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

Abstract

To provide a detection device, an inspection device, a magnetic tape cartridge, a magnetic tape, a magnetic tape drive, a magnetic tape system, a detection method, an inspection method, and a program capable of accurately detecting servo pattern signals.SOLUTION: A detection device includes a processor. The processor detects a servo pattern signal indicating a servo pattern by comparing a servo band signal which is a result of reading a servo band by a servo reading element from a magnetic tape having the servo band on which the servo pattern is recorded, with a threshold value. The threshold value is determined according to an angle formed by the servo pattern and the servo reading element.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The technology disclosed herein relates to a detection device, an inspection device, a magnetic tape cartridge, a magnetic tape, a magnetic tape drive, a magnetic tape system, a detection method, an inspection method, and a program. [Background technology]

[0002] Patent Document 1 cites a problem in magnetic tape devices in which read and / or write errors occur when the tape does not pass over the head with the appropriate tension and / or skew angle. To solve this problem, the system described in Patent Document 1 includes a head having an array of at least one of readers and writers, a drive mechanism for passing magnetic recording tape over the head, and a skew induction mechanism coupled to the head, which adjusts the skew angle of the longitudinal axis of the array relative to a direction perpendicular to the direction in which the tape moves over the head, and a controller communicating with the head. The system described in Patent Document 1 also determines a dimensionally stable state of the tape, adjusts the skew angle in a direction away from the normal to the direction of tape movement, and reduces the tape tension across the head if the dimensionally stable state of the tape is in a contracted state.

[0003] Patent Document 2 discloses a method for reading data tracks of a magnetic tape that are subject to lateral distortion by selectively using longitudinally offset read elements. The read elements are part of a tape head that has an azimuth angle with respect to the tape, and a lateral offset is created between the read elements. This lateral offset is used to minimize the effect of lateral tape distortion.

[0004] Patent Document 3 discloses a head device including a head unit in which a plurality of magnetic elements, each of which performs at least one of reproducing data recorded on a plurality of data tracks provided on a magnetic tape and recording data to each of the data tracks, are arranged side by side at equal intervals on a first straight line, a movement mechanism for moving the head unit, and a control unit for performing tracking control to move the head unit relative to the movement mechanism so that each of the magnetic elements is on-track with each of the data tracks. In the head device described in Patent Document 3, the movement mechanism is configured to be able to perform rotational drive to rotate the head unit in a direction that increases or decreases the angle between a second straight line along the width of the magnetic tape and the first straight line, and the control unit, during tracking control, rotationally drives the head unit relative to the movement mechanism by an amount of increase or decrease in angle corresponding to a change in the spacing between each of the data tracks, so that each magnetic element is on-track with each of the data tracks. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 8,094,402 [Patent Document 2] U.S. Patent No. 6,781,784 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-123288 Summary of the Invention

[0006] One embodiment of the disclosed technology provides a detection device, an inspection device, a magnetic tape cartridge, a magnetic tape, a magnetic tape drive, a magnetic tape system, a detection method, an inspection method, and a program that can detect servo pattern signals with high accuracy. [Means for solving the problem]

[0007] A first aspect of the technology disclosed herein is a detection device that includes a processor, which detects a servo pattern signal indicating a servo pattern by comparing a servo band signal, which is the result of a servo read element reading a servo band on which a servo pattern is recorded, with a threshold value, and the threshold value is determined according to the angle formed by the servo pattern and the servo read element.

[0008] A second aspect of the technique of the present disclosure is the detection device according to the first aspect, in which the threshold is a variable value that changes depending on the angle.

[0009] A third aspect of the technology disclosed herein is a detection device according to the second aspect, in which the threshold is changed while the magnetic tape is running, and a processor associates specific information identifying the position on the magnetic tape where the threshold was changed with the threshold changed at that position and stores the associated information in a storage medium.

[0010] A fourth aspect of the technology of the present disclosure is a detection device according to the third aspect, in which the magnetic tape is housed in a cartridge, and the cartridge is provided with a non-contact storage medium as a storage medium, which is capable of communicating with the processor contactlessly.

[0011] A fifth aspect of the technique of the present disclosure is the detection device according to the third aspect, in which the storage medium is a magnetic tape.

[0012] A sixth aspect of the technology of the present disclosure is a detection device according to any one of the first to fifth aspects, in which the processor, on condition that the angle has been changed, derives a threshold value corresponding to the changed angle, and detects the servo pattern signal by comparing the derived threshold value with the servo band signal.

[0013] A seventh aspect of the technology disclosed herein is a detection device according to any one of the first to sixth aspects, wherein the servo pattern is at least one pair of linear magnetization regions, the pair of linear magnetization regions being a linearly magnetized first linear magnetization region and a linearly magnetized second linear magnetization region, the first linear magnetization region and the second linear magnetization region being inclined in opposite directions with respect to a first virtual line along the width direction of the magnetic tape, the angles being classified into a first angle formed by the first linear magnetization region and the servo read element and a second angle formed by the second linear magnetization region and the servo read element, the thresholds being classified into a first threshold and a second threshold, the first threshold being determined according to the first angle, and the second threshold being determined according to the second angle.

[0014] An eighth aspect of the technology of the present disclosure is an inspection device comprising a detection device according to any one of the first to seventh aspects, and an inspection processor that inspects a servo band on a magnetic tape in which a servo pattern is recorded based on a servo pattern signal detected by the detection device.

[0015] A ninth aspect of the technology of the present disclosure is a magnetic tape cartridge comprising a memory storing a threshold value that is compared with a servo band signal by a processor included in a detection device according to any one of the first to seventh aspects, and a magnetic tape.

[0016] A tenth aspect of the technology of the present disclosure is a magnetic tape storing a threshold value that is compared with a servo band signal by a processor included in a detection device according to any one of the first to seventh aspects.

[0017] An eleventh aspect of the technique of the present disclosure is the magnetic tape according to the tenth aspect, in which a data band is formed and a threshold value is stored in the data band.

[0018] A twelfth aspect of the technology of the present disclosure is a magnetic tape according to the eleventh aspect, in which the threshold value is changed while the magnetic tape is running, and the threshold value is stored in an area within the data band corresponding to the position where the threshold value was changed.

[0019] A thirteenth aspect of the technique of the present disclosure is a magnetic tape cartridge containing the magnetic tape according to any one of the tenth to twelfth aspects.

[0020] A fourteenth aspect of the technology disclosed herein is a magnetic tape drive comprising a detection device according to any one of the first to seventh aspects and a magnetic head that operates in accordance with the servo pattern signal detected by the detection device.

[0021] A fifteenth aspect of the technology of the present disclosure is a magnetic tape system comprising a magnetic tape drive having a detection device according to any one of the first to seventh aspects, a magnetic head that operates in accordance with a servo pattern signal detected by the detection device, and a magnetic tape that is magnetically processed by the magnetic head.

[0022] A sixteenth aspect of the technology of the present disclosure is a detection method that includes acquiring a servo band signal that is the result of a servo band being read by a servo read element from a magnetic tape having a servo band on which a servo pattern is recorded, and detecting a servo pattern signal that indicates the servo pattern by comparing the acquired servo band signal with a threshold value, wherein the threshold value is determined according to the angle formed by the servo pattern and the servo read element.

[0023] A seventeenth aspect of the technology of the present disclosure is an inspection method that includes inspecting a servo band on a magnetic tape in which a servo pattern is recorded, based on a servo pattern signal detected by a detection method according to the sixteenth aspect of the technology of the present disclosure.

[0024] An 18th aspect of the technology of the present disclosure is a program for causing a computer to execute processing, the processing including acquiring a servo band signal that is the result of a servo band being read by a servo read element from a magnetic tape having a servo band on which a servo pattern is recorded, and detecting a servo pattern signal that indicates the servo pattern by comparing the acquired servo band signal with a threshold value, the threshold value being determined according to the angle formed by the servo pattern and the servo read element. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a block diagram showing an example of the configuration of a magnetic tape system according to an embodiment; [Figure 2] 1 is a schematic perspective view showing an example of the appearance of a magnetic tape cartridge according to an embodiment. [Figure 3] FIG. 1 is a schematic diagram illustrating an example of a hardware configuration of a magnetic tape drive according to an embodiment. [Figure 4] 1 is a schematic perspective view showing an example of a magnetic field emitted by a non-contact read / write device from the bottom side of a magnetic tape cartridge according to an embodiment. FIG. [Figure 5] FIG. 1 is a schematic diagram illustrating an example of a hardware configuration of a magnetic tape drive according to an embodiment. [Figure 6] 1 is a conceptual diagram showing an example of a state in which a magnetic head is disposed on a magnetic tape according to an embodiment, as observed from the surface side of the magnetic tape. [Figure 7] 1A and 1B are conceptual diagrams showing an example of a state in which a magnetic tape according to an embodiment is observed from the surface side of the magnetic tape before and after the width of the magnetic tape is reduced. [Figure 8] FIG. 2 is a conceptual diagram showing an example of a state in which a magnetic head is skewed on a magnetic tape according to an embodiment, as observed from the surface side of the magnetic tape. [Figure 9] FIG. 2 is a conceptual diagram illustrating an example of functions of a processing device included in a magnetic tape drive according to an embodiment. [Figure 10]3 is a conceptual diagram showing an example of a first processing content of a control unit and a position detection unit of a processing device included in a magnetic tape drive according to an embodiment. FIG. [Figure 11] FIG. 10 is a conceptual diagram showing an example of second processing details of a control unit and a position detection unit of a processing device included in the magnetic tape drive according to the embodiment. [Figure 12] FIG. 10 is a conceptual diagram showing an example of a third process performed by a control unit and a position detection unit of a processing device included in a magnetic tape drive according to an embodiment. [Figure 13] FIG. 10 is a conceptual diagram showing an example of a fourth processing content of a control unit and a position detection unit of a processing device included in the magnetic tape drive according to the embodiment. [Figure 14] FIG. 2 is a conceptual diagram showing an example of the configuration of a servo writer according to the embodiment. [Figure 15] 10 is a flowchart illustrating an example of the flow of a servo pattern detection process according to the embodiment. [Figure 16] 10 is a flowchart showing an example of the flow of a first setting process according to the embodiment. [Figure 17] 10 is a flowchart showing an example of the flow of a second setting process according to the embodiment. [Figure 18] This is a conceptual diagram showing a first modified example, and a conceptual diagram showing a modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of the magnetic tape observed from the surface side of the magnetic tape). [Figure 19] FIG. 10 is a conceptual diagram showing a first modified example, illustrating an example of the relationship between the geometric characteristics of an actual servo pattern and the geometric characteristics of a virtual servo pattern. [Figure 20] This is a conceptual diagram showing a first modified example, which shows an example of a state in which corresponding frames between adjacent servo bands in the width direction of the magnetic tape are shifted by a predetermined interval, as observed from the surface side of the magnetic tape. [Figure 21] This is a conceptual diagram showing the first modified example, which is a conceptual diagram showing an example of the state in which a servo pattern is read by a servo read element included in a magnetic head that is not skewed on the magnetic tape, observed from the surface side of the magnetic tape. [Figure 22] This is a conceptual diagram showing a first modified example, and is a conceptual diagram showing an example of the state in which a servo pattern is read by a servo read element included in a magnetic head skewed above the magnetic tape, observed from the surface side of the magnetic tape. [Figure 23] This is a conceptual diagram showing a second modified example, and is a conceptual diagram showing a modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of the magnetic tape observed from the surface side of the magnetic tape). [Figure 24] FIG. 10 is a conceptual diagram showing a second modified example, illustrating an example of a form of a servo pattern included in a magnetic tape. [Figure 25] This is a conceptual diagram showing a third modified example, and is a conceptual diagram showing a modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of the magnetic tape observed from the surface side of the magnetic tape). [Figure 26] FIG. 10 is a conceptual diagram showing a third modified example, illustrating an example of a form of a servo pattern included in a magnetic tape. [Figure 27] This is a conceptual diagram showing a fourth modified example, and is a conceptual diagram showing an example of a state in which corresponding frames between adjacent servo bands in the width direction of the magnetic tape of the embodiment are shifted by a predetermined interval, as observed from the surface side of the magnetic tape. [Figure 28] This is a conceptual diagram showing a fifth modified example, and is a conceptual diagram showing a modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of the magnetic tape observed from the surface side of the magnetic tape). [Figure 29] FIG. 13 is a conceptual diagram showing a fifth modified example, illustrating an example of the relationship between the geometric characteristics of an actual servo pattern and the geometric characteristics of a virtual servo pattern. [Figure 30] This is a conceptual diagram showing the fifth modified example, which shows an example of a state in which corresponding frames between adjacent servo bands in the width direction of the magnetic tape are shifted by a predetermined interval, as observed from the surface side of the magnetic tape. [Figure 31]This is a conceptual diagram showing the fifth modified example, and is a conceptual diagram showing an example of the state in which a servo pattern is read by a servo read element included in a magnetic head skewed above the magnetic tape, observed from the surface side of the magnetic tape. [Figure 32] This is a conceptual diagram showing a sixth modified example, and a conceptual diagram showing a modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of the magnetic tape observed from the surface side of the magnetic tape). [Figure 33] FIG. 13 is a conceptual diagram showing a sixth modified example, illustrating an example of a form of a servo pattern included in a magnetic tape. [Figure 34] This is a conceptual diagram showing a seventh modified example, and a conceptual diagram showing a modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of the magnetic tape observed from the surface side of the magnetic tape). [Figure 35] FIG. 13 is a conceptual diagram showing a seventh modified example, illustrating an example of a mode of a servo pattern included in a magnetic tape. [Figure 36] This is a conceptual diagram showing an eighth modified example, a conceptual diagram showing a modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of the magnetic tape observed from the surface side of the magnetic tape). [Figure 37] FIG. 1 is a conceptual diagram showing an example of how a program stored in a storage medium is installed in a computer of a processing device. DETAILED DESCRIPTION OF THE INVENTION

[0026] Below, examples of embodiments of the magnetic tape, magnetic tape cartridge, servo pattern recording device, magnetic tape drive, magnetic tape system, detection device, inspection device, servo pattern recording method, magnetic tape manufacturing method, detection method, and inspection method relating to the technology disclosed herein will be described with reference to the attached drawings.

[0027] First, the terms used in the following description will be explained.

[0028] NVM is an abbreviation for "Non-volatile memory". CPU is an abbreviation for "Central Processing Unit". RAM is an abbreviation for "Random Access Memory". EEPROM is an abbreviation for "Electrically Erasable and Programmable Read Only Memory". SSD is an abbreviation for "Solid State Drive". HDD is an abbreviation for "Hard Disk Drive". ASIC is an abbreviation for "Application Specific Integrated Circuit". FPGA is an abbreviation for "Field-Programmable Gate Array". PLC is an abbreviation for "Programmable Logic Controller". SoC is an abbreviation for "System-on-a-chip". IC is an abbreviation for "Integrated Circuit". RFID is an abbreviation for "Radio Frequency Identifier". BOT is an abbreviation for "Beginning Of Tape". EOT is an abbreviation for "End Of Tape". UI is an abbreviation for "User Interface". WAN is an abbreviation for "Wide Area Network." LAN is an abbreviation for "Local Area Network." In the following description, geometric characteristics refer to commonly recognized geometric characteristics such as length, shape, orientation, and / or position.

[0029] As an example, as shown in Figure 1, a magnetic tape system 10 includes a magnetic tape cartridge 12 and a magnetic tape drive 14. The magnetic tape cartridge 12 is loaded into the magnetic tape drive 14. The magnetic tape cartridge 12 contains a magnetic tape MT. The magnetic tape drive 14 pulls out the magnetic tape MT from the loaded magnetic tape cartridge 12 and, while running the pulled-out magnetic tape MT, records data on the magnetic tape MT and reads data from the magnetic tape MT.

[0030] In this embodiment, the magnetic tape MT is an example of a "magnetic tape" according to the technology of the present disclosure. Also, in this embodiment, the magnetic tape system 10 is an example of a "magnetic tape system" according to the technology of the present disclosure. Also, in this embodiment, the magnetic tape drive 14 is an example of a "magnetic tape drive" according to the technology of the present disclosure. Also, in this embodiment, the magnetic tape cartridge 12 is an example of a "cartridge" and a "magnetic tape cartridge" according to the technology of the present disclosure.

[0031] Next, an example of the configuration of the magnetic tape cartridge 12 will be described with reference to Figures 2 to 4. In the following description, for convenience of explanation, the loading direction of the magnetic tape cartridge 12 into the magnetic tape drive 14 is indicated by arrow A in Figures 2 to 4, the direction of arrow A is the front direction of the magnetic tape cartridge 12, and the front side of the magnetic tape cartridge 12 is the 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.

[0032] 2 to 4, for convenience of explanation, the direction of arrow B, which is perpendicular to the direction of arrow A, is defined as the right direction, and the right side of the magnetic tape cartridge 12 is defined as the 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.

[0033] 2 to 4, for convenience of explanation, the direction opposite to the direction of arrow B is referred to as the left direction, and the left side of the magnetic tape cartridge 12 is referred to as the left side of the magnetic tape cartridge 12. In the following explanation of the structure, "left" refers to the left side of the magnetic tape cartridge 12.

[0034] 2 to 4, for convenience of explanation, the direction perpendicular to the directions of arrows A and B is indicated by arrow C, the direction of arrow C is the upward direction of the magnetic tape cartridge 12, and the upward side of the magnetic tape cartridge 12 is the upper side of the magnetic tape cartridge 12. In the explanation of the structure below, "upper" refers to the upper side of the magnetic tape cartridge 12.

[0035] 2 to 4, for convenience of explanation, the direction opposite to the front direction of the magnetic tape cartridge 12 is referred to as the rear direction of the magnetic tape cartridge 12, and the rear side of the magnetic tape cartridge 12 is referred to as the 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.

[0036] 2 to 4, for convenience of explanation, the direction opposite to the upper direction of the magnetic tape cartridge 12 is referred to as the lower direction of the magnetic tape cartridge 12, and the lower side of the magnetic tape cartridge 12 is referred to as the 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.

[0037] As an example, as shown in Figure 2, the magnetic tape cartridge 12 has a box-like case 16 that is generally rectangular in plan view. The case 16 houses a magnetic tape MT. The case 16 is made of resin such as polycarbonate and has an upper case 18 and a lower case 20. The upper case 18 and the lower case 20 are joined by welding (for example, ultrasonic welding) and screw fastening, with the lower peripheral surface of the upper case 18 and the upper peripheral surface of the lower case 20 in contact with each other. The joining method is not limited to welding and screw fastening, and other joining methods may also be used.

[0038] The supply reel 22 is rotatably housed inside the case 16. The supply reel 22 includes a reel hub 22A, an upper flange 22B1, and a lower flange 22B2. The reel hub 22A is cylindrical. The reel hub 22A is the axial center of the supply reel 22, and its axial direction is aligned with the vertical direction of the case 16, and it is disposed in the center of the case 16. The upper flange 22B1 and the lower flange 22B2 are each formed in an annular shape. The center of the upper flange 22B1 in a plan view is fixed to the upper end of the reel hub 22A, and the center of the lower flange 22B2 in a plan view is fixed to the lower end of the reel hub 22A. The reel hub 22A and the lower flange 22B2 may be integrally molded.

[0039] A magnetic tape MT is wound around the outer peripheral surface of the reel hub 22A, and the widthwise ends of the magnetic tape MT are held by an upper flange 22B1 and a lower flange 22B2.

[0040] An opening 16B is formed in the front side of the right wall 16A of the case 16. The magnetic tape MT is pulled out through the opening 16B.

[0041] The lower case 20 is provided with a cartridge memory 24. Specifically, the cartridge memory 24 is housed in the right rear end portion of the lower case 20. An IC chip having an NVM is mounted on the cartridge memory 24. In this embodiment, a so-called passive RFID tag is used as the cartridge memory 24, and various pieces of information are read and written to the cartridge memory 24 in a contactless manner.

[0042] The cartridge memory 24 stores management information for managing the magnetic tape cartridge 12. The management information includes, for example, information about the cartridge memory 24 (e.g., information that can identify the magnetic tape cartridge 12), information about the magnetic tape MT (e.g., information indicating the recording capacity of the magnetic tape MT, information indicating an outline of the data recorded on the magnetic tape MT, information indicating the items of data recorded on the magnetic tape MT, information indicating the recording format of the data recorded on the magnetic tape MT, etc.), and information about the magnetic tape drive 14 (e.g., information indicating the specifications of the magnetic tape drive 14 and signals used in the magnetic tape drive 14). The cartridge memory 24 is an example of a "storage medium," a "non-contact storage medium," and a "memory" according to the techniques of the present disclosure.

[0043] 3, the magnetic tape drive 14 includes a controller 25, a transport device 26, a magnetic head 28, a UI 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 includes a processing device 30 and storage 32. The processing device 30 is an example of a "processor" according to the technology of the present disclosure.

[0044] A magnetic tape cartridge 12 is loaded into the magnetic tape drive 14 in the direction of arrow A. In the magnetic tape drive 14, the magnetic tape MT is pulled out from the magnetic tape cartridge 12 and used.

[0045] The magnetic tape MT includes a magnetic layer 29A, a base film 29B, and a backcoat layer 29C. The magnetic layer 29A is formed on one side of the base film 29B, and the backcoat layer 29C is formed on the other side of the base film 29B. Data is recorded in the magnetic layer 29A. The magnetic layer 29A contains ferromagnetic powder. Examples of the ferromagnetic powder include ferromagnetic powders commonly used in the magnetic layers of various magnetic recording media. A preferred example of the ferromagnetic powder is hexagonal ferrite powder. Examples of the hexagonal ferrite powder include hexagonal strontium ferrite powder and hexagonal barium ferrite powder. The backcoat layer 29C is a layer containing a nonmagnetic powder such as carbon black. The base film 29B, also referred to as a support, is made of, for example, polyethylene terephthalate, polyethylene naphthalate, or polyamide. A nonmagnetic layer may be formed between the base film 29B and the magnetic layer 29A. In the magnetic tape MT, the surface on which the magnetic layer 29A is formed is the front surface 31 of the magnetic tape MT, and the surface on which the backcoat layer 29C is formed is the back surface 33 of the magnetic tape MT.

[0046] The magnetic tape drive 14 performs magnetic processing on the surface 31 of the magnetic tape MT using the magnetic head 28. Here, magnetic processing refers to recording data on the surface 31 of the magnetic tape MT and reading data from the surface 31 of the magnetic tape MT (i.e., reproducing data). In this embodiment, the magnetic tape drive 14 selectively records data on the surface 31 of the magnetic tape MT and reads data from the surface 31 of the magnetic tape MT using the magnetic head 28. That is, the magnetic tape drive 14 pulls out the magnetic tape MT from the magnetic tape cartridge 12 and uses the magnetic head 28 to record data on the surface 31 of the pulled-out magnetic tape MT, or uses the magnetic head 28 to read data from the surface 31 of the pulled-out magnetic tape MT.

[0047] The processing device 30 controls the entire magnetic tape drive 14. In this embodiment, the processing device 30 is realized by an ASIC, but 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. The processing device 30 may also be realized by a computer including a CPU, flash memory (e.g., EEPROM and / or SSD, etc.), and RAM. The processing device 30 may also be realized by a combination of two or more of the ASIC, FPGA, PLC, and computer. In other words, the processing device 30 may be realized by a combination of hardware and software.

[0048] The storage 32 is connected to the processing device 30, and the processing device 30 writes various types of information to the storage 32 and reads various types of information from the storage 32. Examples of the storage 32 include a flash memory and / or a hard disk drive (HDD). The flash memory and the HDD are merely examples, and any non-volatile memory that can be mounted in the magnetic tape drive 14 may be used.

[0049] The UI-based device 34 is a device having a reception function for receiving an instruction signal indicating an instruction from a user and a presentation function for presenting information to the user. The reception function is realized by, for example, a touch panel, hard keys (e.g., a keyboard), and / or a mouse. The presentation function is realized by, for example, a display, a printer, and / or a speaker. The UI-based device 34 is connected to the processing device 30. The processing device 30 acquires the instruction signal received by the UI-based device 34. The UI-based device 34 presents various information to the user under the control of the processing device 30.

[0050] The communication interface 35 is connected to the processing device 30. The communication interface 35 is also connected to an external device 37 via a communication network (not shown) such as a WAN and / or LAN. The communication interface 35 controls the exchange of various information (e.g., data to be recorded on the magnetic tape MT, data read from the magnetic tape MT, and / or instruction signals given to the processing device 30) between the processing device 30 and the external device 37. The external device 37 may be, for example, a personal computer or a mainframe.

[0051] The transport device 26 is a device that selectively transports the magnetic tape MT in the forward or reverse direction along a predetermined path, and is equipped with a feed motor 36, a take-up reel 38, a take-up motor 40, and multiple guide rollers GR. Note that here, the forward direction refers to the feed direction of the magnetic tape MT, and the reverse direction refers to the rewind direction of the magnetic tape MT.

[0052] The supply motor 36 rotates the supply reel 22 in the magnetic tape cartridge 12 under the control of the processing device 30. The processing device 30 controls the supply motor 36 to control the rotation direction, rotation speed, rotation torque, etc. of the supply reel 22.

[0053] The take-up motor 40 rotates the take-up reel 38 under the control of the processing device 30. The processing device 30 controls the take-up motor 40 to control the rotation direction, rotation speed, rotation torque, etc. of the take-up reel 38.

[0054] When the magnetic tape MT is wound by the take-up reel 38, the processing device 30 rotates the supply motor 36 and the take-up motor 40 so that the magnetic tape MT runs in the forward direction along a predetermined path. The rotational speed, rotational torque, etc. of the supply motor 36 and the take-up motor 40 are adjusted according to the speed at which the magnetic tape MT is wound onto the take-up reel 38. Furthermore, tension is imparted to the magnetic tape MT by adjusting the rotational speed, rotational torque, etc. of each of the supply motor 36 and the take-up motor 40 by the processing device 30. Furthermore, the tension imparted to the magnetic tape MT is controlled by adjusting the rotational speed, rotational torque, etc. of each of the supply motor 36 and the take-up motor 40 by the processing device 30.

[0055] When the magnetic tape MT is rewound onto the supply reel 22, the processing device 30 rotates the supply motor 36 and the take-up motor 40 so that the magnetic tape MT travels in the reverse direction along the predetermined path.

[0056] In this embodiment, the tension applied to the magnetic tape MT is controlled by controlling the rotational speed and rotational torque of the supply motor 36 and the take-up 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 using a dancer roller, or may be controlled by drawing the magnetic tape MT into a vacuum chamber.

[0057] Each of the guide rollers GR guides the magnetic tape MT. The predetermined path, i.e., the travel path of the magnetic tape MT, is determined by disposing the guide rollers GR at separate positions across the magnetic head 28 between the magnetic tape cartridge 12 and the take-up reel 38.

[0058] The magnetic head 28 includes a magnetic element unit 42 and a holder 44. The magnetic element unit 42 is held by the holder 44 so as to come into contact with the running magnetic tape MT. The magnetic element unit 42 has a plurality of magnetic elements.

[0059] The magnetic element unit 42 records data on the magnetic tape MT transported by the transport device 26, and reads data from the magnetic tape MT transported by the transport device 26. Here, data refers to, for example, the servo patterns 52 (see FIGS. 6 to 9) and data other than the servo patterns 52, i.e., data recorded in the data band DB (see FIGS. 6 to 9).

[0060] The magnetic tape drive 14 is equipped with a non-contact read / write device 46. The non-contact read / write device 46 is disposed below the magnetic tape cartridge 12 when the magnetic tape cartridge 12 is loaded so as to directly face the back surface 24A of the cartridge memory 24, and reads and writes information from and to the cartridge memory 24 in a non-contact manner.

[0061] 4, the non-contact read / write device 46 emits a magnetic field MF from the bottom side of the magnetic tape cartridge 12 toward the cartridge memory 24. The magnetic field MF penetrates the cartridge memory 24.

[0062] The non-contact read / write device 46 is connected to the processing device 30. The processing device 30 outputs a control signal to the non-contact read / write device 46. The control signal is a signal that controls the cartridge memory 24. The non-contact read / write device 46 generates a magnetic field MF in accordance with the control signal input from the processing device 30, and emits the generated magnetic field MF toward the cartridge memory 24.

[0063] The non-contact read / write device 46 performs contactless communication with the cartridge memory 24 via the magnetic field MF, thereby performing processing on the cartridge memory 24 in accordance with a control signal. For example, under the control of the processing device 30, the non-contact read / write device 46 selectively performs processing to read information from the cartridge memory 24 and processing to store information in the cartridge memory 24 (i.e., processing to write information to the cartridge memory 24). In other words, the processing device 30 reads information from the cartridge memory 24 and stores information in the cartridge memory 24 by communicating contactlessly with the cartridge memory 24 via the non-contact read / write device 46.

[0064] As an example, as shown in FIG. 5, the magnetic tape drive 14 includes a movement mechanism 48. The movement mechanism 48 has a movement actuator 48A. Examples of the movement actuator 48A include a voice coil motor and / or a piezoelectric actuator. The movement actuator 48A is connected to the processing device 30, which controls the movement actuator 48A. The movement actuator 48A generates power under the control of the processing device 30. The movement mechanism 48 receives the power generated by the movement actuator 48A to move the magnetic head 28 in the width direction of the magnetic tape MT.

[0065] The magnetic tape drive 14 is equipped with a tilt mechanism 49. The tilt mechanism 49 has a tilt actuator 49A. Examples of the tilt actuator 49A include a voice coil motor and / or a piezoelectric actuator. The tilt actuator 49A is connected to the processing device 30, which controls the tilt actuator 49A. The tilt actuator 49A generates power under the control of the processing device 30. By receiving the power generated by the tilt actuator 49A, the tilt mechanism 49 tilts the magnetic head 28 toward the longitudinal direction LD of the magnetic tape MT with respect to the width direction WD of the magnetic tape MT (see FIG. 8). In other words, the magnetic head 28 is skewed on the magnetic tape MT under the control of the processing device 30.

[0066] 6, for example, servo bands SB1, SB2, and SB3 and data bands DB1 and DB2 are formed on the surface 31 of the magnetic tape MT. For ease of explanation, the servo bands SB1 to SB3 will be referred to as servo bands SB, and the data bands DB1 and DB2 will be referred to as data bands DB unless a distinction is particularly required.

[0067] The servo bands SB1 to SB3 and the data bands DB1 and DB2 are formed along the longitudinal direction LD (i.e., the overall length direction) of the magnetic tape MT. Here, the overall length direction of the magnetic tape MT refers to the running direction of the magnetic tape MT. The running direction of the magnetic tape MT is defined as two directions: the forward direction (hereinafter also simply referred to as the "forward direction") in which the magnetic tape MT runs from the supply reel 22 side to the take-up reel 38 side, and the reverse direction (hereinafter also simply referred to as the "reverse direction") in which the magnetic tape MT runs from the take-up reel 38 side to the supply reel 22 side.

[0068] The servo bands SB1 to SB3 are arranged at positions spaced apart in the width direction WD of the magnetic tape MT (hereinafter also simply referred to as the "width direction WD"). For example, the servo bands SB1 to SB3 are arranged at equal intervals along the width direction WD. In this embodiment, "equal intervals" refers to not only perfectly equal intervals, but also equal intervals that include an error that is generally acceptable in the technical field to which the technology of the present disclosure belongs and that does not contradict the spirit of the technology of the present disclosure.

[0069] The data band DB1 is arranged between the servo bands SB1 and SB2, and the data band DB2 is arranged between the servo bands SB2 and SB3. In other words, the servo bands SB and the data bands DB are arranged alternately along the width direction WD.

[0070] In the example shown in Figure 6, for the sake of convenience, three servo bands SB and two data bands DB are shown, but this is merely an example, and the technology disclosed herein can be applied to two servo bands SB and one data band DB, or even to four or more servo bands SB and three or more data bands DB.

[0071] A plurality of servo patterns 52 are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. The servo patterns 52 are classified into servo patterns 52A and servo patterns 52B. The plurality of servo patterns 52 are arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT. In this embodiment, "constant" refers not only to perfect uniformity but also to uniformity that includes an error that is generally acceptable in the technical field to which the technology of the present disclosure pertains and that does not contradict the spirit of the technology of the present disclosure.

[0072] The servo band SB is divided into a plurality of frames 50 along the longitudinal direction LD of the magnetic tape MT. Each frame 50 is defined by a set of servo patterns 52. In the example shown in Fig. 6, servo patterns 52A and 52B are shown as an example of a set of servo patterns 52. The servo patterns 52A and 52B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 50, the servo pattern 52A is located on the upstream side in the forward direction, and the servo pattern 52B is located on the downstream side in the forward direction.

[0073] The servo pattern 52 is made up of linear magnetization region pairs 54. The linear magnetization region pairs 54 are an example of the "linear magnetization region pairs" according to the technology of the present disclosure. The linear magnetization region pairs 54 are classified into linear magnetization region pairs 54A and linear magnetization region pairs 54B.

[0074] The servo pattern 52A is made up of a pair of linear magnetization regions 54A. In the example shown in FIG. 6, linear magnetization regions 54A1 and 54A2 are shown as an example of the pair of linear magnetization regions 54A. Each of the linear magnetization regions 54A1 and 54A2 is a linearly magnetized region. The linear magnetization region 54A1 is an example of a "first linear magnetization region" according to the technology of the present disclosure, and the linear magnetization region 54A2 is an example of a "second linear magnetization region" according to the technology of the present disclosure.

[0075] The linear magnetized regions 54A1 and 54A2 are inclined in opposite directions with respect to a virtual line C1, which is a virtual line along the width direction WD. In the example shown in Fig. 6, the linear magnetized regions 54A1 and 54A2 are inclined axisymmetrically with respect to the virtual line C1. More specifically, the linear magnetized regions 54A1 and 54A2 are formed non-parallel to each other and 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 virtual line C1 as the axis of symmetry.

[0076] The linear magnetization region 54A1 is a set of five magnetized straight lines, ie, magnetization lines 54A1a, and the linear magnetization region 54A2 is a set of five magnetized straight lines, ie, magnetization lines 54A2a.

[0077] The interval between the third and second magnetization lines 54A1a (hereinafter referred to as the "first interval") and the interval between the third and fourth magnetization lines 54A1a (hereinafter referred to as the "second interval") among the five magnetization lines 54A1a can be changed for each servo pattern 52A. By varying the first interval and the second interval for each servo pattern 52A, it is possible to embed at least one bit of information in each servo pattern 52A. For example, position identification information 99 is embedded in the servo pattern 52A. The position identification information 99 is information that can identify the position of each servo pattern 52A in the longitudinal direction LD of the magnetic tape MT. Furthermore, by combining multiple servo patterns 52, it is possible to embed even more information (e.g., information identifying the servo band SB and / or information identifying the manufacturer of the magnetic tape MT, etc.) in the servo band SB.

[0078] The servo pattern 52B is made up of a pair of linear magnetization regions 54B. In the example shown in FIG. 6, linear magnetization regions 54B1 and 54B2 are shown as an example of the pair of linear magnetization regions 54B. Each of the linear magnetization regions 54B1 and 54B2 is a linearly magnetized region. The linear magnetization region 54B1 is an example of a "first linear magnetization region" according to the technology of the present disclosure, and the linear magnetization region 54B2 is an example of a "second linear magnetization region" according to the technology of the present disclosure.

[0079] The linear magnetized regions 54B1 and 54B2 are inclined in opposite directions with respect to a virtual line C2, which is a virtual line along the width direction WD. In the example shown in Fig. 6, the linear magnetized regions 54B1 and 54B2 are inclined in line symmetry with respect to the virtual line C2. More specifically, the linear magnetized regions 54B1 and 54B2 are formed non-parallel to each other and 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 virtual line C2 as the axis of symmetry.

[0080] The linear magnetization region 54B1 is a set of four magnetized straight lines, ie, magnetization lines 54B1a, and the linear magnetization region 54B2 is a set of four magnetized straight lines, ie, magnetization lines 54B2a.

[0081] The magnetic head 28 is disposed on the surface 31 side of the magnetic tape MT configured in this manner. The holder 44 is formed in a rectangular parallelepiped shape and is disposed so as to cross the surface 31 of the magnetic tape MT in the width direction WD. The multiple magnetic elements of the magnetic element unit 42 are linearly arranged along the longitudinal direction of the holder 44. The magnetic element unit 42 has, as its multiple magnetic elements, a pair of servo read elements SR and multiple data read / write elements DRW. The longitudinal length of the holder 44 is sufficiently long relative to the width of the magnetic tape MT. For example, the longitudinal length of the holder 44 is set to be longer than the width of the magnetic tape MT regardless of where the magnetic element unit 42 is disposed on the magnetic tape MT.

[0082] The magnetic head 28 is equipped with a pair of servo read elements SR. In the magnetic head 28, the relative positional relationship between the holder 44 and the pair of servo read elements SR is fixed. The pair of servo read elements SR consists of servo read elements SR1 and SR2. The servo read element SR1 is disposed at one end of the magnetic element unit 42, and the servo read element SR2 is disposed at the other end of the magnetic element unit 42. In the example shown in FIG. 6, the servo read element SR1 is provided at a position corresponding to the servo band SB2, and the servo read element SR2 is provided at a position corresponding to the servo band SB3.

[0083] The plurality of data read / write elements DRW are arranged linearly between the servo read element SR1 and the servo read element SR2. The plurality of data read / write elements DRW are arranged at intervals along the longitudinal direction of the magnetic head 28 (for example, arranged 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 DB2.

[0084] The processing device 30 acquires a servo pattern signal resulting from the servo read element SR reading the servo pattern 52, and performs servo control in accordance with the acquired servo pattern signal. Here, servo control refers to control that moves the magnetic head 28 in the width direction WD of the magnetic tape MT by operating the movement mechanism 48 in accordance with the servo pattern 52 read by the servo read element SR.

[0085] By performing servo control, the plurality of data read / write elements DRW are positioned on designated areas in the data band DB and perform magnetic processing on the designated areas in the data band DB. In the example shown in Fig. 6, the plurality of data read / write elements DRW perform magnetic processing on designated areas in the data band DB2.

[0086] Furthermore, when the data band DB from which the magnetic element unit 42 reads data is changed (in the example shown in FIG. 6, when the data band DB from which the magnetic element unit 42 reads data is changed from data band DB2 to data band DB1), the movement mechanism 48, under the control of the processing device 30, moves the magnetic head 28 in the width direction WD to change the positions of the pair of servo read elements SR. That is, by moving the magnetic head 28 in the width direction WD, the movement mechanism 48 moves the servo read element SR1 to a position corresponding to servo band SB1 and moves the servo read element SR2 to a position corresponding to servo band SB2. As a result, the positions of the multiple data read / write elements DRW are changed from on data band DB2 to on data band DB1, and the multiple data read / write elements DRW perform magnetic processing on data band DB1.

[0087] Recently, research has been conducted into technologies to reduce the effects of TDS (Transverse Dimensional Stability). TDS is affected by factors such as temperature, humidity, the pressure applied to the magnetic tape around the reel, and deterioration over time. If no countermeasures are taken, TDS will increase, causing off-track (i.e., misalignment of the data read / write element DRW with respect to the track in the data band DB) when magnetic processing is performed on the data band DB.

[0088] In the example shown in FIG. 7, the width of the magnetic tape MT shrinks over time. In this case, off-track occurs. The width of the magnetic tape MT may also expand, causing off-track. That is, when the width of the magnetic tape MT shrinks or expands over time, the position of the servo read element SR relative to the servo pattern 52 deviates in the width direction WD from the predetermined position determined by design (e.g., the center position of each of the linear magnetized regions 54A1, 54A2, 54B1, and 54B2). When the position of the servo read element SR relative to the servo pattern 52 deviates in the width direction WD from the predetermined position determined by design, the accuracy of servo control decreases, and the track in the data band DB and the position of the data read / write element DRW become misaligned. As a result, magnetic processing is no longer performed on the originally intended track.

[0089] One known method for reducing the effects of TDS is to skew the magnetic head 28 on the magnetic tape MT, as shown in Figure 8, to maintain the position of the servo read element SR relative to the servo pattern 52 at a predetermined position determined by design.

[0090] The magnetic head 28 has a rotation axis RA. The rotation axis RA is located at a position corresponding to the center of the magnetic element unit 42 included in the magnetic head 28 in a planar view. The magnetic head 28 is rotatably held by a tilting mechanism 49 via the rotation axis RA. A virtual line C3, which is a virtual center line, is provided in the magnetic head 28. The virtual line C3 passes through the rotation axis RA and extends in the longitudinal direction of the magnetic head 28 in a planar view (i.e., the direction in which multiple data read / write elements DRW are arranged). The magnetic head 28 is held by the tilting mechanism 49 so that the virtual line C3 is tilted toward the longitudinal direction LD of the magnetic tape MT with respect to a virtual line C4, which is a virtual line along the width direction WD. In the example shown in FIG. 8, the magnetic head 28 is held by the tilting mechanism 49 in a position in which the virtual line C3 is tilted toward the supply reel 22 with respect to the virtual line C4 (i.e., a position inclined counterclockwise when viewed from the front side of the paper surface of FIG. 8). In the following, the angle formed by the imaginary lines C3 and C4 will also be referred to as the "skew angle." The skew angle is defined as an angle in which the counterclockwise direction when viewed from the front side of the paper in FIG. 8 is positive and the clockwise direction when viewed from the front side of the paper in FIG. 8 is negative.

[0091] The tilt mechanism 49 receives power from a tilt actuator 49A (see FIG. 5) and rotates the magnetic head 28 about the rotation axis RA on the surface 31 of the magnetic tape MT. Under the control of the processing device 30, the tilt mechanism 49 rotates the magnetic head 28 about the rotation axis RA on the surface 31 of the magnetic tape MT, thereby changing the direction and angle of tilt (i.e., azimuth) of the imaginary line C3 with respect to the imaginary line C4.

[0092] The direction and angle of inclination of the virtual line C3 relative to the virtual line C4 are changed according to temperature, humidity, the pressure at which the magnetic tape MT is wound around the reel, deterioration over time, etc., or the expansion and contraction of the magnetic tape MT in the width direction WD due to these factors, thereby maintaining the position of the servo read element SR relative to the servo pattern 52 at a predetermined position determined by design.

[0093] The servo read element SR is formed linearly along the virtual straight line C3. Therefore, when the servo read element SR reads the servo pattern 52A, the angle formed by the linear magnetized region 54A1 and the servo read element SR is different from the angle formed by the linear magnetized region 54A2 and the servo read element SR in the linear magnetized region pair 54A. This difference in angle causes variations (e.g., variations in signal level and waveform distortion) due to azimuth loss between the servo pattern signal derived from the linear magnetized region 54A1 (i.e., the servo pattern signal obtained by reading the linear magnetized region 54A1 with the servo read element SR) and the servo pattern signal derived from the linear magnetized region 54A2 (i.e., the servo pattern signal obtained by reading the linear magnetized region 54A2 with the servo read element SR). 8, the angle formed by the servo read element SR and the linear magnetized region 54A1 is larger than the angle formed by the servo read element SR and the linear magnetized region 54A2, resulting in a smaller output of the servo pattern signal and a wider waveform. This results in variations in the servo pattern signal read by the servo read element SR across the servo band SB while the magnetic tape MT is running. Furthermore, when the servo read element SR reads the servo pattern 52B, variations due to azimuth loss occur between the servo pattern signal derived from the linear magnetized region 54B1 and the servo pattern signal derived from the linear magnetized region 54B2. Such variations in the servo pattern signal can be a factor in reducing the accuracy of servo control.

[0094] A known method for detecting a servo pattern signal is to compare the signal level of the servo pattern signal with a threshold value. However, as described above, the signal level of the servo pattern signal varies. Therefore, if the threshold value is always a fixed value, servo pattern signals with low signal levels may not be detected or noise may be erroneously detected as the servo pattern signal. Furthermore, when the magnetic head 28 is skewed on the magnetic tape MT, both the angle formed by the servo read element SR and the linear magnetized region 54A1 and the angle formed by the servo read element SR and the linear magnetized region 54A2 change, and the signal level of the servo pattern signal also changes. Therefore, if the threshold value is always a fixed value, the reliability of the detected servo pattern signal decreases.

[0095] In view of these circumstances, the controller 25 (see FIG. 3) of the magnetic tape drive 14 according to this embodiment performs a threshold use method detection process. The threshold use method detection process includes a servo pattern detection process (see FIG. 15), a first setting process (see FIG. 16), and a second setting process (see FIG. 17). The threshold use method detection process detects a servo pattern signal indicating the servo pattern 52 by comparing a servo band signal (hereinafter simply referred to as a "servo band signal") resulting from the servo read element SR reading the servo band SB with a threshold value TH (see FIGS. 10 to 12) determined according to the angle formed by the servo pattern 52 and the servo read element SR. The threshold use method detection process will be specifically described below.

[0096] 9, the processing device 30 includes a control unit 30A and a position detection unit 30B. The threshold use method detection process is realized by the control unit 30A and the position detection unit 30B.

[0097] The position detection unit 30B has a first position detection unit 30B1 and a second position detection unit 30B2. The position detection unit 30B acquires a servo band signal from the servo read 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 not only a servo pattern signal resulting from reading the servo pattern 52 but also signals unnecessary for servo control (e.g., noise, etc.). Therefore, in order to realize control based on the servo pattern signal (e.g., servo control, etc.) with high accuracy, the processing device 30 needs to detect the servo pattern signal from the servo band signal with high accuracy.

[0098] The position detection unit 30B acquires servo band signals from the magnetic head 28. The servo band signals are classified into a first servo band signal S1 and a second servo band signal S2. The first servo band signal S1 is a signal indicating the result of reading the servo band SB by the servo read element SR1, and the second servo band signal S2 is a signal indicating the result of reading the servo band SB by the servo read element SR2. The first position detection unit 30B1 acquires the first servo band signal S1, and the second position detection unit 30B2 acquires the second servo band signal S2. In the example shown in FIG. 9, an example of the first servo band signal S1 is a signal obtained by reading the servo band SB2 by the servo read element SR1, and an example of the second servo band signal S2 is a signal obtained by reading the servo band SB3 by the servo read element SR2. In the following description, for the sake of convenience, when there is no need to distinguish between the first servo band signal S1 and the second servo band signal S2, they will be referred to as "servo band signals" without being assigned reference numerals.

[0099] The first position detector 30B1 detects the position of the servo read element SR1 relative to the servo band SB2 based on the first servo band signal S1, and the second position detector 30B2 detects the position of the servo read element SR2 relative to the servo band SB3 based on the second servo band signal S2.

[0100] The control unit 30A performs various controls based on the position detection result by the first position detection unit 30B1 (i.e., the result of position detection by the first position detection unit 30B1) and the position detection result by the second position detection unit 30B2 (i.e., the result of position detection by the second position detection unit 30B2). Here, the various controls refer to, for example, servo control, skew angle control, and / or tension control. Tension control refers to control of the tension applied to the magnetic tape MT (e.g., tension to reduce the effects of TDS).

[0101] Next, an example of the processing contents of the control unit 30A and the position detection unit 30B when the processing device 30 performs the servo pattern detection processing will be described with reference to FIG.

[0102] In this embodiment, since the configuration of the first position detection unit 30B1 and the configuration of the second position detection unit 30B2 are identical, in the following, the processing contents of the position detection unit 30B will be explained mainly by taking the specific processing contents of the first position detection unit 30B1 as an example, and the explanation of the specific processing contents of the second position detection unit 30B2 will be omitted.

[0103] For ease of explanation, the servo pattern signal derived from the linear magnetization region 54A1 or 54B1 (see FIGS. 8 and 9) will also be referred to as the "first linear magnetization region signal," and the servo pattern signal derived from the linear magnetization region 54A2 or 54B2 (see FIGS. 8 and 9) will also be referred to as the "second linear magnetization region signal." In this embodiment, the servo pattern signal is a signal composed of the first linear magnetization region signal and the second linear magnetization region signal. Therefore, detection of the first linear magnetization region signal and the second linear magnetization region signal by the position detection unit 30B means that the servo pattern signal is detected by the position detection unit 30B.

[0104] 10, a first servo band signal S1 is input to the first position detector 30B1. The first servo band signal S1 includes a first linear magnetization region signal S1a and a second linear magnetization region signal S1b. The first linear magnetization region signal S1a and the second linear magnetization region signal S1b are servo pattern signals (i.e., analog servo pattern signals) read by the servo read element SR1 (see FIG. 9).

[0105] The first position detector 30B1 has a threshold value TH that is compared with the first servo band signal S1. As described above, the threshold value TH is determined according to the angle formed between the servo pattern 52 (see FIG. 9) and the servo read element SR (see FIG. 9). Assuming that the geometric characteristics of the servo pattern 52 are fixed on the magnetic tape MT, the angle formed between the servo pattern 52 and the servo read element SR is uniquely determined according to the skew angle.

[0106] The threshold values ​​TH are classified into a first threshold value TH1 and a second threshold value TH2. The first threshold value TH1 is determined according to a first angle, and the second threshold value TH2 is determined according to a second angle. The first angle refers to the angle formed between the linear magnetized region 54A1 or 54B1 (see FIGS. 6 to 9) and the servo read element SR (see FIGS. 6 to 9) (for example, the angle formed between the magnetization straight line 54A1a or 54B1a (see FIGS. 6 to 9) and the servo read element SR (see FIGS. 6 to 9)). The second angle refers to the angle formed between the linear magnetized region 54A2 or 54B2 (see FIGS. 6 to 9) and the servo read element SR (see FIGS. 6 to 9) (for example, the angle formed between the magnetization straight line 54A2a or 54B2a (see FIGS. 6 to 9) and the servo read element SR (see FIGS. 6 to 9)).

[0107] The control unit 30A sets the first threshold value TH1 and the second threshold value TH2 corresponding to the skew angle in the first position detection unit 30B1. That is, the first threshold value TH1 and the second threshold value TH2 corresponding to the angle formed by the servo pattern 52 and the servo read element SR are set in the first position detection unit 30B1.

[0108] In this case, first, the control unit 30A derives the first threshold TH1 and the second threshold TH2 using correspondence information 100. The correspondence information 100 refers to information that associates the skew angle with the first threshold TH1 and the second threshold TH2. The correspondence information 100 may be, for example, an arithmetic expression or a table. An example of the arithmetic expression is an arithmetic expression in which the skew angle is an independent variable and the first threshold TH1 and the second threshold TH2 are dependent variables. An example of the table is a table in which the skew angle is associated with the first threshold TH1 and the second threshold TH2.

[0109] The control unit 30A uses an arithmetic formula or a table to derive a first threshold value TH1 and a second threshold value TH2 corresponding to the current skew angle, and sets the derived first threshold value TH1 and second threshold value TH2 in the first position detection unit 30B1.

[0110] Similar to the first position detector 30B1, the second position detector 30B2 also has a first threshold value TH1 and a second threshold value TH2. Since the configuration of the second position detector 30B2 is similar to the configuration of the first position detector 30B1, the first threshold value TH1 and the second threshold value TH2 are set for the second position detector 30B2 by the control unit 30A in the same manner as for the first position detector 30B1.

[0111] The first position detection unit 30B1 detects the servo pattern signal S1A by comparing the first servo band signal S1 with a first threshold value TH1 and a second threshold value TH2. More specifically, the first position detection unit 30B1 detects a signal in the first servo band signal S1 whose signal level exceeds the second threshold value TH2 as the second linear magnetization region signal S1b. The first position detection unit 30B1 also detects a signal in the first servo band signal S1 whose signal level exceeds the first threshold value TH1 and falls below the second threshold value TH2 as the first linear magnetization region signal S1a. The first position detection unit 30B1 then digitizes the first linear magnetization region signal S1a and the second linear magnetization region signal S1b to generate the servo pattern signal S1A and outputs the generated servo pattern signal S1A to the control unit 30A.

[0112] Since the configuration of the second position detection unit 30B2 is the same as that of the first position detection unit 30B1, the second position detection unit 30B2 also outputs a servo pattern signal S2A obtained from the second servo band signal S2 to the control unit 30A in the same manner as the first position detection unit 30B1.

[0113] The position of the servo read element SR relative to the servo band SB is determined based on, for example, the distance in the longitudinal direction LD (see FIG. 9) between the servo patterns 52A and 52B (see FIG. 9). For example, the distance in the longitudinal direction LD between the servo patterns 52A and 52B is determined in accordance with the servo pattern signal S1A. As the servo read element SR is positioned above the servo pattern 52 (i.e., above the front view of the paper in FIG. 9), the distance between the linear magnetization region 54A1 and the linear magnetization region 54A2 becomes narrower, and the distance between the linear magnetization region 54B1 and the linear magnetization region 54B2 also becomes narrower. On the other hand, as the servo read element SR is positioned below the servo pattern 52 (i.e., below the front view of the paper in FIG. 9), the distance between the linear magnetization region 54A1 and the linear magnetization region 54A2 becomes wider, and the distance between the linear magnetization region 54B1 and the linear magnetization region 54B2 also becomes wider.

[0114] In this way, the first position detection unit 30B1 detects the position of the servo read element SR relative to the servo band SB using the interval between the linear magnetization region 54A1 and the linear magnetization region 54A2 and the interval between the linear magnetization region 54B1 and the linear magnetization region 54B2, which are determined in accordance with the servo pattern signal S1A. Similarly to the first position detection unit 30B1, the second position detection unit 30B2 also detects the position of the servo read element SR relative to the servo band SB using the interval between the linear magnetization region 54A1 and the linear magnetization region 54A2 and the interval between the linear magnetization region 54B1 and the linear magnetization region 54B2, which are determined in accordance with the servo pattern signal S2A. Note that, for convenience of explanation, the servo pattern signal S1A and the servo pattern signal S2A will be referred to as the "servo pattern signal" without reference numerals unless they need to be distinguished from each other.

[0115] Next, an example of the processing contents of the control unit 30A and the position detection unit 30B when the first setting processing is performed by the processing device 30 will be described with reference to Fig. 11. The first setting processing is a processing performed by the processing device 30 while the magnetic tape MT is running.

[0116] As an example, as shown in FIG. 11, the control unit 30A determines whether the magnetic head 28 is skewed on the magnetic tape MT. If the magnetic head 28 is skewed on the magnetic tape MT while the magnetic tape MT is running, the control unit 30A derives a first threshold value TH1 and a second threshold value TH2 corresponding to the current skew angle from the correspondence information 100 (see FIG. 10). The control unit 30A then sets the derived first threshold value TH1 and second threshold value TH2 in the position detection unit 30B. If the skew angle has been changed, the control unit 30A derives a first threshold value TH1 and a second threshold value TH2 corresponding to the changed skew angle, and sets the derived first threshold value TH1 and second threshold value TH2 in the position detection unit 30B. In this way, the first threshold value TH1 and the second threshold value TH2 are variable values ​​that change depending on the skew angle and are changed while the magnetic tape MT is running.

[0117] The position detection unit 30B detects the servo pattern signal by comparing the servo band signal with a first threshold value TH1 and a second threshold value TH2 that are derived by the control unit 30A and set in the position detection unit 30B. That is, the first position detection unit 30B1 detects the servo pattern signal S1A by comparing the first servo band signal S1 with the first threshold value TH1 and the second threshold value TH2, and the second position detection unit 30B2 detects the servo pattern signal S2A by comparing the second servo band signal S2 with the first threshold value TH1 and the second threshold value TH2.

[0118] The control unit 30A identifies the skew angle change position on the magnetic tape MT by referring to the servo pattern signal detected by the position detection unit 30B. The skew angle change position refers to the position on the magnetic tape MT where the skew angle of the magnetic head 28 has been changed. The skew angle change position is identified from the servo pattern signal detected by the position detection unit 30B (for example, position identification information 99 (see FIG. 6) embedded in each servo pattern 52A as information regarding the position of each servo pattern 52A in the longitudinal direction LD of the magnetic tape MT). For example, the control unit 30A obtains the position identification information 99 from the servo pattern signal first detected by the position detection unit 30B after the skew angle has been changed, and identifies the position identified from the obtained position identification information 99 as the skew angle change position.

[0119] The control unit 30A generates position threshold information 102 and stores the generated position threshold information 102 in the cartridge memory 24 via the non-contact read / write device 46 (see FIGS. 3 and 4). The position threshold information 102 is information that associates skew position identification information, which can identify a skew angle change position identified based on the servo pattern signal detected by the position detection unit 30B, with the first threshold value TH1 and the second threshold value TH2 currently set in the position detection unit 30B. In other words, the position threshold information 102 is information that associates information (i.e., skew position identification information), which can identify a position on the magnetic tape MT where the first threshold value TH1 and the second threshold value TH2 have been changed as the skew angle is changed, with the first threshold value TH1 and the second threshold value TH2 currently set in the position detection unit 30B. The first threshold value TH1 and the second threshold value TH2 currently set in the position detection unit 30B refer to the first threshold value TH1 and the second threshold value TH2 corresponding to the skew angle changed at the skew angle change position identified from the skew position identification information.

[0120] The skew angle change position is an example of a "position on the magnetic tape where the threshold value is changed" according to the technology of the present disclosure, and the skew position identification information is an example of "identification information" according to the technology of the present disclosure.

[0121] Next, an example of the processing contents of the control unit 30A and the position detection unit 30B when the second setting processing is performed by the processing device 30 will be described with reference to Fig. 12. The second setting processing is a processing performed by the processing device 30 when the running of the magnetic tape MT is started, on the premise that the position threshold information 102 is stored in the cartridge memory 24.

[0122] 12, the control unit 30A acquires position threshold information 102 from the cartridge memory 24. Then, the control unit 30A sets a first threshold TH1 and a second threshold TH2 in the position detection unit 30B by referring to the position threshold information 102. That is, the control unit 30A derives the first threshold TH1 and the second threshold TH2 corresponding to the current position of the magnetic head 28 on the magnetic tape MT (i.e., the position identified from the latest servo pattern signal detected by the position detection unit 30B) from the position threshold information 102, and sets the derived first threshold TH1 and second threshold TH2 in the position detection unit 30B. This allows the control unit 30A to acquire the first threshold TH1 and the second threshold TH2 that were set for the position detection unit 30B at a position where the skew angle was previously changed, at the same position on the magnetic tape MT, without using the correspondence information 100, and set them in the position detection unit 30B.

[0123] 13, the control unit 30A adjusts the position of the magnetic head 28 by operating the moving mechanism 48 based on the position detection result (i.e., servo pattern signals S1A and S2A) by the position detection unit 30B. The control unit 30A also causes the magnetic element unit 42 to perform magnetic processing on the data band DB of the magnetic tape MT. That is, the control unit 30A obtains a read signal from the magnetic element unit 42 (i.e., data read from the data band DB of the magnetic tape MT by the magnetic element unit 42) and supplies a recording signal to the magnetic element unit 42 to record data corresponding to the recording signal on the data band DB of the magnetic tape MT.

[0124] Furthermore, to reduce the effects of TDS, the control unit 30A calculates the servo band pitch from the position detection results (i.e., servo pattern signals S1A and S2A) of the position detection unit 30B, and performs tension control and skews the magnetic head 28 on the magnetic tape MT according to the calculated servo band pitch. Tension control is achieved by adjusting the rotation speed and rotation torque of each of the feed motor 36 and the take-up motor 40. Skew of the magnetic head 28 is achieved by operating a tilt mechanism 49.

[0125] Next, among the multiple steps included in the manufacturing process of the magnetic tape MT, an example of a servo pattern recording step of recording the servo patterns 52 on the servo bands SB of the magnetic tape MT and a winding step of winding the magnetic tape MT will be described.

[0126] As an example, as shown in Figure 14, a servo writer SW is used in the servo pattern recording process. The servo writer SW includes a supply reel SW1, a take-up reel SW2, a drive unit SW3, a pulse signal generator SW4, a servo writer controller SW5, multiple guides SW6, a transport path SW7, a servo pattern recording head WH, and a verify head VH. The servo writer controller SW5 incorporates devices equivalent to the control unit 30A and position detection unit 30B described above.

[0127] In this embodiment, the servo writer SW is an example of an "inspection device" according to the technique of the present disclosure. Also, in this embodiment, the servo writer controller SW5 is an example of an "inspection processor" according to the technique of the present disclosure.

[0128] The servo writer controller SW5 controls the entire servo writer SW. In this embodiment, the servo writer controller SW5 is implemented by an ASIC, but the technology of the present disclosure is not limited to this. For example, the servo writer controller SW5 may be implemented by an FPGA and / or a PLC. The servo writer controller SW5 may also be implemented by a computer including a CPU, flash memory (e.g., EEPROM and / or SSD), and RAM. The servo writer controller SW5 may also be implemented by a combination of two or more of the ASIC, FPGA, PLC, and computer. In other words, the servo writer controller SW5 may be implemented by a combination of hardware and software.

[0129] A pancake is set on the supply reel SW1. A pancake is a large diameter roll of magnetic tape MT, which is cut to the product width from a wide web before the servo pattern 52 is written, wound around a hub.

[0130] The drive unit SW3 has a motor (not shown) and gears (not shown) and is mechanically connected to the supply reel SW1 and the take-up reel SW2. When the magnetic tape MT is wound by the take-up reel SW2, the drive unit SW3 generates power in accordance with instructions from the servo writer controller SW5 and transmits the generated power to the supply reel SW1 and the take-up reel SW2 to rotate them. That is, the supply reel SW1 receives power from the drive unit SW3 and rotates to feed the magnetic tape MT to a predetermined transport path SW7. The take-up reel SW2 receives power from the drive unit SW3 and rotates to wind the magnetic tape MT fed from the supply reel SW1. The rotation speed and rotation torque of the supply reel SW1 and the take-up reel SW2 are adjusted according to the speed at which the magnetic tape MT is wound around the take-up reel SW2.

[0131] A plurality of guides SW6 and a servo pattern recording head WH are arranged on the transport path SW7. The servo pattern recording head WH is arranged between the plurality of guides SW6 on the side of the surface 31 of the magnetic tape MT. The magnetic tape MT sent out from the supply reel SW1 to the transport path SW7 is guided by the plurality of guides SW6, passes over the servo pattern recording head WH, and is taken up by the take-up reel SW2.

[0132] The manufacturing process for magnetic tape MT includes several steps in addition to the servo pattern recording step, including an inspection step and a winding step.

[0133] For example, the inspection process is a process of inspecting the servo bands SB formed on the surface 31 of the magnetic tape MT by the servo pattern recording head WH. Inspecting the servo bands SB refers to, for example, a process of determining whether the servo patterns 52 recorded on the servo bands SB are correct. Determining whether the servo patterns 52 are correct refers to, for example, determining whether the magnetization lines 54A1a, 54A2a, 54B1a, and 54B2a of the servo patterns 52A and 52B are recorded exactly and within the allowable error with respect to predetermined locations on the surface 31 (i.e., verifying the servo patterns 52).

[0134] The inspection process is performed using a servo writer controller SW5 and a verify head VH. The verify head VH is located downstream of the servo pattern recording head WH in the transport direction of the magnetic tape MT. Similar to the magnetic head 28, the verify head VH is provided with multiple servo read elements (not shown), which read multiple servo bands SB. Similar to the magnetic head 28, the verify head VH is skewed above the surface 31 of the magnetic tape MT.

[0135] The verify head VH is connected to the servo writer controller SW5. The verify head VH is disposed at a position directly facing the servo band SB when viewed from the surface 31 side of the magnetic tape MT (i.e., the back side of the verify head VH). The verify head VH reads the servo patterns 52 recorded on the servo band SB and outputs the read results (hereinafter referred to as "servo pattern read results") to the servo writer controller SW5. The servo writer controller SW5 inspects the servo band SB (e.g., determines whether the servo patterns 52 are correct) based on the servo pattern read results (e.g., servo pattern signals) input from the verify head VH. For example, since the servo writer controller SW5 incorporates a device equivalent to the position detector 30B, the servo writer controller SW5 obtains position detection results from the servo pattern read results and uses the position detection results to inspect the servo band SB.

[0136] The servo writer controller SW5 outputs information indicating the results of inspecting the servo band SB (for example, the results of determining whether the servo pattern 52 is correct or not) to a predetermined output destination (for example, storage 32 (see Figure 3), UI-related device 34 (see Figure 3), and / or external device 37 (see Figure 3), etc.).

[0137] For example, after the inspection process is completed, the winding process is carried out next. The winding process is a process of winding the magnetic tape MT onto the supply reel 22 (see FIGS. 2 to 4) housed in the magnetic tape cartridge 12 (see FIGS. 1 to 4)) used for each of the multiple magnetic tape cartridges 12 (see FIGS. 1 to 4). In the winding process, a winding motor M is used. The winding motor M is mechanically connected to the supply reel 22 via a gear or the like. Under the control of a processing device (not shown), the winding motor M applies a rotational force to the supply reel 22 to rotate the supply reel 22. The magnetic tape MT wound onto the take-up reel SW2 is wound onto the supply reel 22 by the rotation of the supply reel 22. In the winding process, a cutting device (not shown) is used. When the required amount of magnetic tape MT is wound onto each of the plurality of supply reels 22, the magnetic tape MT fed from the take-up reel SW2 to the supply reel 22 is cut by a cutting device.

[0138] The pulse signal generator SW4 generates a pulse signal under the control of the servo writer controller SW5 and supplies the generated pulse signal to the servo pattern recording head WH. While the magnetic tape MT is traveling at a constant speed on the transport path SW, the servo pattern recording head WH records the servo pattern 52 on the servo band SB in accordance with the pulse signal supplied from the pulse signal generator SW4.

[0139] Next, the operation of the magnetic tape system 10 will be described.

[0140] The magnetic tape cartridge 12 contains a magnetic tape MT shown in Fig. 6. The magnetic tape cartridge 12 is loaded into a magnetic tape drive 14. In the magnetic tape drive 14, when magnetic processing is performed on the magnetic tape MT by the magnetic element unit 42 (see Figs. 3 and 6, etc.), the magnetic tape MT is pulled out of the magnetic tape cartridge 12, and the servo patterns 52 in the servo bands SB are read by the servo read element SR of the magnetic head 28 (see Figs. 8 and 9).

[0141] 8, when a servo pattern 52A is read by a servo read element SR, the angle formed by a linear magnetization region 54A1 and the servo read element SR is different from the angle formed by a linear magnetization region 54A2 and the servo read element SR in a linear magnetization region pair 54A. This difference in angle causes a variation due to azimuth loss between the servo pattern signal derived from the linear magnetization region 54A1, i.e., the first linear magnetization region signal S1a (see FIGS. 10 to 12), and the servo pattern signal derived from the linear magnetization region 54A2, i.e., the second linear magnetization region signal S1b (see FIGS. 10 to 12). The variation between the first linear magnetization region signal S1a and the second linear magnetization region signal S1b can be a factor in reducing the accuracy of servo control, etc.

[0142] Therefore, in the magnetic tape system 10 according to this embodiment, the controller 25 (see FIG. 3) performs a servo pattern detection process (see FIG. 15), a first setting process (see FIG. 16), and a second setting process (see FIG. 17). The flow of the servo pattern detection process shown in FIG. 15, the flow of the first setting process shown in FIG. 16, and the flow of the second setting process shown in FIG. 17 are examples of a "detection method" according to the technology of the present disclosure.

[0143] First, the servo pattern detection process shown in Fig. 15 will be described. For convenience of explanation, the servo pattern detection process shown in Fig. 15 is performed on the assumption that the first threshold value TH1 and the second threshold value TH2 have already been set for the position detection unit 30B.

[0144] 15, first, in step ST10, the position detection unit 30B acquires a servo band signal. For example, the first position detection unit 30B1 acquires a first servo band signal S1, and the second position detection unit 30B2 acquires a second servo band signal S2. After the processing of step ST10 is executed, the servo pattern detection processing proceeds to step ST12.

[0145] In step ST12, the position detection unit 30B compares the servo band signal acquired in step ST10 with a first threshold value TH1 and a second threshold value TH2. That is, the first position detection unit 30B1 compares the first servo band signal S1 with the first threshold value TH1 and the second threshold value TH2. The second position detection unit 30B2 compares the second servo band signal S2 with the first threshold value TH1 and the second threshold value TH2. After the processing of step ST12 is executed, the servo pattern detection processing proceeds to step ST14.

[0146] In step ST14, the first position detection unit 30B1 acquires a first linear magnetization region signal S1a based on the comparison result in step ST12, and acquires a second linear magnetization region signal S1b based on the comparison result in step ST12. Furthermore, the second position detection unit 30B2 acquires the first linear magnetization region signal S1a based on the comparison result in step ST12, and acquires a second linear magnetization region signal S1b based on the comparison result in step ST12. After the process of step ST14 is executed, the servo pattern detection process proceeds to step ST16.

[0147] In step ST16, the first position detection unit 30B1 generates a servo pattern signal S1A, which is the logical sum of the first linear magnetization region signal S1a and the second linear magnetization region signal S1b acquired in step ST14, and outputs the generated signal to the control unit 30A. In addition, the second position detection unit 30B2 generates a servo pattern signal S2A, which is the logical sum of the first linear magnetization region signal S1a and the second linear magnetization region signal S1b acquired in step ST14, and outputs the generated signal to the control unit 30A. After the processing of step ST16 is performed, the servo pattern detection processing proceeds to step ST18.

[0148] In step ST18, the control unit 30A determines whether a condition for terminating the servo pattern detection process (hereinafter referred to as the "servo pattern detection process termination condition") is satisfied. Examples of the servo pattern detection process termination condition include a condition that an instruction to terminate the servo pattern detection process is accepted by the UI device 34, or a condition that the running of the magnetic tape MT is completed. In step ST18, if the servo pattern detection process termination condition is not satisfied, the determination is negative, and the servo pattern detection process proceeds to step ST10. In step ST18, if the servo pattern detection process termination condition is satisfied, the determination is positive, and the servo pattern detection process ends.

[0149] Next, the first setting process shown in FIG. 16 will be described.

[0150] 16, first, in step ST20, the control unit 30A determines whether the magnetic head 28 is skewed. If the magnetic head 28 is not skewed in step ST20, the determination is negative, and the first setting process proceeds to step ST30. If the magnetic head 28 is skewed in step ST20, the determination is positive, and the first setting process proceeds to step ST22.

[0151] In step ST22, the control unit 30A derives a first threshold value TH1 and a second threshold value TH2 corresponding to the skew angle from the correspondence information 100. After the process of step ST22 is executed, the first setting process proceeds to step ST24.

[0152] In step ST24, the control unit 30A sets the first threshold value TH1 and the second threshold value TH2 derived in step ST22 in the position detection unit 30B. After the process of step ST24 is executed, the first setting process proceeds to step ST26.

[0153] In step ST26, the control unit 30A identifies the skew angle change position by referring to the latest servo pattern signal detected by the position detection unit 30B. After the process of step ST26 is executed, the first setting process proceeds to step ST28.

[0154] In step ST28, the control unit 30A generates position threshold information 102 by associating the first threshold value TH1 and the second threshold value TH2 derived in step ST22 with the skew position identification information capable of identifying the skew angle change position identified in step ST26. Then, the control unit 30A stores the generated position threshold information 102 in the cartridge memory 24. After the processing of step ST28 is executed, the first setting processing proceeds to step ST30.

[0155] In step ST30, the control unit 30A determines whether a condition for terminating the first setting process (hereinafter referred to as the "first setting process termination condition") has been satisfied. Examples of the first setting process termination condition include a condition that an instruction to terminate the first setting process has been accepted by the UI device 34, or a condition that the running of the magnetic tape MT has been completed. If the first setting process termination condition has not been satisfied in step ST30, the determination is negative, and the first setting process proceeds to step ST20. If the first setting process termination condition has been satisfied in step ST30, the determination is positive, and the first setting process ends.

[0156] Next, the second setting process shown in Fig. 17 will be described. For ease of explanation, the second setting process shown in Fig. 17 is performed on the assumption that the position threshold information 102 is stored in the cartridge memory 24 and that the magnetic tape MT has started running.

[0157] 17, first, in step ST32, the control section 30A acquires position threshold information from the cartridge memory 24. After the processing of step ST32 is executed, the second setting processing proceeds to step ST34.

[0158] In step ST34, the control unit 30A determines whether the magnetic head 28 has reached the same position on the magnetic tape MT as the skew angle change position identified from the skew position identification information included in the position threshold information 102 acquired in step ST32. If the magnetic head 28 has not reached the same position on the magnetic tape MT as the skew angle change position identified from the skew position identification information included in the position threshold information 102 in step ST34, the determination is negative, and the second setting process proceeds to step ST38. If the magnetic head 28 has reached the same position on the magnetic tape MT as the skew angle change position identified from the skew position identification information included in the position threshold information 102 in step ST34, the determination is positive, and the second setting process proceeds to step ST36.

[0159] In step ST36, the control unit 30A derives the first threshold value TH1 and the second threshold value TH2 corresponding to the current position of the magnetic head 28 on the magnetic tape MT from the position threshold information 102, and sets the derived first threshold value TH1 and second threshold value TH2 in the position detection unit 30B. After the processing of step ST36 is executed, the second setting processing proceeds to step ST38.

[0160] In step ST38, the control unit 30A determines whether a condition for terminating the second setting process (hereinafter referred to as the "second setting process termination condition") has been satisfied. Examples of the second setting process termination condition include a condition that an instruction to terminate the second setting process has been accepted by the UI device 34, or a condition that the running of the magnetic tape MT has been completed. If the second setting process termination condition has not been satisfied in step ST38, the determination is negative, and the second setting process proceeds to step ST34. If the second setting process termination condition has been satisfied in step ST38, the determination is positive, and the second setting process ends.

[0161] As described above, in the magnetic tape system 10 according to this embodiment, the position detector 30B detects the servo pattern signal by comparing the servo band signal with the threshold value TH. The threshold value TH is determined according to the angle formed between the servo pattern 52 and the servo read element SR. For example, the angle formed between the linear magnetized region 54A1 and the servo read element SR is different from the angle formed between the linear magnetized region 54A2 and the servo read element SR. A first threshold value TH1 is determined according to the angle formed between the linear magnetized region 54A1 and the servo read element SR, and a second threshold value TH2 is determined according to the angle formed between the linear magnetized region 54A2 and the servo read element SR. Therefore, the first linear magnetization region signal S1a corresponding to the linear magnetization region 54A1 is detected by the position detection unit 30B by referring to the first threshold value TH1, and the second linear magnetization region signal S1b corresponding to the linear magnetization region 54A2 is detected by the position detection unit 30B by referring to the first threshold value TH1 and the second threshold value TH2 (see FIGS. 10 to 12). Therefore, with this configuration, the servo pattern signal can be detected more accurately than when the servo pattern signal is detected by comparing the servo band signal with the threshold value TH, which is a fixed value determined regardless of the angle formed by the servo pattern 52 and the servo read element SR.

[0162] Furthermore, in the magnetic tape system 10 according to this embodiment, a variable value that changes depending on the angle formed by the servo pattern 52 and the servo read element SR is used as the threshold value TH that is compared with the servo band signal by the position detection unit 30B. Therefore, according to this configuration, the servo pattern signal can be detected with higher accuracy than when the threshold value TH is constant regardless of the angle formed by the servo pattern 52 and the servo read element SR.

[0163] Furthermore, in the magnetic tape system 10 according to this embodiment, the threshold value TH is changed while the magnetic tape MT is running. Then, the control unit 30A stores position threshold information 102, which is information in which the threshold value TH is associated with skew position identification information, which is information for identifying the position where the threshold value TH has been changed, in the cartridge memory 24. Storing the position threshold information 102 in the cartridge memory 24 in this manner makes it possible to implement the second setting process (see FIG. 17). Performing the second setting process eliminates the need to derive the first threshold value TH1 and the second threshold value TH2 using the correspondence information 100 (see FIG. 10), thereby reducing the load on deriving the first threshold value TH1 and the second threshold value TH2.

[0164] Furthermore, in the magnetic tape system 10 according to this embodiment, the position threshold information 102 is stored in the cartridge memory 24. Therefore, according to this configuration, even if a magnetic tape cartridge 12 is loaded into a magnetic tape drive 14 other than the magnetic tape drive 14 (hereinafter referred to as an "other magnetic tape drive 14") and the other magnetic tape drive 14 does not have the correspondence information 100, the other magnetic tape drive 14 can set the first threshold TH1 and the second threshold TH2, which were set for the position detection unit 30B at a position on the magnetic tape MT where the skew angle was previously changed, for the position detection unit 30B at the same position on the magnetic tape MT.

[0165] Furthermore, in the magnetic tape system 10 according to this embodiment, when the angle formed by the servo pattern 52 and the servo read element SR is changed, a threshold value TH corresponding to the changed angle is derived, and the derived threshold value TH is compared with the servo band signal to detect the servo pattern signal. Therefore, according to this configuration, even if the angle formed by the servo pattern 52 and the servo read element SR is changed, the servo pattern signal can be detected with higher accuracy than when the threshold value TH is always constant.

[0166] In the magnetic tape system 10 according to this embodiment, the threshold values ​​TH are classified into a first threshold value TH1 and a second threshold value TH2. The first threshold value TH1 is determined according to the angle between the linear magnetization region 54A1 and the servo read element SR, and the second threshold value TH2 is determined according to the angle between the linear magnetization region 54A2 and the servo read element SR. Therefore, the first linear magnetization region signal S1a corresponding to the linear magnetization region 54A1 is detected by the position detection unit 30B by referring to the first threshold value TH1, and the second linear magnetization region signal S1b corresponding to the linear magnetization region 54A2 is detected by the position detection unit 30B by referring to the first threshold value TH1 and the second threshold value TH2. Therefore, with this configuration, the linear magnetization regions 54A1 and 54B can be detected more accurately than when the first threshold TH1 is a fixed value set regardless of the angle formed between the linear magnetization region 54A1 and the servo read element SR and the second threshold is a fixed value set regardless of the angle formed between the linear magnetization region 54A2 and the servo read element SR.

[0167] In the servo writer SW according to this embodiment, devices equivalent to the control unit 30A and position detection unit 30B shown in Fig. 9 are incorporated into the servo writer controller SW5. Therefore, the servo writer controller SW5 can inspect the servo band SB by obtaining a position detection result from the servo pattern read result and using the position detection result to determine whether the servo pattern 52 is correct. The servo writer controller SW5 incorporating devices equivalent to the control unit 30A and position detection unit 30B can detect the servo pattern signal with higher accuracy than when detecting the servo pattern signal using only a method of determining whether the signal level exceeds a threshold value TH, which is a single fixed value. Therefore, the servo writer SW incorporating the servo writer controller SW5 can inspect the servo band SB with higher accuracy.

[0168] In the above embodiment, an example in which the position threshold information 102 is stored in the cartridge memory 24 has been described, but the technology of the present disclosure is not limited to this. For example, the position threshold information 102 may be stored on the magnetic tape MT. In this case, examples of specific storage locations include a BOT area (not shown) provided at the beginning of the magnetic tape MT and / or an EOT area (not shown) provided at the end of the magnetic tape MT.

[0169] In this way, even when the position threshold information 102 is stored on the magnetic tape MT, it is possible to obtain the same effect as when the position threshold information 102 is stored in the cartridge memory 24. Furthermore, when the position threshold information 102 is stored on the magnetic tape MT instead of the cartridge memory 24, the capacity of the cartridge memory 24 can be increased by the amount of the position threshold information 102 not stored.

[0170] Furthermore, the storage location of the position threshold information 102 is not limited to the cartridge memory 24 and the magnetic tape MT. For example, the position threshold information 102 may be stored in the memory (not shown) of the storage 32 and / or the external device 37. In this case, the control unit 30A may acquire the position threshold information 102 from the memory of the storage 32 and / or the external device 37.

[0171] Furthermore, when the threshold value TH (e.g., the first threshold value TH and the second threshold value TH2) is changed while the magnetic tape MT is running, the threshold value TH may be stored in the data band DB (see FIGS. 8 and 9). Storing the threshold value TH in the data band DB means that the threshold value TH is recorded in the data band DB. The threshold value TH in the data band DB may be stored, for example, in an empty area of ​​the data band DB. In this case, the threshold value TH (e.g., the first threshold value TH and the second threshold value TH2) may be stored in an empty area of ​​the data band DB of the magnetic tape MT that corresponds to the position on the magnetic tape MT where the threshold value TH was changed (i.e., an empty area that corresponds to the position where the skew angle was changed). In this case, the threshold value TH stored in the data band DB may be read by the magnetic element unit 42, and the read threshold value TH may be set in the position detection unit 30B by the control unit 30A.

[0172] Furthermore, in the above embodiment, the servo pattern 52 is exemplified, but the servo pattern 52 is merely an example, and the technology of the present disclosure is valid even if other types of servo patterns (i.e., servo patterns with geometric characteristics different from those of the servo pattern 52) are used. In the following first to eighth modified examples, types of servo patterns different from the servo pattern 52 will be described.

[0173] [First Modification] As an example, as shown in Figure 18, the magnetic tape MT according to the first modification differs from the magnetic tape MT shown in Figure 6 in that it has frames 56 instead of frames 50. The frames 56 are 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 arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT, similar to the plurality of servo patterns 52 recorded on the magnetic tape MT shown in Figure 6.

[0174] 18, servo patterns 58A and 58B are shown as an example of a set of servo patterns 58 included in a frame 56. The servo patterns 58A and 58B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 56, the servo pattern 58A is located on the upstream side in the forward direction, and the servo pattern 58B is located on the downstream side in the forward direction.

[0175] The servo pattern 58 is made up of linear magnetization region pairs 60. The linear magnetization region pairs 60 are classified into linear magnetization region pairs 60A and linear magnetization region pairs 60B.

[0176] The servo pattern 58A is made up of a pair of linear magnetization regions 60A. In the example shown in Fig. 18, linear magnetization regions 60A1 and 60A2 are shown as an example of the pair of linear magnetization regions 60A. Each of the linear magnetization regions 60A1 and 60A2 is a linearly magnetized region.

[0177] The linear magnetization regions 60A1 and 60A2 are tilted in opposite directions with respect to the virtual line C1. The linear magnetization regions 60A1 and 60A2 are non-parallel to each other and tilt at different angles with respect to the virtual line C1. The linear magnetization region 60A1 has a steeper tilt angle with respect to the virtual line C1 than the linear magnetization region 60A2. Here, "steep" means, for example, that the angle of the linear magnetization region 60A1 with respect to the virtual line C1 is smaller than the angle of the linear magnetization region 60A2 with respect to the virtual line C1. Furthermore, the total length of the linear magnetization region 60A1 is shorter than the total length of the linear magnetization region 60A2.

[0178] In the servo pattern 58A, the linear magnetization region 60A1 includes a plurality of magnetization lines 60A1a, and the linear magnetization region 60A2 includes a plurality of magnetization lines 60A2a. The number of magnetization lines 60A1a included in the linear magnetization region 60A1 is the same as the number of magnetization lines 60A2a included in the linear magnetization region 60A2.

[0179] The linear magnetization region 60A1 is a set of five magnetized straight lines 60A1a, and the linear magnetization region 60A2 is a set of five magnetized straight lines 60A2a. Within the servo band SB, the positions of both ends of the linear magnetization region 60A1 (i.e., the positions of both ends of each of the five magnetization straight lines 60A1a) and the positions of both ends of the linear magnetization region 60A2 (i.e., the positions of both ends of each of the five magnetization straight lines 60A2a) are aligned in the width direction WD. Note that, although an example is given here in which the positions of both ends of each of the five magnetization lines 60A1a and the positions of both ends of each of the five magnetization lines 60A2a are aligned, this is merely an example, and it is sufficient that the positions of both ends of one or more of the five magnetization lines 60A1a and the positions of both ends of one or more of the five magnetization lines 60A2a are aligned. Furthermore, in this embodiment, the concept of "aligned" not only means completely aligned, but also includes the meaning of "aligned" that includes an error that is generally acceptable in the technical field to which the technology of the present disclosure belongs and that does not contradict the spirit of the technology of the present disclosure.

[0180] The servo pattern 58B is made up of a pair of linear magnetization regions 60B. In the example shown in Fig. 18, linear magnetization regions 60B1 and 60B2 are shown as an example of the pair of linear magnetization regions 60B. Each of the linear magnetization regions 60B1 and 60B2 is a linearly magnetized region.

[0181] The linear magnetization regions 60B1 and 60B2 are tilted in opposite directions with respect to the virtual line C2. The linear magnetization regions 60B1 and 60B2 are non-parallel to each other and tilt at different angles with respect to the virtual line C2. The linear magnetization region 60B1 has a steeper tilt angle with respect to the virtual line C2 than the linear magnetization region 60B2. Here, "steep" means, for example, that the angle of the linear magnetization region 60B1 with respect to the virtual line C2 is smaller than the angle of the linear magnetization region 60B2 with respect to the virtual line C2. Furthermore, the total length of the linear magnetization region 60B1 is shorter than the total length of the linear magnetization region 60B2.

[0182] In the servo pattern 58B, the linear magnetization region 60B1 includes a plurality of magnetization lines 60B1a, and the linear magnetization region 60B2 includes a plurality of magnetization lines 60B2a. The number of magnetization lines 60B1a included in the linear magnetization region 60B1 is the same as the number of magnetization lines 60B2a included in the linear magnetization region 60B2.

[0183] The total number of magnetization lines 60B1a and 60B2a included in the servo pattern 58B is different from the total number of magnetization lines 60A1a and 60A2a included in the servo pattern 58A. In the example shown in Fig. 18, the total number of magnetization lines 60A1a and 60A2a included in the servo pattern 58A is 10, while the total number of magnetization lines 60B1a and 60B2a included in the servo pattern 58B is 8.

[0184] The linear magnetization region 60B1 is a set of four magnetized straight lines, ie, magnetization lines 60B1a, and the linear magnetization region 60B2 is a set of four magnetized straight lines, ie, magnetization lines 60B2a. Within the servo band SB, the positions of both ends of the linear magnetization region 60B1 (i.e., the positions of both ends of each of the four magnetization lines 60B1a) and the positions of both ends of the linear magnetization region 60B2 (i.e., the positions of both ends of each of the four magnetization lines 60B2a) are aligned in the width direction WD.

[0185] Here, an example is given in which the positions of both ends of each of the four magnetization lines 60B1a and the positions of both ends of each of the four magnetization lines 60B2a are aligned, but this is merely one example, and it is sufficient that the positions of both ends of one or more of the four magnetization lines 60B1a and the positions of both ends of one or more of the four magnetization lines 60B2a are aligned.

[0186] Furthermore, here, an example of a linear magnetization region 60A1 is a set of magnetization lines 60A1a, which are five magnetized lines; an example of a linear magnetization region 60A2 is a set of magnetization lines 60A2a, which are five magnetized lines; an example of a linear magnetization region 60B1 is a set of magnetization lines 60B1a, which are four magnetized lines; and an example of a linear magnetization region 60B2 is a set of magnetization lines 60B2a, which are four magnetized lines, but the technology of the present disclosure is not limited to this. For example, the linear magnetization region 60A1 may be a number of magnetization lines 60A1a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT, the linear magnetization region 60A2 may be a number of magnetization lines 60A2a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT, the linear magnetization region 60B1 may be a number of magnetization lines 60B1a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT, and the linear magnetization region 60B2 may be a number of magnetization lines 60B2a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT.

[0187] Here, the geometric characteristics of the linear magnetized region pair 60A on the magnetic tape MT will be described with reference to FIG.

[0188] 19, the geometric characteristics of the linear magnetization region pair 60A on the magnetic tape MT can be expressed using a virtual linear region pair 62. The virtual linear region pair 62 is made up of a virtual linear region 62A and a virtual linear region 62B. The geometric characteristics of the linear magnetization region pair 60A on the magnetic tape MT correspond to the geometric characteristics based on the virtual linear region pair 62 when the entire virtual linear region pair 62 is tilted with respect to the virtual line C1 by tilting the symmetry axes SA1 of the virtual linear regions 62A and 62B, which are tilted line-symmetrically with respect to the virtual line C1, with respect to the virtual line C1.

[0189] The virtual linear region pair 62 is a virtual linear magnetization region pair having the same geometric characteristics as the linear magnetization region pair 54A shown in Fig. 8. The virtual linear region pair 62 is a virtual magnetization region used for convenience in explaining the geometric characteristics of the linear magnetization region pair 60A on the magnetic tape MT, and is not an actual magnetization region.

[0190] The virtual linear region 62A has the same geometric characteristics as the linear magnetization region 54A1 shown in Fig. 8 and is made up of five virtual straight lines 62A1 corresponding to the five magnetization straight lines 54A1a shown in Fig. 8. The virtual linear region 62B has the same geometric characteristics as the linear magnetization region 54B1 shown in Fig. 8 and is made up of five virtual straight lines 62B1 corresponding to the five magnetization straight lines 54A2a shown in Fig. 8.

[0191] A center O1 is provided in the virtual linear region pair 62. For example, the center O1 is the center of a line segment L0 connecting the center of the straight line 62A1 located most upstream in the forward direction among the five straight lines 62A1 and the center of the straight line 62B1 located most downstream in the forward direction among the five straight lines 62B1.

[0192] 8, the virtual linear region pair 62 has the same geometric characteristics as the linear magnetization region pair 54A shown in FIG. 8, so the virtual linear region 62A and the virtual linear region 62B are tilted symmetrically with respect to the virtual line C1. Consider a case where the servo read element SR reads the virtual linear region pair 62 in a state where the entire virtual linear region pair 62 is tilted with respect to the virtual line C1 by tilting the symmetry axis SA1 of the virtual linear regions 62A and 62B by an angle a (for example, 10 degrees) with respect to the virtual line C1, with the center O1 as the rotation axis. In this case, there are some portions of the virtual linear region pair 62 in the width direction WD where the virtual linear region 62A is read but the virtual linear region 62B is not, or where the virtual linear region 62A is not read but the virtual linear region 62B is read. That is, when reading is performed by the servo read element SR in each of the imaginary linear regions 62A and 62B, there are insufficient portions and unnecessary portions.

[0193] Therefore, by supplementing the missing parts and cutting out the unnecessary parts, the positions of both ends of the imaginary linear region 62A (i.e., the positions of both ends of each of the five straight lines 62A1) are aligned with the positions of both ends of the imaginary linear region 62B (i.e., the positions of both ends of each of the five straight lines 62B1) in the width direction WD.

[0194] The geometric characteristics of the virtual linear region pair 62 thus obtained (i.e., the geometric characteristics of the virtual servo pattern) correspond to the geometric characteristics of the actual servo pattern 58 A. That is, in the servo band SB, a linear magnetization region pair 60A having geometric characteristics equivalent to the geometric characteristics of the virtual linear region pair 62 obtained by aligning the positions of both ends of the virtual linear region 62A and the positions of both ends of the virtual linear region 62B in the width direction WD is recorded.

[0195] The linear magnetization region pair 60B differs from the linear magnetization region pair 60A only in that it has four magnetization lines 60B1a instead of the five magnetization lines 60A1a and four magnetization lines 60B2a instead of the five magnetization lines 60A2a. Therefore, in the servo band SB, a linear magnetization region pair 60B having geometric characteristics equivalent to the geometric characteristics of a virtual linear region pair (not shown) obtained by aligning the positions of both ends of each of the four lines 62A1 and the positions of both ends of each of the four lines 62B1 in the width direction WD is recorded.

[0196] 20, a plurality of servo bands SB are formed on the magnetic tape MT in the width direction WD, and the frames 56 corresponding to each other between the servo bands SB are shifted at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent to each other in the width direction WD. This means that the servo patterns 58 corresponding to each other between the servo bands SB are shifted at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent to each other in the width direction WD.

[0197] The predetermined interval is determined based on the angle α, the pitch between adjacent servo bands SB in the width direction WD (hereinafter also referred to as the "servo band pitch"), and the frame length. In the example shown in FIG. 20, the angle α is exaggerated to make it easier to understand visually, but in reality, the angle α is, for example, approximately 15 degrees. The angle α is the angle formed by the imaginary line C1 and a pair of frames 56 that do not correspond to each other between adjacent servo bands SB in the width direction WD. In the example shown in FIG. 20, as an example of the angle α, the angle formed by the imaginary line C1 and one frame 56 (in the example shown in FIG. 20, one frame 56 of servo band SB3) of a pair of frames 56 that correspond to each other between adjacent servo bands SB in the width direction WD and a frame 56 adjacent to the other frame 56 (in the example shown in FIG. 20, one frame 56 of servo band SB2 that corresponds to the one frame 56 of servo band SB3) of the pair of frames 56 is shown. In this case, the frame length refers to the total length of the frame 56 in the longitudinal direction LD of the magnetic tape MT. The predetermined interval is defined by the following formula (1). Note that Mod(A / B) means the remainder when "A" is divided by "B".

[0198] (Default interval) = Mod{(servo band pitch × tan α) / (frame length)} (1)

[0199] 20 illustrates the angle α as the angle formed by the imaginary line C1 and one frame 56 (hereinafter also referred to as the "first frame") of a pair of frames 56 corresponding to each other in the width direction WD between adjacent servo bands SB, and the frame 56 adjacent to the other frame 56 (hereinafter also referred to as the "second frame") of the pair of frames 56. However, the technology of the present disclosure is not limited to this. For example, the angle α may be the angle formed by the imaginary line C1 and a frame 56 (hereinafter also referred to as the "third frame") that is two or more frames away from the second frame within the same servo band SB as the second frame. In this case, the "frame length" used in equation (1) is the pitch between the second frame and the third frame in the longitudinal direction LD of the magnetic tape MT (e.g., the distance from the leading edge of the second frame to the leading edge of the third frame).

[0200] 21, when the servo read element SR reads the servo pattern 58A (i.e., the pair of linear magnetized regions 60A) in a state where the directions of the virtual straight lines C1 and C3 are aligned (i.e., the longitudinal direction of the magnetic head 28 is aligned with the width direction WD), variations due to azimuth loss occur between the servo pattern signals derived from the linear magnetized regions 60A1 and the servo pattern signals derived from the linear magnetized regions 60A2. A similar phenomenon also occurs when the servo read element SR reads the servo pattern 58B (i.e., the pair of linear magnetized regions 60B) in a state where the directions of the virtual straight lines C1 and C3 are aligned (i.e., the longitudinal direction of the magnetic head 28 is aligned with the width direction WD).

[0201] 22, the tilting mechanism 49 (see FIG. 8) skews the magnetic head 28 about the rotation axis RA on the magnetic tape MT so that the virtual line C3 is tilted by an angle β (i.e., the angle β in the counterclockwise direction when viewed from the front side of the paper in FIG. 22) upstream in the forward direction with respect to the virtual line C1. Since the magnetic head 28 is tilted by the angle β upstream in the forward direction on the magnetic tape MT in this manner, the variation due to azimuth loss between the servo pattern signals derived from the linear magnetized regions 60A1 and the servo pattern signals derived from the linear magnetized regions 60A2 is reduced compared to the example shown in FIG. 21. Similarly, when the servo read element SR reads the servo pattern 58B (i.e., the linear magnetized region pair 60B), the variation due to azimuth loss between the servo pattern signals derived from the linear magnetized regions 60B1 and the servo pattern signals derived from the linear magnetized regions 60B2 is reduced.

[0202] [Second Modification] In the first modified example described above, an example in which the servo band SB is separated by a plurality of frames 56 along the longitudinal direction LD of the magnetic tape MT has been described, but the technology of the present disclosure is not limited to this. For example, as shown in FIG. 23 , the servo band SB may be separated by frames 70 along the longitudinal direction LD of the magnetic tape MT. The frame 70 is defined by a set of servo patterns 72. The servo band SB has a plurality of servo patterns 72 recorded along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns 72 are arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT, similar to the plurality of servo patterns 58.

[0203] 23, servo patterns 72A and 72B are shown as an example of a set of servo patterns 72. Each of the servo patterns 72A and 72B is an M-shaped magnetized servo pattern. The servo patterns 72A and 72B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 70, the servo pattern 72A is located on the upstream side in the forward direction, and the servo pattern 72B is located on the downstream side in the forward direction.

[0204] 24, as an example, a servo pattern 72 is made up of linear magnetization region pairs 74. The linear magnetization region pairs 74 are classified into linear magnetization region pairs 74A and linear magnetization region pairs 74B.

[0205] The servo pattern 72A is made up of a pair of linear magnetized regions 74A, which are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

[0206] 24 shows linear magnetization regions 74A1 and 74A2 as an example of the linear magnetization region pair 74A. The linear magnetization region pair 74A is configured similarly to the linear magnetization region pair 60A described in the first modified example above, and has similar geometric characteristics to the linear magnetization region pair 60A. That is, the linear magnetization region 74A1 is configured similarly to the linear magnetization region 60A1 described in the first modified example above, and has similar geometric characteristics to the linear magnetization region 60A1, and the linear magnetization region 74A2 is configured similarly to the linear magnetization region 60A2 described in the first modified example above, and has similar geometric characteristics to the linear magnetization region 60A2.

[0207] The servo pattern 72B is made up of a pair of linear magnetized regions 74B, which are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

[0208] 24 shows linear magnetization regions 74B1 and 74B2 as an example of the linear magnetization region pair 74B. The linear magnetization region pair 74B is configured similarly to the linear magnetization region pair 60B described in the first modified example above, and has similar geometric characteristics to the linear magnetization region pair 60B. That is, the linear magnetization region 74B1 is configured similarly to the linear magnetization region 60B1 described in the first modified example above, and has similar geometric characteristics to the linear magnetization region 60B1, and the linear magnetization region 74B2 is configured similarly to the linear magnetization region 60B2 described in the first modified example above, and has similar geometric characteristics to the linear magnetization region 60B2.

[0209] [Third Modification] In the example shown in Figure 23, the servo band SB is separated 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 Figure 25, the servo band SB may be separated by frames 76 along the longitudinal direction LD of the magnetic tape MT. The frame 76 is defined by a set of servo patterns 78. The servo band SB has a plurality of servo patterns 78 recorded along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns 78 are arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT, similar to the plurality of servo patterns 72 (see Figure 23).

[0210] 25, servo patterns 78A and 78B are shown as an example of a set of servo patterns 78. Each of the servo patterns 78A and 78B is an N-shaped magnetized servo pattern. The servo patterns 78A and 78B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 76, the servo pattern 78A is located on the upstream side in the forward direction, and the servo pattern 78B is located on the downstream side in the forward direction.

[0211] 26, the servo pattern 78 is made up of linear magnetization region groups 80. The linear magnetization region groups 80 are classified into linear magnetization region groups 80A and linear magnetization region groups 80B.

[0212] The servo pattern 78A is made up of a linear magnetization region group 80A. The linear magnetization region group 80A is made up of linear magnetization regions 80A1, 80A2, and 80A3. The linear magnetization regions 80A1, 80A2, and 80A3 are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions 80A1, 80A2, and 80A3 are arranged in this order from the upstream side in the forward direction.

[0213] The linear magnetization regions 80A1 and 80A2 are configured similarly to the linear magnetization region pair 74A shown in Fig. 24 and have similar geometric characteristics. That is, the linear magnetization region 80A1 is configured similarly to the linear magnetization region 74A1 shown in Fig. 24 and has similar geometric characteristics, and the linear magnetization region 80A2 is configured similarly to the linear magnetization region 74A2 shown in Fig. 24 and has similar geometric characteristics. Furthermore, the linear magnetization region 80A3 is configured similarly to the linear magnetization region 80A1 and has similar geometric characteristics.

[0214] The servo pattern 78B is made up of a linear magnetization region group 80B. The linear magnetization region group 80B is made up of linear magnetization regions 80B1, 80B2, and 80B3. The linear magnetization regions 80B1, 80B2, and 80B3 are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions 80B1, 80B2, and 80B3 are arranged in this order from the upstream side in the forward direction.

[0215] The linear magnetization regions 80B1 and 80B2 are configured similarly to the linear magnetization region pair 74B shown in Fig. 24 and have similar geometric characteristics. That is, the linear magnetization region 80B1 is configured similarly to the linear magnetization region 74B1 shown in Fig. 24 and has similar geometric characteristics, and the linear magnetization region 80B2 is configured similarly to the linear magnetization region 74B2 shown in Fig. 24 and has similar geometric characteristics. Furthermore, the linear magnetization region 80B3 is configured similarly to the linear magnetization region 80B1 and has similar geometric characteristics.

[0216] [Fourth Modification] In the first modified example described above, the predetermined interval is defined based on the angle α, the servo band pitch, and the frame length. However, 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. 27, the predetermined interval is defined based on the angle α formed by the virtual line C1 and the frame 56 (in the example shown in Fig. 27, the line segment L3) that corresponds between the servo bands SB adjacent in the width direction WD, and the pitch between the servo bands SB adjacent in the width direction WD (i.e., the servo band pitch). In this case, for example, the predetermined interval is calculated using the following mathematical formula (2):

[0217] (default interval) = (servo band pitch) × tan α (2)

[0218] As described above, the frame length is not included in formula (2). This means that the predetermined interval can be calculated without taking the frame length into consideration. Therefore, with this configuration, the predetermined interval can be calculated more easily than when the predetermined interval is calculated from formula (1).

[0219] [Fifth Modification] In the first modified example described above, the servo bands SB are separated by a 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. 28, the servo bands SB may be separated by frames 82 along the longitudinal direction LD of the magnetic tape MT.

[0220] A 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 arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT, similar to the plurality of servo patterns 52 (see FIG. 6) recorded on the magnetic tape MT (see FIG. 6).

[0221] 28, servo patterns 84A and 84B are shown as an example of a set of servo patterns 84 included in a frame 82. The servo patterns 84A and 84B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 82, the servo pattern 84A is located on the upstream side in the forward direction, and the servo pattern 84B is located on the downstream side in the forward direction.

[0222] The servo pattern 84A is made up of a pair of linear magnetization regions 86A. In the example shown in Fig. 28, linear magnetization regions 86A1 and 86A2 are shown as an example of the pair of linear magnetization regions 86A. Each of the linear magnetization regions 86A1 and 86A2 is a linearly magnetized region.

[0223] The linear magnetization regions 86A1 and 86A2 are tilted in opposite directions with respect to the virtual line C1. The linear magnetization regions 86A1 and 86A2 are non-parallel to each other and tilt at different angles with respect to the virtual line C1. The linear magnetization region 86A1 has a steeper tilt angle with respect to the virtual line C1 than the linear magnetization region 86A2. Here, "steep" means, for example, that the angle of the linear magnetization region 86A1 with respect to the virtual line C1 is smaller than the angle of the linear magnetization region 86A2 with respect to the virtual line C1.

[0224] Furthermore, the overall position of the linear magnetization region 86A1 and the overall position of the linear magnetization region 86A2 are misaligned in the width direction WD. That is, the positions of one end of the linear magnetization region 86A1 and one end of the linear magnetization region 86A2 are not aligned in the width direction WD, and the positions of the other end of the linear magnetization region 86A1 and the other end of the linear magnetization region 86A2 are not aligned in the width direction WD.

[0225] In the servo pattern 84A, the linear magnetization region 86A1 includes a plurality of magnetization lines 86A1a, and the linear magnetization region 86A2 includes a plurality of magnetization lines 86A2a. The number of magnetization lines 86A1a included in the linear magnetization region 86A1 is the same as the number of magnetization lines 86A2a included in the linear magnetization region 86A2.

[0226] The linear magnetization region 86A1 is a set of five magnetized straight lines 86A1a, and the linear magnetization region 86A2 is a set of five magnetized straight lines 86A2a.

[0227] In the servo band SB, the positions in the width direction WD of one end of all the magnetization straight lines 86A1a included in the linear magnetization region 86A1 are aligned, and the positions in the width direction WD of the other end of all the magnetization straight lines 86A1a included in the linear magnetization region 86A1 are also aligned. Also, in the servo band SB, the positions in the width direction WD of one end of all the magnetization straight lines 86A2a included in the linear magnetization region 86A2 are aligned, and the positions in the width direction WD of the other end of all the magnetization straight lines 86A2a included in the linear magnetization region 86A2 are also aligned.

[0228] The servo pattern 84B is made up of a pair of linear magnetization regions 86B. In the example shown in Fig. 28, linear magnetization regions 86B1 and 86B2 are shown as an example of the pair of linear magnetization regions 86B. Each of the linear magnetization regions 86B1 and 86B2 is a linearly magnetized region.

[0229] The linear magnetization regions 86B1 and 86B2 are tilted in opposite directions with respect to the virtual line C2. The linear magnetization regions 86B1 and 86B2 are non-parallel to each other and tilt at different angles with respect to the virtual line C2. The linear magnetization region 86B1 has a steeper tilt angle with respect to the virtual line C2 than the linear magnetization region 86B2. Here, "steep" means, for example, that the angle of the linear magnetization region 86B1 with respect to the virtual line C2 is smaller than the angle of the linear magnetization region 86B2 with respect to the virtual line C2.

[0230] Furthermore, the overall position of the linear magnetization region 86B1 and the overall position of the linear magnetization region 86B2 are misaligned in the width direction WD. That is, the positions of one end of the linear magnetization region 86B1 and one end of the linear magnetization region 86B2 are not aligned in the width direction WD, and the positions of the other end of the linear magnetization region 86B1 and the other end of the linear magnetization region 86B2 are not aligned in the width direction WD.

[0231] In the servo pattern 84B, the linear magnetization region 86B1 includes a plurality of magnetization lines 86B1a, and the linear magnetization region 86B2 includes a plurality of magnetization lines 86B2a. The number of magnetization lines 86B1a included in the linear magnetization region 86B1 is the same as the number of magnetization lines 86B2a included in the linear magnetization region 86B2.

[0232] The total number of magnetization lines 86B1a and 86B2a included in the servo pattern 84B is different from the total number of magnetization lines 86A1a and 86A2a included in the servo pattern 84A. In the example shown in Fig. 28, the total number of magnetization lines 86A1a and 86A2a included in the servo pattern 84A is 10, while the total number of magnetization lines 86B1a and 86B2a included in the servo pattern 84B is 8.

[0233] The linear magnetization region 86B1 is a set of four magnetized straight lines 86B1a, and the linear magnetization region 86B2 is a set of four magnetized straight lines 86B2a.

[0234] In the servo band SB, the positions in the width direction WD of one end of all the magnetization straight lines 86B1a included in the linear magnetization region 86B1 are aligned, and the positions in the width direction WD of the other end of all the magnetization straight lines 86B1a included in the linear magnetization region 86B1 are also aligned. Also, in the servo band SB, the positions in the width direction WD of one end of all the magnetization straight lines 86B2a included in the linear magnetization region 86B2 are also aligned, and the positions in the width direction WD of the other end of all the magnetization straight lines 86B2a included in the linear magnetization region 86B2 are also aligned.

[0235] Here, an example of a linear magnetization region 86A1 is a set of five magnetized straight lines, namely, magnetization lines 86A1a; an example of a linear magnetization region 86A2 is a set of five magnetized straight lines, namely, magnetization lines 86A2a; an example of a linear magnetization region 86B1 is a set of four magnetized straight lines, namely, magnetization lines 86B1a; and an example of a linear magnetization region 86B2 is a set of four magnetized straight lines, namely, magnetization lines 86B2a; however, the technology disclosed herein is not limited to this. For example, the linear magnetization region 86A1 may be a number of magnetization lines 86A1a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT, the linear magnetization region 86A2 may be a number of magnetization lines 86A2a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT, the linear magnetization region 86B1 may be a number of magnetization lines 86B1a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT, and the linear magnetization region 86B2 may be a number of magnetization lines 86B2a that contribute to determining the position of the magnetic head 28 on the magnetic tape MT.

[0236] Here, the geometric characteristics of the linear magnetized region pair 86A on the magnetic tape MT will be described with reference to FIG.

[0237] 29, the geometric characteristics of the linear magnetization region pair 86A on the magnetic tape MT can be expressed using the virtual linear region pair 62. Here, the symmetry axis SA1 of the virtual linear regions 62A and 62B is tilted by an angle a (e.g., 10 degrees) with respect to the virtual line C1, with the center O1 as the rotation axis, to tilt the entire virtual linear region pair 62 with respect to the virtual line C1. Then, in this state, the positions of one end of all straight lines 62A1 included in the virtual linear region 62A of the virtual linear region pair 62 in the width direction WD are aligned, and the positions of the other end of all straight lines 62A1 included in the virtual linear region 62A are also aligned. Similarly, the positions of one end of all straight lines 62B1 included in the virtual linear region 62B of the virtual linear region pair 62 are aligned, and the positions of the other end of all straight lines 62B1 included in the virtual linear region 62B are also aligned. As a result, the imaginary linear region 62A and the imaginary linear region 62B are shifted in the width direction WD.

[0238] That is, one end of the virtual linear region 62A and one end of the virtual linear region 62B are offset in the width direction WD by a constant interval Int1, and the other end of the virtual linear region 62A and the other end of the virtual linear region 62B are offset in the width direction WD by a constant interval Int2.

[0239] The geometric characteristics of the virtual linear region pair 62 thus obtained (i.e., the geometric characteristics of the virtual servo pattern) correspond to the geometric characteristics of the actual servo pattern 84 A. That is, the geometric characteristics of the linear magnetization region pair 86A on the magnetic tape MT correspond to the geometric characteristics based on the virtual linear region pair 62 when the entire virtual linear region pair 62 is tilted with respect to the virtual line C1 by tilting the symmetry axes SA1 of the virtual linear regions 62A and 62B, which are tilted line-symmetrically with respect to the virtual line C1, with respect to the virtual line C1.

[0240] The virtual linear region 62A corresponds to the linear magnetization region 86A1 of the servo pattern 84A, and the virtual linear region 62B corresponds to the linear magnetization region 86A2 of the servo pattern 84A. Therefore, the servo band SB records a servo pattern 84A consisting of a pair of linear magnetization regions 86A in which one end of the linear magnetization region 86A1 and one end of the linear magnetization region 86A2 are shifted in the width direction WD by a constant interval Int1, and the other end of the linear magnetization region 86A1 and the other end of the linear magnetization region 86A2 are shifted in the width direction WD by a constant interval Int2 (see FIG. 28).

[0241] The pair of linear magnetization regions 86B differs from the pair of linear magnetization regions 86A only in that it has four magnetization lines 86B1a instead of five magnetization lines 86A1a and four magnetization lines 86B2a instead of five magnetization lines 86A2a (see FIG. 28). Thus, a servo pattern 84B is recorded on the servo band SB, which is made up of the pair of linear magnetization regions 86B in which one end of the linear magnetization region 86B1 and one end of the linear magnetization region 86B2 are shifted in the width direction WD by a constant interval Int1 and the other end of the linear magnetization region 86B1 and the other end of the linear magnetization region 86B2 are shifted in the width direction WD by a constant interval Int2 (see FIG. 28).

[0242] 30, a plurality of servo bands SB are formed on the magnetic tape MT in the width direction WD, and frames 82 corresponding to each other between the servo bands SB are shifted at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between adjacent servo bands SB in the width direction WD. This means that servo patterns 84 corresponding to each other between the servo bands SB are shifted at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between adjacent servo bands SB in the width direction WD. The predetermined interval is defined by the formula (1) described in the first modified example above.

[0243] As in the first modified example, in the fifth modified example, as shown in FIG. 31 as an example, the tilting mechanism 49 (see FIG. 8) skews the magnetic head 28 about the rotation axis RA on the magnetic tape MT so that the imaginary line C3 is tilted by an angle β upstream in the forward direction relative to the imaginary line C1 (i.e., the angle β counterclockwise when viewed from the front side of the paper in FIG. 31). That is, the magnetic head 28 is tilted by an angle β upstream in the forward direction on the magnetic tape MT. In this state, when the servo read element SR reads the servo pattern 84A along the longitudinal direction LD within the range R where the linear magnetized regions 86A1 and 86A2 overlap in the width direction WD, the variation due to azimuth loss between the servo pattern signals derived from the linear magnetized regions 86A1 and 86A2 is smaller than in the example shown in FIG. 21. Similarly, when the servo pattern 84B (i.e., the linear magnetization region pair 86B) is read by the servo read element SR, the variation due to azimuth loss between the servo pattern signal derived from the linear magnetization region 86B1 and the servo pattern signal derived from the linear magnetization region 86B2 is reduced.

[0244] [Sixth Modification] In the fifth modified example described above, an example in which the servo band SB is separated by a plurality of frames 82 along the longitudinal direction LD of the magnetic tape MT has been described, but the technology of the present disclosure is not limited to this. For example, as shown in FIG. 32, the servo band SB may be separated by frames 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 on the servo band SB along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns 90 are arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT, similar to the plurality of servo patterns 84 (see FIG. 28).

[0245] 32, servo patterns 90A and 90B are shown as an example of a set of servo patterns 90. Each of the servo patterns 90A and 90B is an M-shaped magnetized servo pattern. The servo patterns 90A and 90B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 88, the servo pattern 90A is located on the upstream side in the forward direction, and the servo pattern 90B is located on the downstream side in the forward direction.

[0246] 33, a servo pattern 90 is made up of linear magnetization region pairs 92. The linear magnetization region pairs 92 are classified into linear magnetization region pairs 92A and linear magnetization region pairs 92B.

[0247] The servo pattern 90A is made up of a set of linear magnetized region pairs 92A, which are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

[0248] 33, linear magnetization regions 92A1 and 92A2 are shown as an example of the linear magnetization region pair 92A. The linear magnetization region pair 92A is configured similarly to the linear magnetization region pair 86A (see FIG. 28) described in the fifth modified example above, and has similar geometric characteristics to the linear magnetization region pair 86A. That is, the linear magnetization region 92A1 is configured similarly to the linear magnetization region 86A1 (see FIG. 28) described in the fifth modified example above, and has similar geometric characteristics to the linear magnetization region 86A1, and the linear magnetization region 92A2 is configured similarly to the linear magnetization region 86A2 (see FIG. 28) described in the fifth modified example above, and has similar geometric characteristics to the linear magnetization region 86A2.

[0249] The servo pattern 90B is made up of a pair of linear magnetized regions 92B, which are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT.

[0250] 33, linear magnetization regions 92B1 and 92B2 are shown as an example of the linear magnetization region pair 92B. The linear magnetization region pair 92B is configured similarly to the linear magnetization region pair 86B (see FIG. 28) described in the fifth modified example above, and has similar geometric characteristics to the linear magnetization region pair 86B. That is, the linear magnetization region 92B1 is configured similarly to the linear magnetization region 86B1 (see FIG. 28) described in the fifth modified example above, and has similar geometric characteristics to the linear magnetization region 86B1, and the linear magnetization region 92B2 is configured similarly to the linear magnetization region 86B2 (see FIG. 28) described in the fifth modified example above, and has similar geometric characteristics to the linear magnetization region 86B2.

[0251] [Seventh Modification] In the example shown in Figure 32, the servo band SB is separated 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 Figure 34, the servo band SB may be separated by frames 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. The plurality of servo patterns 96 are arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT, similar to the plurality of servo patterns 90 (see Figure 32).

[0252] 34, servo patterns 96A and 96B are shown as an example of a set of servo patterns 96. Each of the servo patterns 96A and 96B is an N-shaped magnetized servo pattern. The servo patterns 96A and 96B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 94, the servo pattern 96A is located on the upstream side in the forward direction, and the servo pattern 96B is located on the downstream side in the forward direction.

[0253] 35, as an example, a servo pattern 96 is made up of linear magnetization region groups 98. The linear magnetization region groups 98 are classified into linear magnetization region groups 98A and linear magnetization region groups 98B.

[0254] The servo pattern 96A is made up of a linear magnetization region group 98A. The linear magnetization region group 98A is made up of linear magnetization regions 98A1, 98A2, and 98A3. The linear magnetization regions 98A1, 98A2, and 98A3 are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions 98A1, 98A2, and 98A3 are arranged in this order from the upstream side in the forward direction.

[0255] The linear magnetization regions 98A1 and 98A2 are configured similarly to the linear magnetization region pair 92A shown in Fig. 33 and have similar geometric characteristics. That is, the linear magnetization region 98A1 is configured similarly to the linear magnetization region 92A1 shown in Fig. 33 and has similar geometric characteristics. The linear magnetization region 98A2 is configured similarly to the linear magnetization region 92A2 shown in Fig. 33 and has similar geometric characteristics. Furthermore, the linear magnetization region 98A3 is configured similarly to the linear magnetization region 92A1 and has similar geometric characteristics.

[0256] The servo pattern 96B is made up of a linear magnetization region group 98B. The linear magnetization region group 98B is made up of linear magnetization regions 98B1, 98B2, and 98B3. The linear magnetization regions 98B1, 98B2, and 98B3 are arranged adjacent to each other along the longitudinal direction LD of the magnetic tape MT. The linear magnetization regions 98B1, 98B2, and 98B3 are arranged in this order from the upstream side in the forward direction.

[0257] The linear magnetization regions 98B1 and 98B2 are configured similarly to the linear magnetization region pair 92B shown in Fig. 33 and have similar geometric characteristics. That is, the linear magnetization region 98B1 is configured similarly to the linear magnetization region 92B1 shown in Fig. 33 and has similar geometric characteristics, and the linear magnetization region 98B2 is configured similarly to the linear magnetization region 92B2 shown in Fig. 33 and has similar geometric characteristics. Furthermore, the linear magnetization region 98B3 is configured similarly to the linear magnetization region 92B1 and has similar geometric characteristics.

[0258] [Eighth Modification] In the above-described first modified example (for example, the example shown in FIG. 18 ), an example in which the servo band SB is separated by a plurality of frames 56 along the longitudinal direction LD of the magnetic tape MT has been described, but the technology of the present disclosure is not limited to this. For example, as shown in FIG. 36 , the servo band SB may be separated by frames 560 along the longitudinal direction LD of the magnetic tape MT. The frame 560 is defined by a set of servo patterns 580. The servo band SB has a plurality of servo patterns 580 recorded along the longitudinal direction LD of the magnetic tape MT. The plurality of servo patterns 580 are arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT, similar to the plurality of servo patterns 58.

[0259] The servo pattern 580 is made up of linear magnetization region pairs 600. The linear magnetization region pairs 600 are classified into linear magnetization region pairs 600A and linear magnetization region pairs 600B. That is, the linear magnetization region pairs 600 differ from the linear magnetization region pairs 60 (see FIG. 18) in that they have linear magnetization region pairs 600A instead of linear magnetization region pairs 60A, and linear magnetization region pairs 600B instead of linear magnetization region pairs 60B.

[0260] The servo pattern 580A is made up of a pair of linear magnetization regions 600A. The pair of linear magnetization regions 600A differs from the pair of linear magnetization regions 60A in that it has a linear magnetization region 600A1 instead of the linear magnetization region 60A1, and a linear magnetization region 600A2 instead of the linear magnetization region 60A2. Each of the linear magnetization regions 600A1 and 600A2 is a linearly magnetized region.

[0261] The linear magnetization regions 600A1 and 600A2 are inclined in opposite directions with respect to the virtual line C1. The linear magnetization regions 600A1 and 600A2 are non-parallel to each other and are inclined at different angles with respect to the virtual line C1. The linear magnetization region 600A2 has a steeper inclination angle with respect to the virtual line C1 than the linear magnetization region 600A1. Here, "steep" means, for example, that the angle of the linear magnetization region 600A2 with respect to the virtual line C1 is smaller than the angle of the linear magnetization region 600A2 with respect to the virtual line C1. Furthermore, the total length of the linear magnetization region 600A2 is shorter than the total length of the linear magnetization region 600A2.

[0262] The linear magnetization region 600A1 differs from the linear magnetization region 60A1 in that it has a plurality of magnetization lines 600A1a instead of the plurality of magnetization lines 60A1a. The linear magnetization region 600A2 differs from the linear magnetization region 60A2 in that it has a plurality of magnetization lines 600A2a instead of the plurality of magnetization lines 60A2a.

[0263] The linear magnetization region 600A1 includes a plurality of magnetization lines 600A1a, and the linear magnetization region 600A2 includes a plurality of magnetization lines 600A2a. The number of magnetization lines 600A1a included in the linear magnetization region 600A1 is the same as the number of magnetization lines 600A2a included in the linear magnetization region 600A2.

[0264] The linear magnetization region 600A1 is a linear magnetization region corresponding to the first axisymmetric region. The first axisymmetric region refers to a region in which the linear magnetization region 60A2 (see FIG. 18) described in the first modified example is formed axisymmetrically with respect to the virtual line C1. In other words, the linear magnetization region 600A1 can also be said to be a linear magnetization region formed with the geometric characteristics of a mirror image of the linear magnetization region 60A2 (see FIG. 18) (i.e., the geometric characteristics obtained by performing a mirror image of the linear magnetization region 60A2 (see FIG. 18) with the virtual line C1 as the axis of axisymmetrical symmetry).

[0265] The linear magnetization region 600A2 is a linear magnetization region corresponding to the second axisymmetric region. The second axisymmetric region refers to a region in which the linear magnetization region 60A1 (see FIG. 18) described in the first embodiment is formed axisymmetrically with respect to the virtual line C1. In other words, the linear magnetization region 600A2 can also be said to be a linear magnetization region formed with the geometric characteristics of a mirror image of the linear magnetization region 60A1 (see FIG. 18) (i.e., the geometric characteristics obtained by performing a mirror image of the linear magnetization region 60A1 (see FIG. 18) with the virtual line C1 as the axis of axisymmetrical symmetry).

[0266] In other words, in the example shown in Figure 19, the symmetry axis SA1 of the virtual linear regions 62A and 62B is tilted clockwise by an angle a when viewed from the front side of the paper in Figure 19 with the center O1 as the rotation axis relative to the virtual straight line C1, thereby aligning the positions of both ends of the virtual linear region 62A and the positions of both ends of the virtual linear region 62B, and the geometric characteristics of the virtual linear region pair 62 obtained by tilting the entire virtual linear region pair 62 relative to the virtual straight line C1 correspond to the geometric characteristics of the servo pattern 580A.

[0267] The servo pattern 580B is made up of a pair of linear magnetization regions 600B. The pair of linear magnetization regions 600B differs from the pair of linear magnetization regions 60B in that it has a linear magnetization region 600B1 instead of the linear magnetization region 60B1, and a linear magnetization region 600B2 instead of the linear magnetization region 60B2. Each of the linear magnetization regions 600B1 and 600B2 is a linearly magnetized region.

[0268] The linear magnetization regions 600B1 and 600B2 are tilted in opposite directions with respect to the virtual line C2. The linear magnetization regions 600B1 and 600B2 are non-parallel to each other and tilt at different angles with respect to the virtual line C2. The linear magnetization region 600B2 has a steeper tilt angle with respect to the virtual line C2 than the linear magnetization region 600B1. Here, "steep" means, for example, that the angle of the linear magnetization region 600B2 with respect to the virtual line C2 is smaller than the angle of the linear magnetization region 600B2 with respect to the virtual line C2.

[0269] The linear magnetization region 600B1 includes a plurality of magnetization lines 600B1a, and the linear magnetization region 600B2 includes a plurality of magnetization lines 600B2a. The number of magnetization lines 600B1a included in the linear magnetization region 600B1 is the same as the number of magnetization lines 600B2a included in the linear magnetization region 600B2.

[0270] The total number of magnetization lines 600B1a and 600B2a included in the servo pattern 580B is different from the total number of magnetization lines 600A1a and 600A2a included in the servo pattern 580A. In the example shown in Fig. 33, the total number of magnetization lines 600A1a and 600A2a included in the servo pattern 580A is 10, while the total number of magnetization lines 600B1a and 600B2a included in the servo pattern 580B is 8.

[0271] The linear magnetization region 600B1 is a set of four magnetized straight lines, ie, magnetization lines 600B1a, and the linear magnetization region 600B2 is a set of four magnetized straight lines, ie, magnetization lines 600B2a. Within the servo band SB, the positions of both ends of the linear magnetization region 600B1 (i.e., the positions of both ends of each of the four magnetization lines 600B1a) and the positions of both ends of the linear magnetization region 600B2 (i.e., the positions of both ends of each of the four magnetization lines 600B2a) are aligned in the width direction WD.

[0272] In this way, the geometric characteristics of servo pattern 580A correspond to the geometric characteristics of the mirror image of linear magnetization region 60A2 (see Figure 18) and the geometric characteristics of the mirror image of linear magnetization region 60A2 (see Figure 18) (i.e., the geometric characteristics of the mirror image of servo pattern 58A shown in Figure 18), and the geometric characteristics of servo pattern 580B correspond to the geometric characteristics of the mirror image of linear magnetization region 60B2 (see Figure 18) and the geometric characteristics of the mirror image of linear magnetization region 60B2 (see Figure 18) (i.e., the geometric characteristics of the mirror image of servo pattern 58B shown in Figure 18). However, this is merely one example, and instead of servo pattern 580, a servo pattern formed with the geometric characteristics of the mirror image of servo pattern 72 shown in Figure 23, the geometric characteristics of the mirror image of servo pattern 78 shown in Figure 25, the geometric characteristics of the mirror image of servo pattern 84 shown in Figure 28, the geometric characteristics of the mirror image of servo pattern 90 shown in Figure 32, or the geometric characteristics of the mirror image of servo pattern 96 shown in Figure 34 may be applied.

[0273] Note that even when the geometric characteristics of the servo pattern are changed in this way, the tilt mechanism 49 changes the direction and angle of the tilt (i.e., azimuth) of the virtual line C3 relative to the virtual line C4 (for example, angle β shown in FIG. 22) in accordance with the geometric characteristics of the servo pattern. In other words, even when the geometric characteristics of the servo pattern are changed, as in the first modified example, the tilt mechanism 49, under the control of the control unit 30A, rotates the magnetic head 28 about the rotation axis RA on the surface 31 of the magnetic tape MT, thereby changing the direction and angle of the tilt (i.e., azimuth) of the virtual line C3 relative to the virtual line C4 (for example, angle β shown in FIG. 22) so as to reduce variations in the servo pattern signals.

[0274] [Other variations] In the above embodiment, the magnetic tape system 10 is exemplified as one in which the magnetic tape cartridge 12 is freely insertable into and removable from the magnetic tape drive 14, but the technology of the present disclosure is not limited to this. For example, the technology of the present disclosure can also be applied to a magnetic tape system in which at least one magnetic tape cartridge 12 is pre-loaded into the magnetic tape drive 14 (i.e., a magnetic tape system in which at least one magnetic tape cartridge 12 and the magnetic tape drive 14 are pre-integrated).

[0275] In the above embodiment, a single magnetic head 28 is exemplified, but the technology of the present disclosure is not limited to this. For example, multiple magnetic heads 28 may be arranged on the magnetic tape MT. For example, a read magnetic head 28 and at least one write magnetic head 28 may be arranged on the magnetic tape MT. The read magnetic head 28 may be used to verify data recorded on the data band DB by the write magnetic head 28. Furthermore, one magnetic head equipped with a read magnetic element unit 42 and at least one write magnetic element unit 42 may be arranged on the magnetic tape MT.

[0276] In the above embodiment, an example in which the processing device 30 (see FIG. 3) is realized by an ASIC has been described. However, the technology of the present disclosure is not limited to this. The processing device 30 may be realized by a software configuration. Furthermore, only the control unit 30A and the position detection unit 30B included in the processing device 30 may be realized by a software configuration. When the control unit 30A and the position detection unit 30B are realized by a software configuration, for example, as shown in FIG. 37, the processing device 30 includes a computer 200. The computer 200 has a processor 200A (e.g., a single CPU or multiple CPUs), an NVM 200B, and a RAM 200C. The processor 200A, the NVM 200B, and the RAM 200C are connected to a bus 200D. A program PG is stored in a portable storage medium 202 (e.g., an SSD or a USB memory), which is a computer-readable non-transitory storage medium.

[0277] The program PG stored in the storage medium 202 is installed in the computer 200. In accordance with the program PG, the processor 200A executes a threshold use method detection process including the servo pattern detection process (see FIG. 15), the first setting process (see FIG. 16), and the second setting process (see FIG. 17) described in the above embodiment.

[0278] The program PG may also be stored in a storage device such as another computer or server device connected to the computer 200 via a communication network (not shown), and the servo pattern detection program PG may be downloaded and installed in the computer 200 in response to a request from the processing device 30. The program PG is an example of a "program" according to the technology of the present disclosure, and the computer 200 is an example of a "computer" according to the technology of the present disclosure.

[0279] 37 illustrates a computer 200, 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 200. Also, a combination of a hardware configuration and a software configuration may be used instead of the computer 200.

[0280] The hardware resources that execute the processing of the processing device 30 (see FIG. 3) and / or the servo writer controller SW5 (see FIG. 14) can be various processors, as listed below. Examples of processors include a CPU, which is a general-purpose processor that functions as a hardware resource that executes processing by executing software, i.e., a program. Examples of processors also include dedicated electronic circuits, such as FPGAs, PLCs, or the exemplary ASICs, which are processors with a circuit configuration specifically designed to execute specific processing. Each processor has built-in or connected memory, and executes processing by using the memory.

[0281] The hardware resources that execute the processing of the processing device 30 and / or the servo writer controller SW5 may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs, or a combination of a CPU and an FPGA). Also, the hardware resources that execute the processing of the processing device 30 and / or the servo writer controller SW5 may be a single processor.

[0282] As an example of a single processor configuration, first, one processor is configured by combining one or more CPUs and software, and this processor functions as a hardware resource that executes processing. Second, there is a configuration in which a processor is used that realizes the functions of an entire system including multiple hardware resources that execute processing on a single IC chip, as typified by SoCs, etc. In this way, the processing of the processing device 30 and / or the servo writer controller SW5 is realized using one or more of the above-mentioned various processors as hardware resources.

[0283] Furthermore, the hardware structure of these various processors can be, more specifically, electronic circuits that combine circuit elements such as semiconductor devices. The processing of the processing device 30 and / or servo writer controller SW5 described above is merely an example. Therefore, it goes without saying that unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged, without departing from the spirit of the invention.

[0284] The above-described description and illustrations are a detailed explanation of the parts related to the technology of the present disclosure and are merely an example of the technology of the present disclosure. For example, the above description of the configuration, functions, actions, and effects is an explanation of an example of the configuration, functions, actions, and effects of the parts related to the technology of the present disclosure. Therefore, it goes without saying that unnecessary parts may be deleted, new elements may be added, or replacements may be made to the above-described description and illustrations within the scope of the gist of the technology of the present disclosure. Furthermore, to avoid confusion and facilitate understanding of the parts related to the technology of the present disclosure, the above-described description and illustrations omit explanations of common technical knowledge that do not require particular explanation to enable the implementation of the technology of the present disclosure.

[0285] In this specification, "A and / or B" is synonymous with "at least one of A and B." In other words, "A and / or B" means that it may be only A, only B, or a combination of A and B. Furthermore, in this specification, the same concept as "A and / or B" is also applied when three or more things are expressed connected by "and / or."

[0286] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference. [Explanation of symbols]

[0287] 10 Magnetic Tape Systems 12 Magnetic tape cartridge 14 Magnetic Tape Drive 16 cases 16A Right Wall 16B opening 18 Upper case 20 Lower case 22, SW1 Delivery reel 22A reel hub 22B1 Upper flange 22B2 bottom flange 24 Cartridge Memory 24B,33 Back side 25 Controller 26 Transport equipment 28 Magnetic Head 29A magnetic layer 29B base film 29C Backcoat layer 30, SW5 Processing equipment 30A control unit 30B Position detection unit 30B1 First position detection unit 30B2 Second position detection unit 31 Surface 32 Storage 34 UI devices 35 Communication Interface 36 Sending motor 37 External device 38,SW2 Take-up reel 39A First detection circuit 39B Second detection circuit 40M Winding motor 42 Magnetic element unit 44 Holder 46 Contactless reading and writing device 48 Moving mechanism 48A Moving Actuator 49 Tilt mechanism 49A Tilt Actuator 50, 56, 70, 76, 82, 88, 560 frames 52, 52A, 52B, 58, 58A, 58B, 72, 72A, 72B, 78, 78A, 78B, 84, 84A, 84B, 90, 90A, 90B, 580, 580A, 580B Servo Pattern 54, 54A, 54B, 60, 60A, 60B, 74, 74A, 74B, 86, 86A, 86B, 92, 92A, 92B, 600, 600A, 600B Linear magnetization region pair 54A1,54A2,54B1,54B2,60A1,60A2,60B1,60B2,74A1,74A2,74B1,74B2,80A1,80A2 ,80A3,86A1,86A2,86B1,86B2,92A1,92A2,92B1,92B2,600A1,600A2,600B1,600B2 linear magnetization region 54A1a,54A2a,54B1a,54B2a,60A1a,60A2a,60B1a,60B2a,86A1a,86A2a,86B1a,86B2a,600A1a,600A2a,600B1a,600B2a Magnetization straight line 62 Virtual Linear Area Pair 62A, 62B Virtual linear area 62A1,62B1 straight line 66,66A,66B,66C Ideal waveform signal 68 Virtual Linear Pairs 68A, 68B Virtual linear area 80,80A,80B Linear magnetization region group 99 Location Identification Information 100 Compatibility Information 102 Position threshold information 200 computers 200A Processor 200B NVM 200C RAM 200D Bus 202 Storage medium A, B, C arrows a, b, α, β angles VH Verify Head C1, C2, C3, C4 Virtual lines DB, DB1, DB2 data band DRW Data read / write element GR guide roller Int1,Int2 interval L0, L1, L2 line segments LD Longitudinal direction LD1,WD1 direction MF magnetic field MT,MT magnetic tape O1,O2 center PG Servo pattern detection program RA rotation axis S1 First servo band signal S1a,S1c 1st linear magnetization region signal S1A, S1B servo pattern signal S1b,S1d 2nd linear magnetization region signal S2 Second servo band signal SA1, SA2 symmetry axis SB, SB1, SB2, SB3 servo band SR, SR1, SR2 servo read element SW Servo Writer SW3 drive unit SW4 Pulse signal generator SW6 Guide SW7 transport path WD Width direction WH servo pattern recording head

Claims

1. a processor; The processor: a servo band signal obtained by reading a servo band recorded on a magnetic tape by a servo read element, the servo band being read from the magnetic tape, and the servo band signal being compared with a threshold value to detect a servo pattern signal indicating the servo pattern; the threshold value is determined according to an angle formed by the servo pattern and the servo read element, the servo pattern is at least one pair of linear magnetized regions, the pair of linear magnetization regions is a linearly magnetized first linear magnetization region and a linearly magnetized second linear magnetization region, the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first virtual line extending along the width direction of the magnetic tape, the angles are classified into a first angle formed by the first linear magnetization region and the servo read element, and a second angle formed by the second linear magnetization region and the servo read element; The thresholds are classified into a first threshold and a second threshold, the first threshold is determined according to the first angle, The second threshold is determined according to the second angle. Detection device.

2. The threshold value is a variable value that changes depending on the angle. The detection device according to claim 1 .

3. the threshold value is changed while the magnetic tape is running; The processor stores, in a storage medium, specific information for identifying a position on the magnetic tape where the threshold value has been changed and the threshold value changed at the position in association with each other. The detection device according to claim 2 .

4. The magnetic tape is housed in a cartridge, The cartridge is provided with a contactless storage medium as the storage medium, which can communicate with the processor in a contactless manner. The detection device according to claim 3 .

5. The storage medium is the magnetic tape. The detection device according to claim 3 .

6. The processor: deriving the threshold value corresponding to the changed angle on the condition that the angle has been changed; The servo pattern signal is detected by comparing the derived threshold value with the servo band signal. The detection device according to any one of claims 1 to 5.

7. A detection device according to any one of claims 1 to 6; an inspection processor that inspects a servo band on the magnetic tape where the servo pattern is recorded, based on the servo pattern signal detected by the detection device; An inspection device comprising:

8. a memory storing the threshold value to be compared with the servo band signal by the processor included in the detection device according to any one of claims 1 to 6; the magnetic tape; A magnetic tape cartridge comprising:

9. 7. A magnetic tape on which the threshold value to be compared with the servo band signal by the processor included in the detection device according to claim 1 is stored.

10. The data band is formed, The threshold value is stored in the data band.

10. The magnetic tape of claim 9.

11. the threshold value is changed while the magnetic tape is running; The threshold value is stored in an area in the data band corresponding to the position where the threshold value has been changed.

11. The magnetic tape of claim 10.

12. A magnetic tape cartridge containing the magnetic tape according to any one of claims 9 to 11.

13. A detection device according to any one of claims 1 to 6; a magnetic head that operates in accordance with the servo pattern signal detected by the detection device; A magnetic tape drive comprising:

14. a magnetic tape drive including the detection device according to any one of claims 1 to 6 and a magnetic head that operates in accordance with the servo pattern signal detected by the detection device; a magnetic tape that is magnetically processed by the magnetic head; A magnetic tape system comprising:

15. Obtaining a servo band signal resulting from reading the servo band by a servo read element from a magnetic tape having a servo band on which a servo pattern is recorded; and detecting a servo pattern signal indicative of the servo pattern by comparing the acquired servo band signal with a threshold value; the threshold value is determined according to an angle formed by the servo pattern and the servo read element, the servo pattern is at least one pair of linear magnetized regions, the pair of linear magnetization regions is a linearly magnetized first linear magnetization region and a linearly magnetized second linear magnetization region, the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first virtual line extending along the width direction of the magnetic tape, the angles are classified into a first angle formed by the first linear magnetization region and the servo read element, and a second angle formed by the second linear magnetization region and the servo read element; The thresholds are classified into a first threshold and a second threshold, the first threshold is determined according to the first angle, The second threshold is determined according to the second angle. Detection Method

16. and inspecting a servo band on the magnetic tape where the servo pattern is recorded, based on the servo pattern signal detected by the detection method according to claim 15. Testing method.

17. A program for causing a computer to execute a process, The process comprises: Obtaining a servo band signal resulting from reading the servo band by a servo read element from a magnetic tape having a servo band on which a servo pattern is recorded; and detecting a servo pattern signal indicative of the servo pattern by comparing the acquired servo band signal with a threshold value; the threshold value is determined according to an angle formed by the servo pattern and the servo read element, the servo pattern is at least one pair of linear magnetized regions, the pair of linear magnetization regions is a linearly magnetized first linear magnetization region and a linearly magnetized second linear magnetization region, the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first virtual line extending along the width direction of the magnetic tape, the angles are classified into a first angle formed by the first linear magnetization region and the servo read element, and a second angle formed by the second linear magnetization region and the servo read element; The thresholds are classified into a first threshold and a second threshold, the first threshold is determined according to the first angle, The second threshold is determined according to the second angle. program.

Images