Magnetic tape reel, magnetic tape drive, storage system and write servo driving system

Abstract

The embodiments of the present application relate to the field of storage. Provided are a magnetic tape reel, a magnetic tape drive, a storage system and a write servo driving system, which are used for providing a servo pattern suitable for high-speed rotation of a magnetic tape. The servo pattern comprises a first servo stripe, a second servo stripe and a third servo stripe, wherein the first servo stripe is parallel to the third servo stripe, and the inclination angles of the servo stripes are small, so that the lateral dimension of the servo pattern can be reduced, and the frame rate of the magnetic tape drive can be increased, making the servo pattern suitable for a high-speed scenario. In addition, servo position information can be acquired simply by means of three servo stripes, the number of repetitions of servo stripes is small, multiple instances of servo peak detection are not required, and the calculation overhead is small, and the calculation speed is high, making the servo pattern suitable for fast calculation in the high-speed scenario. Moreover, the trajectory of the second servo stripe is a curve, the curve has different slopes at different positions, and the smaller the slope at a position, the higher the accuracy of position calculation. Therefore, a smaller number of stripes can be used to achieve the same or better accuracy as conventional servos, thereby ensuring the calculation accuracy.

Description

Magnetic tape reel, tape drive, storage system, write servo drive system

[0001] This application claims priority to the Chinese patent application No. 202410878728.8, filed on June 29, 2024, and entitled “Magnetic tape reel, tape drive, storage system, write servo drive system”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of storage, and in particular to a magnetic tape reel, a tape drive, a storage system, and a write servo drive system. BACKGROUND

[0003] Due to the low cost and low energy consumption characteristics, tape storage is still widely used as a long-term offline archiving storage method. Based on linear tape open (LTO) tape storage technology, during the movement of the tape, the head is controlled to move relative to the width direction of the tape to determine the read-write position for read or write operation, and the determination of the head position depends on the servo pattern in the tape.

[0004] However, the current servo pattern design is complex, and the amount of operation to obtain the head position is large, which is only suitable for low-speed rotating scenes and cannot meet the needs in high-speed rotating scenes. SUMMARY

[0005] The present application provides a magnetic tape reel, a tape drive, a storage system, and a write servo drive system, which are used to provide a servo pattern suitable for high-speed rotation of the tape.

[0006] In a first aspect, the present application provides a magnetic tape reel, the magnetic tape reel comprising a reel and a magnetic tape wound on the reel. The magnetic tape comprises a tape body and a servo pattern, the servo pattern being 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 second servo stripe has a curved track, and the distance from each position of the second servo stripe to the third servo stripe is not equal; 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.

[0007] The magnetic tape reel provided by the embodiments of the present application comprises a first servo stripe, a second servo stripe and a third servo stripe. The first servo stripe and the third servo stripe are parallel. Compared with the case where the first servo stripe and the third servo stripe are not parallel, the first servo stripe and the third servo stripe are arranged in parallel, the inclination angle of the servo stripe in the servo pattern is small, the size (lateral distance) of the servo pattern in the first direction can be reduced, the frame rate of the tape drive is improved, and the servo pattern is applicable to high-speed scenarios. In addition, the servo position information can be obtained through three servo stripes, the number of servo stripe repetitions is small, multiple servo peak searching is not required, the calculation cost is small, the calculation speed is high, and the servo pattern is applicable to high-speed scenarios for fast calculation. Moreover, the track of the second servo stripe is a curve, the curve has different slopes (large lateral distance variation) at different positions, the position calculation accuracy is higher at positions with smaller slopes, and therefore the same or better accuracy as the traditional servo can be achieved with fewer stripes, thereby ensuring the calculation accuracy.

[0008] In a possible implementation, the first servo stripe is parallel to the second direction. In this way, the size of the servo pattern in the first direction can be reduced, each servo pattern occupies less time, the space utilization is high, the frame rate of the tape drive can be improved, and the servo control with higher frequency can be supported.

[0009] In a possible implementation, the track of the curve satisfies a preset function relationship. The track of the second servo stripe satisfies the preset function relationship, which can facilitate the establishment of a conversion formula between the second servo stripe and the longitudinal displacement of the servo head, and can simplify the calculation amount.

[0010] In a possible implementation, the track of the curve comprises a part satisfying a first preset function relationship and a part satisfying a second preset function relationship. In this way, the track of the second servo stripe can be adjusted so that the slopes at different positions of the second servo stripe are all small, and the position calculation accuracy is improved.

[0011] In a possible implementation, the track of the curve satisfies a tangent function relationship. The tangent function relationship forms a track with a small slope in the middle region, and therefore the detection accuracy of the middle region can be improved.

[0012] In a possible implementation, the servo pattern further comprises a fourth servo stripe, the fourth servo stripe being 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 a distance between the fourth servo stripe and the first servo stripe is a first set value or a second set value. By adding the fourth servo stripe to the servo pattern, the servo pattern can be bit-encoded to determine the transverse position of the magnetic head on the magnetic tape. Moreover, since the fourth servo stripe is arranged at the edge of the servo pattern, it is not limited by the positional relationship among the first servo stripe, the second servo stripe, and the third servo stripe. Therefore, a larger distance can be used for bit encoding. That is, the first set value and the second set value can be larger, and the difference between the first set value and the second set value can be larger, the tolerable error is large, the recognition accuracy is high, and the servo pattern can be applied to a high-speed scenario. In addition, after adding the fourth servo stripe, the moving speed of the magnetic head can be obtained according to the distance between the fourth servo stripe and the first servo stripe, and the moving speed of the magnetic head can be obtained according to the distance between the first servo stripe and the third servo stripe, and the two moving speeds are averaged. That is, the moving speed of the magnetic head can be repeatedly measured to improve the detection accuracy of the speed.

[0013] In a possible implementation, the fourth servo stripe of the adjacent servo pattern is the same servo stripe as the third servo stripe. The adjacent servo patterns share the servo stripe, which can improve the space utilization of the tape body and optimize the control bandwidth of the tape drive.

[0014] In a 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. That is, the servo pattern is an integrated structure. The integrated servo stripe enables the first servo stripe, the second servo stripe, and the third servo stripe to be written on the tape body synchronously, reduces the writing servo distance control error caused by asynchronous writing of parallel stripes, improves the speed estimation accuracy, and thus improves the precision of the servo analysis result. In addition, the integrated servo stripe can further reduce the size of the servo pattern in the first direction, improve the frame rate of the tape drive, and optimize the control bandwidth of the tape drive.

[0015] In a possible implementation, the servo pattern further comprises a fifth servo stripe, the fifth servo stripe is adjacent to and parallel to the second servo stripe, and a spacing between the fifth servo stripe and the second servo stripe is a third set value or a fourth set value. By adding the fifth servo stripe in the servo pattern, the servo pattern can be bit encoded to determine the lateral position of the magnetic head on the magnetic tape. Moreover, since the servo pattern comprises a small number of servo stripes, the remaining position space for encoding is relatively large under the same lateral size. Therefore, a larger spacing can be used for bit encoding. That is, the third set value and the fourth set value can have a larger value, and the difference between the third set value and the fourth set value can be larger, the tolerable error is large, the recognition accuracy is high, and the servo pattern can be applied to a high-speed scenario. In addition, after adding the fifth servo stripe, the longitudinal displacement of the servo head can be calculated in combination with the spacing between the fifth servo stripe and the first servo stripe and the spacing between the second servo stripe and the first servo stripe, so as to improve the detection accuracy of the longitudinal displacement.

[0016] In a possible implementation, 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. By repeating each servo stripe multiple times, the average moving speed of the magnetic head can be calculated by multiple groups of repeated stripes. That is, the moving speed of the magnetic head can be repeatedly measured, so as to improve the detection accuracy of the speed.

[0017] In a possible implementation, a spacing between a group of adjacent first sub servo stripes in the plurality of parallel first sub servo stripes is a fifth set value or a sixth set value. The servo pattern can be encoded by adjusting the spacing between the adjacent first sub servo stripes. Moreover, since the servo pattern comprises a small number of servo stripes, the remaining position space for encoding is relatively large under the same lateral size. Compared with shifting a specific stripe in a limited space in the pattern, the servo pattern can use a larger spacing to encode the "1" and "0" of the lateral position, the difference between the set values can be larger, the tolerable error is large, the recognition accuracy is high, and the servo pattern can meet the requirement of the recognition accuracy in a high-speed scenario.

[0018] In a possible implementation, the intervals between a group of adjacent second sub-servo fringes in the plurality of parallel second sub-servo fringes are of a seventh set value or an eighth set value. The intervals between the adjacent second sub-servo fringes can be adjusted to encode the servo pattern, and because the servo pattern includes a small number of servo fringes, a larger position space is left for encoding under the same lateral size. Compared with displacing a specific fringe in a limited space in the pattern, the servo pattern of the present application can use a larger interval to encode the "1" and "0" of the lateral position, the difference between the set values can be larger, the tolerable error can be larger, the recognition accuracy is high, and the requirement of recognition accuracy in a high-speed scenario can be met.

[0019] In a possible implementation, the intervals between a group of adjacent third sub-servo fringes in the plurality of parallel third sub-servo fringes are of a ninth set value or a tenth set value. The intervals between the adjacent third sub-servo fringes can be adjusted to encode the servo pattern, and because the servo pattern includes a small number of servo fringes, a larger position space is left for encoding under the same lateral size. Compared with displacing a specific fringe in a limited space in the pattern, the servo pattern of the present application can use a larger interval to encode the "1" and "0" of the lateral position, the difference between the set values can be larger, the tolerable error can be larger, the recognition accuracy is high, and the requirement of recognition accuracy in a high-speed scenario can be met.

[0020] In a possible implementation, along the width direction of the first servo fringes, the first servo fringes are half of the first polarity and half of the second polarity; and the first polarity and the second polarity are the south pole and the north pole. By making the servo fringes in the servo pattern have a magnetic distribution state of half of the south pole and half of the north pole, the magnetization density of the servo pattern can be improved.

[0021] In a possible implementation, along the width direction of the second servo fringes, the second servo fringes are half of the first polarity and half of the second polarity; and the first polarity and the second polarity are the south pole and the north pole. By making the servo fringes in the servo pattern have a magnetic distribution state of half of the south pole and half of the north pole, the magnetization density of the servo pattern can be improved.

[0022] In a possible implementation, along the width direction of the third servo fringes, the third servo fringes are half of the first polarity and half of the second polarity; and the first polarity and the second polarity are the south pole and the north pole. By making the servo fringes in the servo pattern have a magnetic distribution state of half of the south pole and half of the north pole, the magnetization density of the servo pattern can be improved.

[0023] In a second aspect of the present application, a magnetic tape drive is provided, the magnetic tape drive includes a magnetic tape disk and a head system, the head system is configured to perform a read operation on the servo pattern; the magnetic tape disk includes the magnetic tape disk of any one of the first aspect.

[0024] The magnetic tape drive provided in the second aspect of the embodiments of the present application comprises the magnetic tape reel of the first aspect, and has the same beneficial effects as the magnetic tape reel, which will not be repeated here.

[0025] In the third aspect of the embodiments of the present application, a storage system is provided, which comprises a processor and a plurality of magnetic tape drives, and the processor is coupled to each of the magnetic tape drives; the magnetic tape drive comprises the magnetic tape drive of the second aspect.

[0026] In the fourth aspect of the embodiments of the present application, a write servo driving system is provided, which 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; a track of the second servo stripe is a curve, and distances from each position of the second servo stripe to the third servo stripe are not equal; the first direction is a length direction of a magnetic tape medium, and the second direction is a width direction of the magnetic tape medium.

[0027] The write servo driving system provided in the fourth aspect of the embodiments of the present application is used to form the magnetic tape reel of the first aspect, and has the same beneficial effects as the magnetic tape reel, which will not be repeated here.

[0028] In a possible implementation manner, the first servo stripe is parallel to the second direction.

[0029] In a possible implementation manner, the track of the curve satisfies a preset function relationship.

[0030] In a possible implementation manner, the track of the curve comprises a part satisfying a first preset function relationship and a part satisfying a second preset function relationship. In a possible implementation manner, the track of the curve satisfies a tangent function relationship.

[0031] In a possible implementation manner, 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 a spacing between the fourth servo stripe and the first servo stripe is a first set value or a second set value.

[0032] In a possible implementation manner, the fourth servo stripe and the third servo stripe of adjacent servo patterns are the same servo stripe.

[0033] In a possible implementation manner, one end of the second servo stripe is connected with the first servo stripe, and the other end of the second servo stripe is connected with the third servo stripe.

[0034] In a possible implementation, the servo pattern further comprises a fifth servo stripe, the fifth servo stripe is adjacent to and parallel to the second servo stripe, and a spacing between the fifth servo stripe and the second servo stripe is a third set value or a fourth set value.

[0035] In a possible implementation, 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.

[0036] In a possible implementation, a spacing between a group of adjacent first sub servo stripes in the plurality of parallel first sub servo stripes is a fifth set value or a sixth set value.

[0037] In a possible implementation, a spacing between a group of adjacent second sub servo stripes in the plurality of parallel second sub servo stripes is a seventh set value or an eighth set value.

[0038] In a possible implementation, a spacing between a group of adjacent third sub servo stripes in the plurality of parallel third sub servo stripes is a ninth set value or a tenth set value. BRIEF DESCRIPTION OF DRAWINGS

[0039] FIG. 1 is a structural schematic diagram of a storage system according to an embodiment of the present application;

[0040] FIG. 2 is a structural schematic diagram of a tape drive according to an embodiment of the present application;

[0041] FIG. 3 is a structural schematic diagram of a tape reel according to an embodiment of the present application;

[0042] FIG. 4 is a partial structural schematic diagram of a tape according to an embodiment of the present application;

[0043] FIG. 5A is a schematic diagram of a servo pattern according to an embodiment of the present application;

[0044] FIG. 5B is a schematic diagram of a servo pattern geometry according to an embodiment of the present application;

[0045] FIG. 5C is a schematic diagram of a servo pattern encoding according to an embodiment of the present application;

[0046] FIG. 6 is a schematic diagram of another servo pattern according to an embodiment of the present application;

[0047] FIGS. 7A-7D are schematic diagrams of a servo pattern according to an embodiment of the present application;

[0048] FIGS. 8A-8D are schematic diagrams of another servo pattern according to an embodiment of the present application;

[0049] FIGS. 9A-9D are schematic diagrams of yet another servo pattern according to embodiments of the present application;

[0050] FIGS. 10A-10D are schematic diagrams of yet another servo pattern according to embodiments of the present application;

[0051] FIGS. 11 and 12 are schematic diagrams of yet another servo pattern according to embodiments of the present application;

[0052] FIGS. 13A and 13B are schematic diagrams of encoding of a servo pattern according to embodiments of the present application;

[0053] FIGS. 14A and 14B are schematic diagrams of encoding of another servo pattern according to embodiments of the present application;

[0054] FIGS. 15A and 15B are schematic diagrams of yet another servo pattern according to embodiments of the present application;

[0055] FIGS. 16A and 16B are schematic diagrams of yet another servo pattern according to embodiments of the present application;

[0056] FIG. 17 is a schematic diagram of yet another servo pattern according to embodiments of the present application;

[0057] FIGS. 18A and 18B are schematic diagrams of yet another servo pattern according to embodiments of the present application;

[0058] FIG. 19 is a schematic diagram of a structure of a magnetic tape according to embodiments of the present application;

[0059] FIGS. 20A and 20B are schematic diagrams of a structure of another magnetic tape according to embodiments of the present application. DETAILED DESCRIPTION

[0060] The technical solutions in embodiments of the present application will be described below with reference to the drawings in embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application.

[0061] Hereinafter, the terms "second", "first", and the like are only used for description convenience, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "second", "first", and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0062] In addition, in the embodiments of the present application, the orientation terms such as "upper", "lower", "left", "right" and the like can include, but are not limited to, the orientation defined by the relative placement of the components in the drawings. It should be understood that these directional terms are relative concepts, and they are used for relative description and clarification, which can change accordingly according to the change of the placement of the components in the drawings.

[0063] In the embodiments of the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, the "connection" can be a fixed connection, or a detachable connection, or an integral; it can be directly connected, or indirectly connected through an intermediate medium. In addition, the term "coupling" 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.

[0064] In the embodiments of the present application, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone, wherein A and B can be singular or plural. The character " / " generally represents that the associated objects before and after it have an "or" relationship.

[0065] In order to facilitate understanding, the main terms involved in the present application are first explained.

[0066] Tape storage: a persistent storage method using magnetic tape as a data storage device.

[0067] Tape driver: refers to an economical, reliable, large-capacity and fast storage device, which is the core of data writing and data reading in a storage system. The tape driver uses high error correction capability coding technology and read-after-write channel technology to improve the reliability of data backup. According to the tape loading method of the tape driver, the tape driver is generally divided into manual tape loading tape driver and automatic tape loading tape driver. According to the form of the tape driver, the tape driver is generally divided into consumer-level tape driver and commercial-level tape driver. According to the height of the tape driver, the tape driver is generally divided into half-height tape driver and full-height tape driver. The height dimension of the full-height tape driver is generally 60mm. The size of the half-height tape driver is generally 40mm.

[0068] Tape: a non-volatile storage medium used to record sound, image, digital, text or other signal with a magnetic layer of tape-shaped material. Usually, the tape is packaged in a rolled state. According to the sequential access characteristics of the tape, the tape is applied to traditional storage and backup and sequential reading and writing of large amounts of data. The tape can also be called a tape body. Alternatively, the tape can also be a device including a tape body and a tape winding reel.

[0069] Tape header: refers to a component for reading and writing a magnetic medium on a tape according to a magnetic principle. The tape header includes a write tape header and a read tape header. The write tape header records data by magnetizing to change the magnetic field of the magnetic medium. The read tape header reads data on the magnetic medium by inducting the magnetic field of the magnetic medium.

[0070] Embodiments of the present application provide a storage system for data storage. The storage system includes a tape cabinet, a computer device, and the like.

[0071] FIG. 1 is a structural schematic diagram of a storage system according to an embodiment of the present application.

[0072] Embodiments of the present application provide a storage system, as shown in FIG. 1, the storage system 100 includes a processor and a plurality of tape drives 10. The processor is configured to generate data, and the processor is also configured to control a read operation or a write operation of the tape drive 10 according to a control signal. The tape drive 10 is configured to store the data generated by the processor.

[0073] The processor can be a central processing unit (CPU), and the processor can also be another general-purpose processor, a digital signal processing (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, and the like. The general-purpose processor can be a microprocessor or any conventional processor, and the like. 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 for controlling program execution of the present application. The processor can be a multi-CPU processor. The processor herein can refer to one or more devices, circuits, and / or computing units for processing data (for example, computer program instructions).

[0074] Due to the low cost and low energy consumption of tape storage, tape storage is still widely used as a long-term offline archiving storage method, and the tape drive 10 is used as a storage unit in the storage system 100.

[0075] Fig. 2 is a structural schematic diagram of a tape drive provided by an embodiment of the present application, Fig. 3 is a structural schematic diagram of a tape reel provided by an embodiment of the present application, and Fig. 4 is a partial structural schematic diagram of a tape provided by an embodiment of the present application.

[0076] An embodiment of the present application provides a tape drive 10, as shown in Fig. 2, which includes a tape reel 1, a head system 2, a controller 3, a roller 4, and a housing 5. The tape reel 1, the head system 2, the controller 3, and the roller 4 are placed in the housing 5.

[0077] As shown in Fig. 3, the tape reel 1 includes a tape 11 and a reel 12. The tape 11 is wound on the reel 12 and is installed in the tape drive 10. The tape 11 is pulled by the reel 12 and the roller 4 to pass through the head system 2.

[0078] The head system 2 includes a tape header 21 and a head driver 22. The tape header 21 is used to perform a read operation or a write operation on the moving tape 11 under the control of the head driver 22.

[0079] The controller 3 is used to control the head driver 22 to move under the control of a control signal, so as to drive the tape header 21 to move, so that the tape header 21 performs a read operation on a servo area and performs a read operation or a write operation on a data track corresponding to servo information indicated by the servo area. For example, the controller 3 controls the tape header 21 to read servo information on the servo area, controls the tape header 21 to read data on the data track according to the servo information, or controls the tape header 21 to write data on the data track according to the servo information. The control signal can be a gate signal or a square pulse signal.

[0080] For example, as shown in Fig. 4, the tape 11 includes a tape body 30, which includes a servo band and a data band. Along the width direction of the tape body 30, a plurality of servo bands and a data band interposed between the servo bands are distributed. For example, Fig. 4 illustrates an example in which the tape body 30 includes five servo bands and four data bands interposed between the servo bands. The servo band includes a plurality of servo patterns 40 arranged along a first direction X, and the data band includes a plurality of data tracks. The data tracks are used to record data, and the servo band is used to record servo information of the data tracks. The servo location of the servo band and the data track of the data band are in one-to-one correspondence. In Fig. 4, the first direction X is the length direction of the tape 11, and the second direction Y is the width direction of the tape 11.

[0081] The magnetic head 21 includes two servo heads 211 at the two ends, a read head 212 and a write head 213 between the two servo heads 211. The servo heads 211 are used to read servo positions of the servo tracks, the read head 212 is used to perform a read operation according to the servo positions determined by the servo heads 211, and the write head 213 is used to perform a write operation according to the servo positions determined by the servo heads 211.

[0082] For example, when performing read / write operations on the data track 4, the two servo heads 211 at the two ends of the magnetic head 21 read servo positions from the servo track 0 and the servo track 1 respectively. Specifically, when the servo head 211 (a tunneling magnetoresistance sensor) on the magnetic head 21 passes through the magnetized servo stripe on the magnetic tape 11, a peak-valley signal corresponding to the change in magnetic flux is generated, and the lateral time interval of the servo stripe can be calculated according to the interval between the peaks. According to the geometric relationship of the servo frame stripe, the position of the magnetic head 21 and the running speed of the magnetic tape 11 can be calculated.

[0083] The read head 212 performs a read operation according to the servo position determined by the center line of the two servo positions, or the write head 213 performs a write operation according to the servo position determined by the center line of the two servo positions.

[0084] In the magnetic tape drive 10, the servo pattern 40 can provide three key information: first, the running speed of the magnetic tape 11, used to control the smooth running of the magnetic tape 11; second, the cross-track position of the magnetic head 21 on the magnetic tape, i.e. the position along the second direction Y (the height direction of the servo pattern 40), used to position the data track; and third, the longitudinal position (LPOS) encoding, encoding the down-track position, i.e. the position along the first direction X (the running direction of the magnetic tape 11, the width direction of the servo pattern 40), each frame representing a data bit 0 or 1 according to a specific rule, combining multiple frames into a binary sequence, and supplemented by encoding and decoding rules, to represent the longitudinal position of the magnetic head 21 on the magnetic tape 11.

[0085] Based on this, the high-precision read / write of the magnetic tape drive 10 relies on an accurate servo detection system to stably maintain the magnetic head 21 in a specific track and control the magnetic tape 11 to run at a specific speed. The servo control system locates the cross-track position of the magnetic head 21 on the magnetic tape 11 and the running speed of the magnetic tape 11 by solving the servo pattern 40 in the reserved servo track on the magnetic tape 11. The pattern of the servo stripes in the servo pattern 40, including stripe shape, width, size, number, etc., will affect the accuracy of the calculation of the cross-track position and the speed of the magnetic head 21. A suitable servo pattern 40 helps to improve the position positioning and speed calculation accuracy of the magnetic tape drive 10, to ensure high-density read / write.

[0086] FIG. 5A is a schematic diagram of a servo pattern according to an embodiment of the present application, FIG. 5B is a schematic diagram of a servo pattern geometry according to an embodiment of the present application, and FIG. 5C is a schematic diagram of a servo pattern encoding according to an embodiment of the present application.

[0087] In some embodiments, as shown in FIG. 5A, 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, each stripe group including at least four servo stripes.

[0088] 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 is fixed, and thus the running speed of the magnetic tape 11 can be calculated.

[0089] The interval dl between the first stripe group A and the second stripe group B or between the third stripe group C and the fourth stripe group D is related to the height of the servo head 211. Therefore, the height of the servo head 211 can be calculated using the geometric relationship of the servo pattern, and the position of the servo head 211 can be located.

[0090] For example, as shown in FIG. 5B, according to the servo pattern design, the interval d between the parallel stripe groups (the first stripe group A and the third stripe group C) is known, the interval dl between the first stripe group A and the second stripe group B is d / 2, d2 is the interval (the interval between adjacent non-parallel groups) measured according to the readback signal of the servo head 211, and δd is equal to (dl-d2) / 2. Since the inclination angle a of the diagonal stripe is known, the longitudinal displacement y between d2 and dl, i.e., the height position of the servo head 211 in the servo pattern 40, can be calculated according to the geometric relationship of the triangle. The accuracy can be improved by calculating multiple pairs (four pairs). The formula for calculating the longitudinal displacement y of a complete servo pattern 40 is as follows:

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

[0092] As shown in FIG. 5C, based on the servo pattern 40 shown in FIG. 5A, by slightly shifting (for example, ±0.25um) the second servo stripe and the fourth servo stripe in the first stripe group A, the distance S between the second servo stripe and the third servo stripe is changed, and the distance S between the fourth servo stripe and the third servo stripe is changed, and by judging the different position deviation directions (the size of the distance S), 0 and 1 are represented, as LPOS encoding.

[0093] In the servo pattern 40 shown in FIG. 5A, the servo stripes (the eight-shaped servo stripes) in the first stripe group A and the second stripe group B are written at the same time, and the servo stripes (the parallel servo stripes in the burst) in the first stripe group A and the third stripe group C are written asynchronously, and the write servo distance control error caused by the asynchronous writing will cause the servo analysis result to be biased. In order to achieve the accuracy requirement, the servo stripes in each stripe group need to be repeated multiple times, which increases the calculation overhead, and cannot respond in time in the high-speed moving scene of the magnetic tape 11. If the number of servo stripe repetitions is not increased, the tilt angle of the servo stripe needs to be increased, and the increase of the angle will cause the horizontal position occupied by the servo stripe to increase, and then the horizontal size of the servo pattern 40 will become longer, the interval between each value (the vertical displacement and the speed) will become longer, and then the servo control will be slower. In addition, due to the limitation of the distance between the stripe patterns, the difference of the distance S of the LPOS encoding is too small, which causes the identification accuracy to be insufficient in the high-speed scene.

[0094] FIG. 6 is a schematic diagram of another servo pattern provided by the embodiment of the application.

[0095] In some embodiments, as shown in FIG. 6, 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] In the servo pattern 40 shown in FIG. 6, due to the different extension directions of the first servo stripe 41, the second servo stripe 42, and the third servo stripe 43, the size of the servo pattern 40 in the first direction X is large. Under the same accuracy, the frame rate of the tape drive 10 caused by the servo pattern 40 is low, which causes the bandwidth to be low. Moreover, when the servo position is obtained, there is no fixed reference distance, and 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) to perform the next operation, which causes the operation amount when the servo position is obtained to be large, and the calculation overhead is increased, which is not suitable for high-speed scenes. In addition, the write servo distance control error caused by the asynchronous writing of the first servo stripe 41 and the third servo stripe 43 will cause the servo analysis result to be biased.

[0097] FIGS. 7A-10D are schematic diagrams of a servo pattern according to embodiments of the present application.

[0098] In some embodiments, as shown in FIG. 7A, 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 in sequence along a 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] In the drawings, the first direction X can be from left to right, or from right to left, and is the length direction of the tape 30.

[0100] The two ends of the first servo stripe 41 are located on the two sides of the servo pattern 40 along a second direction Y, the two ends of the second servo stripe 42 are located on the two sides of the servo pattern 40 along the second direction Y, and the two ends of the third servo stripe 43 are located on the two sides of the servo pattern 40 along the second direction Y. The second direction Y is the width direction of the tape 30. For example, as long as one end of the second servo stripe 42 is located on the upper side of the center line parallel to the first direction X and the other end is located on the lower side of the center line, it is considered that the two ends of the second servo stripe 42 are located on the two sides of the servo pattern 40 along the second direction Y.

[0101] The first servo stripe 41 and the third servo stripe 43 are parallel along the first direction X, and the distance d from each position of the third servo stripe 43 to the first servo stripe 41 is equal. In the present application, the parallel includes fluctuations within a process error (±5°).

[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. As long as the first servo stripe 41 and the third servo stripe 43 are parallel, they can be straight lines or curves.

[0103] For example, as shown in FIGS. 7A-7D, the first servo stripe 41 and the third servo stripe 43 are not parallel to the second direction Y. In this way, the calculation accuracy of the longitudinal displacement y of the servo head 211 can be improved.

[0104] As shown in FIGS. 7A-8D, the inclination 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] Alternatively, as shown in FIGS. 9A-9D, the first servo stripe 41 and the third servo stripe 43 are parallel to the second direction Y. In this way, the size of the servo pattern 40 in the first direction X can be reduced, each servo pattern 40 occupies less time, the space utilization is high, the frame rate of the tape drive 10 can be improved, higher frequency servo control can be supported, and the vertical stripe peak seeking precision is higher.

[0106] In some embodiments, the second servo stripe 42 has a curved trajectory 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 distance A from each position of the second servo stripe 42 to the third servo stripe 43 is unique, so that the longitudinal displacement y obtained by the distance A has a one-to-one correspondence with the data tracks of the data band.

[0107] The present application does not limit the curved trajectory of the second servo stripe 42, 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 curved trajectory of the second servo stripe 42 satisfies a predetermined function relationship. After the function relationship is fixed, the second servo stripe 42 can be the entire curve corresponding to the function relationship, or the second servo stripe 42 can be a segment of the curve corresponding to the function relationship.

[0109] For example, the curved trajectory of the second servo stripe 42 satisfies a predetermined function relationship.

[0110] For example, as shown in FIG. 9A, the curved trajectory of the second servo stripe 42 satisfies a circular arc function relationship.

[0111] Alternatively, for example, as shown in FIG. 9B, the curved trajectory of the second servo stripe 42 satisfies a hyperbolic function relationship.

[0112] Alternatively, for example, as shown in FIG. 9C, the curved trajectory of the second servo stripe 42 satisfies an exponential function relationship.

[0113] Alternatively, for example, as shown in FIG. 9D, the curved trajectory of the second servo stripe 42 satisfies a tangent function relationship.

[0114] The curved trajectory of the second servo stripe 42 satisfies the predetermined function relationship, which can facilitate the establishment of a conversion formula between the second servo stripe 42 and the longitudinal displacement of the servo head 211, and can simplify the calculation amount.

[0115] In some examples, the curve of the second servo stripe 42 satisfies a plurality of preset function relationships. For example, the curve of the second servo stripe 42 includes a portion satisfying a first preset function relationship and a portion satisfying a second preset function relationship. In this way, the slope of the second servo stripe 42 at each position can be relatively small, and the position calculation accuracy can be improved.

[0116] In some examples, as shown in FIGS. 7A-9D, 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 some other examples, 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 yet some other examples, as shown in FIGS. 10A-10D, 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 integrated. For example, the servo pattern 40 can be formed by using a servo pattern writing technology.

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

[0120] In some examples, 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, as shown in FIG. 10A, 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] FIGS. 11 and 12 are schematic diagrams of another servo pattern provided by the examples of the present application.

[0123] Alternatively, for example, as shown in FIG. 11, 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] Alternatively, as shown in FIG. 12, 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 the present application do not limit the value of n, and the embodiments of the present application are only an enumeration, not an exhaustive enumeration.

[0126] By repeating each servo stripe multiple times, the average moving speed of the magnetic head 21 can be calculated by multiple groups of repeated stripes. It is equivalent to repeatedly measuring the moving speed of the magnetic head 21 to improve the detection accuracy of the speed. In addition, multiple groups of sub stripes can be written at the same time based on the same template, and there is no servo writing error, which does not affect the speed detection accuracy.

[0127] Based on the servo pattern 40 provided by the embodiments of the present 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] Wherein d is the fixed interval 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 / time interval between two sampling points, B i 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.

[0129] When the curved trajectory of the second servo stripe 42 satisfies the circular arc function relationship shown in FIG. 10A:

[0130] Wherein d is the fixed interval between the first servo stripe 41 and the third servo stripe 43, A i 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, B i 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, and n is the number of sub servo stripes included in each servo stripe.

[0131] When the curved trajectory of the second servo stripe 42 satisfies the hyperbolic function relationship shown in FIG. 10B:

[0132] wherein d is a fixed interval between the first servo stripe 41 and the third servo stripe 43, A i is a distance between the i-th second sub servo stripe 421 in the second servo stripe 42 and the i-th third sub servo stripe 431 in the third servo stripe 43, B i is a distance between the i-th first sub servo stripe 411 in the first servo stripe 41 and the i-th third sub servo stripe 431 in the third servo stripe 43, a is a real half axis of the hyperbola, b is an imaginary half axis of the hyperbola, and n is a number of sub servo stripes included in each servo stripe.

[0133] When the curved trajectory of the second servo stripe 42 satisfies an exponential function relationship as shown in FIG. 10C:

[0134] wherein e is a mathematical constant in the exponential function, the center axis of the second servo stripe 42 is a middle position between the first servo stripe 41 and the third servo stripe 43, A i is a distance between the i-th second sub servo stripe 421 in the second servo stripe 42 and the i-th third sub servo stripe 431 in the third servo stripe 43, B i is a distance between the i-th first sub servo stripe 411 in the first servo stripe 41 and the i-th third sub servo stripe 431 in the third servo stripe 43, d is a fixed interval between the first servo stripe 41 and the third servo stripe 43, and n is a number of sub servo stripes included in each servo stripe.

[0135] When the curved trajectory of the second servo stripe 42 satisfies a tangent function relationship as shown in FIG. 10D:

[0136] wherein amp is an amplification factor depending on a height of the servo stripe desired to be designed, w is an angular frequency of the trigonometric function, and A i is a distance between the i-th second sub servo stripe 421 in the second servo stripe 42 and the i-th third sub servo stripe 431 in the third servo stripe 43, B i is a distance between the i-th first sub servo stripe 411 in the first servo stripe 41 and the i-th third sub servo stripe 431 in the third servo stripe 43, d is a fixed interval between the first servo stripe 41 and the third servo stripe 43, and n is a number of sub servo stripes included in each servo stripe.

[0137] The servo pattern 40 provided by the embodiments of the present application 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 with the case where the first servo stripe 41 and the third servo stripe 43 are not parallel, in the case where the first servo stripe 41 and the third servo stripe 43 are parallel, the same detection accuracy and the width (the size in the second direction Y) of the servo pattern 40 are achieved, the inclination angle of the servo stripe in the servo pattern 40 is small, the size (the lateral distance) of the servo pattern 40 in the first direction X can be reduced, the frame rate of the tape drive 10 is improved, and the servo pattern 40 is suitable for high-speed scenarios. In addition, the servo position information can be obtained by using three servo stripes, the number of repetitions of the servo stripe is small, a plurality of servo peak searching is not required, the calculation cost is small, the calculation speed is high, and the servo pattern 40 is suitable for fast calculation in high-speed scenarios. Moreover, the track of the second servo stripe 42 is a curve, the curve has different slopes (the lateral distance changes greatly) at different positions, the position calculation accuracy is higher at the position where the slope is smaller, and therefore the same or better accuracy as the conventional servo can be achieved by using a smaller number of stripes, and the calculation accuracy is ensured.

[0138] FIGS. 13A and 13B are schematic diagrams of encoding of a servo pattern provided by the embodiments of the present application.

[0139] Regarding the structure of the first sub-servo stripe 411 in the servo pattern 40:

[0140] In some embodiments, as shown in FIG. 13A, in the plurality of parallel first sub-servo stripes 411, the interval between a group of adjacent first sub-servo stripes 411 is a fifth set value S5. At this time, the servo pattern 40 represents a first code, for example, the first code is “1”.

[0141] Alternatively, as shown in FIG. 13B, in the plurality of parallel first sub-servo stripes 411, the interval between a group of adjacent first sub-servo stripes 411 is a sixth set value S6. At this time, the servo pattern 40 represents a second code, for example, the second code is “0”.

[0142] The group of adjacent first sub-servo stripes 411 can be any two adjacent first sub-servo stripes 411 in the first servo stripe 41, and FIGS. 13A and 13B are only a schematic diagram.

[0143] The fifth set value S5 can be greater than the sixth set value S6, or the fifth set value S5 can be smaller than the sixth set value S6, as long as the fifth set value S5 is not equal to the sixth set value S6. In FIGS. 13A and 13B, the fifth set value S5 is greater than the sixth set value S6 is taken as an example for illustration, and the first sub-servo stripe 411 between the interval is the fifth set value S5, and the first sub-servo stripe 411 between the interval is the sixth set value S6 is taken as an example for illustration, and the code can also be interchanged.

[0144] That is, when the servo pattern 40 provided by the embodiment of the present application is applied to the magnetic tape 11, each servo band of the tape body 30 is provided with a plurality of groups of servo patterns 40, and the servo pattern 40 has a group of adjacent first sub servo fringes 411 with a spacing of a fifth set value S5 or a sixth set value S6. The spacing between the above-mentioned group of adjacent first sub servo fringes 411 in different servo patterns 40 can be different, and the specific value of the spacing between the first sub servo fringes 411 in the servo pattern 40 is related to the encoding of the servo band.

[0145] At this time, in the servo pattern 40 shown in FIGS. 13A and 13B, the spacing between the remaining adjacent first sub servo fringes 411 is a same set value, which can be equal to the fifth set value S5 or the sixth set value S6, or can be different from the fifth set value S5 and the sixth set value S6.

[0146] In other embodiments, the spacing between the adjacent first sub servo fringes 411 in the servo pattern 40 encoding "1" or "0" is a set value. The encoding "1" and "0" are distinguished by the second sub servo fringe 421 or the third sub servo fringe 431.

[0147] FIGS. 14A and 14B are schematic diagrams of encoding of another servo pattern provided by the embodiment of the present application.

[0148] Regarding the structure of the second sub servo fringe 421 in the servo pattern 40:

[0149] In some embodiments, as shown in FIGS. 14A and 14B, the spacing between the adjacent second sub servo fringes 421 in the servo pattern 40 encoding "1" or "0" is a set value.

[0150] The encoding "1" and "0" are distinguished by the fifth set value S5 and the sixth set value S6, which can simplify the amount of calculation.

[0151] In other embodiments, as shown in FIG. 13A, a group of adjacent second sub servo fringes 421 has a spacing of a seventh set value S7.

[0152] Or, as shown in FIG. 13B, a group of adjacent second sub servo fringes 421 has a spacing of an eighth set value S8.

[0153] The relationship between the second sub servo fringe 421 and the seventh set value S7 and the eighth set value S8 can be referred to the above-mentioned description of the relationship between the first sub servo fringe 411 and the fifth set value S5 and the sixth set value S6, which will not be described here.

[0154] The seventh setting value S7 and the eighth setting value S8 are not equal, and the value of the seventh setting value S7 can be equal to or different from the value of the fifth setting value S5. The value of the eighth setting value S8 can be equal to or different from the value of the sixth setting value S6.

[0155] The fifth setting value S5, the sixth setting value S6, the seventh setting value S7 and the eighth setting value S8 are combined to distinguish the code "1" and the code "0", which can improve the recognition accuracy of the code and can be applied to a high-speed scene.

[0156] Regarding the structure of the third sub-servo fringe 431 in the servo pattern 40:

[0157] In some embodiments, as shown in FIGS. 14A and 14B, the interval between adjacent third sub-servo fringes 431 in the servo pattern 40 is a setting value, regardless of the code "1" or the code "0". Only the fifth setting value S5 and the sixth setting value S6 are used to distinguish the code "1" and the code "0". Alternatively, the fifth setting value S5, the sixth setting value S6, the seventh setting value S7 and the eighth setting value S8 are used to distinguish the code "1" and the code "0". In this way, the amount of calculation can be simplified.

[0158] In other embodiments, as shown in FIG. 13A, the interval between a group of adjacent third sub-servo fringes 431 is a ninth setting value S9.

[0159] Alternatively, as shown in FIG. 13B, the interval between a group of adjacent third sub-servo fringes 431 is a tenth setting value S10.

[0160] The ninth setting value S9 and the tenth setting value S10 are not equal, and the value of the ninth setting value S9 can be equal to or different from the value of the fifth setting value S5 and the seventh setting value S7. The value of the tenth setting value S10 can be equal to or different from the value of the sixth setting value S6 and the eighth setting value S8.

[0161] The servo pattern 40 provided by the embodiments of the present application can be any combination of the above-mentioned multiple cases, as long as at least one group of the above-mentioned variables capable of distinguishing the code "1" and the code "0" is included.

[0162] Since the servo pattern 40 includes a small number of servo fringes, the position space left for the code is relatively large under the same lateral size. Compared with the displacement of a specific fringe in the limited space within the pattern, the servo pattern 40 of the present application can use a larger interval to code the "1" and "0" of the lateral position, the difference between the values of the setting values can be larger, the error can be tolerated, the recognition accuracy is high, and the requirement of recognition accuracy in a high-speed scene can be met.

[0163] FIG. 15A and FIG. 15B are schematic diagrams of another servo pattern according to the embodiments of the present application.

[0164] In some embodiments, as shown in FIG. 15A, the first direction X is a direction from left to right (e.g. the moving direction of the tape 30), and the servo pattern 40 further comprises a fourth servo stripe 44, which is parallel to the first servo stripe 41. The fourth servo stripe 44 is arranged on the side of the first servo stripe 41 away from the second servo stripe 42.

[0165] As shown in FIG. 15A, the interval between the fourth servo stripe 44 and the first servo stripe 41 is the first set value S1. At this time, the servo pattern 40 represents the first encoding.

[0166] Alternatively, as shown in FIG. 15B, the interval 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 encoding.

[0167] The first set value S1 can be greater than the second set value S2, or the first set value S1 can be less than the second set value S2, as long as the first set value S1 is not equal to the second set value S2. In FIG. 15A and FIG. 15B, the first set value S1 is greater than the second set value S2 is taken as an example, and the encoding is taken as an example that the interval between the fourth servo stripe 44 and the first servo stripe 41 is the first set value S1 when the encoding is "1", and the interval between the fourth servo stripe 44 and the first servo stripe 41 is the second set value S2 when the encoding is "0". The encoding can also be interchanged.

[0168] That is, when the servo pattern 40 provided by the embodiments of the present application is applied to the magnetic tape 11, each servo band of the tape 30 is provided with a plurality of servo patterns 40, the interval between the fourth servo stripe 44 and the first servo stripe 41 in the servo pattern 40 is the first set value S1 or the second set value S2, and the interval between the fourth servo stripe 44 and the first servo stripe 41 in different servo patterns 40 can be different. The specific value of the interval 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 band.

[0169] The servo pattern 40 can comprise one or more fourth servo stripes 44, and the embodiments of the present application only take the servo pattern 40 comprising one fourth servo stripe 44 as an example.

[0170] By adding the fourth servo stripe 44 in the servo pattern 40, the servo pattern 40 can be bit encoded to determine the lateral position of the magnetic head 21 on the magnetic tape 11. Moreover, since the fourth servo stripe 44 is arranged at the edge position of the servo pattern 40, it is not limited by the positional relationship among the first servo stripe 41, the second servo stripe 42 and the third servo stripe 43. Therefore, a larger interval can be used for bit encoding. That is, the first set value S1 and the second set value S2 can be larger, and the difference between the first set value S1 and the second set value S2 can be larger, the error tolerance is large, the recognition accuracy is high, and it can be applied to high-speed scenarios. In addition, after adding the fourth servo stripe 44, the moving speed of the magnetic head 21 can be obtained according to the interval between the fourth servo stripe 44 and the first servo stripe 41, and the moving speed of the magnetic head 21 can be obtained according to the interval between the first servo stripe 41 and the third servo stripe 43, and the two moving speeds are averaged. That is, the moving speed of the magnetic head 21 can be repeatedly measured to improve the detection accuracy of the speed.

[0171] FIGS. 16A and 16B are schematic diagrams of another servo pattern provided by embodiments of the present application.

[0172] In some embodiments, as shown in FIG. 16A, the first direction X is a direction from right to left (for example, opposite to the movement direction of the tape body 30), and the servo pattern 40 further includes a fourth servo stripe 44, which is parallel to the first servo stripe 41. The fourth servo stripe 44 is arranged on the side of the third servo stripe 43 away from the second servo stripe 42.

[0173] As shown in FIG. 16A, the interval 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 encoding.

[0174] Alternatively, as shown in FIG. 16B, the interval 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 encoding.

[0175] In some embodiments, the fourth servo stripe 44 is arranged on the side of the first servo stripe 41 away from the second servo stripe 42, and the fourth servo stripe 44 is also arranged on the side of the third servo stripe 43 away from the second servo stripe 42.

[0176] By adding two fourth servo stripes 44 in the servo pattern 40, the discrimination of bit encoding can be further improved to improve the accuracy of encoding recognition.

[0177] FIG. 17 is a schematic diagram of another servo pattern provided by embodiments of the present application.

[0178] In some embodiments, as shown in FIG. 17, the first servo stripe 41 is provided with a fourth servo stripe 44 on the side away from the second servo stripe 42, and the third servo stripe 43 is also provided with a fourth servo stripe 44 on the side away from the second servo stripe 42.

[0179] By adding two fourth servo stripes 44 in the servo pattern 40, the distinguishability of the bit coding can be further improved, so as to improve the accuracy of the coding recognition.

[0180] FIGS. 18A and 18B are schematic diagrams of another servo pattern according to embodiments of the present application.

[0181] In some embodiments, as shown in FIG. 18A, the servo pattern 40 further includes a fifth servo stripe 45, which is adjacent to and parallel to the second servo stripe 42, and the interval between the fifth servo stripe 45 and the second servo stripe 42 is a third set value S3.

[0182] Alternatively, as shown in FIG. 18B, the servo pattern 40 further includes a fifth servo stripe 45, which is adjacent to and parallel to the second servo stripe 42, and the interval between the fifth servo stripe 45 and the second servo stripe 42 is a fourth set value S4.

[0183] The third set value S3 can be greater than the fourth set value S4, or the third set value S3 can be less than the fourth set value S4, as long as the third set value S3 and the fourth set value S4 are not equal. In FIGS. 18A and 18B, the third set value S3 is greater than the fourth set value S4 is taken as an example, and the coding is taken as an example, that is, when the interval between the fifth servo stripe 45 and the second servo stripe 42 is the third set value S3, it is coded as “1”, and when the interval between the fifth servo stripe 45 and the second servo stripe 42 is the fourth set value S4, it is coded as “0”. The coding can also be interchanged.

[0184] By adding the fifth servo stripe 45 in the servo pattern 40, the servo pattern 40 can be bit-coded to determine the lateral position of the magnetic head 21 on the magnetic tape 11. Moreover, since the servo pattern 40 includes a small number of servo stripes, the position space left for coding is relatively large under the same lateral size. Therefore, a larger interval can be used for bit coding. That is, the third set value S3 and the fourth set value S4 can have a larger value, and the difference between the third set value S3 and the fourth set value S4 can be larger. The tolerance error is large, the recognition accuracy is high, and it can be applied to high-speed scenarios. In addition, after adding the fifth servo stripe 45, the interval between the fifth servo stripe 45 and the first servo stripe 41 and the interval between the second servo stripe 42 and the first servo stripe 41 can be combined to calculate the longitudinal displacement of the servo head 211, so as to improve the detection accuracy of the longitudinal displacement.

[0185] In some embodiments, along the width direction of the first servo fringe 41, the first servo fringe 41 is half of the first polarity and half of the second polarity. The first polarity and the second polarity are mutually the south pole and the north pole.

[0186] In some embodiments, along the width direction of the second servo fringe 42, the second servo fringe 42 is half of the first polarity and half of the second polarity. The first polarity and the second polarity are mutually the south pole and the north pole.

[0187] In some embodiments, along the width direction of the third servo fringe 43, the third servo fringe 43 is half of the first polarity and half of the second polarity. The first polarity and the second polarity are mutually the south pole and the north pole.

[0188] In some embodiments, along the width direction of the fourth servo fringe 44, the fourth servo fringe 44 is half of the first polarity and half of the second polarity. The first polarity and the second polarity are mutually the south pole and the north pole.

[0189] For example, when the servo pattern 40 provided by the embodiments of the present application is applied to the magnetic tape 11, the tape body 30 does not have polarity.

[0190] By making the servo fringe in the servo pattern 40 have a magnetic distribution state of half of the south pole and half of the north pole, the magnetization density of the servo pattern 40 can be improved.

[0191] FIG. 19 is a structural schematic diagram of a magnetic tape provided by the embodiments of the present application.

[0192] The servo pattern 40 provided by the embodiments of the present application can be applied in data storage of a magnetic tape machine 10. For example, as shown in FIG. 19, any one of the servo patterns 40 described above is applied to the magnetic tape 11 provided by the embodiments of the present application, and the magnetic tape 11 includes a tape body 30, and the servo pattern 40 is arranged on the tape body 30 and located in a servo tape area.

[0193] FIGS. 20A and 20B are structural schematic diagrams of another magnetic tape provided by the embodiments of the present application.

[0194] In some embodiments, as shown in FIGS. 20A and 20B, the magnetic tape 11 includes a plurality of groups of servo patterns 40, and the servo pattern 40 includes the fourth servo fringe 44, which is located on the side of the first servo fringe 41 away from the second servo fringe 42. The fourth servo fringe 44 and the third servo fringe 43 of adjacent servo patterns 40 are the same servo fringe.

[0195] In some embodiments, on the basis of sharing the fourth servo fringe 44, the interval between the fourth servo fringe 44 and the first servo fringe 41 can be adjusted to encode “1” and “0”.

[0196] The adjacent servo patterns 40 share the servo fringe, which can improve the space utilization of the tape body 30 and improve the storage capacity.

[0197] The embodiment of the present application also provides a write servo driving system, which comprises a driving unit and a servo write head. The driving unit is used for outputting a driving signal, and the servo write head is used for writing a servo pattern 40 under the driving of the driving signal. The servo pattern 40 can be any of the above structures.

[0198] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any change or replacement within the technical scope disclosed by the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A magnetic tape, characterized in that, The magnetic tape includes: reel; A magnetic tape is wound on the reel; the magnetic tape includes a tape body and multiple sets of servo patterns, the multiple sets of servo patterns 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 is parallel to the third servo stripe, the first servo stripe is not parallel to the second servo stripe, the trajectory of the second servo stripe is a curve, and the distances from each position of the second servo stripe to the first servo stripe are not equal; the first direction is the length direction of the strip body, and the second direction is the width direction of the strip body.

2. The magnetic tape reel according to claim 1, characterized in that, The first servo stripe is parallel to the second direction.

3. The magnetic tape reel according to claim 1 or 2, characterized in that, The trajectory of the curve satisfies a preset functional relationship.

4. The magnetic tape according to claim 3, characterized in that, The trajectory of the curve includes a portion that satisfies a first preset functional relationship and a portion that satisfies a second preset functional relationship.

5. The magnetic tape reel according to claim 3, characterized in that, The trajectory of the curve satisfies the tangent function relationship.

6. The magnetic tape according to any one of claims 1-5, characterized in that, The servo pattern also includes a fourth servo stripe, which is parallel to the first servo stripe. The fourth servo stripe is disposed 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.

7. The magnetic tape according to claim 6, characterized in that, The fourth servo stripe of the adjacent servo pattern is the same servo stripe as the third servo stripe.

8. The magnetic tape according to any one of claims 1-7, characterized in that, 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 according to any one of claims 1-5, characterized in that, The servo pattern also 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 set value or a fourth set value.

10. The magnetic tape according to any one of claims 1-5, characterized in that, 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. The spacing between a group of adjacent first sub-servo stripes in the plurality of parallel first sub-servo stripes is a fifth or a sixth preset value. or, The spacing between a group of adjacent second sub-servo stripes in the plurality of parallel second sub-servo stripes is a seventh set value or an eighth set value. or, Among the multiple parallel third sub-servo stripes, the spacing between a group of adjacent third sub-servo stripes is a ninth or tenth preset value.

11. The magnetic tape according to any one of claims 1-10, characterized in that, Along the width direction of the first servo stripe, the first servo stripe is half first polarity and half 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, Along the width direction of the third servo stripe, the third servo stripe is half of the first polarity and half of the second polarity; The first polarity and the second polarity are the South Pole and the North Pole, respectively.

12. A magnetic tape drive, characterized in that, The magnetic tape drive includes a magnetic tape reel and a head system, the head system being used to perform a read operation on the servo pattern; the magnetic tape reel includes the magnetic tape reel according to any one of claims 1-11.

13. A storage system, characterized in that, The storage system includes a processor and a plurality of magnetic tape drives, the processor being coupled to each of the magnetic tape drives; the magnetic tape drives include the magnetic tape drive of claim 12.

14. A write servo drive system, characterized in that, The write servo drive system includes: The drive unit is used to output drive signals; A servo writing head is used to write 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 is parallel to the third servo stripe, the first servo stripe is not parallel to the second servo stripe, the trajectory of the second servo stripe is a curve, and the distances from each position of the second servo stripe to the first servo stripe are not equal; the first direction is the length direction of the strip body, and the second direction is the width direction of the strip body.

15. The write servo drive system according to claim 14, characterized in that, The servo pattern also includes a fourth servo stripe, which is parallel to the first servo stripe. The fourth servo stripe is disposed 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.

16. The write servo drive system according to claim 14 or 15, characterized in that, The servo pattern also 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 set value or a fourth set value.

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