Tape reel, tape unit, storage system, and write servo drive system

Abstract

The embodiment of the invention provides a tape reel, a tape unit, a storage system and a write servo driving system, relates to the field of storage, and is used for providing a servo pattern suitable for high-speed rotation of a tape. The servo pattern comprises the first servo stripe, the second servo stripe and the third servo stripe, the first servo stripe is parallel to the third servo stripe, the inclination angle of the servo stripes is small, the transverse size of the servo pattern can be reduced, the frame rate of the magnetic tape unit is improved, and the servo pattern is suitable for high-speed scenes. In addition, the servo position information can be obtained through three servo stripes, the number of times of repetition of the servo stripes is small, multiple servo peak searching is not needed, the calculation overhead is small, the resolving speed is high, and the method can be suitable for rapid resolving of a high-speed scene. And the trajectory of the second servo stripe is a curve, the curve has different slopes at different positions, and the position calculation precision is higher at the position with the smaller slope, so that the precision same as or better than that of a traditional servo can be achieved by using fewer stripes, and the calculation precision is ensured.

Description

Technical Field

[0001] This application relates to the field of storage, and more particularly to a magnetic tape disk, a magnetic tape drive, a storage system, and a write servo drive system. Background Technology

[0002] Due to its low cost and low energy consumption, magnetic tape storage is still widely used as a storage method for long-term offline archiving. Based on linear tape open (LTO) magnetic tape storage technology, during the movement of the magnetic tape, the magnetic head is controlled to move relative to the width of the tape to determine the read or write position for reading or writing operations, and the determination of the magnetic head position depends on the servo pattern in the magnetic tape.

[0003] However, current servo patterns are complex to design and require a large amount of computation to obtain the position of the magnetic head. They are only suitable for low-speed rotation scenarios and cannot meet the requirements in high-speed rotation scenarios. Summary of the Invention

[0004] This application provides a magnetic tape, a magnetic tape drive, a storage system, and a write servo drive system for providing a servo pattern suitable for high-speed magnetic tape rotation.

[0005] A first aspect of this application provides a magnetic tape reel, which includes a reel and a magnetic tape wound on the reel. The magnetic tape includes a tape body and a servo pattern, the servo pattern being disposed on the tape body. The servo pattern includes a first servo stripe, a second servo stripe, and a third servo stripe; the first servo stripe, the second servo stripe, and the third servo stripe are arranged sequentially along a first direction; the two ends of the first servo stripe, the two ends of the second servo stripe, and the two ends of the third servo stripe are respectively located on both sides of the servo pattern along a second direction. The first servo stripe and the third servo stripe are parallel; the trajectory of the second servo stripe is a curve, and the distance from each position of the second servo stripe to the third servo stripe is unequal; the first direction is the length direction of the magnetic tape medium, and the second direction is the width direction of the magnetic tape medium.

[0006] In the magnetic tape provided in this application embodiment, the servo pattern includes a first servo stripe, a second servo stripe, and a third servo stripe. The first and third servo stripes are parallel. Compared to a non-parallel arrangement of the first and third servo stripes, under the same detection accuracy and servo pattern width (dimension in the second direction), the parallel arrangement of the first and third servo stripes results in fewer tilt angles in the servo pattern, reducing the size of the servo pattern along the first direction (lateral distance) and improving the frame rate of the tape drive, making it suitable for high-speed scenarios. Furthermore, servo position information can be obtained using only three servo stripes. The fewer repetitions of the servo stripes, the less need for multiple servo peak finding, resulting in lower computational overhead and higher calculation speed, making it suitable for rapid calculation in high-speed scenarios. Moreover, the trajectory of the second servo stripe is a curve with different slopes (large lateral distance variations) at different positions. Positions with smaller slopes have higher accuracy, thus requiring fewer stripes to achieve the same or better accuracy as traditional servos, ensuring computational accuracy.

[0007] In one possible implementation, the first servo stripe is parallel to the second direction. This reduces the size of the servo pattern in the first direction, reduces the time required for each servo pattern, increases space utilization, improves the tape drive's frame rate, and enables higher frequency servo control.

[0008] In one possible implementation, the trajectory of the curve satisfies a preset functional relationship. The trajectory of the second servo stripe also satisfies this preset functional relationship, which facilitates the establishment of a conversion formula between the second servo stripe and the longitudinal displacement of the servo head, thus simplifying the computation.

[0009] In one possible implementation, the curve's trajectory includes portions satisfying a first preset functional relationship and portions satisfying a second preset functional relationship. This allows adjustment of the second servo stripe's trajectory, ensuring that the slope at each position of the second servo stripe is relatively small, thereby improving the accuracy of position calculation.

[0010] In one possible implementation, the trajectory of the curve satisfies a tangent function relationship. The slope of the trajectory formed by the tangent function is smaller in the middle region, thus improving the detection accuracy in the middle region.

[0011] In one possible implementation, the servo pattern further includes a fourth servo stripe, which is parallel to the first servo stripe. The fourth servo stripe is positioned on the side of the first servo stripe away from the second servo stripe, and the spacing between the fourth servo stripe and the first servo stripe is either a first preset value or a second preset value. By adding a fourth servo stripe to the servo pattern, bit encoding can be performed on the servo pattern to determine the lateral position of the magnetic head on the magnetic tape. Moreover, since the fourth servo stripe is positioned at the edge of the servo pattern, it is not limited by the positional relationship between the first, second, and third servo stripes. Therefore, a larger spacing can be used for bit encoding. That is, the values ​​of the first and second preset values ​​can be larger, and the difference between the first and second preset values ​​can be greater, allowing for larger tolerances and higher recognition accuracy, making it suitable for high-speed scenarios. Furthermore, with the addition of the fourth servo stripe, the movement speed of the magnetic head can be obtained based on the spacing between the fourth and first servo stripes, and the movement speed can be obtained based on the spacing between the first and third servo stripes, with the two movement speeds averaged. This is equivalent to repeatedly measuring the movement speed of the magnetic head to improve the accuracy of speed detection.

[0012] In one possible implementation, the fourth servo stripe of an adjacent servo pattern is the same as the third servo stripe. Adjacent servo patterns sharing a servo stripe can improve the space utilization of the tape body and optimize the control bandwidth of the tape drive.

[0013] In one possible implementation, one end of the second servo stripe is connected to the first servo stripe, and the other end is connected to the third servo stripe. That is, the servo pattern is an integrated structure. This integrated servo stripe allows the first, second, and third servo stripes to be written synchronously onto the tape, reducing the write servo distance control error caused by asynchronous writing errors of parallel stripes, improving speed estimation accuracy, and thus improving the accuracy of servo resolution results. Furthermore, the integrated servo stripe can further reduce the size of the servo pattern in the first direction, increasing the tape drive's frame rate and optimizing the tape drive's control bandwidth.

[0014] In one possible implementation, the servo pattern further includes a fifth servo stripe, which is adjacent to and parallel to the second servo stripe. The spacing between the fifth and second servo stripes is a third or fourth preset value. By adding a fifth servo stripe to the servo pattern, bit-level encoding can be performed on the servo pattern to determine the lateral position of the magnetic head on the magnetic tape. Moreover, since the servo pattern includes a small number of servo stripes, there is a relatively large space left for encoding within the same lateral dimension. Therefore, a larger spacing can be used for bit-level encoding. That is, the values ​​of the third and fourth preset values ​​can be larger, and the difference between the third and fourth preset values ​​can be greater, allowing for larger tolerances and higher recognition accuracy, making it suitable for high-speed scenarios. Furthermore, after adding the fifth servo stripe, the longitudinal displacement of the servo head can be calculated by combining the spacing between the fifth and first servo stripes and the spacing between the second and first servo stripes, thereby improving the detection accuracy of the longitudinal displacement.

[0015] In one possible implementation, the first servo stripe comprises multiple parallel first sub-servo stripes, the second servo stripe comprises multiple parallel second sub-servo stripes, and the third servo stripe comprises multiple third sub-servo stripes. By repeating each servo stripe multiple times, the average movement speed of the read / write head can be calculated from multiple sets of repeated stripes. This is equivalent to repeatedly measuring the movement speed of the read / write head to improve the accuracy of speed detection.

[0016] In one possible implementation, the spacing between a group of adjacent first sub-servo stripes in a plurality of parallel first sub-servo stripes is a fifth or a sixth preset value. The servo pattern can be encoded by adjusting the spacing between adjacent first sub-servo stripes. Furthermore, since the servo pattern includes a small number of servo stripes, the remaining space for encoding is relatively large for the same lateral dimension. Compared to displacing specific stripes only within a limited space of the pattern, the servo pattern of this application can use a larger spacing to encode the lateral positions of "1" and "0", allowing for greater differences between preset values, a larger tolerance for error, and higher recognition accuracy, thus meeting the accuracy requirements of high-speed scenarios.

[0017] In one possible implementation, the spacing between a set of adjacent second sub-servo stripes in a plurality of parallel second sub-servo stripes is a seventh or eighth preset value. The servo pattern can be encoded by adjusting the spacing between adjacent second sub-servo stripes. Furthermore, since the servo pattern includes a small number of servo stripes, the remaining space for encoding is relatively large for the same lateral dimension. Compared to displacing specific stripes only within a limited space of the pattern, the servo pattern of this application can use a larger spacing to encode the lateral positions of "1" and "0", allowing for greater differences between preset values, a larger tolerance for error, and higher recognition accuracy, thus meeting the accuracy requirements of high-speed scenarios.

[0018] In one possible implementation, the spacing between a group of adjacent third sub-servo stripes in a plurality of parallel third sub-servo stripes is a ninth or tenth preset value. The servo pattern can be encoded by adjusting the spacing between adjacent third sub-servo stripes. Furthermore, since the servo pattern includes a small number of servo stripes, the remaining space for encoding is relatively large for the same lateral dimension. Compared to displacing specific stripes only within a limited space of the pattern, the servo pattern of this application can use a larger spacing to encode the lateral positions of "1" and "0", allowing for greater differences between preset values, a larger tolerance for error, and higher recognition accuracy, thus meeting the accuracy requirements of high-speed scenarios.

[0019] In one possible implementation, along the width direction of the first servo stripe, the first servo stripe is half first polarity and half second polarity; the first polarity and the second polarity are opposite poles (north and south). By making the servo stripe in the servo pattern have a magnetic distribution state with half north and half south poles, the magnetization density of the servo pattern can be increased.

[0020] In one possible implementation, along the width direction of the second servo stripe, the second servo stripe is half first polarity and half second polarity; the first polarity and the second polarity are opposite poles. By making the servo stripe in the servo pattern have a magnetic distribution state with half north and half south poles, the magnetization density of the servo pattern can be increased.

[0021] In one possible implementation, along the width direction of the third servo stripe, the third servo stripe is half first polarity and half second polarity; the first polarity and the second polarity are opposite poles. By making the servo stripe in the servo pattern have a magnetic distribution state with half north and half south poles, the magnetization density of the servo pattern can be increased.

[0022] A second aspect of the embodiments of this application provides a magnetic tape drive, which includes a magnetic tape reel and a magnetic head system, the magnetic head system being used to perform a read operation on a servo pattern; the magnetic tape reel includes any of the magnetic tape reels of the first aspect.

[0023] The magnetic tape drive provided in the second aspect of the embodiments of this application includes the magnetic tape reel of the first aspect, and its beneficial effects are the same as those of the magnetic tape reel, which will not be repeated here.

[0024] A third aspect of the embodiments of this application provides a storage system, the storage system including a processor and a plurality of magnetic tape drives, the processor being coupled to each magnetic tape drive respectively; the magnetic tape drives include those of the second aspect.

[0025] A fourth aspect of this application provides a write servo drive system, comprising: a drive unit for outputting a drive signal; and a servo write head for writing a servo pattern under the drive signal. The servo pattern includes a first servo stripe, a second servo stripe, and a third servo stripe. The first servo stripe, the second servo stripe, and the third servo stripe are arranged sequentially along a first direction. The two ends of the first servo stripe, the two ends of the second servo stripe, and the two ends of the third servo stripe are respectively located on both sides of the servo pattern along a second direction. The first servo stripe and the third servo stripe are parallel. The trajectory of the second servo stripe is a curve, and the distances from each position of the second servo stripe to the third servo stripe are unequal. The first direction is the length direction of the magnetic tape medium, and the second direction is the width direction of the magnetic tape medium.

[0026] The write servo drive system provided in the fourth aspect of the embodiments of this application is used to form the magnetic tape disk of the first aspect, and its beneficial effects are the same as those of the magnetic tape disk, which will not be repeated here.

[0027] In one possible implementation, the first servo stripe is parallel to the second direction.

[0028] In one possible implementation, the trajectory of the curve satisfies a predefined functional relationship.

[0029] In one possible implementation, the trajectory of the curve includes a portion satisfying a first preset functional relationship and a portion satisfying a second preset functional relationship. In another possible implementation, the trajectory of the curve satisfies a tangent function relationship.

[0030] In one possible implementation, the servo pattern further includes a fourth servo stripe, which is parallel to the first servo stripe; the fourth servo stripe is located on the side of the first servo stripe away from the second servo stripe, and the spacing between the fourth servo stripe and the first servo stripe is a first set value or a second set value.

[0031] In one possible implementation, the fourth servo stripe of an adjacent servo pattern is the same servo stripe as the third servo stripe.

[0032] In one possible implementation, one end of the second servo stripe is connected to the first servo stripe, and the other end of the second servo stripe is connected to the third servo stripe.

[0033] In one possible implementation, the servo pattern further includes a fifth servo stripe, which is adjacent to and parallel to the second servo stripe, and the spacing between the fifth servo stripe and the second servo stripe is a third or fourth set value.

[0034] In one possible implementation, the first servo stripe includes multiple parallel first sub-servo stripes, the second servo stripe includes multiple parallel second sub-servo stripes, and the third servo stripe includes multiple third sub-servo stripes.

[0035] In one possible implementation, the spacing between a set of adjacent first sub-servo stripes in a plurality of parallel first sub-servo stripes is a fifth or a sixth set value.

[0036] In one possible implementation, the spacing between a set of adjacent second sub-servo stripes in a plurality of parallel second sub-servo stripes is a seventh or eighth set value.

[0037] In one possible implementation, the spacing between a set of adjacent third sub-servo stripes in a plurality of parallel third sub-servo stripes is a ninth or tenth set value. Attached Figure Description

[0038] Figure 1 This application provides a schematic diagram of the structure of a storage system according to an embodiment of the present application.

[0039] Figure 2 This is a schematic diagram of the structure of a magnetic tape drive provided in an embodiment of this application;

[0040] Figure 3 This is a schematic diagram of the structure of a magnetic tape disk provided in an embodiment of this application;

[0041] Figure 4 A partial structural diagram of a magnetic tape provided in an embodiment of this application;

[0042] Figure 5A A schematic diagram of a servo pattern provided in an embodiment of this application;

[0043] Figure 5B A schematic diagram of the geometric relationship of a servo pattern provided in an embodiment of this application;

[0044] Figure 5C A schematic diagram of a servo pattern encoding provided in an embodiment of this application;

[0045] Figure 6 A schematic diagram of another servo pattern provided in an embodiment of this application;

[0046] Figures 7A-7DA schematic diagram of a servo pattern provided in an embodiment of this application;

[0047] Figures 8A-8D A schematic diagram of another servo pattern provided in an embodiment of this application;

[0048] Figures 9A-9D A schematic diagram of yet another servo pattern provided in an embodiment of this application;

[0049] Figures 10A-10D A schematic diagram of yet another servo pattern provided in an embodiment of this application;

[0050] Figure 11 and Figure 12 A schematic diagram of yet another servo pattern provided in an embodiment of this application;

[0051] Figure 13A and Figure 13B A schematic diagram of a servo pattern encoding provided in an embodiment of this application;

[0052] Figure 14A and Figure 14B A schematic diagram illustrating the encoding of another servo pattern provided in an embodiment of this application;

[0053] Figure 15A and Figure 15B A schematic diagram of yet another servo pattern provided in an embodiment of this application;

[0054] Figure 16A and Figure 16B A schematic diagram of yet another servo pattern provided in an embodiment of this application;

[0055] Figure 17 A schematic diagram of yet another servo pattern provided in an embodiment of this application;

[0056] Figure 18A and Figure 18B A schematic diagram of yet another servo pattern provided in an embodiment of this application;

[0057] Figure 19 A schematic diagram of a magnetic tape structure provided in an embodiment of this application;

[0058] Figure 20A and Figure 20B This is a schematic diagram of another magnetic tape structure provided in an embodiment of this application. Detailed Implementation

[0059] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0060] Hereinafter, the terms "second," "first," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "second," "first," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0061] Furthermore, in the embodiments of this application, directional terms such as "upper," "lower," "left," and "right" may be defined relative to the orientation in which the components are schematically placed in the accompanying drawings. It should be understood that these directional terms can be relative concepts, used for relative description and clarification, and can change accordingly based on the orientation of the components in the accompanying drawings.

[0062] In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, the term "coupled connection" can be a direct electrical connection or an indirect electrical connection through an intermediate medium. The term "contact" can be direct contact or indirect contact through an intermediate medium.

[0063] In this embodiment of the application, "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0064] To facilitate understanding, the main terms used in this application will be explained first.

[0065] Tape storage: a persistent storage method that uses magnetic tape as a data storage device.

[0066] A tape drive is an economical, reliable, high-capacity, and high-speed storage device, serving as the core of a storage system for data writing and reading. Tape drives employ high-error-correction coding technology and write-after-read channel technology to improve the reliability of data backup. Based on the tape loading method, tape drives are generally divided into manual-loading tape drives and automatic-loading tape drives. Based on the tape drive's form factor, tape drives are generally divided into consumer-grade tape drives and commercial-grade tape drives. Based on the tape drive's height, tape drives are divided into half-height tape drives and full-height tape drives. Full-height tape drives are typically 60mm high, while half-height tape drives are typically 40mm high.

[0067] Magnetic tape: A non-volatile storage medium, a strip of magnetically loaded material used to record sound, images, numbers, text, or other signals. Magnetic tape is typically packaged in a reel. Due to its sequential access characteristics, magnetic tape is used in traditional storage and backup, as well as for sequentially reading and writing large amounts of data. Magnetic tape can also be called a tape body. Optionally, magnetic tape can also be a device comprising a tape body and a reel wound around it.

[0068] A magnetic head (or read / write head) is a component that reads and writes data onto a magnetic tape based on magnetic principles. Magnetic heads are divided into write heads and read heads. Write heads record data by magnetizing the magnetic medium to change its magnetic field. Read heads read data from the magnetic medium by sensing its magnetic field.

[0069] This application provides a storage system for data storage. The storage system may include, for example, tape drives, computer equipment, etc.

[0070] Figure 1 This is a schematic diagram of the structure of a storage system provided in an embodiment of this application.

[0071] This application provides a storage system, such as... Figure 1 As shown, the storage system 100 includes a processor and multiple tape drives 10. The processor generates data and can also control read or write operations on the tape drives 10 according to control signals. The tape drives 10 are used to store the data generated by the processor.

[0072] The processor can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor can also be a graphics processing unit (GPU), a neural network processing unit (NPU), a microprocessor, an ASIC, or one or more integrated circuits used to control the execution of the program according to this application. The processor can be a multi-core (multi-CPU) processor. Here, "processor" can refer to one or more devices, circuits, and / or computing units used to process data (e.g., computer program instructions).

[0073] Due to its low cost and low energy consumption, magnetic tape storage is still widely used as a storage method for long-term offline archiving. The magnetic tape drive 10 is used as a storage unit in the storage system 100.

[0074] Figure 2 This is a schematic diagram of the structure of a magnetic tape drive provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of a magnetic tape disk provided in an embodiment of this application. Figure 4 This is a partial structural diagram of a magnetic tape provided in an embodiment of this application.

[0075] This application provides a magnetic tape drive 10, such as... Figure 2 As shown, the tape drive 10 includes a tape reel 1, a magnetic head system 2, a controller 3, a roller 4, and a housing 5, with the tape reel 1, magnetic head system 2, controller 3, and roller 4 housed inside the housing 5.

[0076] like Figure 3 As shown, the magnetic tape 1 includes a magnetic tape 11 and a reel 12. The magnetic tape 11 is wound on the reel 12 and installed in the magnetic tape drive 10. The magnetic tape 11 is pulled through the magnetic head system 2 by the reel 12 and the roller 4.

[0077] The magnetic head system 2 includes a magnetic head 21 and a magnetic head driver 22. The magnetic head 21 is used to perform read or write operations on the moving magnetic tape 11 under the control of the magnetic head driver 22.

[0078] The controller 3 controls the movement of the head driver 22 according to the control signal, thereby moving the head 21 to perform read operations on the servo area and read or write operations on the data track corresponding to the servo information indicated by the servo area. For example, the controller 3 controls the head 21 to read servo information on the servo area, read data on the data track according to the servo information, or write data on the data track according to the servo information. The control signal can be a gate signal or a square wave pulse signal.

[0079] For example, such as Figure 4 As shown, the magnetic tape 11 includes a tape body 30, which includes servo bands and data bands. Multiple servo bands and data bands sandwiched between the servo bands are distributed along the width of the tape body 30. For example, Figure 4 The following diagram illustrates a servo belt 30 comprising five servo belts and four data belts sandwiched between them. Each servo belt includes multiple servo patterns 40 arranged along a first direction X. Each data belt includes multiple data tracks for recording data, and the servo belts record servo information for these tracks. There is a one-to-one correspondence between the servo locations of the servo belts and the data tracks of the data belts. Figure 4 In the first direction X, the length direction of the magnetic tape 11 is defined, and in the second direction Y, the width direction of the magnetic tape 11 is defined.

[0080] The magnetic head 21 includes a servo head 211, a read head 212, and a write head 213. The servo head 211 is located at both ends, and the read head 212 and the write head 213 are located between the two servo heads 211. The servo head 211 is used to read the servo position of the servo tape, the read head 212 is used to perform a read operation based on the servo position determined by the servo head 211, and the write head 213 is used to perform a write operation based on the servo position determined by the servo head 211.

[0081] For example, when reading and writing are performed on data tape 4, two servo heads 211 located at both ends of the magnetic head 21 read the servo position from servo tape 0 and servo tape 1, respectively. Specifically, when the servo head 211 (a magnetoresistive sensor utilizing the tunneling magnetoresistive effect) on the magnetic head 21 passes through the magnetized servo stripes on the magnetic tape 11, it generates peak and trough signals caused by corresponding changes in magnetic flux. Based on the interval between the peaks, the lateral time interval of the servo stripes can be calculated. Furthermore, based on the geometric relationship of the servo frame stripes, information such as the position of the magnetic head 21 and the running speed of the magnetic tape 11 can be deduced.

[0082] The read head 212 performs a read operation based on the servo position determined by the center line determined by the two servo positions, or the write head 213 performs a write operation based on the servo position determined by the center line determined by the two servo positions.

[0083] In the tape drive 10, the servo pattern 40 provides three key pieces of information: first, the running speed of the tape 11, used to control the smooth operation of the tape 11; second, the cross-track position of the head 21 on the tape, i.e., its position along the second direction Y (the height direction of the servo pattern 40), used to locate the data track; and third, the longitudinal position (LPOS) encoding, which encodes the down-track position, i.e., its position along the first direction X (the running direction of the tape 11, the width direction of the servo pattern 40). Each frame represents a data bit (0 or 1) according to specific rules. Multiple frames are combined into a binary sequence, supplemented by encoding and decoding rules, to represent the lateral position of the head 21 on the tape 11.

[0084] Based on this, the high-precision reading and writing of the tape drive 10 relies on a precise servo detection system to stably maintain the magnetic head 21 within a specific track and control the tape 11 to run stably at a specific speed. The servo control system positions the magnetic head 21 in the longitudinal position and the tape 11's running speed by calculating the servo pattern 40 reserved in the servo stripe on the tape 11. The pattern of the servo stripes in the servo pattern 40, including the stripe shape, width, size, and number, all affect the calculation accuracy of the longitudinal position and speed of the magnetic head 21. A suitable servo pattern 40 helps improve the positioning and speed calculation accuracy of the tape drive 10, ensuring high-density reading and writing.

[0085] Figure 5A This is a schematic diagram of a servo pattern provided in an embodiment of this application. Figure 5B This is a schematic diagram of the geometric relationship of a servo pattern provided in an embodiment of this application. Figure 5C This is a schematic diagram of a servo pattern encoding provided in an embodiment of this application.

[0086] In some embodiments, such as Figure 5A As shown, the servo pattern 40 includes a first stripe group A, a second stripe group B, a third stripe group C, and a fourth stripe group D, with each stripe group including at least 4 servo stripes.

[0087] The servo stripes in the first stripe group A and the third stripe group C are parallel, and the servo stripes in the second stripe group B and the fourth stripe group D are parallel. Taking the second stripe group B and the fourth stripe group D as an example, when the servo head 211 is at any height of the servo pattern 40, the interval d between the second stripe group B and the fourth stripe group D remains constant, thus allowing the calculation of the running speed of the magnetic tape 11.

[0088] The spacing d1 between the first stripe group A and the second stripe group B, or the third stripe group C and the fourth stripe group D, is related to the servo height of the read / write head 21. Therefore, the height of the read / write head 21 can be determined and its position located using the geometric relationship of the servo pattern.

[0089] For example, such as Figure 5B As shown, according to the servo pattern design, the interval between parallel stripe groups (first stripe group A and third stripe group C) is known to be d, the distance d1 between the first stripe group A and the second stripe group B is d / 2, and d2 is the interval (interval between adjacent non-parallel groups) measured by the servo head 211 readback signal. Therefore, δd equals (d1-d2) / 2. Since the tilt angle α of the diagonal stripes is known, the longitudinal displacement y between d2 and d1 can be calculated based on the geometric relationship of triangles, which is the height position of the servo head 211 in the servo pattern 40. Accuracy can be improved by calculating multiple pairs (4 pairs). The formula for calculating the longitudinal displacement y of a complete servo pattern 40 is as follows:

[0090]

[0091] α is the angle between the servo stripe in the second stripe group B and the second direction Y, and d is the interval between the first stripe group A and the third stripe group C. i Let B be the distance from the i-th servo stripe in the first stripe group A to the i-th servo stripe in the second stripe group B. i Let y be the distance from the i-th servo stripe in the first stripe group A to the i-th servo stripe in the third stripe group C, and let y be the longitudinal displacement of the servo head 211.

[0092] like Figure 5C As shown, based on Figure 5A The servo pattern 40 shown changes the distance S between the second and third servo stripes and the fourth servo stripe in the first stripe group A by making a small translation (e.g. ±0.25um) to change the distance S between the second and third servo stripes and the fourth servo stripe. The different positional deviation directions (the magnitude of the distance S) are used to represent 0 and 1 as LPOS encoding.

[0093] Figure 5AIn the servo pattern 40 shown, the servo stripes (figure-eight servo stripes) in the first stripe group A and the second stripe group B are written simultaneously, while the servo stripes in the first stripe group A and the third stripe group C (parallel servo stripes in adjacent stripe groups (bursts)) are written asynchronously. The write servo distance control error caused by asynchronous writing will lead to bias in the servo parsing results. In order to achieve the accuracy requirements, the servo stripes in each stripe group need to be repeated multiple times, which increases the computational overhead and makes it impossible to respond in time in high-speed moving scenarios of tape 11. If the number of servo stripe repetitions is not increased, the tilt angle of the servo stripes needs to be increased. However, the increase in angle leads to an increase in the lateral space occupied by the servo stripes, which in turn leads to a longer lateral dimension of the servo pattern 40 and a longer interval between each output value (vertical displacement and velocity), resulting in slower servo control. In addition, due to the limitation of the spacing between the stripe patterns, the difference in the distance S of LPOS encoding is too small, resulting in insufficient recognition accuracy in high-speed scenarios.

[0094] Figure 6 This is a schematic diagram of another servo pattern provided in an embodiment of this application.

[0095] In some embodiments, such as Figure 6 As shown, the servo pattern 40 includes a first servo stripe 41, a second servo stripe 42, and a third servo stripe 43, and the extension directions of the first servo stripe 41, the second servo stripe 42, and the third servo stripe 43 are different.

[0096] Figure 6 In the servo pattern 40 shown, the extension directions of the first servo stripe 41, the second servo stripe 42, and the third servo stripe 43 are different, resulting in a larger size of the servo pattern 40 in the first direction X. At the same precision, the servo pattern 40 results in a lower frame rate for the tape drive 10, leading to lower bandwidth. Furthermore, when acquiring the servo position, there is no fixed reference distance. The positions of the second servo stripe 42 and the third servo stripe 43 need to be calculated and averaged to obtain a virtual servo stripe (a stripe parallel to the first servo stripe 41) for the next step of calculation. This results in a large computational load when acquiring the servo position, increasing computational overhead and making it unsuitable for high-speed scenarios. Additionally, the asynchronous writing of the first servo stripe 41 and the third servo stripe 43 causes write servo distance control errors, leading to biased servo parsing results.

[0097] Figures 7A-10D This is a schematic diagram of a servo pattern provided in an embodiment of this application.

[0098] In some embodiments, such as Figure 7AAs shown, the servo pattern 40 includes a first servo stripe 41, a second servo stripe 42, and a third servo stripe 43. The first servo stripe 41, the second servo stripe 42, and the third servo stripe 43 are arranged sequentially along the first direction X. That is, the second servo stripe 42 is located between the first servo stripe 41 and the third servo stripe 43.

[0099] Wherein, the first direction X is the length direction of the belt 30. The first direction X can be from left to right as seen in the figure, or from right to left as seen in the figure. Figure 7A This is just an illustration.

[0100] The two ends of the first servo stripe 41 are respectively located on both sides of the servo pattern 40 along the second direction Y. The two ends of the second servo stripe 42 are respectively located on both sides of the servo pattern 40 along the second direction Y. The two ends of the third servo stripe 43 are respectively located on both sides of the servo pattern 40 along the second direction Y. The second direction Y is the width direction of the strip 30. Taking the second servo stripe 42 as an example, the servo pattern 40 has a center line parallel to the first direction X. As long as one end of the second servo stripe 42 is located above the center line and the other end is located below the center line, it belongs to the "two ends of the second servo stripe 42 are respectively located on both sides of the servo pattern 40 along the second direction Y" in the embodiments of this application.

[0101] The first servo stripe 41 and the third servo stripe 43 are parallel, and along the first direction X, the distance d from each position of the third servo stripe 43 to the first servo stripe 41 is equal. Fluctuations within the process error range (±5°) are considered parallelism in this embodiment.

[0102] In some embodiments, the first servo stripe 41 and the third servo stripe 43 are straight lines. Alternatively, in other embodiments, the first servo stripe 41 and the third servo stripe 43 are curves. The first servo stripe 41 and the third servo stripe 43 simply need to be parallel.

[0103] For example, such as Figures 7A-7D As shown, the first servo stripe 41 and the third servo stripe 43 are not parallel to the second direction Y. This can improve the calculation accuracy of the longitudinal displacement y of the servo head 211.

[0104] like Figures 7A-8D As shown, the tilt direction of the first servo stripe 41 and the third servo stripe 43 can be any direction, as long as it is not parallel to the second direction Y.

[0105] Or, for example, such as Figures 9A-9DAs shown, the first servo stripe 41 and the third servo stripe 43 are parallel to the second direction Y. This reduces the size of the servo pattern 40 in the first direction X, reduces the time occupied by each servo pattern 40, increases space utilization, improves the frame rate of the tape drive 10, supports higher frequency servo control, and achieves higher vertical stripe peak finding accuracy.

[0106] In some embodiments, the trajectory of the second servo stripe 42 is a curve along the first direction X, and the distance A from each position of the second servo stripe 42 to the third servo stripe 43 is not equal. Alternatively, the distance from each position of the second servo stripe 42 to the first servo stripe 41 is not equal. That is, the value of the distance A from each position of the second servo stripe 42 to the third servo stripe 43 is unique, so that the value of the longitudinal displacement y obtained through the distance A has a one-to-one correspondence with the data track of the data tape.

[0107] In this embodiment, the curve trajectory of the second servo stripe 42 is not limited, as long as the distance A from each position of the second servo stripe 42 to the first servo stripe 41 is not equal.

[0108] In some embodiments, the curve trajectory of the second servo stripe 42 satisfies a preset functional relationship. After the functional relationship is fixed, the second servo stripe 42 can be the entire curve corresponding to the functional relationship, or it can be a segment of the curve corresponding to the functional relationship.

[0109] For example, the curve trajectory of the second servo stripe 42 satisfies a preset functional relationship.

[0110] For example, such as Figure 9A As shown, the curve trajectory of the second servo stripe 42 satisfies the circular arc function relationship.

[0111] Or, for example, such as Figure 9B As shown, the curve trajectory of the second servo stripe 42 satisfies the hyperbolic function relationship.

[0112] Or, for example, such as Figure 9C As shown, the curve trajectory of the second servo stripe 42 satisfies an exponential function relationship.

[0113] Or, for example, such as Figure 9D As shown, the curve trajectory of the second servo stripe 42 satisfies the tangent function relationship.

[0114] The curve trajectory of the second servo stripe 42 satisfies the preset function relationship, which makes it easy to establish the conversion formula between the longitudinal displacement of the second servo stripe 42 and the servo head 211, and can simplify the calculation.

[0115] In other examples, the trajectory of the second servo stripe 42 curve satisfies multiple preset functional relationships. For instance, the trajectory of the second servo stripe 42 curve includes portions that satisfy a first preset functional relationship and portions that satisfy a second preset functional relationship. This ensures that the slope at each position of the second servo stripe 42 is relatively small, improving the accuracy of position calculation.

[0116] In some embodiments, such as Figures 7A-9D As shown, the two ends of the second servo stripe 42 are not connected to the first servo stripe 41 and the third servo stripe 43.

[0117] In other embodiments, one end of the second servo stripe 42 is connected to the first servo stripe 41. Alternatively, one end of the second servo stripe 42 is connected to the third servo stripe 43.

[0118] In some other embodiments, such as Figures 10A-10D As shown, one end of the second servo stripe 42 is connected to the first servo stripe 41, and the other end of the second servo stripe 42 is connected to the third servo stripe 43. That is, the first servo stripe 41, the second servo stripe 42, and the third servo stripe 43 are a single integrated structure. For example, servo pattern writing technology can be used to form the servo pattern 40.

[0119] The integrated servo stripes enable the first servo stripe 41, the second servo stripe 42, and the third servo stripe 43 to be written synchronously onto the tape body 30. This reduces the write servo distance control error caused by asynchronous writing errors of parallel stripes, improves speed estimation accuracy, and thus improves the accuracy of servo parsing results. In addition, the integrated servo stripes can further reduce the size of the servo pattern 40 in the first direction X, increase the frame rate of the tape drive 10, and optimize the bandwidth of the tape drive 10.

[0120] In some embodiments, the first servo stripe 41 includes n parallel first sub-servo stripes, the second servo stripe 42 includes n parallel second sub-servo stripes, and the third servo stripe 43 includes n third sub-servo stripes. n is an integer greater than or equal to 1.

[0121] For example, such as Figure 10A As shown, n=1, the first servo stripe 41 is the first sub-servo stripe, the second servo stripe 42 is the second sub-servo stripe, and the third servo stripe 43 is the third sub-servo stripe.

[0122] Figure 11 and Figure 12 This is a schematic diagram of yet another servo pattern provided in an embodiment of this application.

[0123] Or, for example, such as Figure 11As shown, n = 2. The first servo stripe 41 includes two parallel first sub-servo stripes 411, the second servo stripe 42 includes two parallel second sub-servo stripes 421, and the third servo stripe 43 includes two parallel third sub-servo stripes 431.

[0124] Or, for example, such as Figure 12 As shown, n = 3. The first servo stripe 41 includes 3 parallel first sub-servo stripes 411, the second servo stripe 42 includes 3 parallel second sub-servo stripes 421, and the third servo stripe 43 includes 3 parallel third sub-servo stripes 431.

[0125] The embodiments of this application do not limit the value of n. The embodiments of this application are merely an example and not an exhaustive list.

[0126] By repeating each servo stripe multiple times, the average moving speed of the read / write head 21 can be calculated from multiple sets of repeating stripes. This is equivalent to repeatedly measuring the moving speed of the read / write head 21, thereby improving the accuracy of speed detection. In addition, multiple sets of sub-stripes can be written simultaneously based on the same template, eliminating servo write errors and not affecting the accuracy of speed detection.

[0127] Based on the servo pattern 40 provided in the embodiments of this application, when the magnetic head 21 passes through the servo pattern 40, the fixed interval between the first servo stripe 41 and the third servo stripe 43 can be used to solve the moving speed V, and the interval between the first servo stripe 41 and the second servo stripe 42 can be used to solve the longitudinal displacement y of the servo head 211.

[0128]

[0129] Where d is the fixed spacing between the first servo stripe 41 and the third servo stripe 43, n is the number of sub-servo stripes included in each servo stripe, fs is the sampling rate of the magnetic head 21 = 1 / the time interval between two sampling points, and B i It is the distance from the i-th first sub-servo stripe 411 in the first servo stripe 41 to the i-th third sub-servo stripe 431 in the third servo stripe 43.

[0130] The curve trajectory of the second servo stripe 42 satisfies Figure 10A When the circular arc function relationship is shown:

[0131]

[0132] Where d is the fixed spacing between the first servo stripe 41 and the third servo stripe 43, and A i B is the distance from the i-th second sub-servo stripe 421 in the second servo stripe 42 to the i-th first sub-servo stripe 411 in the first servo stripe 41. iLet n be the distance from the i-th first sub-servo stripe 411 in the first servo stripe 41 to the i-th third sub-servo stripe 431 in the third servo stripe 43, and n be the number of sub-servo stripes included in each servo stripe.

[0133] The curve trajectory of the second servo stripe 42 satisfies Figure 10B The hyperbolic function relationship shown is as follows:

[0134]

[0135] Where d is the fixed spacing between the first servo stripe 41 and the third servo stripe 43, and A i B is the distance from the i-th second sub-servo stripe 421 in the second servo stripe 42 to the i-th third sub-servo stripe 431 in the third servo stripe 43. i Let be the distance from the i-th first sub-servo stripe 411 in the first servo stripe 41 to the i-th third sub-servo stripe 431 in the third servo stripe 43, where a is the real semi-axis of the hyperbola, b is the imaginary semi-axis of the hyperbola, and n is the number of sub-servo stripes included in each servo stripe.

[0136] The curve trajectory of the second servo stripe 42 satisfies Figure 10C When the exponential function relationship is shown:

[0137]

[0138] Where e is a mathematical constant in the exponential function, the central axis of the second servo stripe 42 is the midpoint between the first servo stripe 41 and the third servo stripe 43, and A i B is the distance from the i-th second sub-servo stripe 421 in the second servo stripe 42 to the i-th third sub-servo stripe 431 in the third servo stripe 43. i d is the distance from the i-th first sub-servo stripe 411 in the first servo stripe 41 to the i-th third sub-servo stripe 431 in the third servo stripe 43, d is the fixed spacing between the first servo stripe 41 and the third servo stripe 43, and n is the number of sub-servo stripes included in each servo stripe.

[0139] The curve trajectory of the second servo stripe 42 satisfies Figure 10D When the tangent function relationship is shown:

[0140]

[0141] Where amp is the amplification factor, which depends on the desired height of the servo stripe; w is the angular frequency of the trigonometric function, which controls the curvature and width of the curve; A iB is the distance from the i-th second sub-servo stripe 421 in the second servo stripe 42 to the i-th third sub-servo stripe 431 in the third servo stripe 43. i d is the distance from the i-th first sub-servo stripe 411 in the first servo stripe 41 to the i-th third sub-servo stripe 431 in the third servo stripe 43, d is the fixed spacing between the first servo stripe 41 and the third servo stripe 43, and n is the number of sub-servo stripes included in each servo stripe.

[0142] The servo pattern 40 provided in this embodiment includes a first servo stripe 41, a second servo stripe 42, and a third servo stripe 43. The first servo stripe 41 and the third servo stripe 43 are parallel. Compared to a non-parallel servo stripe 43, under the same detection accuracy and servo pattern 40 width (the dimension in the second direction Y), the parallel arrangement of the first servo stripe 41 and the third servo stripe 43 results in fewer tilt angles in the servo pattern 40, which can reduce the dimension (lateral distance) of the servo pattern 40 along the first direction X, thereby increasing the frame rate of the tape drive 10 and making it suitable for high-speed scenarios. Furthermore, servo position information can be obtained through three servo stripes. The fewer repetitions of the servo stripes, the less need for multiple servo peak finding, resulting in lower computational overhead and higher calculation speed, making it suitable for fast calculation in high-speed scenarios. Moreover, the trajectory of the second servo stripe 42 is a curve with different slopes (large lateral distance variations) at different positions. The smaller the slope, the higher the position calculation accuracy. Therefore, fewer stripes can be used to achieve the same or better accuracy as traditional servos, ensuring computational accuracy.

[0143] Figure 13A and Figure 13B This is a schematic diagram of the encoding of a servo pattern provided in an embodiment of this application.

[0144] Regarding the structure of the first sub-servo stripe 411 in servo pattern 40:

[0145] In some embodiments, such as Figure 13A As shown, among the multiple parallel first sub-servo stripes 411, a fifth set value S5 is set between a group of adjacent first sub-servo stripes 411. At this time, the servo pattern 40 represents the first code, for example, the first code is "1".

[0146] Or, such as Figure 13B As shown, among the multiple parallel first sub-servo stripes 411, a set of adjacent first sub-servo stripes 411 have a spacing of a sixth set value S6. At this time, the servo pattern 40 represents the second code, for example, the second code is "0".

[0147] The aforementioned set of adjacent first sub-servo stripes 411 can be any two adjacent first sub-servo stripes 411 within the first servo stripes 41. Figure 13A and Figure 13B This is for illustrative purposes only.

[0148] The fifth setting value S5 can be greater than the sixth setting value S6, or the fifth setting value S5 can be less than the sixth setting value S6, as long as the fifth setting value S5 and the sixth setting value S6 are not equal. Figure 13A and Figure 13B The example given is that the fifth setting value S5 is greater than the sixth setting value S6. The code is "1" when the spacing between the first sub-servo stripes 411 is the fifth setting value S5, and "0" when the spacing between the first sub-servo stripes 411 is the sixth setting value S6. The codes can also be interchanged.

[0149] That is, when the servo pattern 40 provided in this application embodiment is applied to the magnetic tape 11, each servo tape of the tape body 30 is provided with multiple sets of servo patterns 40. The spacing between a set of adjacent first sub-servo stripes 411 in the servo pattern 40 is a fifth set value S5 or a sixth set value S6. The value of the spacing between the set of adjacent first sub-servo stripes 411 in different servo patterns 40 may be different. The specific value of the spacing between the first sub-servo stripes 411 in the servo pattern 40 is related to the encoding of the servo tape.

[0150] at this time, Figure 13A and Figure 13B In the servo pattern 40 shown, the spacing between the other adjacent first sub-servo stripes 411 is the same set value. This set value can be equal to the fifth set value S5 or the sixth set value S6, or it can be different from both the fifth set value S5 and the sixth set value S6.

[0151] In other embodiments, the spacing between adjacent first sub-servo stripes 411 is a set value in both the servo pattern 40 coded with "1" and the coded "0". The coded "1" and the coded "0" are distinguished by the second sub-servo stripe 421 or the third sub-servo stripe 431.

[0152] Figure 14A and Figure 14B This is a schematic diagram of the encoding of another servo pattern provided in an embodiment of this application.

[0153] Regarding the structure of the second sub-servo stripe 421 in servo pattern 40:

[0154] In some embodiments, such as Figure 14A and Figure 14B As shown, in the servo pattern 40, whether encoded as "1" or "0", the spacing between adjacent second sub-servo stripes 421 is a set value.

[0155] By using the fifth setting value S5 and the sixth setting value S6 mentioned above to distinguish between the code "1" and the code "0", the amount of calculation can be simplified.

[0156] In other embodiments, such as Figure 13A As shown, the spacing between a set of adjacent second sub-servo stripes 421 is the seventh setting value S7.

[0157] Or, such as Figure 13B As shown, the spacing between a set of adjacent second sub-servo stripes 421 is the eighth setting value S8.

[0158] The relationship between the second sub-servo stripe 421 and the seventh setting value S7 and the eighth setting value S8 can be referred to the above description of the relationship between the first sub-servo stripe 411 and the fifth setting value S5 and the sixth setting value S6, which will not be repeated here.

[0159] The seventh setting value S7 and the eighth setting value S8 are not equal. The seventh setting value S7 and the fifth setting value S5 can be equal or unequal. The eighth setting value S8 and the sixth setting value S6 can be equal or unequal.

[0160] By combining the fifth setting value S5, the sixth setting value S6, the seventh setting value S7, and the eighth setting value S8 to distinguish between the code "1" and the code "0", the recognition accuracy of the code can be improved, making it suitable for high-speed scenarios.

[0161] Regarding the structure of the third sub-servo stripe 431 in servo pattern 40:

[0162] In some embodiments, such as Figure 14A and Figure 14B As shown, in the servo pattern 40, whether coded "1" or "0", the spacing between adjacent third sub-servo stripes 431 is a set value. The codes "1" and "0" are distinguished only by the aforementioned fifth set value S5 and sixth set value S6. Alternatively, the codes "1" and "0" can be distinguished by the aforementioned fifth set value S5, sixth set value S6, seventh set value S7, and eighth set value S8. This simplifies the computational workload.

[0163] In other embodiments, such as Figure 13A As shown, the spacing between a set of adjacent third sub-servo stripes 431 is the ninth setting value S9.

[0164] Or, such as Figure 13B As shown, the spacing between a set of adjacent third sub-servo stripes 431 is the tenth set value S10.

[0165] The ninth setting value S9 and the tenth setting value S10 are not equal. The ninth setting value S9 may be equal to or unequal to the fifth setting value S5 and the seventh setting value S7. The tenth setting value S10 may be equal to or unequal to the sixth setting value S6 and the eighth setting value S8.

[0166] The servo pattern 40 provided in this application embodiment, the structure of the first sub-servo stripe 411, the second sub-servo stripe 421, and the third sub-servo stripe 431 can be any combination of the above-mentioned situations, as long as it includes at least one set of variables that can distinguish between the code "1" and the code "0".

[0167] Because the servo pattern 40 includes a small number of servo stripes, there is a relatively large space left for encoding positions under the same horizontal dimension. Compared to displacing specific stripes only within the limited space of the pattern, the servo pattern 40 of this application can use a larger spacing to encode the horizontal positions of "1" and "0", the difference between the set values ​​can be larger, the tolerance for error is large, and the recognition accuracy is high, which can meet the recognition accuracy requirements of high-speed scenarios.

[0168] Figure 15A and Figure 15B This is a schematic diagram of yet another servo pattern provided in an embodiment of this application.

[0169] In some embodiments, such as Figure 15A As shown, the first direction X is from left to right (e.g., the direction of movement of the belt 30). The servo pattern 40 also includes a fourth servo stripe 44, which is parallel to the first servo stripe 41. The fourth servo stripe 44 is located on the side of the first servo stripe 41 away from the second servo stripe 42.

[0170] like Figure 15A As shown, the spacing between the fourth servo stripe 44 and the first servo stripe 41 is a first set value S1. At this time, the servo pattern 40 represents the first code.

[0171] Or, such as Figure 15B As shown, the spacing between the fourth servo stripe 44 and the first servo stripe 41 is the second set value S2. At this time, the servo pattern 40 represents the second code.

[0172] The first setting value S1 can be greater than the second setting value S2, and the first setting value S1 can also be less than the second setting value S2, as long as the first setting value S1 and the second setting value S2 are not equal. Figure 15A and Figure 15BThe example is given with the first setting value S1 being greater than the second setting value S2. The code is "1" when the distance between the fourth servo stripe 44 and the first servo stripe 41 is the first setting value S1, and "0" when the distance between the fourth servo stripe 44 and the first servo stripe 41 is the second setting value S2. The codes can also be interchanged.

[0173] That is, when the servo pattern 40 provided in this application embodiment is applied to the magnetic tape 11, each servo tape of the tape body 30 is provided with multiple sets of servo patterns 40. The spacing between the fourth servo stripe 44 and the first servo stripe 41 in the servo pattern 40 is a first set value S1 or a second set value S2. The spacing between the fourth servo stripe 44 and the first servo stripe 41 in different servo patterns 40 may be different. The specific value of the spacing between the fourth servo stripe 44 and the first servo stripe 41 in the servo pattern 40 is related to the encoding of the servo tape.

[0174] The servo pattern 40 may include one or more fourth servo stripes 44. This embodiment of the application is only used as an example to illustrate that the servo pattern 40 includes one fourth servo stripe 44.

[0175] By adding a fourth servo stripe 44 to the servo pattern 40, bit encoding can be performed on the servo pattern 40 to determine the lateral position of the magnetic head 21 on the magnetic tape 11. Furthermore, since the fourth servo stripe 44 is located at the edge of the servo pattern 40, it is not limited by the positional relationship between the first servo stripe 41, the second servo stripe 42, and the third servo stripe 43. Therefore, a larger spacing can be used for bit encoding. That is, the values ​​of the first setpoint S1 and the second setpoint S2 can be larger, and the difference between the first setpoint S1 and the second setpoint S2 can be greater, allowing for larger tolerances and higher recognition accuracy, making it suitable for high-speed scenarios. In addition, after adding the fourth servo stripe 44, the movement speed of the magnetic head 21 can be obtained based on the spacing between the fourth servo stripe 44 and the first servo stripe 41, and the movement speed of the magnetic head 21 can be obtained based on the spacing between the first servo stripe 41 and the third servo stripe 43, with the two movement speeds averaged. This is equivalent to repeatedly measuring the movement speed of the magnetic head 21 to improve the speed detection accuracy.

[0176] Figure 16A and Figure 16B This is a schematic diagram of yet another servo pattern provided in an embodiment of this application.

[0177] In some embodiments, such as Figure 16AAs shown, the first direction X is from right to left (e.g., opposite to the direction of movement of the belt 30), and the servo pattern 40 also includes a fourth servo stripe 44, which is parallel to the first servo stripe 41. The fourth servo stripe 44 is located on the side of the third servo stripe 43 away from the second servo stripe 42.

[0178] like Figure 16A As shown, the spacing between the fourth servo stripe 44 and the third servo stripe 43 is the first set value S1. At this time, the servo pattern 40 represents the first code.

[0179] Or, such as Figure 16B As shown, the spacing between the fourth servo stripe 44 and the third servo stripe 43 is the second set value S2. At this time, the servo pattern 40 represents the second code.

[0180] In some embodiments, a fourth servo stripe 44 is provided on the side of the first servo stripe 41 away from the second servo stripe 42, and a fourth servo stripe 44 is also provided on the side of the third servo stripe 43 away from the second servo stripe 42.

[0181] By adding two fourth servo stripes 44 to the servo pattern 40, the distinguishability of bit encoding can be further improved, thereby enhancing the accuracy of encoding recognition.

[0182] Figure 17 This is a schematic diagram of yet another servo pattern provided in an embodiment of this application.

[0183] In some embodiments, such as Figure 17 As shown, a fourth servo stripe 44 is provided on the side of the first servo stripe 41 away from the second servo stripe 42, and a fourth servo stripe 44 is also provided on the side of the third servo stripe 43 away from the second servo stripe 42.

[0184] By adding two fourth servo stripes 44 to the servo pattern 40, the distinguishability of bit encoding can be further improved, thereby enhancing the accuracy of encoding recognition.

[0185] Figure 18A and Figure 18B This is a schematic diagram of yet another servo pattern provided in an embodiment of this application.

[0186] In some embodiments, such as Figure 18A As shown, the servo pattern 40 also includes a fifth servo stripe 45, which is adjacent to and parallel to the second servo stripe 42, and the distance between the fifth servo stripe 45 and the second servo stripe 42 is a third set value S3.

[0187] Or, such as Figure 18BAs shown, the servo pattern 40 also includes a fifth servo stripe 45, which is adjacent to and parallel to the second servo stripe 42, and the spacing between the fifth servo stripe 45 and the second servo stripe 42 is a fourth set value S4.

[0188] The third setting value S3 can be greater than the fourth setting value S4, or the third setting value S3 can be less than the fourth setting value S4, as long as the third setting value S3 and the fourth setting value S4 are not equal. Figure 18A and Figure 18B The example given is that the third setting value S3 is greater than the fourth setting value S4. The code is "1" when the distance between the fifth servo stripe 45 and the second servo stripe 42 is the third setting value S3, and "0" when the distance between the fifth servo stripe 45 and the second servo stripe 42 is the fourth setting value S4. The codes can also be interchanged.

[0189] By adding a fifth servo stripe 45 to the servo pattern 40, bit-level encoding can be performed on the servo pattern 40 to determine the lateral position of the magnetic head 21 on the magnetic tape 11. Furthermore, since the servo pattern 40 includes a small number of servo stripes, the remaining space for encoding is relatively large for the same lateral dimension. Therefore, a larger spacing can be used for bit-level encoding. That is, the values ​​of the third setting value S3 and the fourth setting value S4 can be larger, and the difference between the values ​​of the third setting value S3 and the fourth setting value S4 can be greater, allowing for larger tolerance of errors and higher recognition accuracy, making it suitable for high-speed scenarios. In addition, after adding the fifth servo stripe 45, the longitudinal displacement of the servo head 211 can be calculated by combining the spacing between the fifth servo stripe 45 and the first servo stripe 41, and the spacing between the second servo stripe 42 and the first servo stripe 41, thereby improving the detection accuracy of the longitudinal displacement.

[0190] In some embodiments, along the width direction of the first servo stripe 41, the first servo stripe 41 is half first polarity and half second polarity. The first polarity and the second polarity are the north and south poles of each other.

[0191] In some embodiments, along the width direction of the second servo stripe 42, the second servo stripe 42 is half first polarity and half second polarity. The first polarity and the second polarity are the north and south poles of each other.

[0192] In some embodiments, along the width direction of the third servo stripe 43, the third servo stripe 43 is half first polarity and half second polarity. The first polarity and the second polarity are the north and south poles of each other.

[0193] In some embodiments, along the width direction of the fourth servo stripe 44, the fourth servo stripe 44 is half first polarity and half second polarity. The first polarity and the second polarity are the north and south poles of each other.

[0194] For example, when the servo pattern 40 provided in this application embodiment is applied to the magnetic tape 11, the tape body 30 has no polarity.

[0195] By making the servo stripes in the servo pattern 40 have a magnetic distribution state with half of them at the north and half at the south pole, the magnetization density of the servo pattern 40 can be increased.

[0196] Figure 19 This is a schematic diagram of the structure of a magnetic tape provided in an embodiment of this application.

[0197] The servo pattern 40 provided in this embodiment can be applied to the data storage of the tape drive 10. For example, as Figure 19 As shown, any of the above-mentioned servo patterns 40 are applied to the magnetic tape 11 provided in the embodiments of this application. The magnetic tape 11 includes a tape body 30, and the servo pattern 40 is disposed on the tape body 30 and located in the servo tape area.

[0198] Figure 20A and Figure 20B This is a schematic diagram of another magnetic tape structure provided in an embodiment of this application.

[0199] In some embodiments, such as Figure 20A and Figure 20B As shown, the magnetic tape 11 includes multiple sets of servo patterns 40, and each servo pattern 40 includes a fourth servo stripe 44, which is located on the side of the first servo stripe 41 away from the second servo stripe 42. The fourth servo stripe 44 and the third servo stripe 43 of adjacent servo patterns 40 are the same servo stripe.

[0200] In some embodiments, based on the shared fourth servo stripe 44, "1" and "0" can be encoded by adjusting the spacing between the fourth servo stripe 44 and the first servo stripe 41.

[0201] Adjacent servo patterns 40 share servo stripes, which can improve the space utilization of the belt body 30 and increase storage capacity.

[0202] This application embodiment also provides a write servo drive system, which includes a drive unit and a servo write head. The drive unit is used to output a drive signal, and the servo write head is used to write a servo pattern 40 under the drive signal. The servo pattern 40 can be any of the structures described above.

[0203] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A magnetic tape reel, characterized by The magnetic tape reel comprises: a reel shaft; a magnetic tape wound on the reel shaft; the magnetic tape comprises a tape body and a plurality of servo patterns arranged on the tape body; the servo pattern comprises a first servo stripe, a second servo stripe and a third servo stripe; the first servo stripe, the second servo stripe and the third servo stripe are arranged in sequence along a first direction; two ends of the first servo stripe, two ends of the second servo stripe and two ends of the third servo stripe are respectively located on both sides of the servo pattern along a second direction; the first servo stripe is parallel to the third servo stripe, the first servo stripe is not parallel to the second servo stripe, the second servo stripe is a curve, the distance from each position of the second servo stripe to the first servo stripe is not equal; the first direction is the length direction of the tape body, and the second direction is the width direction of the tape body.

2. The magnetic tape cartridge of claim 1, wherein, The first servo stripe is parallel to the second direction.

3. The magnetic tape reel of claim 1 or 2, wherein, The curve satisfies a preset function relationship.

4. The magnetic tape cartridge of claim 3, wherein, The curve comprises a part satisfying a first preset function relationship and a part satisfying a second preset function relationship.

5. The magnetic tape cartridge of claim 3, wherein, The curve satisfies a tangent function relationship.

6. The magnetic tape reel of any one of claims 1-5, wherein, The servo pattern further comprises a fourth servo stripe, the fourth servo stripe is parallel to the first servo stripe; The fourth servo stripe is arranged on the side of the first servo stripe away from the second servo stripe, and the distance between the fourth servo stripe and the first servo stripe is a first set value or a second set value.

7. The magnetic tape cartridge of claim 6, wherein, The fourth servo stripe and the third servo stripe of adjacent servo patterns are the same servo stripe.

8. The magnetic tape reel of any one of claims 1-7, wherein, One end of the second servo stripe is connected to the first servo stripe, and the other end of the second servo stripe is connected to the third servo stripe.

9. The magnetic tape cartridge of any of claims 1-5, wherein, The servo pattern further comprises a fifth servo stripe, the fifth servo stripe is adjacent to and parallel to the second servo stripe, and the distance between the fifth servo stripe and the second servo stripe is a third set value or a fourth set value.

10. The magnetic tape reel of any one of claims 1-5, wherein, The first servo stripe comprises a plurality of parallel first sub servo stripes, the second servo stripe comprises a plurality of parallel second sub servo stripes, and the third servo stripe comprises a plurality of third sub servo stripes; In the plurality of parallel first sub servo stripes, the distance between a group of adjacent first sub servo stripes is a fifth set value or a sixth set value; Or, In the plurality of parallel second sub servo stripes, the distance between a group of adjacent second sub servo stripes is a seventh set value or an eighth set value; Or, In the plurality of parallel third sub servo stripes, the distance between a group of adjacent third sub servo stripes is a ninth set value or a tenth set value.

11. The magnetic tape reel according to any one of claims 1-10, wherein, along the width direction of the first servo stripe, the first servo stripe is half of a first polarity and half of a second polarity; Or, along the width direction of the second servo stripe, the second servo stripe is half of the first polarity and half of the second polarity; Or, The third servo stripe is half of the first polarity and half of the second polarity along a width direction of the third servo stripe. The first polarity and the second polarity are mutually a south pole and a north pole.

12. A tape drive, characterized by The tape drive comprises a tape reel and a head system, the head system being configured to perform a read operation on the servo pattern; the tape reel comprises the tape reel of any one of claims 1-11.

13. A storage system, characterized by The storage system comprises a processor and a plurality of tape drives, the processor being coupled to each of the tape drives respectively; the tape drive comprises the tape drive of claim 12.

14. A write servo drive system characterized by, The write servo drive system comprises: a driving unit configured to output a driving signal; a servo write head configured to write a servo pattern under the driving of the driving signal; The servo pattern comprises a first servo stripe, a second servo stripe and a third servo stripe; the first servo stripe, the second servo stripe and the third servo stripe are arranged in sequence along a first direction; two ends of the first servo stripe, two ends of the second servo stripe and two ends of the third servo stripe are respectively located on two sides of the servo pattern along a second direction; The first servo stripe is parallel to the third servo stripe, the first servo stripe is not parallel to the second servo stripe, the second servo stripe is a curve, the distance from each position of the second servo stripe to the first servo stripe is not equal; the first direction is a length direction of the tape body, and the second direction is a width direction of the tape body.

15. The write servo drive system of claim 14, wherein, The servo pattern further comprises a fourth servo stripe, the fourth servo stripe is parallel to the first servo stripe; The fourth servo stripe is arranged on a side of the first servo stripe away from the second servo stripe, and the distance between the fourth servo stripe and the first servo stripe is a first set value or a second set value.

16. A write servo drive system as claimed in claim 14 or 15, wherein, The servo pattern further comprises a fifth servo stripe, the fifth servo stripe is adjacent to and parallel to the second servo stripe, and the distance between the fifth servo stripe and the second servo stripe is a third set value or a fourth set value.

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