2athat are positioned fourth from the most upstream side to the downstream side in the running direction of the magnetic tape MT in the linear magnetization regions54A1and54A2.

In Expression (1), the first distance “Bi” refers to a distance between the magnetization straight line54A1aand the magnetization straight line54B1aat positions that correspond to each other in a case where the servo reading element SR crosses the servo pattern52A and the servo pattern52B that is adjacent to the servo pattern52A on the forward direction side along the longitudinal direction LD. Here, the phrase “the magnetization straight line54A1aand the magnetization straight line54B1aat positions that correspond to each other” refers to fifth to eighth magnetization straight line pairs. The fifth magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54B1athat are positioned on the most upstream side in the running direction of the magnetic tape MT in the linear magnetization region54A1in the servo pattern52A and the linear magnetization region54B1in the servo pattern52B that is adjacent to the servo pattern52A on the forward direction side. The sixth magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54B1athat are positioned second from the most upstream side to the downstream side in the running direction of the magnetic tape MT in the linear magnetization region54A1in the servo pattern52A and the linear magnetization region54B1in the servo pattern52B that is adjacent to the servo pattern52A on the forward direction side. The seventh magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54B1athat are positioned third from the most upstream side to the downstream side in the running direction of the magnetic tape MT in the linear magnetization region54A1in the servo pattern52A and the linear magnetization region54B1in the servo pattern52B that is adjacent to the servo pattern52A on the forward direction side. The eighth magnetization straight line pair refers to the magnetization straight line54A1aand the magnetization straight line54B1athat are positioned fourth from the most upstream side to the downstream side in the running direction of the magnetic tape MT in the linear magnetization region54A1in the servo pattern52A and the linear magnetization region54B1in the servo pattern52B that is adjacent to the servo pattern52A on the forward direction side.

In Expression (1), “d” is a distance determined in advance as a distance in the longitudinal direction LD between the linear magnetization region54A1and the linear magnetization region54B1. An example of “d” is a distance determined in advance as a distance between the magnetization straight line54A1aand the magnetization straight line54B1aat positions that correspond to each other in a case where the servo reading element SR crosses the servo patterns52A and52B along the longitudinal direction LD.

The control device30detects the position of the servo reading element SR1with respect to the servo band SB2based on the first PES. In addition, the control device30detects the position of the servo reading element SR2with respect to the servo band SB3based on the second PES. As a result, the control device30calculates the servo band interval SBP.

Incidentally, as described above, the servo band interval SBP is calculated in order to accurately position the data read/write element DRW with respect to the division data track. In other words, the servo band interval SBP is required for positioning for each division data track. For example, a method of storing a servo band interval used in the skew control in a case where the magnetic processing is performed on each division data track in a memory (for example, the storage32(seeFIG.3) or the cartridge memory24(seeFIG.2)) in advance for each division data track is considered. However, in a case where the servo band interval for each division data track is stored in the memory, the storage capacity of the memory is strained as the number of the division data tracks in each data band DB increases.

Therefore, as shown inFIG.15as an example, the control device30performs servo band interval calculation processing. In the servo band interval calculation processing, the control device30calculates the servo band interval by using the first PES and the second PES calculated in the PES calculation processing as described above. Here, the servo band interval is calculated for a specific section along the running direction of the magnetic tape MT in the BOT region31A (hereinafter, also simply referred to as a “specific section”) in units of the data band DB. The calculated servo band interval is used in the skew control in a case where the magnetic processing is performed on each of the processing target division data tracks.

Here, the specific section refers to, for example, a partial section of the BOT region31A of the magnetic tape MT (that is, a partial section of the magnetic tape MT along the running direction). Examples of the partial section of the magnetic tape MT include a section included in the first half of the BOT region31A of the magnetic tape MT, a section included in the second half of the BOT region31A of the magnetic tape MT, a section included in the middle of the BOT region31A of the magnetic tape MT, and an intermittent section along the entire length direction of the BOT region31A of the magnetic tape MT. The intermittent section refers to, for example, equally spaced sections or non-equally spaced sections. In addition, a time interval in which the servo band interval is calculated is, for example, a certain time interval (for example, a sampling period determined in accordance with a clock frequency).

In average value calculation processing, the control device30calculates a value obtained by statistically processing the calculation results obtained in the servo band interval calculation processing. Here, the value obtained by statistically processing the calculation results in the servo band interval calculation processing refers to, for example, an average value. Here, the calculation results in the servo band interval calculation processing are an example of “results of measuring an interval between the first servo pattern and the second servo pattern for each of the division areas in a case where the magnetic tape is run” according to the technology of the present disclosure and “results of measuring an interval between the first servo pattern and the second servo pattern in a partial section of the division areas along a running direction of the magnetic tape for each of the division areas in a case where the magnetic tape is run” according to the technology of the present disclosure.

In the average value calculation processing, the control device30calculates a servo band average interval for each data band DB based on the calculation result from the servo band interval calculation processing. The servo band average interval is an average value of the servo band intervals SBP calculated in the servo band interval calculation processing for each processing target division data track for the specific section. In addition, here, the servo band average interval is an example of an “average value of results of measuring an interval between the first servo pattern and the second servo pattern for each of the division areas” according to the technology of the present disclosure.

The servo band average interval is an example of a representative interval between the first servo pattern, which is the servo pattern52in the first servo band (that is, one servo band SB) of the pair of servo bands SB adjacent to each other via the data band DB, and the second servo pattern, which is the servo pattern52in the second servo band (that is, the other servo band SB) of the pair of servo bands SB adjacent to each other via the data band DB.

In the example shown inFIG.15, a first average interval and a second average interval are shown as an example of the servo band average interval calculated for each data band DB. The first average interval is an example of a representative interval between the servo pattern52in the servo band SB1(seeFIG.7) and the servo pattern52in the servo band SB2(seeFIG.7). The second average interval is an example of a representative interval between the servo pattern52in the servo band SB2(seeFIG.7) and the servo pattern52in the servo band SB3(seeFIG.7).

In the average value calculation processing, the control device30calculates the average value of the servo band intervals used in the tracking control in a case where the magnetic processing is performed on each processing target division data track in the data band DB1for the specific section, as the first average interval. The first average interval is commonly used for each division data track included in the data band DB1as a servo band interval used for the skew control in a case where the magnetic processing is performed on each division data track included in the data band DB1designated as the processing target data band.

In the average value calculation processing, the control device30calculates the average value of the servo band intervals used in the tracking control in a case where the magnetic processing is performed on each processing target division data track in the data band DB2for the specific section, as the second average interval. The second average interval is commonly used for each division data track included in the data band DB2as a servo band interval used for the skew control in a case where the magnetic processing is performed on each division data track included in the data band DB2designated as the processing target data band.

In the example shown inFIG.15, the average value is shown as the representative interval of the servo band interval SBP for each data band DB, but this is merely an example. The representative interval of the servo band interval SBP for each data band DB may be a statistical value such as a median, a mode, a maximum value, or a minimum value.

As shown inFIG.16as an example, the front surface31of the magnetic tape MT is roughly divided into the BOT region31A and a non-BOT region31B. The non-BOT region31B refers to a region other than the BOT region31A in the front surface31. In the present embodiment, the BOT region31A is an example of a “storage medium”, a “BOT region”, and a “partial region of the magnetic tape” according to the technology of the present disclosure. The control device30performs BOT region processing and non-BOT region processing in a state in which the magnetic tape MT is running in one direction (for example, in the forward direction) at a constant speed. The BOT region processing is performed on the BOT region31A in a state in which the magnetic head28is skewed at the angle β as described above. The non-BOT region processing is performed on the non-BOT region31B in a state in which the magnetic head28is skewed at the angle β.

In the BOT region processing, the control device30calculates the first PES and the second PES in the BOT region31A. The control device30calculates a first servo band interval SBP1from the calculated first PES and second PES. The first servo band interval SBP1is the servo band interval SBP in the BOT region31A. For example, the first servo band interval SBP1is a first average interval SBP1aand a second average interval SBP1bfor each data band DB in the BOT region31A, as the servo band interval in the BOT region31A.

In the non-BOT region processing, the control device30calculates the first PES and the second PES in the non-BOT region31B. The control device30calculates a second servo band interval SBP2from the calculated first PES and second PES. The second servo band interval SBP2is the servo band interval SBP in the non-BOT region31B. For example, the second servo band interval SBP2is a first average interval SBP2aand a second average interval SBP2bfor each data band DB in the non-BOT region31B, as the servo band interval in the non-BOT region31B.

The control device30calculates a difference64between the first servo band interval SBP1and the second servo band interval SBP2. The difference64is a difference between the servo band interval SBP for each data band DB included in the first servo band interval SBP1and the servo band interval SBP for each data band DB included in the second servo band interval SBP2. For example, the control device30calculates a first difference64athat is a difference between the first average interval SBP1aand the first average interval SBP2a(that is, a difference between an average value of the servo band interval SBP of the data band DB1in the BOT region31A and an average value of the servo band interval SBP of the data band DB1in the non-BOT region31B). In addition, the control device30calculates a second difference64bthat is a difference between the second average interval SBP1band the second average interval SBP2b(that is, a difference between an average value of the servo band interval SBP of the data band DB2in the BOT region31A and an average value of the servo band interval SBP of the data band DB2in the non-BOT region31B).

An example of the first difference64ais a value obtained by subtracting the first average interval SBP2afrom the first average interval SBP1a. Note that this is merely an example, and the first difference64amay be a value obtained by subtracting the first average interval SBP1afrom the first average interval SBP2a. In addition, the first difference64amay be a proportion of the first average interval SBP1ato the first average interval SBP2a, or a proportion of the first average interval SBP2ato the first average interval SBP1a. As described above, a difference degree between the first average interval SBP1aand the first average interval SBP2amay be any value as long as the difference degree can be specified. In addition, similarly to the first difference64a, the second difference64bmay be any value as long as a difference degree between the second average interval SBP1band the second average interval SBP2bcan be specified.

As shown inFIG.17as an example, the control device30performs the skew control based on the first servo band interval SBP1and the second servo band interval SBP2. For example, the control device30performs the skew control by using the difference64obtained from the first servo band interval SBP1and the second servo band interval SBP2. The skew control is implemented by operating the inclination mechanism49such that an angle formed by the imaginary straight line C1and the imaginary straight line C2is an angle θ determined from the difference64.

In addition, the control device30may perform the tension control based on the first servo band interval SBP1and the second servo band interval SBP2. The tension control is implemented by operating the feeding motor36and the winding motor40such that the rotation speed, the rotation torque, and the like of each of the feeding motor36and the winding motor40are the rotation speed, the rotation torque, and the like uniquely determined from the servo band interval SBP adjusted by using the difference64.

In addition, the control device30performs various types of control based on the result (that is, the servo pattern signals S1A and S2A) of the position detection by the position detection device30B. For example, the control device30performs the tracking control based on the result of the position detection by the position detection device30B. That is, the control device30adjusts the position of the magnetic head28by operating the moving mechanism48based on the result of the position detection by the position detection device30B.

In the present embodiment, the form example has been described in which the first linear magnetization region signal S1aand the second linear magnetization region signal S1bare detected by using the autocorrelation coefficient, but the technology of the present disclosure is not limited to this, and the first linear magnetization region signal S1aand the second linear magnetization region signal S1bmay be detected by using a plurality of threshold values. Examples of the plurality of threshold values include a first threshold value and a second threshold value. A magnitude relationship between the first threshold value and the second threshold value is “first threshold value>second threshold value”. The first threshold value is a value derived in advance based on an amplitude expected as the amplitude of the waveform of the second linear magnetization region signal S1b, and is used to detect the second linear magnetization region signal S1b. The second threshold value is a value derived in advance based on an amplitude expected as the amplitude of the waveform of the first linear magnetization region signal S1aand the amplitude expected as the amplitude of the waveform of the second linear magnetization region signal S1b. The first threshold value and the second threshold value are used to detect the first linear magnetization region signal S1a.

Next, the action of the magnetic tape system10will be described with reference toFIGS.18and19.

FIGS.18and19show an example of a flow of control processing executed by the control device30in a case where the magnetic tape MT runs in the forward direction from the BOT region31A to an EOT region (not shown). The control processing is an example of “signal processing” according to the technology of the present disclosure. The control processing includes the BOT region processing and the non-BOT region processing. The flow of the flowchart shown inFIGS.18and19is an example of a “signal processing method” according to the technology of the present disclosure.

In step ST10shown inFIG.18, the control device30determines whether or not the BOT region31A is running on the magnetic head28. In step ST10, in a case where the BOT region31A is not running on the magnetic head28, a negative determination is made, and the determination in step ST10is made again. In step ST10, in a case where the BOT region31A is running on the magnetic head28, a positive determination is made, and the control processing proceeds to step ST12.

In step ST12, the control device30acquires the first servo band signal S1from the servo reading element SR1, and acquires the second servo band signal S2from the servo reading element SR2. After executing the processing of step ST12, the control processing proceeds to step ST14.

In step ST14, the control device30generates the first servo pattern signal S1A from the first servo band signal S1acquired in step ST12, and generates the second servo pattern signal S2A from the second servo band signal S2. After executing the processing of step ST14, the control processing proceeds to step ST16.

In step ST16, the control device30calculates the first PES from the first servo pattern signal S1A generated in step ST14, and calculates the second PES from the second servo pattern signal S2A generated in step ST14. After executing the processing of step ST16, the control processing proceeds to step ST18.

In step ST18, the control device30calculates the servo band interval SBP for each processing target division data track for the specific section along the running direction of the magnetic tape MT, from the first PES and the second PES calculated in step ST16. After executing the processing of step ST18, the control processing proceeds to step ST20.

In step ST20, the control device30calculates the average interval between adjacent servo bands for each data band DB (for example, the first average interval SBP1aand the second average interval SBP1b) from the servo band interval SBP calculated in step ST18. After executing the processing of step ST20, the control processing proceeds to step ST22.

In step ST22, the control device30determines whether or not the non-BOT region31B is present on the magnetic head28. In step ST22, in a case where the non-BOT region31B is not present on the magnetic head28, a negative determination is made, and the determination in step ST22is made again. In step ST22, in a case where the non-BOT region31B is present on the magnetic head28, a positive determination is made, and the control processing proceeds to step ST24.

In step ST24, the control device30determines whether or not a timing for acquiring the servo band signal (hereinafter, referred to as a “servo band signal acquisition timing”) has arrived. A first example of the servo band signal acquisition timing is a timing at which the beginning of the frame50reaches over the magnetic element unit42. As a second example of the servo band signal acquisition timing is a timing at which the beginning of the frame50reaches on the magnetic element unit42after a predetermined number of frames50(for example, a predetermined number within a range of tens to tens of millions) pass over the magnetic element unit42. A third example of the servo band signal acquisition timing is a timing at which a certain time (for example, a time determined within a range of several milliseconds to several minutes) has elapsed since the processing of step ST24is started.

In step ST24, in a case where the servo band signal acquisition timing has not arrived, a negative determination is made, and the control processing proceeds to step ST40. In step ST24, in a case where the servo band signal acquisition timing has arrived, a positive determination is made, and the control processing proceeds to step ST26.

In step ST26, the control device30acquires the first servo band signal S1from the servo reading element SR1, and acquires the second servo band signal S2from the servo reading element SR2. After executing the processing of step ST26, the control processing proceeds to step ST28.

In step ST28, the control device30generates the first servo pattern signal S1A from the first servo band signal S1acquired in step ST26, and generates the second servo pattern signal S2A from the second servo band signal S2. After executing the processing of step ST28, the control processing proceeds to step ST30.

In step ST30, the control device30calculates the first PES from the first servo pattern signal S1A generated in step ST28, and calculates the second PES from the second servo pattern signal S2A generated in step ST28. After executing the processing of step ST28, the control processing proceeds to step ST32.

In step ST32, the control device30calculates the servo band interval SBP for each processing target division data track for the specific section along the running direction of the magnetic tape MT, from the first PES and the second PES calculated in step ST30. After executing the processing of step ST32, the control processing proceeds to step ST34.

In step ST34shown inFIG.19, the control device30calculates the average interval between adjacent servo bands for each data band DB (for example, the first average interval SBP2aand the second average interval SBP2b) from the servo band interval SBP calculated in step ST32. After executing the processing of step ST34, the control processing proceeds to step ST36.

In step ST36, the control device30calculates the difference64between the first servo band interval SBP1calculated in step ST20and the second servo band interval SBP2calculated in step ST34. After executing the processing of step ST36, the control processing proceeds to step ST38.

In step ST38, the control device30performs the skew control by using the difference64calculated in step ST38. The skew control is implemented by operating the inclination mechanism49such that an angle formed by the imaginary straight line C1and the imaginary straight line C2is an angle θ determined from the difference64. After executing the processing of step ST38, the control processing proceeds to step ST40.

In step ST40, the control device30determines whether or not a condition for ending the control processing (hereinafter, referred to as an “end condition”) is satisfied. A first example of the end condition is a condition that an instruction to end the control processing is received by the UI system device34. A second example of the end condition is a condition that the number of the frames50passing over the magnetic element unit42has reached a predetermined number (for example, a number determined within a range of several to tens of thousands). A third example of the end condition is a condition that a predetermined time (for example, a time designated in advance) has elapsed since the execution of the control processing is started. In step ST40, in a case where the end condition is not satisfied, a negative determination is made, and the control processing proceeds to step ST24. In step ST40, in a case where the end condition is satisfied, a positive determination is made, and the control processing ends.

Here, the form example has been described in which the first servo band interval SBP1is calculated on the BOT region31A (see steps ST12to ST20), but this is merely an example. For example, in a case where the first servo band interval SBP1is already stored in the storage medium such as the cartridge memory24and/or the BOT region31A, the processing of steps ST12to ST20may be replaced with the processing of “reading out the first servo band interval SBP1from the storage medium”.

As described above, in the magnetic tape system10, the magnetic head28of the magnetic tape drive14is provided with the servo reading elements SR1and SR2. The servo reading element SR1corresponds to the servo band SB2, and the servo reading element SR2corresponds to the servo band SB3. The servo reading element SR1outputs the first servo band signal S1by reading the servo pattern52from the servo band SB2, and the servo reading element SR2outputs the second servo band signal S2by reading the servo pattern52from the servo band SB3.

The skew control performed by control device30is based on the first servo band signal S1and the second servo band signal S2. Therefore, in a case where there is a variation in the servo band interval SBP for each data band because of design tolerances of the servo band interval SBP, the accuracy of the skew control is reduced by at least the variation in the servo band interval SBP.

In the present configuration, the servo reading element SR1on the reference region outputs the first servo band signal S1by reading the servo pattern52from the servo band SB2, and the servo reading element SR2on the reference region outputs the second servo band signal S2by reading the servo pattern52from the servo band SB3. The servo band interval SBP is calculated based on the first PES and the second PES. Then, the skew control is performed based on the servo band interval SBP. Therefore, with the present configuration, the skew control taking into consideration the servo band interval SBP for each of the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT is implemented.

For example, in the magnetic tape, highly accurate skew control is implemented by taking into consideration the servo band interval SBP for each of the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT, as compared with a case where the skew control is performed by always applying a constant servo band interval SBP to all pairs of servo bands SB.

In addition, in the magnetic tape system10, a method of storing the servo band interval SBP used in the skew control in a case of performing the magnetic processing on each division data track in advance in a memory (for example, the storage32(seeFIG.3) or the cartridge memory24(seeFIG.2)) for each division data track is considered. However, in a case where the servo band interval SBP for each division data track is stored in the memory, the storage capacity of the memory is strained as the number of the division data tracks in each data band increases.

Therefore, in the present embodiment, as the servo band interval SBP used for the skew control, a representative interval between the servo pattern52in one servo band SB of the pair of servo bands SB adjacent to each other via the data band DB and the servo pattern52in the other servo band SB is used. The representative interval is commonly used for all the division data tracks in the data band DB.

Therefore, with the present configuration, a degree of pressure with respect to the storage capacity of the memory caused by the servo band interval SBP used in a case where the skew control is performed can be reduced. For example, the degree of pressure on the storage capacity of the memory can be reduced as compared with a method in which the servo band interval SBP is stored in the memory (for example, the storage32) for each division data track and each time the magnetic processing is performed on the division data track, the servo band interval SBP corresponding to the division data track to be subjected to the magnetic processing is acquired from the memory.

In addition, in the magnetic tape system10, in a case where the magnetic tape MT is caused to run in a stage before the magnetic processing is performed on the data band DB, a value (for example, an average value) obtained by statistically processing the results of measuring the servo band interval SBP for each of the division data tracks included in the data band DB is used as the servo band interval SBP in a case where the skew control is performed. Therefore, with the present configuration, it is possible to reduce the amount of data used for the skew control for each data band DB as compared with a case where the actual measured value of the servo band interval SBP for each division data track is used.

In addition, in the magnetic tape system10, in a case where the magnetic tape MT is caused to run in a stage before the magnetic processing is performed on the data band DB, a value obtained by statistically processing the results of measuring the servo band interval SBP in a partial section along the running direction of the magnetic tape MT for each division data track included in the data band DB is used as the servo band interval SBP used in a case where the skew control is performed. Therefore, with the present configuration, it is possible to reduce the amount of data used for the skew control for each data band DB as compared with a case where the servo band interval SBP is measured in the entire section of the magnetic tape MT along the running direction.

In addition, in the magnetic tape system10, the representative interval is an average value of results of measuring the interval between the first servo pattern and the second servo pattern for each of the division data tracks in a case where the magnetic tape MT is run. Therefore, with the present configuration, it is possible to reduce the amount of data used for the skew control for each data band DB as compared with a case where the actual measured value of the servo band interval SBP for each division data track is used as the servo band interval SBP.

In addition, in the magnetic tape system10, the servo reading element SR1on the BOT region31A outputs the first servo band signal S1by reading the servo pattern52from the servo band SB2. In addition, the servo reading element SR2on the BOT region31A outputs the second servo band signal S2by reading the servo pattern52from the servo band SB3. The servo band interval SBP is calculated based on the first PES and the second PES. Then, the skew control is performed based on the servo band interval SBP. Therefore, with the present configuration, the skew control taking into consideration the variation in the servo band interval SBP inherent to the magnetic tape MT (for example, the variation in the servo band interval SBP due to the tolerance) is implemented.

The servo band interval SBP in the BOT region31A reflects the servo band interval SBP in the magnetic tape MT. That is, the variation in the servo band interval SBP in the BOT region31A reflects the variation in the servo band interval SBP inherent to the magnetic tape MT. Therefore, the servo band interval SBP inherent to the magnetic tape MT can be obtained by obtaining the servo band interval SBP based on the servo band signal derived from the reading result of the servo band SB in the BOT region31A. Further, by performing the skew control based on the servo band interval SBP, the skew control taking into consideration the variation in the servo band interval SBP is implemented. As a result, the highly accurate skew control taking into consideration the servo band interval SBP for each of the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT is implemented.

In the above-described embodiment, the form example has been described in which the specific section along the running direction of the magnetic tape MT in the BOT region31A is a partial section of the magnetic tape MT in the BOT region31A, but the technology of the present disclosure is not limited to this. For example, the specific section may be the entire section in the BOT region31A of the magnetic tape MT.

As described above, in the magnetic tape system10, in a case where the magnetic tape MT is caused to run in a stage before the magnetic processing is performed on the data band DB, a value obtained by statistically processing the results of measuring the servo band interval SBP in the entire section along the running direction of the magnetic tape MT for each division data track included in the data band DB is used as the servo band interval SBP used in a case where the skew control is performed. Therefore, with the present configuration, it is possible to improve the accuracy of data used for the skew control for each data band DB as compared with a case where the servo band interval SBP is measured only in a partial section of the magnetic tape MT along the running direction.

First Modification Example

In the above-described embodiment, the form example has been described in which the control device30performs the skew control based on the first servo band interval SBP1and the second servo band interval SBP2, but the technology of the present disclosure is not limited to this. In this first modification example, as shown inFIG.20as an example, at least the first servo band interval SBP1among the first servo band interval SBP1, the second servo band interval SBP2, and the difference64is stored in the storage medium, such as the storage32, the cartridge memory24, the BOT region31A, and/or an EOT region31C, as a signal by the control device30. In this case, the skew control is implemented by referring to the signal stored in the storage medium. Examples of the values of the first servo band interval SBP1, the second servo band interval SBP2, and the difference64stored in the storage medium include values calculated in a case of the initial use of the magnetic tape cartridge12.

As described above, in the magnetic tape system10, a signal indicating the first servo band interval SBP1is stored in the storage medium, such as the storage32, the cartridge memory24, the BOT region31A, and/or the EOT region31C. The control device30reads out the stored first servo band interval SBP1. Further, the control device30performs the skew control by using the read-out first servo band interval SBP1. Therefore, with the present configuration, the skew control taking into consideration the servo band interval for each of the servo bands adjacent to each other in the width direction WD of the magnetic tape MT is implemented.

In addition, in the magnetic tape system10, a signal indicating the first servo band interval SBP1is stored in the cartridge memory24as the storage medium. Therefore, with the present configuration, it is easier to store a signal indicating the first servo band interval SBP1as compared with a case where a separate recording medium is provided.

In addition, in the magnetic tape system10, a signal indicating the first servo band interval SBP1is stored in the BOT region31A and/or the EOT region31C as the storage medium. Therefore, with the present configuration, it is easier to store a signal indicating the first servo band interval SBP1as compared with a case where a separate recording medium is provided.

In addition, at least the first servo band interval SBP1among the first servo band interval SBP1, the second servo band interval SBP2, and the difference64may be output to a display and/or a speaker. In this case, the servo band interval SBP between the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT can be perceived by the user or the like.

Second Modification Example

In the above-described embodiment, the form example has been described in which the off-track suppression control is performed based on the difference64obtained from the first servo band interval SBP1and the second servo band interval SBP2, but the technology of the present disclosure is not limited to this. For example, the technology of the present disclosure can also be applied in a case where the servo writer SW records the servo pattern52in the servo band SB of the magnetic tape MT. In the example shown inFIG.21, the servo writer SW comprises a feeding reel SW1, a winding reel SW2, a driving device SW3, a pulse signal generator SW4, a servo writer controller SW5, a plurality of guides SW6, a transport passage SW7, a servo pattern recording head WH, and a verification head VH. The servo writer controller SW5incorporates a device corresponding to the controller25described above.

In a servo pattern recording step, the servo writer SW is used. The servo writer SW comprises a feeding reel SW1, a winding reel SW2, a driving device SW3, a pulse signal generator SW4, a servo writer controller SW5, a plurality of guides SW6, a transport passage SW7, a servo pattern recording head WH, and a verification head VH. The servo writer controller SW5incorporates a device corresponding to the controller25(seeFIG.3) described above.

The servo writer controller SW5controls the entirety of the servo writer SW. In the present embodiment, the servo writer controller SW5is implemented by an ASIC, but the technology of the present disclosure is not limited to this. For example, the servo writer controller SW5may be implemented by an FPGA and/or a PLC. In addition, the servo writer controller SW5may be implemented by the computer including a CPU, a flash memory (for example, an EEPROM and/or an SSD), and a RAM. In addition, the servo writer controller SW5may be implemented by combining two or more of an ASIC, an FPGA, a PLC, and a computer. That is, the servo writer controller SW5may be implemented by a combination of a hardware configuration and a software configuration.

A pancake is set in the feeding reel SW1. The pancake refers to a large-diameter roll in which the magnetic tape MT cut into a product width from a wide web raw material before writing the servo pattern52is wound around a hub.

The driving device SW3has a motor (not shown) and a gear (not shown), and is mechanically connected to the feeding reel SW1and the winding reel SW2. In a case where the magnetic tape MT is wound by the winding reel SW2, the driving device SW3generates power in accordance with instructions from the servo writer controller SW5, and transmits the generated power to the feeding reel SW1and the winding reel SW2to rotate the feeding reel SW1and the winding reel SW2. That is, the feeding reel SW1receives the power from the driving device SW3and rotates to feed the magnetic tape MT to the predetermined transport passage SW7. The winding reel SW2receives the power from the driving device SW3and rotates to wind the magnetic tape MT fed from the feeding reel SW1. The rotation speed, the rotation torque, and the like of the feeding reel SW1and the winding reel SW2are adjusted in accordance with a speed at which the magnetic tape MT is wound around the winding reel SW2. The rotation speed, rotation torque, and the like of the feeding reel SW1and the winding reel SW2may be adjusted in the same manner as in the tension control in the above-described embodiment.

The plurality of guides SW6and the servo pattern recording head WH are disposed on the transport passage SW7. The servo pattern recording head WH is disposed on the front surface31side of the magnetic tape MT between the plurality of guides SW6. The magnetic tape MT fed from the feeding reel SW1to the transport passage SW7is guided by the plurality of guides SW6and is wound by the winding reel SW2via the servo pattern recording head WH.

In the servo pattern recording step, the pulse signal generator SW4generates a pulse signal under the control of the servo writer controller SW5, and supplies the generated pulse signal to the servo pattern recording head WH. In a state in which the magnetic tape MT runs on the transport passage SW7at a constant speed, the servo pattern recording head WH records the servo pattern52on the servo band SB in response to the pulse signal supplied from the pulse signal generator SW4. As a result, for example, the plurality of servo patterns52are recorded on the servo band SB of the magnetic tape MT over the total length of the magnetic tape MT (seeFIGS.6to9).

In a case where the servo band SB is recorded by the servo pattern recording head WH, the servo band interval may be adjusted by using the first servo band interval SBP1and the second servo band interval SBP2. For example, during a period in which the servo pattern52is recorded in the BOT region31A, the servo band SB is recorded using the first servo band interval SBP1. In addition, for example, during a period in which the servo pattern52is recorded in the non-BOT region31B, the servo band SB is recorded using the second servo band interval SBP2. As a result, it is possible to suppress the variation in the servo band interval SBP, which is determined by recording the servo pattern52on the servo band SB, between the servo writers SW as compared with a case where the servo band interval SBP is not adjusted.

A manufacturing process of the magnetic tape MT includes a plurality of steps in addition to the servo pattern recording step. The plurality of steps include an inspection step and a winding step.

For example, the inspection step is a step of inspecting the servo band SB formed on the front surface31of the magnetic tape MT by the servo pattern recording head WH. The inspection of the servo band SB refers to, for example, processing of determining whether the servo pattern52recorded on the servo band SB is correct or not. The determination of the correctness of the servo pattern52refers to, for example, a determination (that is, verification of the servo pattern52) whether or not the servo patterns52A and52B are recorded in a predetermined portion of the front surface31without excess or deficiency of the magnetization straight lines54A1a,54A2a,54B1a, and54B2aand within an allowable error.

The inspection step is performed by using the servo writer controller SW5and the verification head VH. The verification head VH is disposed on the downstream side of the servo pattern recording head WH in a transport direction of the magnetic tape MT. In addition, similarly to the magnetic head28, the verification head VH includes a plurality of servo reading elements (not shown), and the plurality of servo bands SB are read by the plurality of servo reading elements. In this case, the skew control, the tracking control, and the tension control may be performed in the same manner as described in the embodiment.

The verification head VH is connected to the servo writer controller SW5. The verification head VH is disposed at a position facing the servo band SB as viewed from the front surface31side of the magnetic tape MT (that is, a rear surface side of the verification head VH), and reads the servo pattern52recorded on the servo band SB and outputs the reading result (hereinafter, referred to as “servo pattern reading result”) to the servo writer controller SW5. The servo writer controller SW5inspects the servo band SB (for example, determines whether the servo pattern52is correct or not) based on the servo pattern reading result (for example, the servo pattern signal) input from the verification head VH. For example, since the servo writer controller SW5incorporates the device corresponding to the controller25(seeFIG.3) described above, the servo writer controller SW5acquires a position detection result from the servo pattern reading result, and inspects the servo band SB by determining whether the servo pattern52is correct or not by using the position detection result.

Here, the servo writer controller SW5performs, for example, servo pattern detection processing to acquire the position detection result from the servo pattern reading result. The ideal waveform signal66used in the servo pattern detection processing by the servo writer controller SW5is the ideal waveform signal66stored in the storage (not shown) in the servo writer controller SW5.

The servo writer controller SW5outputs information indicating the result obtained by inspecting the servo band SB (for example, the result obtained by determining whether the servo pattern52is correct or not) to a predetermined output destination (for example, a storage, a display, a tablet terminal, a personal computer, and/or a server).

For example, in a case where the inspection step is ended, the winding step is then performed. The winding step is a step of winding the magnetic tape MT around the feeding reel22(that is, the feeding reel22(seeFIGS.2to4) accommodated in the magnetic tape cartridge12(seeFIGS.1to4)) used for each of a plurality of the magnetic tape cartridges12(seeFIGS.1to4). In the winding step, the winding motor (not shown) is used. The winding motor is mechanically connected to the feeding reel22via a gear and the like. The winding motor rotates the feeding reel22by applying a rotation force to the feeding reel22under the control of a processing device (not shown). The magnetic tape MT wound around the winding reel SW2is wound around the feeding reel22by the rotation of the feeding reel22. In the winding step, a cutting device (not shown) is used. In a case where a required amount of the magnetic tape MT is wound around the feeding reel22for each of the plurality of feeding reels22, the magnetic tape MT fed from the winding reel SW2to the feeding reel22is cut by the cutting device.

In addition, for example, as shown inFIG.21, in a manufacturing stage of the magnetic tape cartridge12, at least the first servo band interval SBP1among the first servo band interval SBP1, the second servo band interval SBP2, and the difference64may be stored in the storage medium, such as the storage32, the cartridge memory24, and/or the BOT region31A, as a signal by the control device30.

In the above description, the servo pattern52has been described as an example, but the servo pattern52is merely an example, and the technology of the present disclosure is established even in a case where other types of servo patterns (that is, servo patterns having the geometrical characteristics different from the geometrical characteristics of the servo pattern52) are used. In the following third modification example to tenth modification example, an aspect example of the magnetic tape MT on which a servo pattern of a type different from that of the servo pattern52is recorded will be described.

Third Modification Example

As shown inFIG.22as an example, the magnetic tape MT according to this third modification example is different from the magnetic tape MT shown inFIG.6in that a frame51is provided instead of the frame50. The frame51is defined by a set of servo patterns53. A plurality of servo patterns53are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns53are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of servo patterns52recorded on the magnetic tape MT shown inFIG.6.

In the example shown inFIG.22, servo patterns53A and53B are shown as an example of the set of servo patterns53included in the frame51. The servo patterns53A and53B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern53A is positioned on the upstream side in the forward direction and the servo pattern53B is positioned on the downstream side in the forward direction in the frame51.

The servo pattern53consists of a linear magnetization region pair60. The linear magnetization region pair60is classified into a linear magnetization region pair60A and a linear magnetization region pair60B.

The servo pattern53A consists of the linear magnetization region pair60A. In the example shown inFIG.22, a pair of linear magnetization regions60A1and60A2is shown as an example of the linear magnetization region pair60A. Each of the linear magnetization regions60A1and60A2is a linearly magnetized region.

The linear magnetization regions60A1and60A2are inclined in opposite directions with respect to the imaginary straight line C1. The linear magnetization regions60A1and60A2are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C1. The linear magnetization region60A1has a steeper inclined angle with respect to the imaginary straight line C1than the linear magnetization region60A2. Here, the term “steep” refers to that, for example, an angle of the linear magnetization region60A1with respect to the imaginary straight line C1is smaller than an angle of the linear magnetization region60A2with respect to the imaginary straight line C1. In addition, a total length of the linear magnetization region60A1is shorter than a total length of the linear magnetization region60A2.

In the servo pattern53A, a plurality of magnetization straight lines60A1aare included in the linear magnetization region60A1, and a plurality of magnetization straight lines60A2aare included in the linear magnetization region60A2. The number of the magnetization straight lines60A1aincluded in the linear magnetization region60A1is the same as the number of the magnetization straight lines60A2aincluded in the linear magnetization region60A2.

The linear magnetization region60A1is a set of magnetization straight lines60A1a, which are five magnetized straight lines, and the linear magnetization region60A2is a set of magnetization straight lines60A2a, which are five magnetized straight lines. In the servo band SB, positions of both ends of the linear magnetization region60A1(that is, positions of both ends of each of the five magnetization straight lines60A1a) and positions of both ends of the linear magnetization region60A2(that is, positions of both ends of each of the five magnetization straight lines60A2a) are aligned in the width direction WD. Here, the example has been described in which the positions of both ends of each of the five magnetization straight lines60A1aand the positions of both ends of each of the five magnetization straight lines60A2aare aligned, but this is merely an example, and the positions of both ends of one or more magnetization straight lines60A1aamong the five magnetization straight lines60A1aand the positions of both ends of one or more magnetization straight lines60A2aamong of the five magnetization straight lines60A2aneed only be aligned. In addition, in the present embodiment, the concept of “aligned” also includes meaning of “aligned” including an error generally allowed in the technical field to which the technology of the present disclosure belongs, which is the error to the extent that it does not contradict the purpose of the technology of the present disclosure, in addition to the meaning of being exactly aligned.

The servo pattern53B consists of the linear magnetization region pair60B. In the example shown inFIG.22, a pair of linear magnetization regions60B1and60B2is shown as an example of the linear magnetization region pair60B. Each of the linear magnetization regions60B1and60B2is a linearly magnetized region.

The linear magnetization regions60B1and60B2are inclined in opposite directions with respect to the imaginary straight line C2. The linear magnetization regions60B1and60B2are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C2. The linear magnetization region60B1has a steeper inclined angle with respect to the imaginary straight line C2than the linear magnetization region60B2. Here, the term “steep” refers to that, for example, an angle of the linear magnetization region60B1with respect to the imaginary straight line C2is smaller than an angle of the linear magnetization region60B2with respect to the imaginary straight line C2. In addition, a total length of the linear magnetization region60B1is shorter than a total length of the linear magnetization region60B2.

In the servo pattern53B, a plurality of magnetization straight lines60B1aare included in the linear magnetization region60B1, and a plurality of magnetization straight lines60B2aare included in the linear magnetization region60B2. The number of the magnetization straight lines60B1aincluded in the linear magnetization region60B1is the same as the number of the magnetization straight lines60B2aincluded in the linear magnetization region60B2.

The total number of the magnetization straight lines60B1aand60B2aincluded in the servo pattern53B is different from the total number of the magnetization straight lines60A1aand60A2aincluded in the servo pattern53A. In the example shown inFIG.22, the total number of the magnetization straight lines60A1aand60A2aincluded in the servo pattern53A is ten, whereas the total number of the magnetization straight lines60B1aand60B2aincluded in the servo pattern53B is eight.

The linear magnetization region60B1is a set of magnetization straight lines60B1a, which are four magnetized straight lines, and the linear magnetization region60B2is a set of magnetization straight lines60B2a, which are four magnetized straight lines. In the servo band SB, positions of both ends of the linear magnetization region60B1(that is, positions of both ends of each of the four magnetization straight lines60B1a) and positions of both ends of the linear magnetization region60B2(that is, positions of both ends of each of the four magnetization straight lines60B2a) are aligned in the width direction WD.

Here, the example has been described in which the positions of both ends of each of the four magnetization straight lines60B1aand the positions of both ends of each of the four magnetization straight lines60B2aare aligned, but this is merely an example, and the positions of both ends of one or more magnetization straight lines60B1aamong the four magnetization straight lines60B1aand the positions of both ends of one or more magnetization straight lines60B2aamong of the four magnetization straight lines60B2aneed only be aligned.

In addition, here, the set of magnetization straight lines60A1a, which are five magnetized straight lines, is described as an example of the linear magnetization region60A1, the set of magnetization straight lines60A2a, which are five magnetized straight lines, is described as an example of the linear magnetization region60A2, the set of magnetization straight lines60B1a, which are four magnetized straight lines, is described as an example of the linear magnetization region60B1, and the set of magnetization straight lines60B2a, which are four magnetized straight lines, is described as an example of the linear magnetization region60B2, but the technology of the present disclosure is not limited to this. For example, the linear magnetization region60A1need only have the number of the magnetization straight lines60A1athat contribute to specifying the position of the magnetic head28on the magnetic tape MT, the linear magnetization region60A2need only have the number of the magnetization straight lines60A2athat contribute to specifying the position of the magnetic head28on the magnetic tape MT, the linear magnetization region60B1need only have the number of the magnetization straight lines60B1athat contribute to specifying the position of the magnetic head28on the magnetic tape MT, and the linear magnetization region60B2need only have the number of the magnetization straight lines60B2athat contribute to specifying the position of the magnetic head28on the magnetic tape MT.

Here, the geometrical characteristics of the linear magnetization region pair60A on the magnetic tape MT will be described with reference toFIG.23.

As shown inFIG.23as an example, the geometrical characteristics of the linear magnetization region pair60A on the magnetic tape MT can be expressed by using an imaginary linear region pair62. The imaginary linear region pair62consists of an imaginary linear region62A and an imaginary linear region62B. The geometrical characteristics of the linear magnetization region pair60A on the magnetic tape MT correspond to the geometrical characteristics based on the imaginary linear region pair62in a case where an entirety of the imaginary linear region pair62is inclined with respect to the imaginary straight line C1by inclining, with respect to the imaginary straight line C1, a symmetry axis SAI of the imaginary linear region62A and the imaginary linear region62B inclined line-symmetrically with respect to the imaginary straight line C1.

The imaginary linear region pair62is an imaginary linear magnetization region pair having the same geometrical characteristics as the linear magnetization region pair54A shown inFIG.6. The imaginary linear region pair62is an imaginary magnetization region used for convenience for describing the geometrical characteristics of the linear magnetization region pair60A on the magnetic tape MT, and is not an actually present magnetization region.

The imaginary linear region62A has the same geometrical characteristics as the linear magnetization region54A1shown inFIG.6, and consists of five imaginary straight lines62A1corresponding to the five magnetization straight lines54A1ashown inFIG.6. The imaginary linear region62B has the same geometrical characteristics as the linear magnetization region54B1shown inFIG.6, and consists of five imaginary straight lines62B1corresponding to the five magnetization straight lines54A2ashown inFIG.6.

A center O1is provided in the imaginary linear region pair62. For example, the center O1is a center of a line segment LO connecting a center of the straight line62A1positioned on the most upstream side in the forward direction among the five straight lines62A1and a center of the straight line62B1positioned on the most downstream side in the forward direction among the five straight lines62B1.

Since the imaginary linear region pair62has the same geometrical characteristics as the linear magnetization region pair54A shown inFIG.6, the imaginary linear region62A and the imaginary linear region62B are inclined line-symmetrically with respect to the imaginary straight line C1. Here, a case will be considered in which reading by the servo reading element SR is performed tentatively with respect to the imaginary linear region pair62in a case where the entirety of the imaginary linear region pair62is inclined with respect to the imaginary straight line C1by inclining the symmetry axis SAI of the imaginary linear regions62A and62B at an angle a (for example, 10 degrees) with respect to the imaginary straight line C1with the center O1as the rotation axis. In this case, in the imaginary linear region pair62, in the width direction WD, a portion is generated in which the imaginary linear region62A is read but the imaginary linear region62B is not read, or the imaginary linear region62A is not read but the imaginary linear region62B is read. That is, in each of the imaginary linear regions62A and62B, in a case where reading by the servo reading element SR is performed, a shortage part and an unnecessary part are generated.

Therefore, by compensating for the shortage part and removing the unnecessary part, the positions of both ends of the imaginary linear region62A (that is, the positions of both ends of each of the five straight lines62A1) and the positions of both ends of the imaginary linear region62B (that is, the positions of both ends of each of the five straight lines62B1) are aligned in the width direction WD.

The geometrical characteristics of the imaginary linear region pair62(that is, the geometrical characteristics of the imaginary servo pattern) obtained as described above correspond to the geometrical characteristics of the actual servo pattern53A. That is, the linear magnetization region pair60A having the geometrical characteristics corresponding to the geometrical characteristics of the imaginary linear region pair62obtained by aligning the positions of both ends of the imaginary linear region62A and the positions of both ends of the imaginary linear region62B in the width direction WD is recorded on the servo band SB.

The linear magnetization region pair60B is different from the linear magnetization region pair60A only in that the four magnetization straight lines60B1aare provided instead of the five magnetization straight lines60A1aand the four magnetization straight lines60B2aare provided instead of the five magnetization straight lines60A2a. Therefore, the linear magnetization region pair60B having the geometrical characteristics corresponding to the geometrical characteristics of the imaginary linear region pair (not shown) obtained by aligning the positions of both ends of each of the four straight lines62A1and the positions of both ends of each of the four straight lines62B1in the width direction WD is recorded on the servo band SB.

As shown inFIG.24as an example, the plurality of servo bands SB are formed on the magnetic tape MT in the width direction WD, and the frames51having a correspondence relationship between the servo bands SB deviate from each other at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent to each other in the width direction WD. The above description means that the servo patterns53having a correspondence relationship between the servo bands SB deviate from each other at the predetermined interval in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent to each other in the width direction WD. The predetermined interval is defined by Expression (1). That is, the positional relationship between the frames51between the servo bands SB and the positional relationship between the servo patterns53between the servo bands SB are the same as those in the example shown inFIG.12.

As shown inFIG.25as an example, in a case where the servo pattern53A (that is, the linear magnetization region pair60A) is read by the servo reading element SR in a state in which the direction of the imaginary straight line C1and the direction of the imaginary straight line C3match (that is, a state in which the longitudinal direction of the magnetic head28and the width direction WD match), the variation due to the azimuth loss occurs between the servo pattern signal derived from the linear magnetization region60A1and the servo pattern signal derived from the linear magnetization region60A2. In addition, also in a case where the servo pattern53B (that is, the linear magnetization region pair60B) is read by the servo reading element SR in a state in which the direction of the imaginary straight line C1and the direction of the imaginary straight line C3match (that is, a state in which the longitudinal direction of the magnetic head28and the width direction WD match), a similar phenomenon occurs.

Therefore, as shown inFIG.26as an example, the inclination mechanism49skews the magnetic head28on the magnetic tape MT around the rotation axis RA such that the imaginary straight line C3is inclined with respect to the imaginary straight line C1to the upstream side in the forward direction at an angle β (that is, the angle β counterclockwise as viewed from the paper surface side ofFIG.26). As described above, since the magnetic head28is inclined to the upstream side in the forward direction at the angle β on the magnetic tape MT, the variation due to the azimuth loss between the servo pattern signal derived from the linear magnetization region60A1and the servo pattern signal derived from the linear magnetization region60A2is smaller than that in the example shown inFIG.25. In addition, also in a case where the servo pattern53B (that is, the linear magnetization region pair60B) is read by the servo reading element SR, similarly, the variation due to the azimuth loss between the servo pattern signal derived from the linear magnetization region60B1and the servo pattern signal derived from the linear magnetization region60B2is small.

Fourth Modification Example

In the third modification example described above, the form example has been described in which the servo band SB is divided by a plurality of frames51along the longitudinal direction LD of the magnetic tape MT, but the technology of the present disclosure is not limited to this. For example, as shown inFIG.27, the servo band SB may be divided by a frame70along the longitudinal direction LD of the magnetic tape MT. The frame70is defined by a set of servo patterns72. A plurality of servo patterns72are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns72are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of servo patterns52.

In the example shown inFIG.27, a pair of servo patterns72A and72B is shown as an example of the set of servo patterns72. Each of the servo patterns72A and72B is an M-shaped magnetized servo pattern. The servo patterns72A and72B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern72A is positioned on the upstream side in the forward direction and the servo pattern72B is positioned on the downstream side in the forward direction in the frame70.

As shown inFIG.28as an example, the servo pattern72consists of a linear magnetization region pair74. The linear magnetization region pair74is classified into a linear magnetization region pair74A and a linear magnetization region pair74B.

The servo pattern72A consists of a set of linear magnetization region pairs74A. The set of linear magnetization region pairs74A is disposed in a state in which the linear magnetization region pairs are adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

In the example shown inFIG.28, a pair of linear magnetization regions74A1and74A2is shown as an example of the linear magnetization region pair74A. The linear magnetization region pair74A is configured in the same manner as the linear magnetization region pair60A described in the third modification example, and has the same geometrical characteristics as the linear magnetization region pair60A. That is, the linear magnetization region74A1is configured in the same manner as the linear magnetization region60A1described in the third modification example, and has the same geometrical characteristics as the linear magnetization region60A1, and the linear magnetization region74A2is configured in the same manner as the linear magnetization region60A2described in the third modification example, and has the same geometrical characteristics as the linear magnetization region60A2.

The servo pattern72B consists of a set of linear magnetization region pairs74B. The set of linear magnetization region pairs74B is disposed in a state in which the linear magnetization region pairs are adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

In the example shown inFIG.28, a pair of linear magnetization regions74B1and74B2is shown as an example of the linear magnetization region pair74B. The linear magnetization region pair74B is configured in the same manner as the linear magnetization region pair60B described in the third modification example, and has the same geometrical characteristics as the linear magnetization region pair60B. That is, the linear magnetization region74B1is configured in the same manner as the linear magnetization region60B1described in the third modification example, and has the same geometrical characteristics as the linear magnetization region60B1, and the linear magnetization region74B2is configured in the same manner as the linear magnetization region60B2described in the third modification example, and has the same geometrical characteristics as the linear magnetization region60B2.

Fifth Modification Example

In the example shown inFIG.27, the form example has been described in which the servo band SB is divided by a plurality of frames70along the longitudinal direction LD of the magnetic tape MT, but the technology of the present disclosure is not limited to this. For example, as shown inFIG.29, the servo band SB may be divided by a frame76along the longitudinal direction LD of the magnetic tape MT. The frame76is defined by a set of servo patterns78. A plurality of servo patterns78are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. Similarly to the plurality of servo patterns72(seeFIG.27), the plurality of servo patterns78are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT.

In the example shown inFIG.29, servo patterns78A and78B are shown as an example of the set of servo patterns78. Each of the servo patterns78A and78B is an N-shaped magnetized servo pattern. The servo patterns78A and78B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern78A is positioned on the upstream side in the forward direction and the servo pattern78B is positioned on the downstream side in the forward direction in the frame76.

As shown inFIG.30as an example, the servo pattern78consists of a linear magnetization region group80. The linear magnetization region group80is classified into a linear magnetization region group80A and a linear magnetization region group80B.

The servo pattern78A consists of the linear magnetization region group80A. The linear magnetization region group80A consists of linear magnetization regions80A1,80A2, and80A3. The linear magnetization regions80A1,80A2, and80A3are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions80A1,80A2, and80A3are disposed in the order of the linear magnetization regions80A1,80A2, and80A3from the upstream side in the forward direction.

The linear magnetization regions80A1and80A2are configured in the same manner as the linear magnetization region pair74A shown inFIG.30, and have the same geometrical characteristics as the linear magnetization region pair74A. That is, the linear magnetization region80A1is configured in the same manner as the linear magnetization region74A1shown inFIG.30, and has the same geometrical characteristics as the linear magnetization region74A1, and the linear magnetization region80A2is configured in the same manner as the linear magnetization region74A2shown inFIG.30, and has the same geometrical characteristics as the linear magnetization region74A2. In addition, the linear magnetization region80A3is configured in the same manner as the linear magnetization region80A1, and has the same geometrical characteristics as the linear magnetization region80A1.

The servo pattern78B consists of the linear magnetization region group80B. The linear magnetization region group80B consists of linear magnetization regions80B1,80B2, and80B3. The linear magnetization regions80B1,80B2, and80B3are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions80B1,80B2, and80B3are disposed in the order of the linear magnetization regions80B1,80B2, and80B3from the upstream side in the forward direction.

The linear magnetization regions80B1and80B2are configured in the same manner as the linear magnetization region pair74B shown inFIG.30, and have the same geometrical characteristics as the linear magnetization region pair74B. That is, the linear magnetization region80B1is configured in the same manner as the linear magnetization region74B1shown inFIG.30, and has the same geometrical characteristics as the linear magnetization region74B1, and the linear magnetization region80B2is configured in the same manner as the linear magnetization region74B2shown inFIG.30, and has the same geometrical characteristics as the linear magnetization region74B2. In addition, the linear magnetization region80B3is configured in the same manner as the linear magnetization region80B1, and has the same geometrical characteristics as the linear magnetization region80B1.

Sixth Modification Example

In the third modification example described above, the form example has been described in which the predetermined interval is defined based on the angle α, the servo band interval, and the frame length, but the technology of the present disclosure is not limited to this, and the predetermined interval may be defined without using the frame length. For example, as shown inFIG.31, the predetermined interval is defined based on the angle α formed by the interval between the frames51having the correspondence relationship between the servo bands SB adjacent to each other in the width direction WD (in the example shown inFIG.31, a line segment L3) and the imaginary straight line C1, and the pitch between the servo bands SB adjacent to each other in the width direction WD (that is, the servo band interval). In this case, for example, the predetermined interval is calculated from Expression (2).

As described above, Expression (2) does not include the frame length. This means that the predetermined interval is calculated even in a case where the frame length is not considered. Therefore, with the present configuration, the predetermined interval can be calculated more easily than in a case of calculating the predetermined interval from Expression (1).

Seventh Modification Example

In the third modification example described above, the form example has been described in which the servo band SB is divided by a plurality of frames51along the longitudinal direction LD of the magnetic tape MT, but the technology of the present disclosure is not limited to this. For example, as shown inFIG.32, the servo band SB may be divided by a frame82along the longitudinal direction LD of the magnetic tape MT.

The frame82is defined by a set of servo patterns84. A plurality of servo patterns84are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns84are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of servo patterns52(seeFIG.6) recorded on the magnetic tape MT.

In the example shown inFIG.32, servo patterns84A and84B are shown as an example of the set of servo patterns84included in the frame82. The servo patterns84A and84B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern84A is positioned on the upstream side in the forward direction and the servo pattern84B is positioned on the downstream side in the forward direction in the frame82.

The servo pattern84A consists of the linear magnetization region pair86A. In the example shown inFIG.32, a pair of linear magnetization regions86A1and86A2is shown as an example of the linear magnetization region pair86A. Each of the linear magnetization regions86A1and86A2is a linearly magnetized region.

The linear magnetization regions86A1and86A2are inclined in opposite directions with respect to the imaginary straight line C1. The linear magnetization regions86A1and86A2are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C1. The linear magnetization region86A1has a steeper inclined angle with respect to the imaginary straight line C1than the linear magnetization region86A2. Here, the term “steep” refers to that, for example, an angle of the linear magnetization region86A1with respect to the imaginary straight line C1is smaller than an angle of the linear magnetization region86A2with respect to the imaginary straight line C1.

In addition, the overall position of the linear magnetization region86A1and the overall position of the linear magnetization region86A2deviate from each other in the width direction WD. That is, a position of one end of the linear magnetization region86A1and a position of one end of the linear magnetization region86A2are not aligned in the width direction WD, and a position of the other end of the linear magnetization region86A1and a position of the other end of the linear magnetization region86A2are not aligned in the width direction WD.

In the servo pattern84A, a plurality of magnetization straight lines86A1aare included in the linear magnetization region86A1, and a plurality of magnetization straight lines86A2aare included in the linear magnetization region86A2. The number of the magnetization straight lines86A1aincluded in the linear magnetization region86A1is the same as the number of the magnetization straight lines86A2aincluded in the linear magnetization region86A2.

The linear magnetization region86A1is a set of magnetization straight lines86A1a, which are five magnetized straight lines, and the linear magnetization region86A2is a set of magnetization straight lines86A2a, which are five magnetized straight lines.

In the servo band SB, a position of one end of each of all the magnetization straight lines86A1aincluded in the linear magnetization region86A1in the width direction WD is aligned, and a position of the other end of each of all the magnetization straight lines86A1aincluded in the linear magnetization region86A1in the width direction WD is also aligned. In addition, in the servo band SB, a position of one end of each of all the magnetization straight lines86A2aincluded in the linear magnetization region86A2in the width direction WD is aligned, and a position of the other end of each of all the magnetization straight lines86A2aincluded in the linear magnetization region86A2in the width direction WD is also aligned.

The servo pattern84B consists of the linear magnetization region pair86B. In the example shown inFIG.32, a pair of linear magnetization regions86B1and86B2is shown as an example of the linear magnetization region pair86B. Each of the linear magnetization regions86B1and86B2is a linearly magnetized region.

The linear magnetization regions86B1and86B2are inclined in opposite directions with respect to the imaginary straight line C2. The linear magnetization regions86B1and86B2are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C2. The linear magnetization region86B1has a steeper inclined angle with respect to the imaginary straight line C2than the linear magnetization region86B2. Here, the term “steep” refers to that, for example, an angle of the linear magnetization region86B1with respect to the imaginary straight line C2is smaller than an angle of the linear magnetization region86B2with respect to the imaginary straight line C2.

In addition, the overall position of the linear magnetization region86B1and the overall position of the linear magnetization region86B2deviate from each other in the width direction WD. That is, a position of one end of the linear magnetization region86B1and a position of one end of the linear magnetization region86B2are not aligned in the width direction WD, and a position of the other end of the linear magnetization region86B1and a position of the other end of the linear magnetization region86B2are not aligned in the width direction WD.

In the servo pattern84B, a plurality of magnetization straight lines86B1aare included in the linear magnetization region86B1, and a plurality of magnetization straight lines86B2aare included in the linear magnetization region86B2. The number of the magnetization straight lines86B1aincluded in the linear magnetization region86B1is the same as the number of the magnetization straight lines86B2aincluded in the linear magnetization region86B2.

The total number of the magnetization straight lines86B1aand86B2aincluded in the servo pattern84B is different from the total number of the magnetization straight lines86A1aand86A2aincluded in the servo pattern84A. In the example shown inFIG.32, the total number of the magnetization straight lines86A1aand86A2aincluded in the servo pattern84A is ten, whereas the total number of the magnetization straight lines86B1aand86B2aincluded in the servo pattern84B is eight.

The linear magnetization region86B1is a set of magnetization straight lines86B1a, which are four magnetized straight lines, and the linear magnetization region86B2is a set of magnetization straight lines86B2a, which are four magnetized straight lines.

In the servo band SB, a position of one end of each of all the magnetization straight lines86B1aincluded in the linear magnetization region86B1in the width direction WD is aligned, and a position of the other end of each of all the magnetization straight lines86B1aincluded in the linear magnetization region86B1in the width direction WD is also aligned. In addition, in the servo band SB, a position of one end of each of all the magnetization straight lines86B2aincluded in the linear magnetization region86B2in the width direction WD is aligned, and a position of the other end of each of all the magnetization straight lines86B2aincluded in the linear magnetization region86B2in the width direction WD is also aligned.

Here, the set of magnetization straight lines86A1a, which are five magnetized straight lines, is described as an example of the linear magnetization region86A1, the set of magnetization straight lines86A2a, which are five magnetized straight lines, is described as an example of the linear magnetization region86A2, the set of magnetization straight lines86B1a, which are four magnetized straight lines, is described as an example of the linear magnetization region86B1, and the set of magnetization straight lines86B2a, which are four magnetized straight lines, is described as an example of the linear magnetization region86B2, but the technology of the present disclosure is not limited to this. For example, the linear magnetization region86A1need only have the number of the magnetization straight lines86A1athat contribute to specifying the position of the magnetic head28on the magnetic tape MT, the linear magnetization region86A2need only have the number of the magnetization straight lines86A2athat contribute to specifying the position of the magnetic head28on the magnetic tape MT, the linear magnetization region86B1need only have the number of the magnetization straight lines86B1athat contribute to specifying the position of the magnetic head28on the magnetic tape MT, and the linear magnetization region86B2need only have the number of the magnetization straight lines86B2athat contribute to specifying the position of the magnetic head28on the magnetic tape MT.

Here, the geometrical characteristics of the linear magnetization region pair86A on the magnetic tape MT will be described with reference toFIG.33.

As shown inFIG.33as an example, the geometrical characteristics of the linear magnetization region pair86A on the magnetic tape MT can be expressed by using an imaginary linear region pair62. Here, the entirety of the imaginary linear region pair62is inclined with respect to the imaginary straight line C1by inclining the symmetry axis SAI of the imaginary linear regions62A and62B at an angle a (for example, 10 degrees) with respect to the imaginary straight line C1with the center O1as the rotation axis. Moreover, a position of one end of each of all the straight lines62A1included in the imaginary linear region62A of the imaginary linear region pair62in this state in the width direction WD is aligned, and a position of the other end of each of all the straight lines62A1included in the imaginary linear region62A in the width direction WD is also aligned. In addition, similarly, a position of one end of each of all the straight lines62B1included in the imaginary linear region62B of the imaginary linear region pair62in the width direction WD is aligned, and a position of the other end of each of all the straight lines62B1included in the imaginary linear region62B in the width direction WD is also aligned. As a result, the imaginary linear region62A and the imaginary linear region62B deviate from each other in the width direction WD.

That is, one end of the imaginary linear region62A and one end of the imaginary linear region62B deviate from each other in the width direction WD at a regular interval Int1, and the other end of the imaginary linear region62A and the other end of the imaginary linear region62B deviate from each other in the width direction WD at a regular interval Int2.

The geometrical characteristics of the imaginary linear region pair62(that is, the geometrical characteristics of the imaginary servo pattern) obtained as described above correspond to the geometrical characteristics of the actual servo pattern84A. That is, the geometrical characteristics of the linear magnetization region pair86A on the magnetic tape MT correspond to the geometrical characteristics based on the imaginary linear region pair62in a case where an entirety of the imaginary linear region pair62is inclined with respect to the imaginary straight line C1by inclining, with respect to the imaginary straight line C1, a symmetry axis SAI of the imaginary linear region62A and the imaginary linear region62B inclined line-symmetrically with respect to the imaginary straight line C1.

The imaginary linear region62A corresponds to the linear magnetization region86A1of the servo pattern84A, and the imaginary linear region62B corresponds to the linear magnetization region86A2of the servo pattern84A. Therefore, on the servo band SB, the servo pattern84A consisting of the linear magnetization region pair86A in which one end of the linear magnetization region86A1and one end of the linear magnetization region86A2deviate from each other in the width direction WD at the regular interval Int1, and the other end of the linear magnetization region86A1and the other end of the linear magnetization region86A2deviate from each other in the width direction WD at the regular interval Int2is recorded (seeFIG.32).

The linear magnetization region pair86B is different from the linear magnetization region pair86A only in that the four magnetization straight lines86B1aare provided instead of the five magnetization straight lines86A1aand the four magnetization straight lines86B2aare provided instead of the five magnetization straight lines86A2a(seeFIG.32). Therefore, on the servo band SB, the servo pattern84B consisting of the linear magnetization region pair86B in which one end of the linear magnetization region86B1and one end of the linear magnetization region86B2deviate from each other in the width direction WD at the regular interval Int1, and the other end of the linear magnetization region86B1and the other end of the linear magnetization region86B2deviate from each other in the width direction WD at the regular interval Int2is recorded (seeFIG.32).

As shown inFIG.34as an example, the plurality of servo bands SB are formed on the magnetic tape MT in the width direction WD, and the frames82having a correspondence relationship between the servo bands SB deviate from each other at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent to each other in the width direction WD. This means that the servo patterns84having a correspondence relationship between the servo bands SB deviate from each other at the predetermined interval described in the third modification example in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent to each other in the width direction WD. The predetermined interval is defined by Expression (1).

Similarly to the third modification example described above, in the seventh modification example, as shown inFIG.35as an example, the inclination mechanism49skews the magnetic head28on the magnetic tape MT around the rotation axis RA such that the imaginary straight line C3is inclined with respect to the imaginary straight line C1to the upstream side in the forward direction at an angle β (that is, the angle β counterclockwise as viewed from the paper surface side ofFIG.35). That is, the magnetic head28is inclined at the angle β to the upstream side in the forward direction on the magnetic tape MT. In this state, in a case where the servo pattern84A is read by the servo reading element SR along the longitudinal direction LD within a range R in which the linear magnetization regions86A1and86A2overlap with each other in the width direction WD, the variation due to the azimuth loss between the servo pattern signal derived from the linear magnetization region86A1and the servo pattern signal derived from the linear magnetization region86A2is smaller than in the example shown inFIG.34. In addition, also in a case where the servo pattern84B (that is, the linear magnetization region pair86B) is read by the servo reading element SR, similarly, the variation due to the azimuth loss between the servo pattern signal derived from the linear magnetization region86B1and the servo pattern signal derived from the linear magnetization region86B2is small.

Eighth Modification Example

In the seventh modification example described above, the form example has been described in which the servo band SB is divided by a plurality of frames82along the longitudinal direction LD of the magnetic tape MT, but the technology of the present disclosure is not limited to this. For example, as shown inFIG.36, the servo band SB may be divided by a frame88along the longitudinal direction LD of the magnetic tape MT. The frame88is defined by a set of servo patterns90. A plurality of servo patterns90are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. Similarly to the plurality of servo patterns84(seeFIG.32), the plurality of servo patterns90are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT.

In the example shown inFIG.36, a pair of servo patterns90A and90B is shown as an example of the set of servo patterns90. Each of the servo patterns90A and90B is an M-shaped magnetized servo pattern. The servo patterns90A and90B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern90A is positioned on the upstream side in the forward direction and the servo pattern90B is positioned on the downstream side in the forward direction in the frame88.

As shown inFIG.37as an example, the servo pattern90consists of a linear magnetization region pair92. The linear magnetization region pair92is classified into a linear magnetization region pair92A and a linear magnetization region pair92B.

The servo pattern90A consists of a set of linear magnetization region pairs92A. The set of linear magnetization region pairs92A is disposed in a state in which the linear magnetization region pairs are adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

In the example shown inFIG.37, a pair of linear magnetization regions92A1and92A2is shown as an example of the linear magnetization region pair92A. The linear magnetization region pair92A is configured in the same manner as the linear magnetization region pair86A (seeFIG.32) described in the seventh modification example, and has the same geometrical characteristics as the linear magnetization region pair86A. That is, the linear magnetization region92A1is configured in the same manner as the linear magnetization region86A1(seeFIG.32) described in the seventh modification example and has the same geometrical characteristics as the linear magnetization region86A1, and the linear magnetization region92A2is configured in the same manner as the linear magnetization region86A2(seeFIG.32) described in the seventh modification example and has the same geometrical characteristics as the linear magnetization region86A2.

The servo pattern90B consists of a set of linear magnetization region pairs92B. The set of linear magnetization region pairs92B is disposed in a state in which the linear magnetization region pairs are adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

In the example shown inFIG.37, a pair of linear magnetization regions92B1and92B2is shown as an example of the linear magnetization region pair92B. The linear magnetization region pair92B is configured in the same manner as the linear magnetization region pair86B (seeFIG.32) described in the seventh modification example, and has the same geometrical characteristics as the linear magnetization region pair86B. That is, the linear magnetization region92B1is configured in the same manner as the linear magnetization region86B1(seeFIG.32) described in the seventh modification example and has the same geometrical characteristics as the linear magnetization region86B1, and the linear magnetization region92B2is configured in the same manner as the linear magnetization region86B2(seeFIG.32) described in the seventh modification example and has the same geometrical characteristics as the linear magnetization region86B2.

Ninth Modification Example

In the example shown inFIG.36, the form example has been described in which the servo band SB is divided by a plurality of frames88along the longitudinal direction LD of the magnetic tape MT, but the technology of the present disclosure is not limited to this. For example, as shown inFIG.38, the servo band SB may be divided by a frame94along the longitudinal direction LD of the magnetic tape MT. The frame94is defined by a set of servo patterns96. A plurality of servo patterns96are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. Similarly to the plurality of servo patterns90(seeFIG.36), the plurality of servo patterns96are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT.

In the example shown inFIG.38, servo patterns96A and96B are shown as an example of the set of servo patterns96. Each of the servo patterns96A and96B is an N-shaped magnetized servo pattern. The servo patterns96A and96B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern96A is positioned on the upstream side in the forward direction and the servo pattern96B is positioned on the downstream side in the forward direction in the frame94.

As shown inFIG.39as an example, the servo pattern96consists of a linear magnetization region group98. The linear magnetization region group98is classified into a linear magnetization region group98A and a linear magnetization region group98B.

The servo pattern96A consists of the linear magnetization region group98A. The linear magnetization region group98A consists of linear magnetization regions98A1,98A2, and98A3. The linear magnetization regions98A1,98A2, and98A3are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions98A1,98A2, and98A3are disposed in the order of the linear magnetization regions98A1,98A2, and98A3from the upstream side in the forward direction.

The linear magnetization regions98A1and98A2are configured in the same manner as the linear magnetization region pair92A shown inFIG.37, and have the same geometrical characteristics as the linear magnetization region pair92A. That is, the linear magnetization region98A1is configured in the same manner as the linear magnetization region92A1shown inFIG.37, and has the same geometrical characteristics as the linear magnetization region92A1, and the linear magnetization region98A2is configured in the same manner as the linear magnetization region92A2shown inFIG.37, and has the same geometrical characteristics as the linear magnetization region92A2. In addition, the linear magnetization region98A3is configured in the same manner as the linear magnetization region92A1, and has the same geometrical characteristics as the linear magnetization region92A1.

The servo pattern96B consists of the linear magnetization region group98B. The linear magnetization region group98B consists of linear magnetization regions98B1,98B2, and98B3. The linear magnetization regions98B1,98B2, and98B3are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions98B1,98B2, and98B3are disposed in the order of the linear magnetization regions98B1,98B2, and98B3from the upstream side in the forward direction.

The linear magnetization regions98B1and98B2are configured in the same manner as the linear magnetization region pair92B shown inFIG.37, and have the same geometrical characteristics as the linear magnetization region pair92B. That is, the linear magnetization region98B1is configured in the same manner as the linear magnetization region92B1shown inFIG.37, and has the same geometrical characteristics as the linear magnetization region92B1, and the linear magnetization region98B2is configured in the same manner as the linear magnetization region92B2shown inFIG.37, and has the same geometrical characteristics as the linear magnetization region92B2. In addition, the linear magnetization region98B3is configured in the same manner as the linear magnetization region92B1, and has the same geometrical characteristics as the linear magnetization region92B1.

Tenth Modification Example

In the third modification example described above (for example, example shown inFIG.22), the form example has been described in which the servo band SB is divided by the plurality of frames51along the longitudinal direction LD of the magnetic tape MT, but the technology of the present disclosure is not limited to this. For example, as shown inFIG.40, the servo band SB may be divided by a frame560along the longitudinal direction LD of the magnetic tape MT. The frame560is defined by a set of servo patterns580. A plurality of servo patterns580are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns580are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of frames51.

The servo pattern580consists of a linear magnetization region pair600. The linear magnetization region pair600is classified into a linear magnetization region pair600A and a linear magnetization region pair600B. That is, the linear magnetization region pair600is different from the linear magnetization region pair60(seeFIG.22) in that the linear magnetization region pair600A is provided instead of the linear magnetization region pair60A, and the linear magnetization region pair600B is provided instead of the linear magnetization region pair60B.

The servo pattern580A consists of the linear magnetization region pair600A. The linear magnetization region pair600A is different from the linear magnetization region pair60A in that the linear magnetization region600A1is provided instead of the linear magnetization region60A1, and the linear magnetization region600A2is provided instead of the linear magnetization region60A2. Each of the linear magnetization regions600A1and600A2is a linearly magnetized region.

The linear magnetization regions600A1and600A2are inclined in opposite directions with respect to the imaginary straight line C1. The linear magnetization regions600A1and600A2are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C1. The linear magnetization region600A2has a steeper inclined angle with respect to the imaginary straight line C1than the linear magnetization region600A1. Here, the term “steep” refers to that, for example, an angle of the linear magnetization region600A2with respect to the imaginary straight line C1is smaller than an angle of the linear magnetization region600A1with respect to the imaginary straight line C1. In addition, a total length of the linear magnetization region600A2is shorter than a total length of the linear magnetization region600A1.

The linear magnetization region600A1is different from the linear magnetization region60A1in that a plurality of magnetization straight lines600A1aare provided instead of the plurality of magnetization straight lines60A1a. The linear magnetization region600A2is different from the linear magnetization region60A2in that a plurality of magnetization straight lines600A2aare provided instead of the plurality of magnetization straight lines60A2a.

The plurality of magnetization straight lines600A1aare included in the linear magnetization region600A1, and the plurality of magnetization straight lines600A2aare included in the linear magnetization region600A2. The number of the magnetization straight lines600A1aincluded in the linear magnetization region600A1is the same as the number of the magnetization straight lines600A2aincluded in the linear magnetization region600A2.

The linear magnetization region600A1is a linear magnetization region corresponding to a first line symmetry region. The first line symmetry region refers to a region in which the linear magnetization region60A2(seeFIG.22) described in the third modification example is formed line-symmetrically with respect to the imaginary straight line C1. That is, the linear magnetization region600A1can be said to be a linear magnetization region formed by geometrical characteristics of a mirror image of the linear magnetization region60A2(seeFIG.22) (that is, geometrical characteristics obtained by performing the mirror image with respect to the linear magnetization region60A2(seeFIG.22) with the imaginary straight line C1as a line symmetry axis).

The linear magnetization region600A2is a linear magnetization region corresponding to a second line symmetry region. The second line symmetry region refers to a region in which the linear magnetization region60A1(seeFIG.22) described in the third modification example is formed line-symmetrically with respect to the imaginary straight line C1. That is, the linear magnetization region600A2can be said to be a linear magnetization region formed by geometrical characteristics of a mirror image of the linear magnetization region60A1(seeFIG.22) (that is, geometrical characteristics obtained by performing the mirror image with respect to the linear magnetization region60A1(seeFIG.22) with the imaginary straight line C1as a line symmetry axis).

That is, in the example shown inFIG.23, the geometrical characteristics of the imaginary linear region pair62obtained by aligning the positions of both ends of the imaginary linear region62A and the positions of both ends of the imaginary linear region62B in a case where the entirety of the imaginary linear region pair62is inclined with respect to the imaginary straight line C1by inclining the symmetry axis SAI of the imaginary linear regions62A and62B with respect to the imaginary straight line C1at the angle α clockwise as viewed from the paper surface side ofFIG.23with the center O1as the rotation axis correspond to the geometrical characteristics of the servo pattern580A.

The servo pattern580B consists of the linear magnetization region pair600B. The linear magnetization region pair600B is different from the linear magnetization region pair60B in that the linear magnetization region600B1is provided instead of the linear magnetization region60B1, and the linear magnetization region600B2is provided instead of the linear magnetization region60B2. Each of the linear magnetization regions600B1and600B2is a linearly magnetized region.

The linear magnetization regions600B1and600B2are inclined in opposite directions with respect to the imaginary straight line C2. The linear magnetization regions600B1and600B2are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C2. The linear magnetization region600B2has a steeper inclined angle with respect to the imaginary straight line C2than the linear magnetization region600B1. Here, the term “steep” refers to that, for example, an angle of the linear magnetization region600B2with respect to the imaginary straight line C2is smaller than an angle of the linear magnetization region600B1with respect to the imaginary straight line C2.

The plurality of magnetization straight lines600B1aare included in the linear magnetization region600B1, and the plurality of magnetization straight lines600B2aare included in the linear magnetization region600B2. The number of the magnetization straight lines600B1aincluded in the linear magnetization region600B1is the same as the number of the magnetization straight lines600B2aincluded in the linear magnetization region600B2.

The total number of the magnetization straight lines600B1aand600B2aincluded in the servo pattern580B is different from the total number of the magnetization straight lines600A1aand600A2aincluded in the servo pattern580A. In the example shown inFIG.40, the total number of the magnetization straight lines600A1aand600A2aincluded in the servo pattern580A is ten, whereas the total number of the magnetization straight lines600B1aand600B2aincluded in the servo pattern580B is eight.

The linear magnetization region600B1is a set of magnetization straight lines600B1a, which are four magnetized straight lines, and the linear magnetization region600B2is a set of magnetization straight lines600B2a, which are four magnetized straight lines. In the servo band SB, the positions of both ends of the linear magnetization region600B1(that is, the positions of both ends of each of the four magnetization straight lines600B1a) and the positions of both ends of the linear magnetization region600B2(that is, the positions of both ends of each of the four magnetization straight lines600B2a) are aligned in the width direction WD.

As described above, the geometrical characteristics of the servo pattern580A correspond to the geometrical characteristics of the mirror image of the linear magnetization region60A2(seeFIG.22) and the geometrical characteristics of the mirror image of the linear magnetization region60A2(seeFIG.22) (that is, geometrical characteristics of the mirror image of the servo pattern53A shown inFIG.22), and the geometrical characteristics of the servo pattern580B correspond to the geometrical characteristics of the mirror image of the linear magnetization region60B2(seeFIG.22) and the geometrical characteristics of the mirror image of the linear magnetization region60B2(seeFIG.22) (that is, geometrical characteristics of the mirror image of the servo pattern53B shown inFIG.22). However, this is merely an example, and instead of the servo pattern580, the servo pattern formed by the geometrical characteristics of the mirror image of the servo pattern72shown inFIG.27, the geometrical characteristics of the mirror image of the servo pattern78shown inFIG.29, the geometrical characteristics of the mirror image of the servo pattern84shown inFIG.32, the geometrical characteristics of the mirror image of the servo pattern90shown inFIG.36, or the geometrical characteristics of the mirror image of the servo pattern96shown inFIG.38may be applied.

Even in a case where the geometrical characteristics of the servo pattern are changed in this way, the inclination mechanism49changes the direction of the inclination (that is, azimuth) of the imaginary straight line C3with respect to the imaginary straight line C4and the inclined angle (for example, angle β shown inFIG.26) in accordance with the geometrical characteristics of the servo pattern. That is, even in a case where the geometrical characteristics of the servo pattern are changed, in the same manner as in the example shown inFIG.26, the inclination mechanism49rotates, under the control of the control device30, the magnetic head28around the rotation axis RA on the front surface31of the magnetic tape MT to change the direction of the inclination of the imaginary straight line C3with respect to the imaginary straight line C4(that is, azimuth) and the inclined angle (for example, angle β shown inFIG.26) such that the variation in the servo pattern signal is reduced.

Other Modification Examples

In the embodiment described above, the form example has been described in which the front surface31of the magnetic tape MT is subjected to the magnetic processing by the magnetic head28, but the technology of the present disclosure is not limited to this. For example, the back surface33of the magnetic tape MT may be formed of the surface of the magnetic layer, and the back surface33may be subjected to the magnetic processing by the magnetic head28.

In the embodiment described above, the magnetic tape system10has been described in which the magnetic tape cartridge12can be inserted and removed with respect to the magnetic tape drive14, but the technology of the present disclosure is not limited to this. For example, even in a case of the magnetic tape system in which at least one magnetic tape cartridge12is loaded in advance into the magnetic tape drive14(that is, the magnetic tape system in which at least one magnetic tape cartridge12and the magnetic tape drive14or the magnetic tape MT are integrated in advance (for example, before the data is recorded in the data band DB)), the technology of the present disclosure is established.

In the embodiment described above, the single magnetic head28has been described, but the technology of the present disclosure is not limited to this. For example, a plurality of magnetic heads28may be disposed on the magnetic tape MT. For example, the magnetic head28for reading and at least one magnetic head28for writing may be disposed on the magnetic tape MT. The magnetic head28for reading may be used for verifying the data recorded on the data band DB by the magnetic head28for writing. In addition, one magnetic head on which the magnetic element unit42for reading and at least one magnetic element unit42for writing are mounted may be disposed on the magnetic tape MT.

In the embodiment described above, the form example has been described in which the control device30(seeFIG.3) is implemented by the ASIC, but the technology of the present disclosure is not limited to this, and the control device30may be implemented by the software configuration. In addition, only the control device30and the position detection device30may be implemented by the software configuration. In a case where the control device30and the position detection device30B are implemented by the software configuration, for example, as shown inFIG.41, the control device30comprises a computer200. The computer200includes a processor200A (for example, a single CPU or a plurality of CPUs), an NVM200B, and a RAM200C. The processor200A, the NVM200B, and the RAM200C are connected to a bus200D. A program PG is stored in a portable storage medium202(for example, an SSD or a USB memory) which is a computer-readable non-transitory storage medium.

The program PG stored in the storage medium202is installed in the computer200. The processor200A executes the control processing (seeFIG.17) in accordance with the program PG.

In addition, the program PG may be stored in a storage device of another computer or server device connected to the computer200via a communication network (not shown), and the program PG may be downloaded in response to a request from the control device30and installed in the computer200. The program PG is an example of a “program” according to the technology of the present disclosure, and the computer200is an example of a “computer” according to the technology of the present disclosure.

In the example shown inFIG.41, although the computer200has been described as an example, the technology of the present disclosure is not limited to this, and a device including an ASIC, an FPGA, and/or a PLC may be applied instead of the computer200. In addition, instead of the computer200, a hardware configuration and a software configuration may be used in combination.

As the hardware resource for executing the processing of the control device30(seeFIG.3), various processors shown below can be used. Examples of the processor include the CPU which is a general-purpose processor functioning as the hardware resource for executing the processing by executing software, that is, a program. In addition, examples of the processor include a dedicated electronic circuit which is a processor having a circuit configuration designed to be dedicated to executing specific processing, such as an FPGA, a PLC, or an ASIC described as an example. A memory is incorporated or connected to any processor, and any processor executes the processing using the memory.

The hardware resource for executing the processing of the control device30and/or the servo writer controller SW5may be composed of one of those various processors or may be composed of a combination of two or more processors of the same type or different types (for example, a combination of a plurality of FPGAs or a combination of a CPU and an FPGA). In addition, the hardware resource for executing the processing of the control device30and/or the servo writer controller SW5may be one processor.

A first example in which the hardware resource is composed of one processor is an aspect in which one or more CPUs and software are combined to constitute one processor and the processor functions as the hardware resource that executes the processing. Secondly, as typified by SoC, there is a form in which a processor that realizes the functions of the entire system including a plurality of hardware resources for executing the processing with one IC chip is used. As described above, the processing of the control device30and/or the servo writer controller SW5is implemented by using one or more of the various processors described above as the hardware resource.

Further, as the hardware structure of these various processors, more specifically, it is possible to use an electronic circuit in which circuit elements, such as semiconductor elements, are combined. In addition, the processing of the control device30and/or the servo writer controller SW5is merely an example. Accordingly, it is possible to delete an unnecessary step, add a new step, or change a processing order without departing from the gist of the present disclosure.

The content of the above description and the content of the drawings are detailed explanations of the parts relating to the technology of the present disclosure, and are merely examples of the technology of the present disclosure. For example, description related to the above configurations, functions, actions, and effects is description related to an example of configurations, functions, actions, and effects of the parts relating to the technology of the present disclosure. Thus, it is needless to say that unnecessary portions may be deleted, new elements may be added, or replacement may be made to the content of the above description and the content of the drawings without departing from the gist of the technology of the present disclosure. In order to avoid complication and easily understand the parts relating to the technology of the present disclosure, in the content of the above description and the content of the drawings, the description regarding common general technical knowledge which is not necessarily particularly described in terms of embodying the technology of the present disclosure is omitted.

In the present specification, “A and/or B” is synonymous with “at least one of A or B”. That is, “A and/or B” may refer to A alone, B alone, or a combination of A and B. In addition, in the present specification, in a case where three or more matters are expressed with the connection of “and/or”, the same concept as “A and/or B” is applied.

All documents, patent applications, and technical standards mentioned in the present specification are incorporated herein by reference to the same extent as in a case in which each document, each patent application, and each technical standard are specifically and individually described by being incorporated by reference.

The disclosure of JP2022-073647 filed on Apr. 27, 2022 is incorporated herein by reference in its entirety.

The following appendices are further disclosed with respect to the above embodiment.

A signal processing device comprising:a processor that acquires and processes data read by a magnetic head from a magnetic tape on which a plurality of servo bands are formed,in which the plurality of servo bands are disposed at intervals in a width direction of the magnetic tape,a plurality of servo patterns are formed in each of the plurality of servo bands along a longitudinal direction of the magnetic tape,the magnetic head has a pair of servo reading elements corresponding to a pair of servo bands adjacent to each other in the width direction among the plurality of servo bands,a first servo reading element included in the pair of servo reading elements reads the servo pattern included in a first servo band included in the pair of servo bands,a second servo reading element included in the pair of servo reading elements reads the servo pattern included in a second servo band included in the pair of servo bands, andthe processoracquires a first signal based on a first result of reading the servo pattern in the first servo band via the first servo reading element while the first servo reading element is positioned on a reference region of the magnetic tape,acquires a second signal based on a second result of reading the servo pattern in the second servo band being via the second servo reading element while the second servo reading element is positioned on the reference region, andexecutes skew processing for a skew mechanism that skews the magnetic head based on a servo band interval signal corresponding to a servo band interval according to the first signal and the second signal, the skew processing being processing of skewing the magnetic head according to the servo band interval.

The signal processing device according to Appendix 1,in which the servo band interval is used in common for a plurality of division areas obtained by dividing a data band in the width direction of the magnetic tape, and is a representative interval between a first servo pattern, which is the servo pattern in the first servo band of the pair of servo bands adjacent to each other via the data band, and a second servo pattern, which is the servo pattern in the second servo band of the pair of servo bands.

The signal processing device according to Appendix 2,in which the representative interval is obtained by statistically processing results of measuring an interval between the firsta servo pattern and the second servo pattern for each of the division areas in a case where the magnetic tape is run.

The signal processing device according to Appendix 2 or 3,in which the representative interval is obtained by statistically processing results of measuring an interval between the first servo pattern and the second servo pattern in a partial section of the division areas along a running direction of the magnetic tape for each of the division areas in a case where the magnetic tape is run.

The signal processing device according to Appendix 2 or 3,in which the representative interval is obtained by statistically processing results of measuring an interval between the first servo pattern and the second servo pattern in an entire section of the division areas along a running direction of the magnetic tape for each of the division areas in a case where the magnetic tape is run.

The signal processing device according to any one of Appendices 2 to 5,in which the representative interval is an average value of results of measuring an interval between the first servo pattern and the second servo pattern for each of the division areas in a case where the magnetic tape is run.

The signal processing device according to any one of Appendices 1 to 6,in which the reference region is a BOT region.

The signal processing device according to any one of Appendices 1 to 7,in which the processor stores the servo band interval signal in a storage medium.

The signal processing device according to Appendix 8,in which the magnetic tape is accommodated in a magnetic tape cartridge,the magnetic tape cartridge is provided with a noncontact storage medium that is able to perform communication in a noncontact manner, andthe storage medium includes the noncontact storage medium.

The signal processing device according to Appendix 8 or 9,in which the storage medium includes a partial region of the magnetic tape.