Patent Publication Number: US-2023139005-A1

Title: Detection device, inspection device, magnetic tape drive, magnetic tape system, detection method, inspection method, and program

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 USC 119 from Japanese Patent Application No. 2021-178343 filed on Oct. 29, 2021, the disclosure of which is incorporated by reference herein. 
     BACKGROUND 
     1. Technical Field 
     The technology of the present disclosure relates to a detection device, an inspection device, a magnetic tape drive, a magnetic tape system, a detection method, an inspection method, and a program. 
     2. Related Art 
     U.S. Pat. No. 8,094,402B raises a problem in a magnetic tape device that a read and/or write error occurs in a case in which a tape does not pass through a head at appropriate tension and/or a skew angle. In order to solve this problem, a system disclosed in U.S. Pat. No. 8,094,402B includes a head having an array of at least one of a reader or a writer, a drive mechanism that causes a magnetic recording tape to pass on the head, and a skew induction mechanism bonded to the head, in which a skew angle of a vertical axis of the array with respect to a direction perpendicular to a direction in which the tape is moved on the head, and a controller that communicates with the head is adjusted. In addition, the system disclosed in U.S. Pat. No. 8,094,402B determines a tape dimension stable state of the tape, adjusts the skew angle in a direction away from a normal line with respect to a tape movement direction, and reduces the tension of the tape on the entire head in a case in which the tape dimension stable state is in a contraction state. 
     U.S. Pat. No. 6,781,784B discloses a method of performing reading by selectively using a reading element offset in a vertical direction with respect to a data track of a magnetic tape in which distortion in a lateral direction occurs. The reading element is a part of a tape head that has an azimuthal angle with respect to the tape and creates an offset in the lateral direction between the reading elements. The offset in the lateral direction is used to minimize the effects of the distortion of the tape in the lateral direction. 
     JP2009-123288A discloses a head device comprising a head unit on which a plurality of magnetic elements that each perform at least one of reproduction of data recorded in a plurality of data tracks provided in a magnetic tape or recording of data in each data track are arranged to be parallel on a first straight line at equal intervals, a moving mechanism that moves the head unit, and a controller that executes a tracking control of causing the magnetic elements to be on-tracked on the data tracks, respectively, by moving the head unit by the moving mechanism. In the head device disclosed in JP2009-123288A, the moving mechanism is configured to perform rotational movement of rotationally moving the head unit in an orientation of increasing or decreasing an angle formed by a second straight line along a width of the magnetic tape line and the first straight line, and, during the execution of the tracking control, the controller causes each magnetic element to be on-tracked on each data track by rotationally moving and driving the head unit by the moving mechanism by an increasing or decreasing amount of the angle in accordance with a change of an interval between the data tracks. 
     SUMMARY 
     One embodiment according to the technology of the present disclosure relates to a detection device, an inspection device, a magnetic tape drive, a magnetic tape system, a detection method, an inspection method, and a program capable of detecting a servo pattern signal with high accuracy even in a case in which there is a variation in a geometrical characteristic of a servo pattern. 
     A first aspect according to the technology of the present disclosure relates to a detection device comprising a processing device, and a storage medium, in which an ideal waveform signal indicating an ideal waveform of a servo pattern signal which is a result of reading a servo pattern recorded in a servo band of a magnetic tape by a servo reading element is stored in advance in the storage medium, and the processing device acquires a servo band signal which is a result of reading the servo band by the servo reading element, and detects the servo pattern signal by comparing the servo band signal with the ideal waveform signal. 
     A second aspect according to the technology of the present disclosure relates to the detection device according to the first aspect, in which the ideal waveform is a waveform determined in accordance with an orientation of the servo reading element on the magnetic tape. 
     A third aspect according to the technology of the present disclosure relates to the detection device according to the second aspect, in which the ideal waveform is a waveform determined in accordance with a geometrical characteristic of the servo pattern and the orientation of the servo reading element on the magnetic tape. 
     A fourth aspect according to the technology of the present disclosure relates to the detection device according to the first aspect, in which the servo reading element is mounted on a magnetic head, and the ideal waveform is a waveform determined in accordance with an orientation of the magnetic head on the magnetic tape. 
     A fifth aspect according to the technology of the present disclosure relates to the detection device according to the fourth aspect, in which the ideal waveform is a waveform determined in accordance with a geometrical characteristic of the servo pattern and the orientation of the magnetic head on the magnetic tape. 
     A sixth aspect according to the technology of the present disclosure relates to the detection device according to any one of the first to fifth aspects, in which the servo pattern is at least one linear magnetization region pair, the linear magnetization region pair includes a first linear magnetization region which is linearly magnetized, and a second linear magnetization region which is linearly magnetized, and the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first imaginary straight line along a width direction of the magnetic tape. 
     A seventh aspect according to the technology of the present disclosure relates to the detection device according to the sixth aspect, in which the ideal waveform signal is classified into a first ideal waveform signal corresponding to the first linear magnetization region and a second ideal waveform signal corresponding to the second linear magnetization region, the servo pattern signal includes a first linear magnetization region signal which is a result of reading the first linear magnetization region by the servo reading element, and a second linear magnetization region signal which is a result of reading the second linear magnetization region by the servo reading element, the processing device includes a first detection circuit and a second detection circuit which are connected in parallel, the first detection circuit acquires the servo band signal, and detects the first linear magnetization region signal by comparing the acquired servo band signal with the first ideal waveform signal, and the second detection circuit acquires the servo band signal, and detects the second linear magnetization region signal by comparing the acquired servo band signal with the second ideal waveform signal. 
     An eighth aspect according to the technology of the present disclosure relates to the detection device according to any one of the first to seventh aspects, in which the processing device detects the servo pattern signal by using an autocorrelation coefficient. 
     A ninth aspect according to the technology of the present disclosure relates to the detection device according to any one of the first to eighth aspects, in which the magnetic tape is accommodated in a cartridge, and a noncontact storage medium capable of communicating with the processing device in a noncontact manner is provided in the cartridge as the storage medium. 
     A tenth aspect according to the technology of the present disclosure relates to the detection device according to any one of the first to ninth aspects, in which the storage medium is the magnetic tape. 
     An eleventh aspect according to the technology of the present disclosure relates to the detection device according to any one of the first to tenth aspects, in which the ideal waveform signal is stored in advance in at least one end portion of both end portions of the magnetic tape. 
     A twelfth aspect according to the technology of the present disclosure relates to an inspection device comprising the detection device according to any one of the first to eleventh aspects, and an inspection processor that performs an inspection of the servo band in which the servo pattern is recorded in the magnetic tape based on the servo pattern signal detected by the detection device. 
     A thirteenth aspect according to the technology of the present disclosure relates to a magnetic tape drive comprising the detection device according to any one of the first to eleventh aspects, and a magnetic head that is operated in response to the servo pattern signal detected by the detection device. 
     A fourteenth aspect according to the technology of the present disclosure relates to a magnetic tape system comprising a magnetic tape drive including the detection device according to any one of the first to eleventh aspects, and a magnetic head that is operated in response to the servo pattern signal detected by the detection device, and a magnetic tape subjected to magnetic processing by the magnetic head. 
     A fifteenth aspect according to the technology of the present disclosure relates to a detection method comprising acquiring a servo band signal which is a result of reading a servo band of a magnetic tape by a servo reading element, and detecting a servo pattern signal which is a result of reading a servo pattern recorded in the servo band by the servo reading element by comparing the servo band signal with an ideal waveform signal indicating an ideal waveform of the servo pattern signal which is stored in advance in a storage medium. 
     A sixteenth aspect according to the technology of the present disclosure relates to an inspection method comprising performing an inspection of the servo band in which the servo pattern is recorded in the magnetic tape based on the servo pattern signal detected by the detection method according to the fifteenth aspect. 
     A seventeenth aspect according to the technology of the present disclosure relates to a program causing a computer to execute a process comprising acquiring a servo band signal which is a result of reading a servo band of a magnetic tape by a servo reading element, and detecting a servo pattern signal which is a result of reading a servo pattern recorded in the servo band by the servo reading element by comparing the servo band signal with an ideal waveform signal indicating an ideal waveform of the servo pattern signal which is stored in advance in a storage medium. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the technology of the disclosure will be described in detail based on the following figures, wherein: 
         FIG.  1    is a block diagram showing an example of a configuration of a magnetic tape system according to an embodiment; 
         FIG.  2    is a schematic perspective view of an example of an appearance of a magnetic tape cartridge according to the embodiment; 
         FIG.  3    is a schematic configuration diagram showing an example of a hardware configuration of a magnetic tape drive according to the embodiment; 
         FIG.  4    is a schematic perspective view showing an example of an aspect in which a magnetic field is released by a noncontact read/write device from a lower side of the magnetic tape cartridge according to the embodiment; 
         FIG.  5    is a schematic configuration diagram showing an example of the hardware configuration of the magnetic tape drive according to the embodiment; 
         FIG.  6    is a conceptual diagram showing an example of an aspect in which a state in which a magnetic head is disposed on a magnetic tape according to the embodiment is observed from a front surface side of the magnetic tape; 
         FIG.  7    is a conceptual diagram showing an example of an aspect in which the magnetic tape according to the embodiment before and after a width of the magnetic tape contracts is observed from the front surface side of the magnetic tape; 
         FIG.  8    is a conceptual diagram showing an example of an aspect in which a state in which the magnetic head is skewed on the magnetic tape according to the embodiment is observed from the front surface side of the magnetic tape; 
         FIG.  9    is a conceptual diagram showing an example of a function of a processing device provided in the magnetic tape drive according to the embodiment; 
         FIG.  10    is a conceptual diagram showing an example of processing contents of a first position detection device provided in the processing device provided in the magnetic tape drive according to the embodiment; 
         FIG.  11    is a conceptual diagram showing an example of processing contents of a control device provided in the processing device provided in the magnetic tape drive according to the embodiment; 
         FIG.  12    is a conceptual diagram showing an example of a configuration of a servo writer according to the embodiment; 
         FIG.  13    is a flowchart showing an example of a flow of servo pattern detection processing according to the embodiment; 
         FIG.  14    is a conceptual diagram showing a first modification example, and is a conceptual diagram showing a modification example of the magnetic tape according to the embodiment (conceptual diagram showing an example of an aspect in which the magnetic tape is observed from the front surface side of the magnetic tape); 
         FIG.  15    is a conceptual diagram showing the first modification example, and is a conceptual diagram showing a relationship between a geometrical characteristic of an actual servo pattern and a geometrical characteristic of an imaginary servo pattern; 
         FIG.  16    is a conceptual diagram showing the first modification example, and is a conceptual diagram showing an example of an aspect in which a state in which frames corresponding to each other between the servo bands adjacent to each other in a width direction of the magnetic tape according to the embodiment deviate from each other at a predetermined interval is observed from the front surface side of the magnetic tape; 
         FIG.  17    is a conceptual diagram showing the first modification example, and is a conceptual diagram showing an example of an aspect in which a state in which the servo pattern is read by a servo reading element provided in the magnetic head that is not skewed on the magnetic tape according to the embodiment is observed from the front surface side of the magnetic tape; 
         FIG.  18    is a conceptual diagram showing the first modification example, and is a conceptual diagram showing an example of an aspect in which a state in which the servo pattern is read by the servo reading element provided in the magnetic head that is skewed on the magnetic tape according to the embodiment is observed from the front surface side of the magnetic tape; 
         FIG.  19    is a conceptual diagram showing the first modification example, and is a conceptual diagram showing an example of processing contents of the first position detection device and the control device provided in the processing device provided in the magnetic tape drive; 
         FIG.  20    is a conceptual diagram showing a second modification example, and is a conceptual diagram showing a modification example of the magnetic tape according to the embodiment (conceptual diagram showing an example of an aspect in which the magnetic tape is observed from the front surface side of the magnetic tape); 
         FIG.  21    is a conceptual diagram showing the second modification example, and is a conceptual diagram showing an example of an aspect of the servo pattern included in the magnetic tape; 
         FIG.  22    is a conceptual diagram showing a third modification example, and is a conceptual diagram showing a modification example of the magnetic tape according to the embodiment (conceptual diagram showing an example of an aspect in which the magnetic tape is observed from the front surface side of the magnetic tape); 
         FIG.  23    is a conceptual diagram showing the third modification example, and is a conceptual diagram showing an example of an aspect of the servo pattern included in the magnetic tape; 
         FIG.  24    is a conceptual diagram showing a fourth modification example, and is a conceptual diagram showing an example of an aspect in which a state in which frames corresponding to each other between the servo bands adjacent to each other in the width direction of the magnetic tape according to the embodiment deviate from each other at a predetermined interval is observed from the front surface side of the magnetic tape; 
         FIG.  25    is a conceptual diagram showing a fifth modification example, and is a conceptual diagram showing a modification example of the magnetic tape according to the embodiment (conceptual diagram showing an example of an aspect in which the magnetic tape is observed from the front surface side of the magnetic tape); 
         FIG.  26    is a conceptual diagram showing the fifth modification example, and is a conceptual diagram showing a relationship between the geometrical characteristic of the actual servo pattern and the geometrical characteristic of the imaginary servo pattern; 
         FIG.  27    is a conceptual diagram showing the fifth modification example, and is a conceptual diagram showing an example of an aspect in which a state in which frames corresponding to each other between the servo bands adjacent to each other in the width direction of the magnetic tape according to the embodiment deviate from each other at a predetermined interval is observed from the front surface side of the magnetic tape; 
         FIG.  28    is a conceptual diagram showing the fifth modification example, and is a conceptual diagram showing an example of an aspect in which a state in which the servo pattern is read by the servo reading element provided in the magnetic head that is skewed on the magnetic tape according to the embodiment is observed from the front surface side of the magnetic tape; 
         FIG.  29    is a conceptual diagram showing a sixth modification example, and is a conceptual diagram showing a modification example of the magnetic tape according to the embodiment (conceptual diagram showing an example of an aspect in which the magnetic tape is observed from the front surface side of the magnetic tape); 
         FIG.  30    is a conceptual diagram showing the sixth modification example, and is a conceptual diagram showing an example of an aspect of the servo pattern included in the magnetic tape; 
         FIG.  31    is a conceptual diagram showing a seventh modification example, and is a conceptual diagram showing a modification example of the magnetic tape according to the embodiment (conceptual diagram showing an example of an aspect in which the magnetic tape is observed from the front surface side of the magnetic tape); 
         FIG.  32    is a conceptual diagram showing the seventh modification example, and is a conceptual diagram showing an example of an aspect of the servo pattern included in the magnetic tape; 
         FIG.  33    is a conceptual diagram showing an eighth modification example, and is a conceptual diagram showing a modification example of the magnetic tape according to the embodiment (conceptual diagram showing an example of an aspect in which the magnetic tape is observed from the front surface side of the magnetic tape); and 
         FIG.  34    is a conceptual diagram showing an example of an aspect in which a servo pattern detection program stored in a storage medium is installed in a computer of the position detection device. 
     
    
    
     DETAILED DESCRIPTION 
     In the following, an example of an embodiment of a detection device, an inspection device, a magnetic tape drive, a magnetic tape system, a detection method, an inspection method, and a program 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. 
     NVM refers to an abbreviation of “non-volatile memory”. CPU refers to an abbreviation of “central processing unit”. RAM refers to an abbreviation of “random access memory”. EEPROM refers to an abbreviation of “electrically erasable and programmable read only memory”. SSD refers to an abbreviation of “solid state drive”. HDD refers to an abbreviation of “hard disk drive”. ASIC refers to an abbreviation of “application specific integrated circuit”. FPGA refers to an abbreviation of “field-programmable gate array”. PLC is an abbreviation of “programmable logic controller”. IC refers to an abbreviation of “integrated circuit”. RFID refers to an abbreviation of “radio frequency identifier”. BOT refers to an abbreviation of “beginning of tape”. EOT refers to an abbreviation of “end of tape”. UI refers to an abbreviation of “user interface”. WAN refers to an abbreviation of “wide area network”. LAN refers to an abbreviation of “local area network”. In addition, in the following description, the geometrical characteristic refers to a generally recognized geometrical characteristic, such as a length, a shape, an orientation, and/or a position. 
     As an example, as shown in  FIG.  1   , a magnetic tape system  10  comprises a magnetic tape cartridge  12  and a magnetic tape drive  14 . A magnetic tape cartridge  12  is loaded into the magnetic tape drive  14 . The magnetic tape cartridge  12  accommodates a magnetic tape MT. The magnetic tape drive  14  pulls out the magnetic tape MT from the loaded magnetic tape cartridge  12 , and records data in the magnetic tape MT and reads data from the magnetic tape MT while causing the pulled out magnetic tape MT to travel. 
     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 system  10  is an example of a “magnetic tape system” according to the technology of the present disclosure. In addition, in the present embodiment, the magnetic tape drive  14  is an example of a “magnetic tape drive” and a “detection device” according to the technology of the present disclosure. In addition, in the present embodiment, the magnetic tape cartridge  12  is 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 cartridge  12  will be described with reference to  FIGS.  2  to  4   . It should be noted that, in the following description, for convenience of description, in  FIGS.  2  to  4   , a loading direction of the magnetic tape cartridge  12  into the magnetic tape drive  14  is indicated by an arrow A, a direction of the arrow A is defined as a front direction of the magnetic tape cartridge  12 , and a side of the magnetic tape cartridge  12  in the front direction is defined as a front side of the magnetic tape cartridge  12 . In the following description of the structure, “front” refers to the front side of the magnetic tape cartridge  12 . 
     In addition, in the following description, for convenience of description, in  FIGS.  2  to  4   , a direction of an arrow B orthogonal to the direction of the arrow A is defined as a right direction, and a side of the magnetic tape cartridge  12  in the right direction is defined as a right side of the magnetic tape cartridge  12 . In the following description of the structure, “right” refers to the right side of the magnetic tape cartridge  12 . 
     In addition, in the following description, for convenience of description, in  FIGS.  2  to  4   , a direction opposite to the direction of the arrow B is defined as a left direction, and a side of the magnetic tape cartridge  12  in the left direction is defined as a left side of the magnetic tape cartridge  12 . In the following description of the structure, “left” refers to the left side of the magnetic tape cartridge  12 . 
     In addition, in the following description, for convenience of description, in  FIGS.  2  to  4   , a direction orthogonal to the direction of the arrow A and 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 cartridge  12 , and a side of the magnetic tape cartridge  12  in the upper direction is defined as an upper side of the magnetic tape cartridge  12 . In the following description of the structure, “upper” refers to the upper side of the magnetic tape cartridge  12 . 
     In addition, in the following description, for convenience of description, in  FIGS.  2  to  4   , a direction opposite to the front direction of the magnetic tape cartridge  12  is defined as a rear direction of the magnetic tape cartridge  12 , and a side of the magnetic tape cartridge  12  in the rear direction is defined as a rear side of the magnetic tape cartridge  12 . In the following description of the structure, “rear” refers to the rear side of the magnetic tape cartridge  12 . 
     In addition, in the following description, for convenience of description, in  FIGS.  2  to  4   , a direction opposite to the upper direction of the magnetic tape cartridge  12  is defined as a lower direction of the magnetic tape cartridge  12 , and a side of the magnetic tape cartridge  12  in the lower direction is defined as a lower side of the magnetic tape cartridge  12 . In the following description of the structure, “lower” refers to the lower side of the magnetic tape cartridge  12 . 
     As an example, as shown in  FIG.  2   , the magnetic tape cartridge  12  has a substantially rectangular shape in a plan view, and comprises a box-shaped case  16 . The case  16  is an example of a “case” according to the technology of the present disclosure. The magnetic tape MT is accommodated in the case  16 . The case  16  is made of resin, such as polycarbonate, and comprises an upper case  18  and a lower case  20 . The upper case  18  and the lower case  20  are bonded by welding (for example, ultrasound welding) and screwing in a state in which a lower peripheral edge surface of the upper case  18  and an upper peripheral edge surface of the lower case  20  are brought into contact with each other. The bonding method is not limited to welding and screwing, and other bonding methods may be used. 
     A sending reel  22  is rotatably accommodated inside the case  16 . The sending reel  22  comprises a reel hub  22 A, an upper flange  22 B 1 , and a lower flange  22 B 2 . The reel hub  22 A is formed in a cylindrical shape. The reel hub  22 A is an axial center portion of the sending reel  22 , has an axial center direction along an up-down direction of the case  16 , and is disposed in a center portion of the case  16 . Each of the upper flange  22 B  1  and the lower flange  22 B 2  is formed in an annular shape. A center portion of the upper flange  22 B 1  in a plan view is fixed to an upper end portion of the reel hub  22 A, and a center portion of the lower flange  22 B 2  in a plan view is fixed to a lower end portion of the reel hub  22 A. It should be noted that the reel hub  22 A and the lower flange  22 B 2  may be integrally molded. 
     The magnetic tape MT is wound around an outer peripheral surface of the reel hub  22 A, and an end portion of the magnetic tape MT in a width direction is held by the upper flange  22 B 1  and the lower flange  22 B 2 . 
     An opening  16 B is formed on a front side of a right wall  16 A of the case  16 . The magnetic tape MT is pulled out from the opening  16 B. 
     A cartridge memory  24  is provided in the lower case  20 . Specifically, the cartridge memory  24  is accommodated in a right rear end portion of the lower case  20 . An IC chip including an NVM is mounted on the cartridge memory  24 . In the present embodiment, a so-called passive RFID tag is adopted as the cartridge memory  24 , and the read/write of various pieces of information is performed with respect to the cartridge memory  24  in a noncontact manner. 
     The cartridge memory  24  stores management information for managing the magnetic tape cartridge  12 . Examples of the management information include information on the cartridge memory  24  (for example, information for specifying the magnetic tape cartridge  12 ), information on the magnetic tape MT (for example, information indicating a recording capacity of the magnetic tape MT, information indicating an outline of the data recorded in the magnetic tape MT, information indicating items of the data recorded in the magnetic tape MT, and information indicating a recording format of the data recorded in the magnetic tape MT), and information on the magnetic tape drive  14  (for example, information indicating a specification of the magnetic tape drive  14  and a signal used in the magnetic tape drive  14 ). It should be noted that the cartridge memory  24  is an example of a “noncontact storage medium” according to the technology of the present disclosure. 
     As an example, as shown in  FIG.  3   , the magnetic tape drive  14  comprises a controller  25 , a transport device  26 , a magnetic head  28 , a UI system device  34 , and a communication interface  35 . The controller  25  is an example of a “detection device” according to the technology of the present disclosure, and comprises a processing device  30  and a storage  32 . The processing device  30  is an example of a “processing device” according to the technology of the present disclosure, and the storage  32  is an example of a “storage medium” according to the technology of the present disclosure. 
     The magnetic tape drive  14  is loaded into the magnetic tape cartridge  12  along the direction of the arrow A. In the magnetic tape drive  14 , the magnetic tape MT is pulled out from the magnetic tape cartridge  12  and used. 
     The magnetic tape MT has a magnetic layer  29 A, a base film  29 B, and a back coating layer  29 C. The magnetic layer  29 A is formed on one surface side of the base film  29 B, and the back coating layer  29 C is formed on the other surface side of the base film  29 B . The data is recorded in the magnetic layer  29 A. The magnetic layer  29 A contains ferromagnetic powder. As the ferromagnetic powder, for example, ferromagnetic powder generally used in the magnetic layer of various magnetic recording media is used. Preferable specific examples of the ferromagnetic powder include hexagonal ferrite powder. Examples of the hexagonal ferrite powder include hexagonal strontium ferrite powder and hexagonal barium ferrite powder. The back coating layer  29 C is a layer containing non-magnetic powder, such as carbon black. The base film  29 B is also referred to as a support, and is made of, for example, polyethylene terephthalate, polyethylene naphthalate, or polyamide. It should be noted that a non-magnetic layer may be formed between the base film  29 B and the magnetic layer  29 A. In the magnetic tape MT, a surface on which the magnetic layer  29 A is formed is a front surface  31  of the magnetic tape MT, and a surface on which the back coating layer  29 C is formed is a back surface  33  of the magnetic tape MT. 
     The magnetic tape drive  14  performs magnetic processing on the front surface  31  of the magnetic tape MT by using the magnetic head  28 . Here, the magnetic processing refers to recording the data in the front surface  31  of the magnetic tape MT and reading the data (that is, reproducing the data) from the front surface  31  of the magnetic tape MT. In the present embodiment, the magnetic tape drive  14  selectively records the data in the front surface  31  of the magnetic tape MT and reads the data from the front surface  31  of the magnetic tape MT by using the magnetic head  28 . That is, the magnetic tape drive  14  pulls out the magnetic tape MT from the magnetic tape cartridge  12 , records the data in the front surface  31  of the pulled out magnetic tape MT by using the magnetic head  28 , or reads the data from the front surface  31  of the pulled out magnetic tape MT by using the magnetic head  28 . 
     The processing device  30  controls the entire magnetic tape drive  14 . In the present embodiment, although the processing device  30  is realized by an ASIC, the technology of the present disclosure is not limited to this. For example, the processing device  30  may be realized by an FPGA and/or a PLC. In addition, the processing device  30  may be realized by the computer including a CPU, a flash memory (for example, an EEPROM and/or an SSD), and a RAM. In addition, the processing device  30  may be realized by combining two or more of an ASIC, an FPGA, a PLC, and a computer. That is, the processing device  30  may be realized by a combination of a hardware configuration and a software configuration. It should be noted that the processing device  30  is an example of a “processor” according to the technology of the present disclosure. 
     The storage  32  is connected to the processing device  30 , and the processing device  30  writes various pieces of information to the storage  32  and reads out various pieces of information from the storage  32 . Examples of the storage  32  include 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 on the magnetic tape drive  14 . 
     The UI system device  34  is a device having the reception function of receiving a command signal indicating a command from a user and the presentation function of presenting the information to the user. The reception function is realized by a touch panel, a hard key (for example, a keyboard), and/or a mouse, for example. The presentation function is realized by a display, a printer, and/or a speaker, for example. The UI system device  34  is connected to the processing device  30 . The processing device  30  acquires the command signal received by the UI system device  34 . The UI system device  34  presents various pieces of information to the user under the control of the processing device  30 . 
     The communication interface  35  is connected to the processing device  30 . In addition, the communication interface  35  is connected to an external device  37  via a communication network (not shown), such as a WAN and/or a LAN. The communication interface  35  controls the exchange of various pieces of information (for example, the data to be recorded in the magnetic tape MT, the data read from the magnetic tape MT, and/or a command signal given to the processing device  30 ) between the processing device  30  and the external device  37 . It should be noted that examples of the external device  37  include a personal computer and a mainframe. 
     The transport device  26  is a device that selectively transports the magnetic tape MT along a predetermined path in a forward direction and a backward direction, and comprises a sending motor  36 , a winding reel  38 , a winding motor  40 , and a plurality of guide rollers GR. It should be noted that, here, the forward direction refers to a sending direction of the magnetic tape MT, and the backward direction refers to a rewinding direction of the magnetic tape MT. In the present embodiment, the transport device  26  is an example of a “travel mechanism” according to the technology of the present disclosure. 
     The sending motor  36  rotates the sending reel  22  in the magnetic tape cartridge  12  under the control of the processing device  30 . The processing device  30  controls the sending motor  36  to control a rotation direction, a rotation speed, a rotation torque, and the like of the sending reel  22 . 
     The winding motor  40  rotates the winding reel  38  under the control of the processing device  30 . The processing device  30  controls the winding motor  40  to control a rotation direction, a rotation speed, a rotation torque, and the like of the winding reel  38 . 
     In a case in which the magnetic tape MT is wound by the winding reel  38 , the processing device  30  rotates the sending motor  36  and the winding motor  40  such that the magnetic tape MT travels along the predetermined path in the forward direction. The rotation speed, the rotation torque, and the like of the sending motor  36  and the winding motor  40  are adjusted in accordance with a speed at which the magnetic tape MT is wound around the winding reel  38 . In addition, by adjusting the rotation speed, the rotation torque, and the like of each of the sending motor  36  and the winding motor  40  by the processing device  30 , the tension is applied 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 sending motor  36  and the winding motor  40  by the processing device  30 . 
     It should be noted that, in a case in which the magnetic tape MT is rewound to the sending reel  22 , the processing device  30  rotates the sending motor  36  and the winding motor  40  such that the magnetic tape MT travels 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 sending motor  36  and the winding motor  40 , 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 which guides the magnetic tape MT. The predetermined path, that is, a traveling path of the magnetic tape MT is determined by separately disposing the plurality of guide rollers GR at positions straddling the magnetic head  28  between the magnetic tape cartridge  12  and the winding reel  38 . 
     The magnetic head  28  comprises a magnetic element unit  42  and a holder  44 . The magnetic element unit  42  is held by the holder  44  to come into contact with the traveling magnetic tape MT. The magnetic element unit  42  includes a plurality of magnetic elements. 
     The magnetic element unit  42  records the data in the magnetic tape MT transported by the transport device  26 , and reads the data from the magnetic tape MT transported by the transport device  26 . Here, the data refers to, for example, a servo pattern  58  (see  FIG.  9   ) and the data other than the servo pattern  58 , that is, the data recorded in a data band DB (see  FIG.  9   ). 
     The magnetic tape drive  14  comprises a noncontact read/write device  46 . The noncontact read/write device  46  is disposed to face a back surface  24 A of the cartridge memory  24  on the lower side of the magnetic tape cartridge  12  in a state in which the magnetic tape cartridge  12  is loaded, and performs the read/write of the information with respect to the cartridge memory  24  in a noncontact manner. 
     As an example, as shown in  FIG.  4   , the noncontact read/write device  46  releases a magnetic field MF from the lower side of the magnetic tape cartridge  12  toward the cartridge memory  24 . The magnetic field MF passes through the cartridge memory  24 . 
     The noncontact read/write device  46  is connected to the processing device  30 . The processing device  30  outputs a control signal to the noncontact read/write device  46 . The control signal is a signal for controlling the cartridge memory  24 . The noncontact read/write device  46  generates the magnetic field MF in response to the control signal input from the processing device  30 , and releases the generated magnetic field MF toward the cartridge memory  24 . 
     The noncontact read/write device  46  performs noncontact communication with the cartridge memory  24  via the magnetic field MF to perform processing on the cartridge memory  24  in response to the control signal. For example, the noncontact read/write device  46  selectively performs, under the control of the processing device  30 , processing of reading the information from the cartridge memory  24  and processing of storing the information in the cartridge memory  24  (that is, processing of writing the information to the cartridge memory  24 ). 
     As an example, as shown in  FIG.  5   , the magnetic tape drive  14  comprises a moving mechanism  48 . The moving mechanism  48  includes a movement actuator  48 A. Examples of the movement actuator  48 A include a voice coil motor and/or a piezo actuator. The movement actuator  48 A is connected to the processing device  30 , and the processing device  30  controls the movement actuator  48 A. The movement actuator  48 A generates power under the control of the processing device  30 . The moving mechanism  48  moves the magnetic head  28  in the width direction of the magnetic tape MT by receiving the power generated by the movement actuator  48 A. 
     The magnetic tape drive  14  comprises an inclination mechanism  49 . The inclination mechanism  49  includes an inclination actuator  49 A. Examples of the inclination actuator  49 A include a voice coil motor and/or a piezo actuator. The inclination actuator  49 A is connected to the processing device  30 , and the processing device  30  controls the inclination actuator  49 A. The inclination actuator  49 A generates power under the control of the processing device  30 . The inclination mechanism  49  inclines the magnetic head  28  to a longitudinal direction LD side of the magnetic tape MT with respect to a width direction WD of the magnetic tape MT by receiving the power generated by the inclination actuator  49 A (see  FIG.  8   ). That is, the magnetic head  28  is skewed on the magnetic tape MT under the control of the processing device  30 . 
     As an example, as shown in  FIG.  6   , on the front surface  31  of the magnetic tape MT, servo bands SB 1 , SB 2 , and SB 3  are data bands DB 1  and DB 2  are formed. It should be noted that, in the following, for convenience of description, in a case in which the distinction is not specifically needed, the servo bands SB 1  to SB 3  are referred to as a servo band SB, and the data bands DB 1  and DB 2  are referred to as the data band DB. 
     The servo bands SB 1  to SB 3  and the data bands DB 1  and DB 2  are formed along the longitudinal direction LD (that is, a total length direction) of the magnetic tape MT. Here, the total length direction of the magnetic tape MT refers to the traveling direction of the magnetic tape MT, in other words. The traveling 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 travels from the sending reel  22  side to the winding reel  38  side (hereinafter, also simply referred to as “forward direction”), and the backward direction which is a direction in which the magnetic tape MT travels from the winding reel  38  side to the sending reel  22  side (hereinafter, also simply referred to as “backward direction”). 
     The servo bands SB 1  to SB 3  are arranged at positions spaced in the width direction WD of the magnetic tape MT (hereinafter, also simply referred to as “width direction WD”). For example, the servo bands SB 1  to SB 3  are arranged at equal intervals along the width direction WD. It should be noted that, in the present embodiment, “equal interval” refers to the equal interval in the sense of 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 exact equal interval. 
     The data band DB 1  is disposed between the servo band SB 1  and the servo band SB 2 , and the data band DB 2  is disposed between a servo band SB 2  and a servo band SB 3 . That is, the servo bands SB and the data bands DB are arranged alternately along the width direction WD. 
     It should be noted that, in the example shown in  FIG.  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 in which four or more servo bands SB and three or more data bands DB are used. 
     A plurality of servo patterns  52  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. The servo patterns  52  are classified into a servo pattern  52 A and a servo pattern  52 B. The plurality of servo patterns  52  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT. It should be noted that, in the present embodiment, “regular” refers to the regularity in the sense of 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 exact regularity. 
     The servo band SB is divided by a plurality of frames  50  along the longitudinal direction LD of the magnetic tape MT. The frame  50  is defined by one set of servo patterns  52 . In the example shown in  FIG.  6   , the servo patterns  52 A and  52 B are shown as an example of the set of servo patterns  52 . The servo patterns  52 A and  52 B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern  52 A is positioned on the upstream side in the forward direction in the frame  50 , and the servo pattern  52 B is positioned on the downstream side in the forward direction. 
     The servo pattern  52  consists of a linear magnetization region pair  54 . The linear magnetization region pair  54  is an example of a “linear magnetization region pair” according to the technology of the present disclosure. The linear magnetization region pair  54  is classified into a linear magnetization region pair  54 A and a linear magnetization region pair  54 B. 
     The servo pattern  52 A consists of the linear magnetization region pair  54 A. In the example shown in  FIG.  6   , linear magnetization regions  54 A 1  and  54 A 2  are shown as an example of the linear magnetization region pair  54 A. Each of the linear magnetization regions  54 A 1  and  54 A 2  is a linearly magnetized region. The linear magnetization region  54 A 1  is an example of a “first linear magnetization region” according to the technology of the present disclosure, and the linear magnetization region  54 A 2  is a “second linear magnetization region” according to the technology of the present disclosure. 
     The linear magnetization regions  54 A 1  and  54 A 2  are inclined in opposite directions with respect to an imaginary straight line C 1  which is an imaginary straight line along the width direction WD. In the example shown in  FIG.  6   , the linear magnetization regions  54 A 1  and  54 A 2  are inclined line-symmetrically with respect to the imaginary straight line C 1 . More specifically, the linear magnetization regions  54 A 1  and  54 A 2  are 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 C 1  as the symmetry axis. 
     The linear magnetization region  54 A 1  is a set of magnetization straight lines  54 A 1   a , which are five magnetized straight lines. The linear magnetization region  54 A 2  is a set of magnetization straight lines  54 A 2   a,  which are five magnetized straight lines. 
     The servo pattern  52 B consists of the linear magnetization region pair  54 B. In the example shown in  FIG.  6   , linear magnetization regions  54 B 1  and  54 B 2  are shown as an example of the linear magnetization region pair  54 B. Each of the linear magnetization regions  54 B 1  and  54 B 2  is a linearly magnetized region. The linear magnetization region  54 B 1  is an example of a “first linear magnetization region” according to the technology of the present disclosure, and the linear magnetization region  54 B 2  is a “second linear magnetization region” according to the technology of the present disclosure. 
     The linear magnetization regions  54 B 1  and  54 B 2  are inclined in opposite directions with respect to an imaginary straight line C 2  which is an imaginary straight line along the width direction WD. In the example shown in  FIG.  6   , the linear magnetization regions  54 B 1  and  54 B 2  are inclined line-symmetrically with respect to the imaginary straight line C 2 . More specifically, the linear magnetization regions  54 B 1  and  54 B 2  are 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 C 2  as the symmetry axis. 
     The linear magnetization region  54 B 1  is a set of magnetization straight lines  54 B 1   a , which are four magnetized straight lines. The linear magnetization region  54 B 2  is a set of magnetization straight lines  54 B 2   a,  which are four magnetized straight lines. 
     The magnetic head  28  is disposed on the front surface  31  side of the magnetic tape MT configured as described above. The holder  44  is formed in a rectangular parallelepiped shape, and is disposed to cross the front surface  31  of the magnetic tape MT along the width direction WD. The plurality of magnetic elements of the magnetic element unit  42  are arranged in a straight line along the longitudinal direction of the holder  44 . The magnetic element unit  42  has a pair of servo reading elements SR and a plurality of data read/write elements DRW as the plurality of magnetic elements. A length of the holder  44  in the longitudinal direction is sufficiently long with respect to the width of the magnetic tape MT. For example, the length of the holder  44  in the longitudinal direction is set to a length exceeding the width of the magnetic tape MT even in a case in which the magnetic element unit  42  is disposed at any position on the magnetic tape MT. 
     The pair of servo reading elements SR are mounted on the magnetic head  28 . In the magnetic head  28 , a relative positional relationship between the holder  44  and the pair of servo reading elements SR is fixed. The pair of servo reading elements SR consists of servo reading elements SR 1  and SR 2 . The servo reading element SR 1  is disposed at one end of the magnetic element unit  42 , and the servo reading element SR 2  is disposed at the other end of the magnetic element unit  42 . In the example shown in  FIG.  6   , the servo reading element SR 1  is provided at a position corresponding to the servo band SB 2 , and the servo reading element SR 2  is provided at a position corresponding to the servo band SB 3 . 
     The plurality of data read/write elements DRW are disposed in a straight line between the servo reading element SR 1  and the servo reading element SR 2 . The plurality of data read/write elements DRW are disposed at intervals along the longitudinal direction of the magnetic head  28  (for example, are disposed at equal intervals along the longitudinal direction of the magnetic head  28 ). In the example shown in  FIG.  6   , the plurality of data read/write elements DRW are provided at positions corresponding to the data band DB 2 . 
     The processing device  30  acquires a servo signal which is a result of reading the servo pattern  52  by the servo reading element SR, and performs a servo control in response to the acquired servo signal. Here, the servo control refers to a control of moving the magnetic head  28  in the width direction WD of the magnetic tape MT by operating the moving mechanism  48  in accordance with the servo pattern  52  read by the servo reading element SR. 
     By performing the servo control, the plurality of data read/write elements DRW are positioned on a designated region in the data band DB, and perform the magnetic processing on the designated region in the data band DB. In the example shown in  FIG.  6   , the plurality of data read/write elements DRW perform the magnetic processing on the designated region in the data band DB 2 . 
     In addition, in a case in which the data band DB of which the data is to be read by the magnetic element unit  42  is changed (in the example shown in  FIG.  6   , the data band DB of which the data is to be read by the magnetic element unit  42  is changed from the data band DB 2  to the data band DB 1 ), the moving mechanism  48  moves, under the control of the processing device  30 , the magnetic head  28  in the width direction WD to change the position of the pair of servo reading elements SR. That is, by moving the magnetic head  28  in the width direction WD, the moving mechanism  48  moves the servo reading element SR 1  to a position corresponding to the servo band SB 1  and moves the servo reading element SR 2  to the position corresponding to the servo band SB 2 . As a result, the positions of the plurality of data read/write elements DRW are changed from the data band DB 2  to the data band DB 1 , and the plurality of data read/write elements DRW perform the magnetic processing on the data band DB 1 . 
     By the way, 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 in which 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 in  FIG.  7   , 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. 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 in which 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 pattern  52  diverges from a predetermined position (for example, the center position of each of the linear magnetization regions  54 A 1 ,  54 A 2 ,  54 B 1 , and  54 B 2 ) determined by design in the width direction WD. In a case in which the position of the servo reading element SR with respect to the servo pattern  52  diverges from the predetermined position determined by the design in the width direction WD, the accuracy of the servo control is deteriorated, and the position of the track 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, as shown in  FIG.  8    as an example, a method of holding the position of the servo reading element SR with respect to the servo pattern  52  at the predetermined position determined by design by skewing the magnetic head  28  on the magnetic tape MT is known. 
     The magnetic head  28  comprises a rotation axis RA. The rotation axis RA is provided at a position corresponding to a center portion of the magnetic element unit  42  provided in the magnetic head  28  in a plan view. The magnetic head  28  is rotatably held by the inclination mechanism  49  via the rotation axis RA. An imaginary straight line C 3  which is an imaginary center line is provided in the magnetic head  28 . The imaginary straight line C 3  is a straight line that passes through the rotation axis RA and extends in the longitudinal direction of the magnetic head  28  in a plan view (that is, the direction in which the plurality of data read/write elements DRW are arranged). The magnetic head  28  is held by the inclination mechanism  49  to have a posture in which the imaginary straight line C 3  is inclined to the longitudinal direction LD side of the magnetic tape MT with respect to an imaginary straight line C 4  which is an imaginary straight line along the width direction WD. In the example shown in  FIG.  8   , the magnetic head  28  is held by the inclination mechanism  49  in a posture in which the imaginary straight line C 3  is inclined toward the sending reel  22  side with respect to the imaginary straight line C 4  (that is, a posture inclined counterclockwise as viewed from a paper surface side of  FIG.  8   ). 
     The inclination mechanism  49  receives the power from the inclination actuator  49 A (see  FIG.  5   ) to rotate the magnetic head  28  around the rotation axis RA on the front surface  31  of the magnetic tape MT. The inclination mechanism  49  rotates, under the control of the processing device  30 , the magnetic head  28  around the rotation axis RA on the front surface  31  of the magnetic tape MT to change the direction of the inclination of the imaginary straight line C 3  with respect to the imaginary straight line C 4  (that is, azimuth) and the inclined angle. 
     By changing the direction of the inclination of the imaginary straight line C 3  with respect to the imaginary straight line C 4  and the inclined 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 pattern  52  is held at the predetermined position determined in design. 
     By the way, the servo reading element SR is formed in a straight line along the imaginary straight line C 3 . Therefore, in a case in which the servo pattern  52 A is read by the servo reading element SR, in the linear magnetization region pair  54 A, an angle formed by the linear magnetization region  54 A 1  and the servo reading element SR and an angle formed by the linear magnetization region  54 A 2  and the servo reading element SR are different. In a case in which the angles are different in this way, a variation due to an azimuth loss (for example, variation in signal level and waveform distortion) occurs between the servo signal derived from the linear magnetization region  54 A 1  (that is, the servo signal obtained by reading the linear magnetization region  54 A 1  by the servo reading element SR) and the servo signal derived from the linear magnetization region  54 A 2  (that is, the servo signal obtained by reading the linear magnetization region  54 A 2  by the servo reading element SR). In the example shown in  FIG.  8   , since the angle formed by the servo reading element SR and the linear magnetization region  54 A 1  is larger than the angle formed by the servo reading element SR and the linear magnetization region  54 A 2 , the output of the servo signal is small, and the waveform also spreads, so that the variation occurs in the servo signal read by the servo reading element SR across the servo band SB in a state in which the magnetic tape MT travels. In addition, also in a case in which the servo pattern  52 B is read by the servo reading element SR, the variation due to the azimuth loss occurs between the servo signal derived from the linear magnetization region  54 B 1  and the servo signal derived from the linear magnetization region  54 B 2 . Such a variation in the servo signal can contribute to a decrease in the accuracy of the servo control. 
     As a method of detecting the servo signal, a method of detecting the servo signal by comparing a signal level of the servo signal with a threshold value is known. However, as described above, since there is a variation in the signal level of the servo signal, the servo signal having a small signal level is not detected in a case in which the threshold value is too large, or the noise is erroneously detected as the servo signal in a case in which the threshold value is too small. 
     Therefore, in view of such circumstances, servo pattern detection processing (see  FIG.  13   ) is performed in the controller  25  (see  FIG.  3   ) of the magnetic tape drive  14  according to the present embodiment. The servo pattern detection processing is processing of detecting the servo pattern signal, which is a result of reading the servo pattern  52  by the servo reading element SR, by comparing the servo signal with an ideal waveform signal indicating an ideal waveform of the servo signal. In the following, the servo pattern detection processing will be specifically described. 
     As an example, as shown in  FIG.  9   , the processing device  30  includes a control device  30 A and a position detection device  30 B. The position detection device  30 B includes a first position detection device  30 B 1  and a second position detection device  30 B 2 . The position detection device  30 B acquires a servo band signal that is a result of reading the servo band SB by the servo reading element SR, and detects the position of the magnetic head  28  on the magnetic tape MT based on the acquired servo band signal. The servo band signal includes a signal (for example, noise) unnecessary for the servo control in addition to the servo pattern signal which is the result of reading the servo pattern  52 . Therefore, in order to realize the control based on the servo pattern signal (for example, servo control) with high accuracy, the processing device  30  needs to detect the servo pattern signal from the servo band signal with high accuracy. 
     The position detection device  30 B acquires the servo band signal from the magnetic head  28 . The servo band signal is classified into a first servo band signal S 1  and a second servo band signal S 2 . The first servo band signal S 1  is the signal indicating a result of reading the servo band SB by the servo reading element SR 1 , and the second servo band signal S 2  is the signal indicating a result of reading the servo band SB by the servo reading element SR 2 . The first position detection device  30 B 1  acquires the first servo band signal S 1 , and the second position detection device  30 B 2  acquires the second servo band signal S 2 . In the example shown in  FIG.  9   , the signal obtained by reading the servo band SB 2  by the servo reading element SR 1  is shown as an example of the first servo band signal S 1 , and the signal obtained by reading the servo band SB 3  by the servo reading element SR 2  is shown as an example of the second servo band signal S 2 . 
     The first position detection device  30 B 1  detects a position of the servo reading element SR 1  with respect to the servo band SB 2  based on the first servo band signal S 1 . The second position detection device  30 B 2  detects a position of the servo reading element SR 2  with respect to the servo band SB 3  based on the second servo band signal S 2 . 
     The control device  30 A performs various controls based on a position detection result by the first position detection device  30 B 1  (that is, a result of detecting the position by the first position detection device  30 B 1 ) and a position detection result by the second position detection device  30 B 2  (that is, a result of detecting the position by the second position detection device  30 B 2 ). Here, the various controls refer to, for example, the servo control, a skew angle control, and/or a tension control. The tension control refers to a control of the tension applied to the magnetic tape MT (for example, the tension for reducing the influence of the TDS). 
     Next, a specific configuration example of the first position detection device  30 B 1  will be described. It should be noted that since a configuration of the second position detection device  30 B 2  is the same as a configuration of the first position detection device  30 B 1 , the description of a specific configuration example of the second position detection device  30 B 2  will be omitted. In addition, in the following, for convenience of description, the servo signal derived from the linear magnetization region  54 A 1  or  54 B 1  (see  FIGS.  8  and  9   ) is also referred to as a “first linear magnetization region signal”, and the servo signal derived from the linear magnetization region  54 A 2  or  54 B 2  (see  FIGS.  8  and  9   ) is also referred to as a “second linear magnetization region signal”. 
     As an example, as shown in  FIG.  10   , the first position detection device  30 B 1  includes a first detection circuit  39 A and a second detection circuit  39 B. The first detection circuit  39 A and the second detection circuit  39 B are connected in parallel and comprise an input terminal  30 B 1   a  and an output terminal  30 B 1   b  common to each other. In the example shown in  FIG.  10   , an aspect example is shown in which the first servo band signal S 1  is input to the input terminal  30 B 1   a . The first servo band signal S 1  includes a first linear magnetization region signal S 1   a  and a second linear magnetization region signal S 1   b . The first linear magnetization region signal S 1   a  and the second linear magnetization region signal S 1   b  are the servo pattern signals (that is, analog servo pattern signals) which are the results of read by the servo reading element SR 1  (see  FIG.  9   ). That is, the servo pattern signal includes the first linear magnetization region signal S 1   a  and the second linear magnetization region signal S 1   b.    
     An ideal waveform signal  66  is stored in advance in the storage  32 . The ideal waveform signal  66  is a signal indicating the ideal waveform of the servo pattern signal (that is, the analog servo pattern signal) which is a result of reading the servo pattern  52  (see  FIGS.  8  and  9   ) recorded in the servo band SB of the magnetic tape MT by the servo reading element SR. The ideal waveform signal  66  can be said to be a sample signal compared with the first servo band signal S 1 . 
     The ideal waveform signal  66  is classified into a first ideal waveform signal  66 A and a second ideal waveform signal  66 B. The first ideal waveform signal  66 A corresponds to the first linear magnetization region signal S 1   a , and is a signal indicating the ideal waveform of the first linear magnetization region signal S 1   a . The second ideal waveform signal  66 B corresponds to the second linear magnetization region signal S 1   b , and is a signal indicating the ideal waveform of the second linear magnetization region signal S 1   b . More specifically, for example, the first ideal waveform signal  66 A is a signal indicating a single ideal waveform included in the first linear magnetization region signal S 1   a  (for example, an ideal signal which is a result of reading one of an ideal magnetization straight lines included in the servo pattern  52  by the servo reading element SR). In addition, for example, the second ideal waveform signal  66 B is a signal indicating a single ideal waveform included in the second linear magnetization region signal S 1   b  (for example, an ideal signal which is a result of reading one of an ideal magnetization straight lines included in the servo pattern  52  by the servo reading element SR). 
     An ideal waveform indicated by a first ideal waveform signal  66 A is a waveform determined in accordance with an orientation of the magnetic head  28  on the magnetic tape MT. A relative positional relationship between the holder  44  (see  FIG.  8   ) of the magnetic head  28  and the servo reading element SR is fixed. Therefore, the ideal waveform indicated by the first ideal waveform signal  66 A 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 signal  66 A is a waveform determined in accordance with a geometrical characteristic of the linear magnetization region  54 A 1  of the servo pattern  52 A (for example, a geometrical characteristic of the magnetization straight line  54 A 1   a ) and the orientation of the magnetic head  28  on the magnetic tape MT. As described above, since the relative positional relationship between the holder  44  (see  FIG.  8   ) of the magnetic head  28  and the servo reading element SR is fixed, the ideal waveform indicated by the first ideal waveform signal  66 A can be said to be a waveform determined in accordance with the geometrical characteristic of the linear magnetization region  54 A 1  of the servo pattern  52 A (for example, geometrical characteristic of the magnetization straight line  54 A 1   a ) and the orientation of the servo reading element SR on the magnetic tape MT. Here, the orientation of the magnetic head  28  on the magnetic tape MT refers to, for example, an angle formed by the linear magnetization region  54 A 1  and the magnetic head  28  on 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 region  54 A 1  and the servo reading element SR on the magnetic tape MT. It should be noted that the ideal waveform indicated by the first ideal waveform signal  66 A may be determined by also adding 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 head  28  in addition to the elements described above. 
     Similarly to the ideal waveform indicated by the first ideal waveform signal  66 A, an ideal waveform indicated by a second ideal waveform signal  66 B is also a waveform determined in accordance with the orientation of the magnetic head  28  on 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 signal  66 B is a waveform determined in accordance with the geometrical characteristic of the linear magnetization region  54 A 2  of the servo pattern  52 A (for example, geometrical characteristic of the magnetization straight line  54 A 2   a ) and the orientation of the magnetic head  28  on the magnetic tape MT, that is, a waveform determined in accordance with the geometrical characteristic of the linear magnetization region  54 A 2  of the servo pattern  52 A (for example, geometrical characteristic of the magnetization straight line  54 A 2   a ) and the orientation of the servo reading element SR on the magnetic tape MT. Here, the orientation of the magnetic head  28  on the magnetic tape MT refers to, for example, an angle formed by the linear magnetization region  54 A 2  and the magnetic head  28  on 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 region  54 A 2  and the servo reading element SR on the magnetic tape MT. It should be noted that, similarly to the ideal waveform indicated by the first ideal waveform signal  66 A the ideal waveform indicated by the second ideal waveform signal  66 B may be determined by also adding 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 head  28  in addition to the elements described above. 
     The first position detection device  30 B 1  detects a servo pattern signal S 1 A by comparing the first servo band signal S 1  with the ideal waveform signal  66 . In the example shown in  FIG.  10   , the first position detection device  30 B 1  detects the servo pattern signal S 1 A by using the first detection circuit  39 A and the second detection circuit  39 B. 
     The first servo band signal S 1  is input to the first detection circuit  39 A via the input terminal  30 B 1   a . The first detection circuit  39 A detects the first linear magnetization region signal S 1   a  from the input first servo band signal S 1  by using an autocorrelation coefficient. 
     The autocorrelation coefficient used by the first detection circuit  39 A is a coefficient indicating a degree of correlation between the first servo band signal S 1  and the first ideal waveform signal  66 A. The first detection circuit  39 A acquires the first ideal waveform signal  66 A from the storage  32  to compare the acquired first ideal waveform signal  66 A with the first servo band signal S 1 . Moreover, the first detection circuit  39 A calculates the autocorrelation coefficient based on the comparison result. The first detection circuit  39 A detects a position at which the correlation between the first servo band signal S 1  and the first ideal waveform signal  66 A is high (for example, position at which the first servo band signal S 1  and the first ideal waveform signal  66 A match) on the servo band SB (for example, servo band SB 2  shown in  FIG.  9   ) in accordance with the autocorrelation coefficient. 
     On the other hand, the first servo band signal S 1  is also input to the second detection circuit  39 B via the input terminal  30 B 1   a . The second detection circuit  39 B detects the second linear magnetization region signal S 1   b  from the input first servo band signal S 1  by using an autocorrelation coefficient. 
     The autocorrelation coefficient used by the second detection circuit  39 B is a coefficient indicating a degree of correlation between the first servo band signal S 1  and the second ideal waveform signal  66 B. The second detection circuit  39 B acquires the second ideal waveform signal  66 B from the storage  32  to compare the acquired second ideal waveform signal  66 B with the first servo band signal S 1 . Moreover, the second detection circuit  39 B calculates the autocorrelation coefficient based on the comparison result. The second detection circuit  39 B detects a position at which the correlation between the first servo band signal S 1  and the second ideal waveform signal  66 B is high (for example, position at which the first servo band signal S 1  and the second ideal waveform signal  66 B match) on the servo band SB (for example, servo band SB 2  shown in  FIG.  9   ) in accordance with the autocorrelation coefficient. 
     The first position detection device  30 B 1  detects the servo pattern signal S 1 A based on a detection result by the first detection circuit  39 A and a detection result by the second detection circuit  39 B. 
     The servo pattern signal S 1 A is output from the output terminal  30 B 1   b  to the control device  30 A. The servo pattern signal S 1 A is a signal indicating a logical sum of the first linear magnetization region signal S 1   a  detected by the first detection circuit  39 A and the second linear magnetization region signal S 1   b  detected by the second detection circuit  39 B (for example, digital signal). 
     The position of the servo reading element SR with respect to the servo band SB is detected based on, for example, an interval between the servo patterns  52 A and  52 B in the longitudinal direction LD. For example, the interval between the servo patterns  52 A and  52 B in the longitudinal direction LD is detected in accordance with the autocorrelation coefficient. In a case in which the servo reading element SR is positioned on the upper side of the servo pattern  52  (that is, the upper side in the front view of the paper in  FIG.  9   ), an interval between the linear magnetization region  54 A 1  and the linear magnetization region  54 A 2  is narrowed, and an interval between the linear magnetization region  54 B 1  and the linear magnetization region  54 B 2  is also narrowed. On the other hand, in a case in which the servo reading element SR is positioned on the lower side of the servo pattern  52  (that is, the lower side in the front view of the paper in  FIG.  9   ), the interval between the linear magnetization region  54 A 1  and the linear magnetization region  54 A 2  is widened, and the interval between the linear magnetization region  54 B 1  and the linear magnetization region  54 B 2  is also widened. As described above, the first position detection device  30 B 1  detects the position of the servo reading element SR with respect to the servo band SB by using the interval between the linear magnetization region  54 A 1  and the linear magnetization region  54 A 2  and the interval between the linear magnetization region  54 B 1  and the linear magnetization region  54 B 2  detected in accordance with the autocorrelation coefficient. 
     It should be noted that, in the example shown in  FIG.  10   , the form example has been described in which the first position detection device  30 B 1  detects the servo pattern signal S 1 A by comparing the first servo band signal S 1  with the ideal waveform signal  66 , similarly, the second position detection device  30 B 2  also detects the servo pattern signal S 2 A by comparing the second servo band signal S 2  with the ideal waveform signal  66 , and outputs the detected servo pattern signal S 2 A to the control device  30 A. 
     As shown in  FIG.  11    as an example, the control device  30 A operates the moving mechanism  48  based on the position detection result (that is, the servo pattern signals S 1 A and S 2 A) in the position detection device  30 B to adjust the position of the magnetic head  28 . In addition, the control device  30 A causes the magnetic element unit  42  to perform the magnetic processing on the data band DB of the magnetic tape MT. That is, the control device  30 A acquires a read signal (that is, data read from the data band DB of the magnetic tape MT by the magnetic element unit  42 ) from the magnetic element unit  42 , or supplies a recording signal to the magnetic element unit  42  to record the data in response to the recording signal in the data band DB of the magnetic tape MT. 
     In addition, in order to reduce the influence of the TDS, the control device  30 A calculates the servo band pitch from the position detection result (that is, the servo pattern signals S 1 A and S 2 A) of the position detection device  30 B, and performs the tension control in accordance with the calculated servo band pitch, or skews the magnetic head  28  on the magnetic tape MT. The tension control is realized by adjusting the rotation speed, rotation torque, and the like of each of the sending motor  36  and the winding motor  40 . The skew of the magnetic head  28  is realized by operating the inclination mechanism  49 . 
     Next, among a plurality of steps included in a manufacturing process of the magnetic tape MT, an example of a servo pattern recording step of recording the servo pattern  52  on the servo band SB of the magnetic tape MT and an example of a winding step of winding the magnetic tape MT will be described. 
     As an example, as shown in  FIG.  12   , a servo writer SW is used in the servo pattern recording step. The servo writer SW comprises a sending reel SW 1 , a winding reel SW 2 , a driving device SW 3 , a pulse signal generator SW 4 , a servo writer controller SW 5 , a plurality of guides SW 6 , a transport passage SW 7 , a servo pattern recording head WH, and a verification head VH. The servo writer controller SW 5  incorporates a device corresponding to the position detection device  30 B described above. 
     In the present embodiment, the servo writer SW is an example of an “inspection device” according to the technology of the present disclosure. In addition, in the present embodiment, the servo writer controller SW 5  is an example of an “inspection processor” according to the technology of the present disclosure. 
     The servo writer controller SW 5  controls the entirety of the servo writer SW. In the present embodiment, although the servo writer controller SW 5  is realized by an ASIC, the technology of the present disclosure is not limited to this. For example, the servo writer controller SW 5  may be realized by an FPGA and/or a PLC. In addition, the servo writer controller SW 5  may be realized 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 SW 5  may be realized by combining two or more of an ASIC, an FPGA, a PLC, and a computer. That is, the servo writer controller SW 5  may be realized by a combination of a hardware configuration and a software configuration. 
     A pancake is set in the sending reel SW 1 . 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 pattern  58  is wound around a hub. 
     The driving device SW 3  has a motor (not shown) and a gear (not shown), and is mechanically connected to the sending reel SW 1  and the winding reel SW 2 . In a case in which the magnetic tape MT is wound by the winding reel SW 2 , the driving device SW 3  generates power in accordance with the command from the servo writer controller SW 5 , and transmits the generated power to the sending reel SW 1  and the winding reel SW 2  to rotate the sending reel SW 1  and the winding reel SW 2 . That is, the sending reel SW 1  receives the power from the driving device SW 3  and is rotated to send the magnetic tape MT to the predetermined transport passage SW 7 . The winding reel SW 2  receives the power from the driving device SW 3  and is rotated to wind the magnetic tape MT sent from the sending reel SW 1 . The rotation speed, the rotation torque, and the like of the sending reel SW 1  and the winding reel SW 2  are adjusted in accordance with a speed at which the magnetic tape MT is wound around the winding reel SW 2 . 
     The plurality of guides SW 6  and the servo pattern recording head WH are disposed on the transport passage SW 7 . The servo pattern recording head WH is disposed on the front surface  31  side of the magnetic tape MT between the plurality of guides SW 6 . The magnetic tape MT sent from the sending reel SW 1  to the transport passage SW 7  is guided by the plurality of guides SW 6  and is wound by the winding reel SW 2  via the servo pattern recording head WH. 
     The 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 the inspection step and the winding step. 
     For example, the inspection step is a step of inspecting the servo band SB formed on the front surface  31  of 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 the correctness of the servo pattern  52  recorded in the servo band SB. The determination of the correctness of the servo pattern  52  refers to, for example, the determination (that is, verification of the servo pattern  52 ) whether or not the servo patterns  52 A and  52 B are recorded in a predetermined portion of the front surface  31  without excess or deficiency of the magnetization straight lines  54 A 1   a ,  54 A 2   a,    54 B 1   a , and  54 B 2   a  and within an allowable error. 
     The inspection step is performed by using the servo writer controller SW 5  and 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, the verification head VH includes a plurality of servo reading elements (not shown) similarly to the magnetic head  28 , and the plurality of servo bands SB are read by the plurality of servo reading elements. Further, the verification head VH is skewed on the front surface  31  of the magnetic tape MT, similarly to the magnetic head  28 . 
     The verification head VH is connected to the servo writer controller SW 5 . The verification head VH is disposed at a position facing the servo band SB as viewed from the front surface  31  side of the magnetic tape MT (that is, the rear surface side of the verification head VH), and reads the servo pattern  52  recorded in the servo band SB, and outputs a reading result (hereinafter, referred to as “servo pattern reading result”) to the servo writer controller SW 5 . The servo writer controller SW 5  inspects the servo band SB (for example, determines the correctness of the servo pattern  52 ) based on the servo pattern reading result (for example, the servo signal) input from the verification head VH. For example, since the servo writer controller SW 5  incorporates the device corresponding to the position detection device  30 B, the servo writer controller SW 5  acquires the position detection result from the servo pattern reading result, and inspects the servo band SB by determining the correctness of the servo pattern  52  by using the position detection result. 
     The servo writer controller SW 5  outputs information indicating the result of inspecting the servo band SB (for example, the result of determining the correctness of the servo pattern  52 ) to a predetermined output destination (for example, the storage  32  (see  FIG.  3   ), the UI system device  34  (see  FIG.  3   ), and/or the external device  37  (see  FIG.  3   )). 
     For example, in a case in which the inspection step is terminated, the winding step is then performed. The winding step is a step of winding the magnetic tape MT around the sending reel  22  (that is, the sending reel  22  (see  FIGS.  2  to  4   ) accommodated in the magnetic tape cartridge  12  (see  FIGS.  1  to  4   )) used for each of the plurality of magnetic tape cartridges  12  (see  FIGS.  1  to  4   ). In the winding step, a winding motor M is used. The winding motor M is mechanically connected to the sending reel  22  via a gear and the like. The winding motor M rotates the sending reel  22  by applying a rotation force to the sending reel  22  under the control of the processing device (not shown). The magnetic tape MT wound around the winding reel SW 2  is wound around the sending reel  22  by the rotation of the sending reel  22 . In the winding step, a cutting device (not shown) is used. In a case in which a required amount of the magnetic tape MT is wound around the sending reel  22  for each of the plurality of sending reels  22 , the magnetic tape MT sent from the winding reel SW 2  to the sending reel  22  is cut by the cutting device. 
     The pulse signal generator SW 4  generates the pulse signal under the control of the servo writer controller SW 5 , and supplies the generated pulse signal to the servo pattern recording head WH. In a state in which the magnetic tape MT travels on the transport passage SW 7  at a regular speed, the servo pattern recording head WH records the servo pattern  52  in the servo band SB in response to the pulse signal supplied from the pulse signal generator SW 4 . 
     Next, an action of the magnetic tape system  10  will be described. 
     The magnetic tape cartridge  12  accommodates the magnetic tape MT shown in  FIG.  6   . The magnetic tape cartridge  12  is loaded into the magnetic tape drive  14 . In the magnetic tape drive  14 , in a case in which the magnetic tape MT is subjected to the magnetic processing by the magnetic element unit  42  (see  FIGS.  3  and  15   ), the magnetic tape MT is pulled out from the magnetic tape cartridge  12 , and the servo pattern  52  in the servo band SB is read by the servo reading element SR of the magnetic head  28  (see  FIGS.  8  and  9   ). 
     As shown in  FIG.  8   , in a case in which the servo pattern  52 A is read by the servo reading element SR, in the linear magnetization region pair  54 A, an angle formed by the linear magnetization region  54 A 1  and the servo reading element SR and an angle formed by the linear magnetization region  54 A 2  and the servo reading element SR are different. In a case in which the angles are different in this way, the variation due to the azimuth loss occurs between the servo signal derived from the linear magnetization region  54 A 1 , that is, the first linear magnetization region signal S 1   a  (see  FIG.  10   ), and the servo signal derived from the linear magnetization region  54 A 2 , that is, the second linear magnetization region signal S 1   b  (See  FIG.  10   ). The variation between the first linear magnetization region signal S 1   a  and the second linear magnetization region signal S 1   b  may contribute to a decrease in the accuracy of the servo control or the like. 
     Then, in the magnetic tape system  10  according to the present embodiment, as shown in  FIG.  13    as an example, servo pattern detection processing is performed by the controller  25  (see  FIG.  3   ). It should be noted that a flow of the servo pattern detection processing shown in  FIG.  13    is an example of a “detection method” according to the technology of the present disclosure. 
     In the servo pattern detection processing shown in  FIG.  13   , first, in step ST 10 , the position detection device  30 B acquires the first ideal waveform signal  66 A and the second ideal waveform signal  66 B from the storage  32 . After the processing of step ST 10  is executed, the servo pattern detection processing proceeds to step ST 12 . 
     In step ST 12 , the position detection device  30 B acquires the servo band signal. For example, the first position detection device  30 B 1  acquires the first servo band signal S 1 , and the second position detection device  30 B 2  acquires the second servo band signal S 2 . After the processing of step ST 12  is executed, the servo pattern detection processing proceeds to step ST 14 . 
     In step ST 14 , the position detection device  30 B compares the servo band signal acquired in step ST 12  with the ideal waveform signal  66  acquired in step ST 10 . That is, in the first position detection device  30 B  1 , the first detection circuit  39 A compares the first servo band signal S 1  with the first ideal waveform signal  66 A, and the second detection circuit  39 B compares the first servo band signal S 1  with the second ideal waveform signal  66 B . On the other hand, in the second position detection device  30 B 2 , the first detection circuit  39 A compares the second servo band signal S 2  with the first ideal waveform signal  66 A, and the second detection circuit  39 B compares the second servo band signal S 2  with the second ideal waveform signal  66 B. After the processing of step ST 14  is executed, the servo pattern detection processing proceeds to step ST 16 . 
     In step ST 16 , the first detection circuit  39 A of the first position detection device  30 B 1  acquires the first linear magnetization region signal S 1   a  based on the comparison result in step ST 14 , and the second detection circuit  39 B of the first position detection device  30 B 1  acquires the second linear magnetization region signal S 1   b  based on the comparison result in step ST 14 . In addition, the first detection circuit  39 A of the second position detection device  30 B 2  acquires the first linear magnetization region signal S 1   a  based on the comparison result in step ST 14 , and the second detection circuit  39 B of the second position detection device  30 B 2  acquires the second linear magnetization region signal S 1   b  based on the comparison result in step ST 14 . After the processing of step ST 16  is executed, the servo pattern detection processing proceeds to step ST 18 . 
     In step ST 18 , the first position detection device  30 B 1  generates the servo pattern signal S 1 A which is the logical sum of the first linear magnetization region signal S 1   a  and the second linear magnetization region signal S 1   b  acquired in step ST 16 , and outputs the generated servo pattern signal S 1 A to the control device  30 A. In addition, the second position detection device  30 B 2  generates the servo pattern signal S 2 A which is the logical sum of the first linear magnetization region signal S 1   a  acquired in step ST 16  and the second linear magnetization region signal S 1   b , and outputs the generated servo pattern signal S 2 A to the control device  30 A. After the processing of step ST 18  is executed, the servo pattern detection processing is terminated. 
     As described above, in the magnetic tape system  10  according to the present embodiment, the ideal waveform signal  66  is stored in advance in the storage  32 , and the servo pattern signal is detected by comparing the servo band signal with the ideal waveform signal  66 . Therefore, with the present configuration, even in a case in which there is the variation in the geometrical characteristic of the servo pattern, the servo pattern signal can be detected with higher accuracy than a case in which the servo pattern signal is detected by using only a method of determining whether or not the signal level exceeds a threshold value. 
     In the magnetic tape system  10  according to the present embodiment, the ideal waveform signal  66  is stored in advance in the storage  32 , but this is merely an example. For example, the ideal waveform signal  66  may be stored in the cartridge memory  24  instead of the storage  32  or together with the storage  32 . In addition, the ideal waveform signal  66  may be recorded in a BOT region (not shown) provided at the beginning of the magnetic tape MT and/or in an EOT region (not shown) provided at the end of the magnetic tape MT. In this case, since it is not necessary to store the ideal waveform signal  66  in the storage  32 , it is possible to increase the capacity of the storage  32  by an amount in which the ideal waveform signal  66  is not stored. 
     In the magnetic tape system  10  according to the present embodiment, as the ideal waveform indicated by the ideal waveform signal  66 , the waveform determined in accordance with the orientation of the magnetic head  28  on the magnetic tape MT, that is, the orientation of the servo reading element SR on the magnetic tape MT is used. Therefore, with the present configuration, it is possible to detect the servo pattern signal from the servo band signal with higher accuracy than in a case in which the ideal waveform is determined regardless of the orientation of the magnetic head  28  on the magnetic tape MT, that is, the orientation of the servo reading element SR on the magnetic tape MT. 
     In the magnetic tape system  10  according to the present embodiment, as the ideal waveform indicated by the ideal waveform signal  66 , the waveform determined in accordance with the geometrical characteristic of the servo pattern  52  and the orientation of the magnetic head  28  on the magnetic tape MT, that is, the geometrical characteristic of the servo pattern  52  and the orientation of the servo reading element SR on the magnetic tape MT is used. Therefore, with the present configuration, it is possible to detect the servo pattern signal from the servo band signal with higher accuracy than in a case in which the ideal waveform is determined regardless of the geometrical characteristic of the servo pattern  52  and the orientation of the magnetic head  28  on the magnetic tape MT, that is, the geometrical characteristic of the servo pattern  52  and the orientation of the servo reading element SR on the magnetic tape MT. 
     In the magnetic tape system  10  according to the present embodiment, the linear magnetization regions  54 A 1  and  54 A 2  inclined in opposite directions with respect to the imaginary straight line C 1  are read by the servo reading element SR. In this case, as described above, there is the variation due to the azimuth loss between the first linear magnetization region signal S 1   a  (see  FIG.  10   ) and the second linear magnetization region signal S 1   b  (see  FIG.  10   ). However, even in a case in which the variation occurs between the first linear magnetization region signal S 1   a  and the second linear magnetization region signal S 1   b , in the magnetic tape system  10  according to the present embodiment, the ideal waveform signal  66  is stored in advance in the storage  32 , and the servo pattern signal is detected by comparing the servo band signal with the ideal waveform signal  66 . Therefore, with the present configuration, even in a case in which the linear magnetization regions  54 A 1  and  54 A 2  inclined in opposite directions with respect to the imaginary straight line C 1  are read by the servo reading element SR, it is possible to detect the servo pattern signal with higher accuracy than in a case in which the servo pattern signal is detected by using only the method of determining whether or not the signal level exceeds the threshold value. 
     In the magnetic tape system  10  according to the present embodiment, the first detection circuit  39 A and the second detection circuit  39 B are connected in parallel, and the common servo band signal is incorporated into the first detection circuit  39 A and the second detection circuit  39 B. Moreover, the first linear magnetization region signal S 1   a  is detected by comparing the servo band signal with the first ideal waveform signal  66 A by the first detection circuit  39 A, and the second linear magnetization region signal S 1   b  is detected by comparing the servo band signal with the second ideal waveform signal  66 B by the second detection circuit  39 B. For example, in the first position detection device  30 B 1 , the logical sum of the first linear magnetization region signal S 1   a  detected by the first detection circuit  39 A and the second linear magnetization region signal S 1   b  detected by the second detection circuit  39 B is detected as the servo pattern signal S 1 A. In addition, in the second position detection device  30 B 2 , the logical sum of the first linear magnetization region signal S 1   a  detected by the first detection circuit  39 A and the second linear magnetization region signal S 1   b  detected by the second detection circuit  39 B is detected as the servo pattern signal S 2 A. Therefore, with the present configuration, it is possible to detect the servo pattern signal more quickly than in a case in which the first linear magnetization region signal S 1   a  and the second linear magnetization region signal S 1   b  are detected in order by sequentially comparing different ideal waveform signals with respect to one servo band signal. 
     In the magnetic tape system  10  according to the present embodiment, the servo pattern signal is detected by using the autocorrelation coefficient. Therefore, with the present configuration, the servo pattern signal can be detected with higher accuracy than a case in which the servo pattern signal is detected by using only a method of determining whether or not the signal level exceeds a threshold value. 
     In the servo writer SW according to the present embodiment, the device corresponding to the position detection device  30 B shown in  FIG.  9    is incorporated into the servo writer controller SW 5 . Therefore, the servo writer controller SW 5  can inspect the servo band SB by acquiring the position detection result from the servo pattern reading result and determining the correctness of the servo pattern  52  by using the position detection result. The servo writer controller SW 5  incorporating the device corresponding to the position detection device  30 B can detect the servo pattern signal with higher accuracy than in a case in which the servo pattern signal is detected by only using the method of determining whether or not the signal level exceeds the threshold value, so that the servo writer SW incorporating the servo writer controller SW 5  can inspect the servo band SB with high accuracy. 
     It should be noted that, in the embodiment described above, the servo pattern  52  is described as an example, but the servo pattern  52  is merely an example, and the technology of the present disclosure is established even in a case in which other types of servo patterns (that is, servo patterns having the geometrical characteristic different from the geometrical characteristic of the servo pattern  52 ) are used. In the following first modification example to seventh modification example, a servo pattern of a type different from that of the servo pattern  52  will be described. 
     First Modification Example 
     As shown in  FIG.  14    as an example, the magnetic tape MT according to the first modification example is different from the magnetic tape MT shown in  FIG.  6    in that a frame  56  is provided instead of the frame  50 . The frame  56  is defined by a set of servo patterns  58 . A plurality of servo patterns  58  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns  58  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of servo patterns  52  recorded in the magnetic tape MT shown in  FIG.  6   . 
     In the example shown in  FIG.  14   , servo patterns  58 A and  58 B are shown as an example of the set of servo patterns  58  included in the frame  56 . The servo patterns  58 A and  58 B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern  58 A is positioned on the upstream side in the forward direction in the frame  56 , and the servo pattern  58 B is positioned on the downstream side in the forward direction. 
     The servo pattern  58  consists of a linear magnetization region pair  60 . The linear magnetization region pair  60  is classified into a linear magnetization region pair  60 A and a linear magnetization region pair  60 B. 
     The servo pattern  58 A consists of the linear magnetization region pair  60 A. In the example shown in  FIG.  14   , linear magnetization regions  60 A 1  and  60 A 2  are shown as an example of the linear magnetization region pair  60 A. Each of the linear magnetization regions  60 A 1  and  60 A 2  is a linearly magnetized region. 
     The linear magnetization regions  60 A 1  and  60 A 2  are inclined in opposite directions with respect to the imaginary straight line C 1 . The linear magnetization regions  60 A 1  and  60 A 2  are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C 1 . The linear magnetization region  60 A 1  has a steeper inclined angle with respect to the imaginary straight line C 1  than the linear magnetization region  60 A 2 . Here, “steep” means that, for example, an angle of the linear magnetization region  60 A 1  with respect to the imaginary straight line C 1  is smaller than an angle of the linear magnetization region  60 A 2  with respect to the imaginary straight line C 1 . In addition, a total length of the linear magnetization region  60 A 1  is shorter than a total length of the linear magnetization region  60 A 2 . 
     In the servo pattern  58 A, a plurality of magnetization straight lines  60 A 1   a  are included in the linear magnetization region  60 A 1 , and a plurality of magnetization straight lines  60 A 2   a  are included in the linear magnetization region  60 A 2 . The number of the magnetization straight lines  60 A 1   a  included in the linear magnetization region  60 A 1  is the same as the number of the magnetization straight lines  60 A 2   a  included in the linear magnetization region  60 A 2 . 
     The linear magnetization region  60 A 1  is a set of magnetization straight lines  60 A 1   a , which are five magnetized straight lines, and the linear magnetization region  60 A 2  is a set of magnetization straight lines  60 A 2   a,  which are five magnetized straight lines. In the servo band SB, the positions of both ends of the linear magnetization region  60 A 1  (that is, the positions of both ends of each of the five magnetization straight lines  60 A 1   a ) and the positions of both ends of the linear magnetization region  60 A 2  (that is, the positions of both ends of each of the five magnetization straight lines  60 A 2   a ) are aligned in the width direction WD. It should be noted that, here, the example has been described in which the positions of both ends of each of the five magnetization straight lines  60 A 1   a  and the positions of both ends of each of the five magnetization straight lines  60 A 2   a  are aligned, but this is merely an example, and the positions of both ends of one or more magnetization straight lines  60 A 1   a  among the five magnetization straight lines  60 A 1   a  and the positions of both ends of one or more magnetization straight lines  60 A 2   a  among of the five magnetization straight lines  60 A 2   a  need 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 pattern  58 B consists of the linear magnetization region pair  60 B. In the example shown in  FIG.  14   , linear magnetization regions  60 B 1  and  60 B 2  are shown as an example of the linear magnetization region pair  60 B. Each of the linear magnetization regions  60 B 1  and  60 B 2  is a linearly magnetized region. 
     The linear magnetization regions  60 B 1  and  60 B 2  are inclined in opposite directions with respect to the imaginary straight line C 2 . The linear magnetization regions  60 B 1  and  60 B 2  are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C 2 . The linear magnetization region  60 B 1  has a steeper inclined angle with respect to the imaginary straight line C 2  than the linear magnetization region  60 B 2 . Here, “steep” means that, for example, an angle of the linear magnetization region  60 B 1  with respect to the imaginary straight line C 2  is smaller than an angle of the linear magnetization region  60 B 2  with respect to the imaginary straight line C 2 . In addition, a total length of the linear magnetization region  60 B 1  is shorter than a total length of the linear magnetization region  60 B 2 . 
     In the servo pattern  58 B, a plurality of magnetization straight lines  60 B 1   a  are included in the linear magnetization region  60 B 1 , and a plurality of magnetization straight lines  60 B 2   a  are included in the linear magnetization region  60 B 2 . The number of the magnetization straight lines  60 B 1   a  included in the linear magnetization region  60 B 1  is the same as the number of the magnetization straight lines  60 B 2   a  included in the linear magnetization region  60 B 2 . 
     The total number of the magnetization straight lines  60 B 1   a  and  60 B 2   a  included in the servo pattern  58 B is different from the total number of the magnetization straight lines  60 A 1   a  and  60 A 2   a  included in the servo pattern  58 A. In the example shown in  FIG.  14   , the total number of the magnetization straight lines  60 A 1   a  and  60 A 2   a  included in the servo pattern  58 A is ten, whereas the total number of the magnetization straight lines  60 B 1   a  and  60 B 2   a  included in the servo pattern  58 B is eight. 
     The linear magnetization region  60 B 1  is a set of magnetization straight lines  60 B 1   a , which are four magnetized straight lines, and the linear magnetization region  60 B 2  is a set of magnetization straight lines  60 B 2   a,  which are four magnetized straight lines. In the servo band SB, the positions of both ends of the linear magnetization region  60 B 1  (that is, the positions of both ends of each of the four magnetization straight lines  60 B 1   a ) and the positions of both ends of the linear magnetization region  60 B 2  (that is, the positions of both ends of each of the four magnetization straight lines  60 B 2   a ) are aligned in the width direction WD. 
     It should be noted that, here, the example has been described in which the positions of both ends of each of the four magnetization straight lines  60 B 1   a  and the positions of both ends of each of the four magnetization straight lines  60 B 2   a  are aligned, but this is merely an example, and the positions of both ends of one or more magnetization straight lines  60 B 1   a  among the four magnetization straight lines  60 B 1   a  and the positions of both ends of one or more magnetization straight lines  60 B 2   a  among of the four magnetization straight lines  60 B 2   a  need only be aligned. 
     In addition, here, the set of magnetization straight lines  60 A 1   a , which are five magnetized straight lines, is described as an example of the linear magnetization region  60 A 1 , the set of magnetization straight lines  60 A 2   a,  which are five magnetized straight lines, is described as an example of the linear magnetization region  60 A 2 , the set of magnetization straight lines  60 B 1   a , which are four magnetized straight lines, is described as an example of the linear magnetization region  60 B 1 , and the set of magnetization straight lines  60 B 2   a,  which are four magnetized straight lines, is described as an example of the linear magnetization region  60 B 2 , but the technology of the present disclosure is not limited thereto. For example, the linear magnetization region  60 A 1  need only have the number of the magnetization straight lines  60 A 1   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT, the linear magnetization region  60 A 2  need only have the number of the magnetization straight lines  60 A 2   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT, the linear magnetization region  60 B 1  need only have the number of the magnetization straight lines  60 B 1   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT, and the linear magnetization region  60 B 2  need only have the number of the magnetization straight lines  60 B 2   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT. 
     Here, the geometrical characteristic of the linear magnetization region pair  60 A on the magnetic tape MT will be described with reference to  FIG.  15   . 
     As an example, as shown in  FIG.  15   , the geometrical characteristic of the linear magnetization region pair  60 A on the magnetic tape MT can be expressed by using an imaginary linear region pair  62 . The imaginary linear region pair  62  consists of an imaginary linear region  62 A and an imaginary linear region  62 B. The geometrical characteristic of the linear magnetization region pair  60 A on the magnetic tape MT corresponds to the geometrical characteristic based on the imaginary linear region pair  62  inclined line-symmetrically with respect to the imaginary straight line C 1  in a case in which an entirety of the imaginary linear region pair  62  is inclined with respect to the imaginary straight line C 1  by inclining a symmetry axis SA 1  of the imaginary linear region  62 A and the imaginary linear region  62 B with respect to the imaginary straight line C 1 . 
     The imaginary linear region pair  62  is an imaginary linear magnetization region pair having the same geometrical characteristic as the linear magnetization region pair  54 A shown in  FIG.  8   . The imaginary linear region pair  62  is an imaginary magnetization region used for convenience for describing the geometrical characteristic of the linear magnetization region pair  60 A on the magnetic tape MT, and is not an actually present magnetization region. 
     The imaginary linear region  62 A has the same geometrical characteristic as the linear magnetization region  54 A 1  shown in  FIG.  8   , and consists of five imaginary straight lines  62 A 1  corresponding to the five magnetization straight lines  54 A 1   a  shown in  FIG.  8   . The imaginary linear region  62 B has the same geometrical characteristic as the linear magnetization region  54 B 1  shown in  FIG.  8   , and consists of five imaginary straight lines  62 B 1  corresponding to the five magnetization straight lines  54 A 2   a  shown in  FIG.  8   . 
     A center O 1  is provided in the imaginary linear region pair  62 . For example, the center O 1  is a center of a line segment L 0  connecting a center of the straight line  62 A 1  positioned on the most upstream side of the five straight lines  62 A 1  in the forward direction and a center of the straight line  62 B 1  positioned on the most downstream side of the five straight lines  62 B 1  in the forward direction. 
     Since the imaginary linear region pair  62  has the same geometrical characteristic as the linear magnetization region pair  54 A shown in  FIG.  8   , the imaginary linear region  62 A and the imaginary linear region  62 B are inclined line-symmetrically with respect to the imaginary straight line C 1 . 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 pair  62  in a case in which the entirety of the imaginary linear region pair  62  is inclined with respect to the imaginary straight line C 1  by inclining the symmetry axis SA 1  of the imaginary linear regions  62 A and  62 B at an angle a (for example, 10 degrees) with respect to the imaginary straight line C 1  with the center O 1  as the rotation axis. In this case, in the imaginary linear region pair  62 , in the width direction WD, a portion is generated in which the imaginary linear region  62 A is read but the imaginary linear region  62 B is not read or the imaginary linear region  62 A is not read is read but the imaginary linear region  62 B. That is, in each of the imaginary linear regions  62 A and  62 B, in a case in which reading by the servo reading element SR is performed, a shortage part and an unnecessary part is generated. 
     Therefore, by compensating for the shortage part and removing the unnecessary part, the positions of both ends of the imaginary linear region  62 A (that is, the positions of both ends of each of the five straight lines  62 A 1 ) and the positions of both ends of the imaginary linear region  62 B (that is, the positions of both ends of each of the five straight lines  62 B 1 ) are aligned in the width direction WD. 
     The geometrical characteristic of the imaginary linear region pair  62  (that is, the geometrical characteristic of the imaginary servo pattern) obtained as described above corresponds to the geometrical characteristic of the actual servo pattern  58 A. That is, the linear magnetization region pair  60 A having the geometrical characteristic corresponding to the geometrical characteristic of the imaginary linear region pair  62  obtained by aligning the positions of both ends of the imaginary linear region  62 A and the positions of both ends of the imaginary linear region  62 B in the width direction WD is recorded in the servo band SB. 
     It should be noted that the linear magnetization region pair  60 B is different from the linear magnetization region pair  60 A only in that the four magnetization straight lines  60 B 1   a  are provided instead of the five magnetization straight lines  60 A 1   a  and the four magnetization straight lines  60 B 2   a  are provided instead of the five magnetization straight lines  60 A 2   a . Therefore, the linear magnetization region pair  60 B having the geometrical characteristic corresponding to the geometrical characteristic of the imaginary linear region pair (not shown) obtained by aligning the positions of both ends of each of the four straight lines  62 A 1  and the positions of both ends of each of the four straight lines  62 B 1  in the width direction WD is recorded in the servo band SB. 
     As an example, as shown in  FIG.  16   , the plurality of servo bands SB are formed on the magnetic tape MT in the width direction WD, and the frames  56  having a correspondence relationship between the servo bands SB deviate from each other at predetermined intervals in the longitudinal direction LD, between the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT. This means that the servo patterns  58  having a correspondence relationship between the servo bands SB deviate from each other at the predetermined interval in the longitudinal direction LD between the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT. 
     The predetermined interval is defined based on an angle α, a pitch between the servo bands SB adjacent to each other in the width direction WD (hereinafter, also referred to as “servo band pitch”), and a frame length. In the example shown in  FIG.  16   , the angle α is exaggerated in order to make it easier to visually grasp the angle α, but in reality, the angle α is, for example, about 15 degrees. The angle α is an angle formed by the frames  56  having no correspondence relationship between the servo bands SB adjacent to each other in the width direction WD and the imaginary straight line C 1 . In the example shown in  FIG.  16   , as an example of the angle α, an angle formed by an interval (in the example shown in  FIG.  16   , a line segment L 1 ) between one frame  56  of a pair of frames  56  having the correspondence relationship between the servo bands SB adjacent to each other in the width direction WD (in the example shown in  FIG.  16   , one frame  56  of the servo band SB 3 ) and the frame  56  adjacent to the other frame  56  of the pair of frames  56  (in the example shown in  FIG.  16   , the frame  56  having the correspondence relationship with one frame  56  of the servo band SB 3  among a plurality of frames  56  in the servo band SB 2 ), and the imaginary straight line C 1  is shown. In this case, the frame length refers to the total length of the frame  56  with respect to the longitudinal direction LD of the magnetic tape MT. The predetermined interval is defined by Expression (1). It should be noted that Mod (A/B) means a remainder generated in a case in which “A” is divided by “B”. 
       (Predetermined interval)=Mod{(Servo band pitch×tanα)/(Frame length)}  (1)
 
     It should be noted that, in the example shown in  FIG.  16   , the angle formed by the interval between one frame  56  of the pair of frames  56  having the correspondence relationship between the servo bands SB adjacent to each other in the width direction WD (hereinafter, also referred to as “first frame”) and the frame  56  adjacent to the other frame  56  of the pair of frames  56  (hereinafter, also referred to as “second frame”), and the imaginary straight line C 1  has been described as the angle α, but the technology of the present disclosure is not limited to this. For example, as the angle α, an angle formed by an interval between the first frame and the frame  56  away from the second frame by two or more frames (hereinafter, also referred to as “third frame”) in the same servo band SB as the second frame, and the imaginary straight line C 1  may be used. In this case, the “frame length” used in Expression (1) is the pitch between the second frame and the third frame in the longitudinal direction LD of the magnetic tape MT (for example, a distance from the distal end of the second frame to the distal end of the third frame). 
     As an example, as shown in  FIG.  17   , in a case in which the servo pattern  58 A (that is, the linear magnetization region pair  60 A) is read by the servo reading element SR in a state in which the direction of the imaginary straight line C 1  and the direction of the imaginary straight line C 3  match (that is, a state in which the longitudinal direction of the magnetic head  28  and the width direction WD match), the variation due to the azimuth loss occurs between the servo signal derived from the linear magnetization region  60 A 1  and the servo signal derived from the linear magnetization region  60 A 2 . In addition, also in a case in which the servo pattern  58 B (that is, the linear magnetization region pair  60 B) is read by the servo reading element SR in a state in which the direction of the imaginary straight line C 1  and the direction of the imaginary straight line C 3  match (that is, a state in which the longitudinal direction of the magnetic head  28  and the width direction WD match), a similar phenomenon occurs. 
     Therefore, as an example, as shown in  FIG.  18   , the inclination mechanism  49  (see  FIG.  8   ) skews the magnetic head  28  on the magnetic tape MT around the rotation axis RA such that the imaginary straight line C 3  is inclined with respect to the imaginary straight line C 1  to the upstream side in the forward direction at an angle β (that is, the angle β counterclockwise as viewed from the paper surface side of  FIG.  18   ). As described above, since the magnetic head  28  is 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 signal derived from the linear magnetization region  60 A 1  and the servo signal derived from the linear magnetization region  60 A 2  is smaller than that in the example shown in  FIG.  17   . In addition, also in a case in which the servo pattern  58 B (that is, the linear magnetization region pair  60 B) is read by the servo reading element SR, similarly, the variation due to the azimuth loss between the servo signal derived from the linear magnetization region  60 B 1  and the servo signal derived from the linear magnetization region  60 B 2  is small. 
     It should be noted that, in the following, for convenience of description, the servo signal derived from the linear magnetization region  60 A 1  or  60 B 1  is also referred to as a “first linear magnetization region signal S 1   c ”, and the servo signal derived from the linear magnetization region  60 A 2  or  60 B 2  is also referred to as a “second linear magnetization region signal S 1   d”.    
     As shown in  FIG.  19    as an example, the first position detection device  30 B 1  according to the first modification example is different from the first position detection device  30 B 1  shown in  FIG.  10    in that a detection circuit  39 C is provided instead of the first detection circuit  39 A and the second detection circuit  39 B. 
     The first servo band signal S 1  is incorporated into the detection circuit  39 C. The first servo band signal S 1  includes the first linear magnetization region signal S 1   c  and the second linear magnetization region signal S 1   d . The detection circuit  39 C detects the servo pattern signal (that is, first linear magnetization region signal S 1   c  and second linear magnetization region signal S 1   d ) from the first servo band signal S 1  in the same manner as in the first detection circuit  39 A described in the embodiment described above. That is, the detection circuit  39 C detects the servo pattern signal, which is the result of reading the servo pattern  58  from the magnetic tape MT by the servo reading element SR, by using an autocorrelation coefficient. 
     An ideal waveform signal  66 C is stored in the storage  32 . The ideal waveform signal  66 C is a signal (for example, an ideal signal which is a result of reading one of an ideal magnetization straight lines included in the servo pattern  58  by the servo reading element SR) indicating a single ideal waveform included in the servo pattern signal (for example, first linear magnetization region signal S 1   c  or second linear magnetization region signal S 1   d ). The ideal waveform indicated by the ideal waveform signal  66 C is determined in the same manner as the ideal waveform signal  66  described in the embodiment described above. 
     The autocorrelation coefficient used by the first position detection device  30 B 1  is a coefficient indicating a degree of correlation between the first servo band signal S 1  and the ideal waveform signal  66 C. The first position detection device  30 B 1  acquires the ideal waveform signal  66 C from the storage  32  to compare the acquired ideal waveform signal  66 C with the first servo band signal S 1 . Moreover, the first position detection device  30 B 1  calculates the autocorrelation coefficient based on the comparison result. The first position detection device  30 B 1  detects a position on the servo band SB at which the correlation between the servo band signal and the ideal waveform signal  66 C is high (for example, a position at which the servo band signal and the ideal waveform signal  66 C match) in accordance with the autocorrelation coefficient. 
     The position of the servo reading element SR with respect to the servo band SB is detected based on, for example, an interval between the servo patterns  58 A and  58 B in the longitudinal direction LD. For example, the interval between the servo patterns  58 A and  58 B in the longitudinal direction LD is detected in accordance with the autocorrelation coefficient. In a case in which the servo reading element SR is positioned on the upper side of the servo pattern  58  (that is, the upper side in the front view of the paper in  FIG.  18   ), an interval between the linear magnetization region  60 A 1  and the linear magnetization region  60 A 2  is narrowed, and an interval between the linear magnetization region  60 B 1  and the linear magnetization region  60 B 2  is also narrowed. On the other hand, in a case in which the servo reading element SR is positioned on the lower side of the servo pattern  58  (that is, the lower side in the front view of the paper in  FIG.  18   ), the interval between the linear magnetization region  60 A 1  and the linear magnetization region  60 A 2  is widened, and the interval between the linear magnetization region  60 B 1  and the linear magnetization region  60 B 2  is also widened. As described above, the first position detection device  30 B 1  detects the position of the servo reading element SR with respect to the servo band SB by using the interval between the linear magnetization region  60 A 1  and the linear magnetization region  60 A 2  and the interval between the linear magnetization region  60 B 1  and the linear magnetization region  60 B 2  detected in accordance with the autocorrelation coefficient. 
     The control device  30 A performs the same control as the example shown in  FIG.  11    based on the position detection result in the first position detection device  30 B 1  (that is, result of detection of the position by the first position detection device  30 B 1 ). 
     Second Modification Example 
     It should be noted that, in the first modification example described above, the form example has been described in which the servo band SB is divided by the plurality of frames  56  along 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 in  FIG.  20   , the servo band SB may be divided by a frame  70  along the longitudinal direction LD of the magnetic tape MT. The frame  70  is defined by a set of servo patterns  72 . A plurality of servo patterns  72  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns  72  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of servo patterns  58 . 
     In the example shown in  FIG.  20   , servo patterns  72 A and  72 B are shown as an example of the set of servo patterns  72 . Each of the servo patterns  72 A and  72 B is an M-shaped magnetized servo pattern. The servo patterns  72 A and  72 B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern  72 A is positioned on the upstream side in the forward direction in the frame  70 , and the servo pattern  72 B is positioned on the downstream side in the forward direction. 
     As an example, as shown in  FIG.  21   , the servo pattern  72  consists of a linear magnetization region pair  74 . The linear magnetization region pair  74  is classified into a linear magnetization region pair  74 A and a linear magnetization region pair  74 B. 
     The servo pattern  72 A consists of a set of linear magnetization region pairs  74 A. The set of linear magnetization region pairs  74 A are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. 
     In the example shown in  FIG.  21   , linear magnetization regions  74 A 1  and  74 A 2  are shown as an example of the linear magnetization region pair  74 A. The linear magnetization region pair  74 A is configured in the same manner as the linear magnetization region pair  60 A described in the above first modification example, and has the same geometrical characteristic as the linear magnetization region pair  60 A. That is, the linear magnetization region  74 A 1  is configured in the same manner as the linear magnetization region  60 A 1  described in the above first modification example, and has the same geometrical characteristic as the linear magnetization region  60 A 1 , and the linear magnetization region  74 A 2  is configured in the same manner as the linear magnetization region  60 A 2  described in the above first modification example, and has the same geometrical characteristic as the linear magnetization region  60 A 2 . 
     The servo pattern  72 B consists of a set of linear magnetization region pairs  74 B . The set of linear magnetization region pairs  74 B are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. 
     In the example shown in  FIG.  21   , linear magnetization regions  74 B 1  and  74 B 2  are shown as an example of the linear magnetization region pair  74 B. The linear magnetization region pair  74 B is configured in the same manner as the linear magnetization region pair  60 B described in the above first modification example, and has the same geometrical characteristic as the linear magnetization region pair  60 B. That is, the linear magnetization region  74 B 1  is configured in the same manner as the linear magnetization region  60 B 1  described in the above first modification example, and has the same geometrical characteristic as the linear magnetization region  60 B 1 , and the linear magnetization region  74 B 2  is configured in the same manner as the linear magnetization region  60 B 2  described in the above first modification example, and has the same geometrical characteristic as the linear magnetization region  60 B 2 . 
     Third Modification Example 
     In the example shown in  FIG.  20   , the form example has been described in which the servo band SB is divided by a plurality of frames  70  along 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 in  FIG.  22   , the servo band SB may be divided by a frame  76  along the longitudinal direction LD of the magnetic tape MT. The frame  76  is defined by a set of servo patterns  78 . A plurality of servo patterns  78  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. Similarly to the plurality of servo patterns  72  (see  FIG.  20   ), the plurality of servo patterns  78  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT. 
     In the example shown in  FIG.  22   , servo patterns  78 A and  78 B are shown as an example of the set of servo patterns  78 . Each of the servo patterns  78 A and  78 B is an N-shaped magnetized servo pattern. The servo patterns  78 A and  78 B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern  78 A is positioned on the upstream side in the forward direction in the frame  76 , and the servo pattern  78 B is positioned on the downstream side in the forward direction. 
     As an example, as shown in  FIG.  23   , the servo pattern  78  consists of a linear magnetization region group  80 . The linear magnetization region group  80  is classified into a linear magnetization region group  80 A and a linear magnetization region group  80 B. 
     The servo pattern  78 A consists of the linear magnetization region group  80 A. The linear magnetization region group  80 A consists of linear magnetization regions  80 A 1 ,  80 A 2 , and  80 A 3 . The linear magnetization regions  80 A 1 ,  80 A 2 , and  80 A 3  are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions  80 A 1 ,  80 A 2 , and  80 A 3  are disposed in the order of the linear magnetization regions  80 A 1 ,  80 A 2 , and  80 A 3  from the upstream side in the forward direction. 
     The linear magnetization regions  80 A 1  and  80 A 2  are configured in the same manner as the linear magnetization region pair  74 A shown in  FIG.  21   , and have the same geometrical characteristics as the linear magnetization region pair  74 A. That is, the linear magnetization region  80 A 1  is configured in the same manner as the linear magnetization region  74 A 1  shown in  FIG.  21   , and has the same geometrical characteristic as the linear magnetization region  74 A 1 , and the linear magnetization region  80 A 2  is configured in the same manner as the linear magnetization region  74 A 2  shown in  FIG.  21   , and has the same geometrical characteristic as the linear magnetization region  74 A 2 . In addition, the linear magnetization region  80 A 3  is configured in the same manner as the linear magnetization region  80 A 1 , and has the same geometrical characteristic as the linear magnetization region  80 A 1 . 
     The servo pattern  78 B consists of the linear magnetization region group  80 B. The linear magnetization region group  80 B consists of linear magnetization regions  80 B 1 ,  80 B 2 , and  80 B 3 . The linear magnetization regions  80 B 1 ,  80 B 2 , and  80 B 3  are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions  80 B 1 ,  80 B 2 , and  80 B 3  are disposed in the order of the linear magnetization regions  80 B 1 ,  80 B 2 , and  80 B 3  from the upstream side in the forward direction. 
     The linear magnetization regions  80 B 1  and  80 B 2  are configured in the same manner as the linear magnetization region pair  74 B shown in  FIG.  21   , and have the same geometrical characteristics as the linear magnetization region pair  74 B. That is, the linear magnetization region  80 B 1  is configured in the same manner as the linear magnetization region  74 B 1  shown in  FIG.  21   , and has the same geometrical characteristic as the linear magnetization region  74 B 1 , and the linear magnetization region  80 B 2  is configured in the same manner as the linear magnetization region  74 B 2  shown in  FIG.  21   , and has the same geometrical characteristic as the linear magnetization region  74 B 2 . In addition, the linear magnetization region  80 B 3  is configured in the same manner as the linear magnetization region  80 B 1 , and has the same geometrical characteristic as the linear magnetization region  80 B 1 . 
     Fourth Modification Example 
     In the first 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 pitch, 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 in  FIG.  24   , the predetermined interval is defined based on the angle a formed by the interval between the frames  56  having the correspondence relationship between the servo bands SB adjacent to each other in the width direction WD (in the example shown in  FIG.  24   , a line segment L 3 ) and the imaginary straight line C 1 , and the pitch between the servo bands SB adjacent to each other in the width direction WD (that is, the servo band pitch). In this case, for example, the predetermined interval is calculated from Expression (2). 
       (Predetermined interval)=(Servo band pitch)×tanα  (2)
 
     As described above, Expression (2) does not include the frame length. This means that the predetermined interval is calculated even in a case in which 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). 
     Fifth Modification Example 
     It should be noted that, in the first modification example described above, the form example has been described in which the servo band SB is divided by the plurality of frames  56  along 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 in  FIG.  25   , the servo band SB may be divided by a frame  82  along the longitudinal direction LD of the magnetic tape MT. 
     The frame  82  is defined by a set of servo patterns  84 . A plurality of servo patterns  84  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns  84  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of servo patterns  52  (see  FIG.  6   ) recorded in the magnetic tape MT (see  FIG.  6   ). 
     In the example shown in  FIG.  25   , servo patterns  84 A and  84 B are shown as an example of the set of servo patterns  84  included in the frame  82 . The servo patterns  84 A and  84 B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern  84 A is positioned on the upstream side in the forward direction in the frame  82 , and the servo pattern  84 B is positioned on the downstream side in the forward direction. 
     The servo pattern  84 A consists of the linear magnetization region pair  86 A. In the example shown in  FIG.  25   , linear magnetization regions  86 A 1  and  86 A 2  are shown as an example of the linear magnetization region pair  86 A. Each of the linear magnetization regions  86 A 1  and  86 A 2  is a linearly magnetized region. 
     The linear magnetization regions  86 A 1  and  86 A 2  are inclined in opposite directions with respect to the imaginary straight line C 1 . The linear magnetization regions  86 A 1  and  86 A 2  are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C 1 . The linear magnetization region  86 A 1  has a steeper inclined angle with respect to the imaginary straight line C 1  than the linear magnetization region  86 A 2 . Here, “steep” means that, for example, an angle of the linear magnetization region  86 A 1  with respect to the imaginary straight line C 1  is smaller than an angle of the linear magnetization region  86 A 2  with respect to the imaginary straight line C 1 . 
     In addition, the overall position of the linear magnetization region  86 A 1  and the overall position of the linear magnetization region  86 A 2  deviate from each other in the width direction WD. That is, the position of one end of the linear magnetization region  86 A 1  and the position of one end of the linear magnetization region  86 A 2  are not uniform in the width direction WD, and the position of the other end of the linear magnetization region  86 A 1  and the position of the other end of the linear magnetization region  86 A 2  are not uniform in the width direction WD. 
     In the servo pattern  84 A, a plurality of magnetization straight lines  86 A 1   a  are included in the linear magnetization region  86 A 1 , and a plurality of magnetization straight lines  86 A 2   a  are included in the linear magnetization region  86 A 2 . The number of the magnetization straight lines  86 A 1   a  included in the linear magnetization region  86 A 1  is the same as the number of the magnetization straight lines  86 A 2   a  included in the linear magnetization region  86 A 2 . 
     The linear magnetization region  86 A 1  is a set of magnetization straight lines  86 A 1   a , which are five magnetized straight lines, and the linear magnetization region  86 A 2  is a set of magnetization straight lines  86 A 2   a,  which are five magnetized straight lines. 
     In the servo band SB, the position of one end of each of all the magnetization straight lines  86 A 1   a  included in the linear magnetization region  86 A 1  in the width direction WD is aligned, and the position of the other end of each of all the magnetization straight lines  86 A 1   a  included in the linear magnetization region  86 A 1  in the width direction WD is also aligned. In addition, in the servo band SB, the position of one end of each of all the magnetization straight lines  86 A 2   a  included in the linear magnetization region  86 A 2  in the width direction WD is aligned, and the position of the other end of each of all the magnetization straight lines  86 A 2   a  included in the linear magnetization region  86 A 2  in the width direction WD is also aligned. 
     The servo pattern  84 B consists of the linear magnetization region pair  86 B. In the example shown in  FIG.  25   , linear magnetization regions  86 B 1  and  86 B 2  are shown as an example of the linear magnetization region pair  86 B. Each of the linear magnetization regions  86 B 1  and  86 B 2  is a linearly magnetized region. 
     The linear magnetization regions  86 B 1  and  86 B 2  are inclined in opposite directions with respect to the imaginary straight line C 2 . The linear magnetization regions  86 B 1  and  86 B 2  are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C 2 . The linear magnetization region  86 B 1  has a steeper inclined angle with respect to the imaginary straight line C 2  than the linear magnetization region  86 B 2 . Here, “steep” means that, for example, an angle of the linear magnetization region  86 B 1  with respect to the imaginary straight line C 2  is smaller than an angle of the linear magnetization region  86 B 2  with respect to the imaginary straight line C 2 . 
     In addition, the overall position of the linear magnetization region  86 B 1  and the overall position of the linear magnetization region  86 B 2  deviate from each other in the width direction WD. That is, the position of one end of the linear magnetization region  86 B 1  and the position of one end of the linear magnetization region  86 B 2  are not uniform in the width direction WD, and the position of the other end of the linear magnetization region  86 B 1  and the position of the other end of the linear magnetization region  86 B 2  are not uniform in the width direction WD. 
     In the servo pattern  84 B, a plurality of magnetization straight lines  86 B 1   a  are included in the linear magnetization region  86 B 1 , and a plurality of magnetization straight lines  86 B 2   a  are included in the linear magnetization region  86 B 2 . The number of the magnetization straight lines  86 B la included in the linear magnetization region  86 B 1  is the same as the number of the magnetization straight lines  86 B 2   a  included in the linear magnetization region  86 B 2 . 
     The total number of the magnetization straight lines  86 B 1   a  and  86 B 2   a  included in the servo pattern  84 B is different from the total number of the magnetization straight lines  86 A 1   a  and  86 A 2   a  included in the servo pattern  84 A. In the example shown in  FIG.  25   , the total number of the magnetization straight lines  86 A 1   a  and  86 A 2   a  included in the servo pattern  84 A is ten, whereas the total number of the magnetization straight lines  86 B 1   a  and  86 B 2   a  included in the servo pattern  84 B is eight. 
     The linear magnetization region  86 B 1  is a set of magnetization straight lines  86 B 1   a , which are four magnetized straight lines, and the linear magnetization region  86 B 2  is a set of magnetization straight lines  86 B 2   a,  which are four magnetized straight lines. 
     In the servo band SB, the position of one end of each of all the magnetization straight lines  86 B 1   a  included in the linear magnetization region  86 B 1  in the width direction WD is aligned, and the position of the other end of each of all the magnetization straight lines  86 B la included in the linear magnetization region  86 B 1  in the width direction WD is also aligned. In addition, in the servo band SB, the position of one end of each of all the magnetization straight lines  86 B 2   a  included in the linear magnetization region  86 B 2  in the width direction WD is aligned, and the position of the other end of each of all the magnetization straight lines  86 B 2   a  included in the linear magnetization region  86 B 2  in the width direction WD is also aligned. 
     It should be noted that, here, the set of magnetization straight lines  86 A 1   a,  which are five magnetized straight lines, is described as an example of the linear magnetization region  86 A 1 , the set of magnetization straight lines  86 A 2   a,  which are five magnetized straight lines, is described as an example of the linear magnetization region  86 A 2 , the set of magnetization straight lines  86 B 1   a , which are four magnetized straight lines, is described as an example of the linear magnetization region  86 B 1 , and the set of magnetization straight lines  86 B 2   a,  which are four magnetized straight lines, is described as an example of the linear magnetization region  86 B 2 , but the technology of the present disclosure is not limited thereto. For example, the linear magnetization region  86 A 1  need only have the number of the magnetization straight lines  86 A 1   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT, the linear magnetization region  86 A 2  need only have the number of the magnetization straight lines  86 A 2   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT, the linear magnetization region  86 B 1  need only have the number of the magnetization straight lines  86 B 1   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT, and the linear magnetization region  86 B 2  need only have the number of the magnetization straight lines  86 B 2   a  that contribute to specifying the position of the magnetic head  28  on the magnetic tape MT. 
     Here, the geometrical characteristic of the linear magnetization region pair  86 A on the magnetic tape MT will be described with reference to  FIG.  26   . 
     As an example, as shown in  FIG.  26   , the geometrical characteristic of the linear magnetization region pair  86 A on the magnetic tape MT can be expressed by using an imaginary linear region pair  62 . Here, the entirety of the imaginary linear region pair  62  is inclined with respect to the imaginary straight line C 1  by inclining the symmetry axis SA 1  of the imaginary linear regions  62 A and  62 B at an angle a (for example, 10 degrees) with respect to the imaginary straight line C 1  with the center O 1  as the rotation axis. Moreover, the position of one end of each of all the straight lines  62 A 1  included in the imaginary linear region  62 A of the imaginary linear region pair  62  in this state in the width direction WD is aligned, and the position of the other end of each of all the straight lines  62 A 1  included in the imaginary linear region  62 A in the width direction WD is also aligned. In addition, similarly, the position of one end of each of all the straight lines  62 B 1  included in the imaginary linear region  62 B of the imaginary linear region pair  62  in the width direction WD is aligned, and the position of the other end of each of all the straight lines  62 B 1  included in the imaginary linear region  62 B in the width direction WD is also aligned. As a result, the imaginary linear region  62 A and the imaginary linear region  62 B deviate from each other in the width direction WD. 
     That is, one end of the imaginary linear region  62 A and one end of the imaginary linear region  62 B deviate from each other in the width direction WD at a regular interval Int 1 , and the other end of the imaginary linear region  62 A and the other end of the imaginary linear region  62 B deviate from each other in the width direction WD at a regular interval Int 2 . 
     The geometrical characteristic of the imaginary linear region pair  62  (that is, the geometrical characteristic of the imaginary servo pattern) obtained as described above corresponds to the geometrical characteristic of the actual servo pattern  84 A. That is, the geometrical characteristic of the linear magnetization region pair  86 A on the magnetic tape MT corresponds to the geometrical characteristic based on the imaginary linear region pair  62  inclined line-symmetrically with respect to the imaginary straight line C 1  in a case in which the entirety of the imaginary linear region pair  62  is inclined with respect to the imaginary straight line C 1  by inclining a symmetry axis SA 1  of the imaginary linear region  62 A and the imaginary linear region  62 B with respect to the imaginary straight line C 1 . 
     The imaginary linear region  62 A corresponds to the linear magnetization region  86 A 1  of the servo pattern  84 A, and the imaginary linear region  62 B corresponds to the linear magnetization region  86 A 2  of the servo pattern  84 A. Therefore, in the servo band SB, the servo pattern  84 A consisting of the linear magnetization region pair  86 A in which one end of the linear magnetization region  86 A 1  and one end of the linear magnetization region  86 A 2  deviate from each other in the width direction WD at the regular interval Intl, and the other end of the linear magnetization region  86 A 1  and the other end of the linear magnetization region  86 A 2  deviate from each other in the width direction WD at the regular interval Int 2  is recorded (see  FIG.  25   ). 
     It should be noted that the linear magnetization region pair  86 B is different from the linear magnetization region pair  86 A only in that the four magnetization straight lines  86 B 1   a  are provided instead of the five magnetization straight lines  86 A 1   a  and the four magnetization straight lines  86 B 2   a  are provided instead of the five magnetization straight lines  86 A 2   a  (see  FIG.  25   ). Therefore, in the servo band SB, the servo pattern  84 B consisting of the linear magnetization region pair  86 B in which one end of the linear magnetization region  86 B 1  and one end of the linear magnetization region  86 B 2  deviate from each other in the width direction WD at the regular interval Int 1 , and the other end of the linear magnetization region  86 B 1  and the other end of the linear magnetization region  86 B 2  deviate from each other in the width direction WD at the regular interval Int 2  is recorded (see  FIG.  25   ). 
     As an example, as shown in  FIG.  27   , the plurality of servo bands SB are formed on the magnetic tape MT in the width direction WD, and the frames  82  having a correspondence relationship between the servo bands SB deviate from each other at predetermined intervals in the longitudinal direction LD, between the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT. This means that the servo patterns  84  having a correspondence relationship between the servo bands SB deviate from each other at the predetermined interval described in the above first modification example in the longitudinal direction LD between the servo bands SB adjacent to each other in the width direction WD of the magnetic tape MT. The predetermined interval is defined by Expression (1) described in the first modification example. 
     Similarly to the first modification example described above, in the fifth modification example, as shown in  FIG.  28    as an example, the inclination mechanism  49  (see  FIG.  8   ) skews the magnetic head  28  on the magnetic tape MT around the rotation axis RA such that the imaginary straight line C 3  is inclined with respect to the imaginary straight line C 1  to the upstream side in the forward direction at an angle β (that is, the angle β counterclockwise as viewed from the paper surface side of  FIG.  28   ). That is, the magnetic head  28  is inclined at the angle β to the upstream side in the forward direction on the magnetic tape MT. In this state, in a case in which the servo pattern  84 A is read by the servo reading element SR along the longitudinal direction LD within a range R in which the linear magnetization regions  86 A 1  and  86 A 2  overlap with each other in the width direction WD, the variation due to the azimuth loss between the servo signal derived from the linear magnetization region  86 A 1  and the servo signal derived from the linear magnetization region  86 A 2  is smaller than in the examples shown in  FIG.  17   . In addition, also in a case in which the servo pattern  84 B (that is, the linear magnetization region pair  86 B) is read by the servo reading element SR, similarly, the variation due to the azimuth loss between the servo signal derived from the linear magnetization region  86 B 1  and the servo signal derived from the linear magnetization region  86 B 2  is small. 
     Sixth Modification Example 
     It should be noted that, in the fifth modification example described above, the form example has been described in which the servo band SB is divided by a plurality of frames  82  along 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 in  FIG.  29   , the servo band SB may be divided by a frame  88  along the longitudinal direction LD of the magnetic tape MT. The frame  88  is defined by a set of servo patterns  90 . A plurality of servo patterns  90  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. Similarly to the plurality of servo patterns  84  (see  FIG.  25   ), the plurality of servo patterns  90  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT. 
     In the example shown in  FIG.  29   , servo patterns  90 A and  90 B are shown as an example of the set of servo patterns  90 . Each of the servo patterns  90 A and  90 B is an M-shaped magnetized servo pattern. The servo patterns  90 A and  90 B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern  90 A is positioned on the upstream side in the forward direction in the frame  88 , and the servo pattern  90 B is positioned on the downstream side in the forward direction. 
     As an example, as shown in  FIG.  30   , the servo pattern  90  consists of a linear magnetization region pair  92 . The linear magnetization region pair  92  is classified into a linear magnetization region pair  92 A and a linear magnetization region pair  92 B. 
     The servo pattern  90 A consists of a set of linear magnetization region pairs  92 A. The set of linear magnetization region pairs  92 A are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. 
     In the example shown in  FIG.  30   , linear magnetization regions  92 A 1  and  92 A 2  are shown as an example of the linear magnetization region pair  92 A. The linear magnetization region pair  92 A is configured in the same manner as the linear magnetization region pair  86 A (see  FIG.  25   ) described in the fifth modification example, and has the same geometrical characteristic as the linear magnetization region pair  86 A. That is, the linear magnetization region  92 A 1  is configured in the same manner as the linear magnetization region  86 A 1  (see  FIG.  25   ) described in the fifth modification example and has the same geometrical characteristic as the linear magnetization region  86 A 1 , and the linear magnetization region  92 A 2  is configured in the same manner as the linear magnetization region  86 A 2  (see  FIG.  25   ) described in the fifth modification example and has the same geometrical characteristic as the linear magnetization region  86 A 2 . 
     The servo pattern  90 B consists of a set of linear magnetization region pairs  92 B. The set of linear magnetization region pairs  92 B are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. 
     In the example shown in  FIG.  30   , linear magnetization regions  92 B 1  and  92 B 2  are shown as an example of the linear magnetization region pair  92 B. The linear magnetization region pair  92 B is configured in the same manner as the linear magnetization region pair  86 B (see  FIG.  25   ) described in the fifth modification example, and has the same geometrical characteristic as the linear magnetization region pair  86 B. That is, the linear magnetization region  92 B 1  is configured in the same manner as the linear magnetization region  86 B 1  (see  FIG.  25   ) described in the fifth modification example and has the same geometrical characteristic as the linear magnetization region  86 B 1 , and the linear magnetization region  92 B 2  is configured in the same manner as the linear magnetization region  86 B 2  (see  FIG.  25   ) described in the fifth modification example and has the same geometrical characteristic as the linear magnetization region  86 B 2 . 
     Seventh Modification Example 
     In the example shown in  FIG.  29   , the form example has been described in which the servo band SB is divided by a plurality of frames  88  along 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 in  FIG.  31   , the servo band SB may be divided by a frame  94  along the longitudinal direction LD of the magnetic tape MT. The frame  94  is defined by a set of servo patterns  96 . A plurality of servo patterns  96  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. Similarly to the plurality of servo patterns  90  (see  FIG.  29   ), the plurality of servo patterns  96  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT. 
     In the example shown in  FIG.  31   , servo patterns  96 A and  96 B are shown as an example of the set of servo patterns  96 . Each of the servo patterns  96 A and  96 B is an N-shaped magnetized servo pattern. The servo patterns  96 A and  96 B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and the servo pattern  96 A is positioned on the upstream side in the forward direction in the frame  94 , and the servo pattern  96 B is positioned on the downstream side in the forward direction. 
     As an example, as shown in  FIG.  32   , the servo pattern  96  consists of a linear magnetization region group  98 . The linear magnetization region group  98  is classified into a linear magnetization region group  98 A and a linear magnetization region group  98 B. 
     The servo pattern  96 A consists of the linear magnetization region group  98 A. The linear magnetization region group  98 A consists of linear magnetization regions  98 A 1 ,  98 A 2 , and  98 A 3 . The linear magnetization regions  98 A 1 ,  98 A 2 , and  98 A 3  are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions  98 A 1 ,  98 A 2 , and  98 A 3  are disposed in the order of the linear magnetization regions  98 A 1 ,  98 A 2 , and  98 A 3  from the upstream side in the forward direction. 
     The linear magnetization regions  98 A 1  and  98 A 2  are configured in the same manner as the linear magnetization region pair  92 A shown in  FIG.  30   , and have the same geometrical characteristics as the linear magnetization region pair  92 A. That is, the linear magnetization region  98 A 1  is configured in the same manner as the linear magnetization region  92 A 1  shown in  FIG.  30   , and has the same geometrical characteristic as the linear magnetization region  92 A 1 , and the linear magnetization region  98 A 2  is configured in the same manner as the linear magnetization region  92 A 2  shown in  FIG.  30   , and has the same geometrical characteristic as the linear magnetization region  92 A 2 . In addition, the linear magnetization region  98 A 3  is configured in the same manner as the linear magnetization region  92 A 1 , and has the same geometrical characteristic as the linear magnetization region  92 A 1 . 
     The servo pattern  96 B consists of the linear magnetization region group  98 B. The linear magnetization region group  98 B consists of linear magnetization regions  98 B 1 ,  98 B 2 , and  98 B 3 . The linear magnetization regions  98 B 1 ,  98 B 2 , and  98 B 3  are disposed in a state of being adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions  98 B 1 ,  98 B 2 , and  98 B 3  are disposed in the order of the linear magnetization regions  98 B 1 ,  98 B 2 , and  98 B 3  from the upstream side in the forward direction. 
     The linear magnetization regions  98 B 1  and  98 B 2  are configured in the same manner as the linear magnetization region pair  92 B shown in  FIG.  30   , and have the same geometrical characteristics as the linear magnetization region pair  92 B. That is, the linear magnetization region  98 B 1  is configured in the same manner as the linear magnetization region  92 B 1  shown in  FIG.  30   , and has the same geometrical characteristic as the linear magnetization region  92 B 1 , and the linear magnetization region  98 B 2  is configured in the same manner as the linear magnetization region  92 B 2  shown in  FIG.  30   , and has the same geometrical characteristic as the linear magnetization region  92 B 2 . In addition, the linear magnetization region  98 B 3  is configured in the same manner as the linear magnetization region  92 B 1 , and has the same geometrical characteristic as the linear magnetization region  92 B 1 . 
     Eighth Modification Example 
     It should be noted that, in the first modification example described above (for example, example shown in  FIG.  14   ), the form example has been described in which the servo band SB is divided by the plurality of frames  56  along 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 in  FIG.  33   , the servo band SB may be divided by a frame  560  along the longitudinal direction LD of the magnetic tape MT. The frame  560  is defined by a set of servo patterns  580 . A plurality of servo patterns  580  are recorded in the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns  580  are disposed at regular intervals along the longitudinal direction LD of the magnetic tape MT, similarly to the plurality of servo patterns  58 . 
     The servo pattern  580  consists of a linear magnetization region pair  600 . The linear magnetization region pair  600  is classified into a linear magnetization region pair  600 A and a linear magnetization region pair  600 B. That is, the linear magnetization region pair  600  is different from the linear magnetization region pair  60  (see  FIG.  14   ) in that the linear magnetization region pair  600 A is provided instead of the linear magnetization region pair  60 A, and the linear magnetization region pair  600 B is provided instead of the linear magnetization region pair  60 B. 
     The servo pattern  580 A consists of the linear magnetization region pair  600 A. The linear magnetization region pair  600 A is different from the linear magnetization region pair  60 A in that the linear magnetization region  600 A 1  is provided instead of the linear magnetization region  60 A 1 , and the linear magnetization region  600 A 2  is provided instead of the linear magnetization region  60 A 2 . Each of the linear magnetization regions  600 A 1  and  600 A 2  is a linearly magnetized region. In the eighth modification example, the linear magnetization region  600 A 1  is an example of a “second linear magnetization region” according to the technology of the present disclosure, and the linear magnetization region  600 A 2  is a “first linear magnetization region” according to the technology of the present disclosure. 
     The linear magnetization regions  600 A 1  and  600 A 2  are inclined in opposite directions with respect to the imaginary straight line C 1 . The linear magnetization regions  600 A 1  and  600 A 2  are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C 1 . The linear magnetization region  600 A 2  has a steeper inclined angle with respect to the imaginary straight line C 1  than the linear magnetization region  600 A 1 . Here, “steep” means that, for example, an angle of the linear magnetization region  600 A 2  with respect to the imaginary straight line C 1  is smaller than an angle of the linear magnetization region  600 A 1  with respect to the imaginary straight line C 1 . In addition, a total length of the linear magnetization region  600 A 2  is shorter than a total length of the linear magnetization region  600 A 1 . 
     The linear magnetization region  600 A 1  is different from the linear magnetization region  60 A 1  in that a plurality of magnetization straight lines  600 A 1   a  are provided instead of the plurality of magnetization straight lines  60 A 1   a . The linear magnetization region  600 A 2  is different from the linear magnetization region  60 A 2  in that a plurality of magnetization straight lines  600 A 2   a  are provided instead of the plurality of magnetization straight lines  60 A 2   a.    
     The plurality of magnetization straight lines  600 A 1   a  are included in the linear magnetization region  600 A 1 , and the plurality of magnetization straight lines  600 A 2   a  are included in the linear magnetization region  600 A 2 . The number of the magnetization straight lines  600 A 1   a  included in the linear magnetization region  600 A 1  is the same as the number of the magnetization straight lines  600 A 2   a  included in the linear magnetization region  600 A 2 . 
     The linear magnetization region  600 A 1  is 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 region  60 A 2  (see  FIG.  14   ) described in the first embodiment is formed line-symmetrically with respect to the imaginary straight line C 1 . That is, the linear magnetization region  600 A 1  can be said to be a linear magnetization region formed by a geometrical characteristic of a mirror image of the linear magnetization region  60 A 2  (see  FIG.  14   ) (that is, geometrical characteristic obtained by performing the mirror image with respect to the linear magnetization region  60 A 2  (see  FIG.  14   ) with the imaginary straight line C 1  as a line symmetry axis). 
     The linear magnetization region  600 A 2  is 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 region  60 A 1  (see  FIG.  14   ) described in the first embodiment is formed line-symmetrically with respect to the imaginary straight line C 1 . That is, the linear magnetization region  600 A 2  can be said to be a linear magnetization region formed by a geometrical characteristic of a mirror image of the linear magnetization region  60 A 1  (see  FIG.  14   ) (that is, geometrical characteristic obtained by performing the mirror image with respect to the linear magnetization region  60 A 1  (see  FIG.  14   ) with the imaginary straight line C 1  as a line symmetry axis). 
     That is, in the example shown in  FIG.  15   , the geometrical characteristic of the imaginary linear region pair  62  obtained by aligning the positions of both ends of the imaginary linear region  62 A and the positions of both ends of the imaginary linear region  62 B in a case in which the entirety of the imaginary linear region pair  62  is inclined with respect to the imaginary straight line C 1  by inclining the symmetry axis SA 1  of the imaginary linear regions  62 A and  62 B with respect to the imaginary straight line C 1  at the angle a clockwise as viewed from the paper surface side of  FIG.  15    with the center O 1  as the rotation axis corresponds to the geometrical characteristic of the servo pattern  580 A. 
     The servo pattern  580 B consists of the linear magnetization region pair  600 B. The linear magnetization region pair  600 B is different from the linear magnetization region pair  60 B in that the linear magnetization region  600 B 1  is provided instead of the linear magnetization region  60 B 1 , and the linear magnetization region  600 B 2  is provided instead of the linear magnetization region  60 B 2 . Each of the linear magnetization regions  600 B 1  and  600 B 2  is a linearly magnetized region. In the eighth modification example, the linear magnetization region  600 B 1  is an example of a “second linear magnetization region” according to the technology of the present disclosure, and the linear magnetization region  600 B 2  is a “first linear magnetization region” according to the technology of the present disclosure. 
     The linear magnetization regions  600 B 1  and  600 B 2  are inclined in opposite directions with respect to the imaginary straight line C 2 . The linear magnetization regions  600 B 1  and  600 B 2  are not parallel to each other and are inclined at different angles with respect to the imaginary straight line C 2 . The linear magnetization region  600 B 2  has a steeper inclined angle with respect to the imaginary straight line C 2  than the linear magnetization region  600 B 1 . Here, “steep” means that, for example, an angle of the linear magnetization region  600 B 2  with respect to the imaginary straight line C 2  is smaller than an angle of the linear magnetization region  600 B 1  with respect to the imaginary straight line C 2 . 
     The plurality of magnetization straight lines  600 B 1   a  are included in the linear magnetization region  600 B 1 , and the plurality of magnetization straight lines  600 B 2   a  are included in the linear magnetization region  600 B 2 . The number of the magnetization straight lines  600 B 1   a  included in the linear magnetization region  600 B 1  is the same as the number of the magnetization straight lines  600 B 2   a  included in the linear magnetization region  600 B 2 . 
     The total number of the magnetization straight lines  600 B 1   a  and  600 B 2   a  included in the servo pattern  580 B is different from the total number of the magnetization straight lines  600 A 1   a  and  600 A 2   a  included in the servo pattern  580 A. In the example shown in  FIG.  33   , the total number of the magnetization straight lines  600 A 1   a  and  600 A 2   a  included in the servo pattern  580 A is ten, whereas the total number of the magnetization straight lines  600 B 1   a  and  600 B 2   a  included in the servo pattern  580 B is eight. 
     The linear magnetization region  600 B 1  is a set of magnetization straight lines  600 B 1   a , which are four magnetized straight lines, and the linear magnetization region  600 B 2  is a set of magnetization straight lines  600 B 2   a,  which are four magnetized straight lines. In the servo band SB, the positions of both ends of the linear magnetization region  600 B 1  (that is, the positions of both ends of each of the four magnetization straight lines  600 B 1   a ) and the positions of both ends of the linear magnetization region  600 B 2  (that is, the positions of both ends of each of the four magnetization straight lines  600 B 2   a ) are aligned in the width direction WD. 
     As described above, the geometrical characteristic of the servo pattern  580 A corresponds to the geometrical characteristic of the mirror image of the linear magnetization region  60 A 2  (see  FIG.  14   ) and the geometrical characteristic of the mirror image of the linear magnetization region  60 A 2  (see  FIG.  14   ) (that is, geometrical characteristic of the mirror image of the servo pattern  58 A shown in  FIG.  14   ), and the geometrical characteristic of the servo pattern  580 B corresponds to the geometrical characteristic of the mirror image of the linear magnetization region  60 B 2  (see  FIG.  14   ) and the geometrical characteristic of the mirror image of the linear magnetization region  60 B 2  (see  FIG.  14   ) (that is, geometrical characteristic of the mirror image of the servo pattern  58 B shown in  FIG.  14   ). However, this is merely an example, and instead of the servo pattern  580 , the servo pattern formed by the geometrical characteristic of the mirror image of the servo pattern  72  shown in  FIG.  20   , the geometrical characteristic of the mirror image of the servo pattern  78  shown in  FIG.  22   , the geometrical characteristic of the mirror image of the servo pattern  84  shown in  FIG.  25   , the geometrical characteristic of the mirror image of the servo pattern  90  shown in  FIG.  29   , or the geometrical characteristic of the mirror image of the servo pattern  96  shown in  FIG.  31    may be applied. 
     It should be noted that, even in a case in which the geometrical characteristic of the servo pattern is changed in this way, the inclination mechanism  49  changes the direction of the inclination (that is, azimuth) of the imaginary straight line C 3  with respect to the imaginary straight line C 4  and the inclined angle (for example, angle β shown in  FIG.  18   ) in accordance with the geometrical characteristic of the servo pattern. That is, even in a case in which the geometrical characteristic of the servo pattern is changed, as in the same manner in the first modification example described above, the inclination mechanism  49  rotates, under the control of the control device  30 A, the magnetic head  28  around the rotation axis RA on the front surface  31  of the magnetic tape MT to change the direction of the inclination of the imaginary straight line C 3  with respect to the imaginary straight line C 4  (that is, azimuth) and the inclined angle (for example, angle β shown in  FIG.  18   ) such that the variation in the servo signal is reduced. 
     Other Modification Examples 
     In the embodiment described above, the magnetic tape system  10  has been described in which the magnetic tape cartridge  12  can be inserted and removed with respect to the magnetic tape drive  14 , 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 cartridge  12  is loaded in advance into the magnetic tape drive  14  (that is, the magnetic tape system in which at least one magnetic tape cartridge  12  and the magnetic tape drive  14  are integrated in advance), the technology of the present disclosure is established. 
     In the embodiment described above, the single magnetic head  28  has been described, but the technology of the present disclosure is not limited to this. For example, a plurality of magnetic heads  28  may be disposed on the magnetic tape MT. For example, the magnetic head  28  for reading and at least one magnetic head  28  for writing may be disposed on the magnetic tape MT. The magnetic head  28  for reading may be used for verifying the data recorded in the data band DB by the magnetic head  28  for writing. In addition, one magnetic head on which the magnetic element unit  42  for reading and at least one magnetic element unit  42  for 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 processing device  30  (see  FIG.  3   ) is realized by the ASIC, but the technology of the present disclosure is not limited to this, and the processing device  30  may be realized by a software configuration. In addition, only the position detection device  30 B provided in the processing device  30  may be realized by the software configuration. In a case in which the position detection device  30 B is realized by the software configuration, for example, as shown in  FIG.  34   , the position detection device  30 B comprises a computer  100 . The computer  100  includes a processor  100 A (for example, a single CPU or a plurality of CPUs), an NVM  100 B, and a RAM  100 C. The processor  100 A, the NVM  100 B, and the RAM  100 C are connected to a bus  100 D. A servo pattern detection program PG is stored in a portable storage medium  102  (for example, an SSD or a USB memory) which is a computer-readable non-transitory storage medium. 
     The servo pattern detection program PG stored in the storage medium  102  is installed in the computer  100 . The processor  100 A executes the servo pattern detection processing (see  FIG.  13   ) in accordance with the servo pattern detection program PG. 
     In addition, the servo pattern detection program PG may be stored in a storage device of another computer or server device connected to the computer  100  via a communication network (not shown), and the servo pattern detection program PG may be downloaded in response to a request from the position detection device  30 B and installed in the computer  100 . It should be noted that the servo pattern detection program PG is an example of a “program” according to the technology of the present disclosure, and the computer  100  is an example of a “computer” according to the technology of the present disclosure. 
     In the example shown in  FIG.  34   , although the computer  100  has 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 computer  100 . In addition, instead of the computer  100 , a hardware configuration and a software configuration may be used in combination. 
     As the hardware resource for executing the processing of the processing device  30  (see  FIG.  3   ) and/or the servo writer controller SW 5  (see  FIG.  12   ), 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 electric 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 built in or connected to any processor, and any processor executes the processing by using the memory. 
     The hardware resource for executing the processing of the processing device  30  and/or the servo writer controller SW 5  may 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 processing device  30  and/or the servo writer controller SW 5  may be one processor. 
     As a configuring example of one processor, first, there is a form in which one processor is composed of a combination of one or more CPUs and software and the processor functions as the hardware resource for executing the processing. Secondly, as represented 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 processing device  30  and/or the servo writer controller SW 5  is realized 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 electric circuit in which circuit elements, such as semiconductor elements, are combined. In addition, the processing of the processing device  30  and/or the servo writer controller SW 5  is merely an example. Therefore, it is needless to say that unnecessary steps may be deleted, new steps may be added, or the processing order may be changed within a range that does not deviate from the gist. 
     The description contents and the shown contents above are the detailed description of the parts according to the technology of the present disclosure, and are merely examples of the technology of the present disclosure. For example, the description of the configuration, the function, the action, and the effect above are the description of examples of the configuration, the function, the action, and the effect of the parts according to the technology of the present disclosure. Accordingly, it is needless to say that unnecessary parts may be deleted, new elements may be added, or replacements may be made with respect to the contents described and shown above within a range that does not deviate from the gist of the technology of the present disclosure. In addition, in order to avoid complications and facilitate understanding of the parts according to the technology of the present disclosure, in the description contents and the shown contents above, the description of common technical knowledge and the like that do not particularly require description for enabling the implementation of the technology of the present disclosure are 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” means that it may be only A, only B, or a combination of A and B. In addition, in the present specification, in a case in which three or more matters are associated and expressed by “and/or”, the same concept as “A and/or B” is applied. 
     All documents, patent applications, and technical standards described in the present specification are incorporated into the present specification by reference to the same extent as in a case in which the individual documents, patent applications, and technical standards are specifically and individually stated to be described by reference.