WO2024087820A1 - 驱动器、磁带装置和磁带存储系统 - Google Patents

驱动器、磁带装置和磁带存储系统 Download PDF

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Publication number
WO2024087820A1
WO2024087820A1 PCT/CN2023/113420 CN2023113420W WO2024087820A1 WO 2024087820 A1 WO2024087820 A1 WO 2024087820A1 CN 2023113420 W CN2023113420 W CN 2023113420W WO 2024087820 A1 WO2024087820 A1 WO 2024087820A1
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WIPO (PCT)
Prior art keywords
magnetic tape
magnetic
data
layer
drive
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PCT/CN2023/113420
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English (en)
French (fr)
Inventor
何昌军
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华为技术有限公司
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Publication of WO2024087820A1 publication Critical patent/WO2024087820A1/zh

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/488—Disposition of heads
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/584—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on tapes
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/596—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on disks

Definitions

  • the present disclosure mainly relates to the field of storage technology, and more specifically, to a magnetic tape drive, a magnetic tape device, and a magnetic tape storage system.
  • Tape storage devices or memory devices can store data through magnetic tape.
  • magnetic tape consists of a strip of material with a magnetizable cover material and is usually packaged in a coiled form.
  • Tape storage devices generally access data in a sequential manner, and the tape after storing data can be stored separately and read out through a tape drive.
  • tape storage has the characteristics of large storage capacity, low cost, low energy consumption, and easy portability, so it is very suitable for traditional storage and backup.
  • tapes have become thinner and longer, so it takes longer and longer to write or read a full tape. For example, it may take more than ten hours to write a full tape.
  • the long read and write time during the use of tape storage devices deteriorates the user experience and is unacceptable for many scenarios with high data real-time requirements, which seriously limits the application of tape storage.
  • the present disclosure provides an improved tape storage system, drive and tape device.
  • a drive comprising: a first driving mechanism, adapted to drive a magnetic tape in a magnetic tape device to roll between two reels, the magnetic tape comprising multiple layers of magnetic tape rolled in parallel; and multiple groups of magnetic heads, corresponding to the multiple layers of magnetic tape respectively, each group of magnetic heads being adapted to read or write data for a corresponding layer of magnetic tape during the rolling of the magnetic tape.
  • the time for reading or writing magnetic tape data can be reduced by multiples while the storage capacity remains unchanged, and the positioning time for reading files from the magnetic tape is also reduced.
  • the drive further comprises: a plurality of sets of rotating shafts, respectively corresponding to the plurality of sets of magnetic heads, each set of rotating shafts being adjacent to the corresponding set of magnetic heads and being adapted to position a section of a corresponding layer of magnetic tape to be read or written between two reels near the corresponding set of magnetic heads during the tape rolling, wherein the plurality of sets of rotating shafts are arranged to eliminate the travel difference between the plurality of layers of magnetic tape.
  • the travel difference caused by the difference in the travel paths of the plurality of layers of magnetic tape can be effectively eliminated, thereby improving the reading operation or writing operation of the magnetic head group.
  • multiple groups of magnetic heads are arranged in sequence along a direction perpendicular to the travel direction of the magnetic tape between the two reels, and are arranged to read or write data in parallel to the same offset address of the same track of the multi-layer magnetic tape.
  • the data reading and writing bandwidth can be increased by multiples in the magnetic tape storage system.
  • the drive is configured to write continuous data to the same offset address of the same track of the multi-layer magnetic tape via multiple sets of magnetic heads. This implementation helps multiple sets of magnetic heads write data to the multi-layer magnetic tape in parallel, thereby increasing the operating speed.
  • each layer of magnetic tape includes a plurality of tracks parallel to each other
  • the drive further includes: a second drive mechanism coupled to the plurality of sets of magnetic heads and adapted to drive each set of magnetic heads to move over different tracks of the corresponding layer of magnetic tape.
  • the plurality of groups of magnetic heads are driven independently or uniformly by the second driving mechanism. This implementation helps to adjust the position of each group of magnetic heads respectively, thereby eliminating the position deviation of each layer of magnetic heads relative to their respective target tracks.
  • each group of magnetic heads includes at least one data head and at least one servo head, at least one data head is suitable for reading or writing data tracks of a corresponding layer of magnetic tape, and at least one servo head is suitable for reading magnetic head position information from the servo tracks of the corresponding layer of magnetic tape for controlling the second driving mechanism. This implementation helps to accurately position the data head above the target track.
  • the drive further comprises one of the two reels.
  • the drive can be applicable to a single-reel magnetic tape device.
  • a magnetic tape device comprising: a reel; and multiple layers of magnetic tapes wound in parallel on the reel.
  • the magnetic tape device further comprises: a plurality of sets of rotating shafts, each corresponding to the multiple layers of magnetic tape, each set of rotating shafts being adapted to position a to-be-read or to-be-written section of the corresponding layer of magnetic tape near a set of magnetic heads corresponding to the corresponding layer of magnetic tape during the magnetic tape rolling, wherein the plurality of sets of rotating shafts are arranged to eliminate the travel difference between the multiple layers of magnetic tape.
  • the travel difference caused by the difference in the travel path of the multiple layers of magnetic tape between the two reels can be effectively eliminated, thereby improving the data reading operation or writing operation of the magnetic tape.
  • each layer of magnetic tape includes a plurality of tracks parallel to each other, the plurality of tracks include a plurality of data tracks and at least one servo track, the plurality of data tracks are suitable for storing data, and the at least one servo track is suitable for storing information for assisting the positioning of the magnetic head.
  • This implementation helps to accurately position the data head above the target track.
  • the continuous data is distributed at the same offset address of the same track of the multi-layer magnetic tape. This implementation helps to read the data of the multi-layer magnetic tape in parallel to shorten the reading time.
  • data distributed on multiple layers of magnetic tapes have a redundant protection relationship. This implementation helps to improve the data storage reliability of a storage system with multiple layers of magnetic tapes.
  • a magnetic tape storage system comprising: the drive according to the first aspect; and the magnetic tape device according to the second aspect.
  • the magnetic tape storage system according to the third aspect provided above comprises a drive according to the first aspect and a magnetic tape device according to the second aspect. Therefore, the explanation or description of the first aspect and the second aspect is also applicable to the third aspect.
  • the beneficial effects that can be achieved by the third aspect can refer to the beneficial effects of the first aspect and the second aspect, which will not be repeated here.
  • FIG. 1 shows a schematic structural diagram of a conventional magnetic tape storage system.
  • FIG2 shows a schematic structural diagram of a tape storage system according to an embodiment of the present disclosure.
  • FIG3 shows a schematic structural diagram of a magnetic tape device of a magnetic tape storage system according to an embodiment of the present disclosure.
  • FIG 4 is an enlarged perspective view of a partial section of a multi-layer magnetic tape according to an embodiment of the present disclosure.
  • FIG. 5 shows an enlarged top view of a partial section of a magnetic tape layer according to an embodiment of the present disclosure.
  • FIG. 6 shows a schematic block diagram of a drive of a magnetic tape storage system according to an embodiment of the present disclosure.
  • FIG. 7 shows a schematic structural diagram of multiple groups of magnetic heads according to an embodiment of the present disclosure.
  • FIG. 8 shows a simplified schematic diagram of data distribution of a multi-layer magnetic tape according to an embodiment of the present disclosure.
  • FIG. 1 shows a schematic diagram of the structure of a conventional magnetic tape storage system 1000'.
  • the magnetic tape storage system 1000' includes a magnetic head 120' and a magnetic tape 220' wound on a reel 210'.
  • the magnetic tape 220' will roll between the reel 210' and another reel 140'.
  • FIG. 1 In the process of the magnetic tape 220' rolling from the reel 210' to the reel 140' or from the reel 140' to the reel 210', the magnetic tape 220' moves back and forth under the magnetic head 120', so that the magnetic head 120' sequentially writes data into the magnetic tape 220' or sequentially reads data in the magnetic tape 220'. It can be seen that for the tape storage system 1000', if the magnetic head 120' writes or reads data to the entire tape 220', the magnetic head 120' must at least pass through the entire length of the entire tape. Therefore, the actual time required to read or write data to the tape is highly correlated with the length of the tape. In the tape device of FIG. 1, there is only one layer of tape (that is, tape 220'), so FIG. 1 describes a single-layer tape storage system. Layer tape device.
  • LTO Ultrium released its first generation product LTO-1 in 2000, and has developed to the ninth generation LTO-9 so far.
  • the following table lists some parameter comparisons from the first generation LTO-1 to the ninth generation LTO-9.
  • the tape capacity has increased from 0.1TB to as high as 18TB, but the tape length has also increased from 609 meters to 1035 meters.
  • the time to write a full tape increases from at least 1 hour and 23 minutes to at least 12 hours and 30 minutes.
  • the average positioning time for reading files from the tape has also increased to about 45 seconds. The long read and write time and longer positioning time deteriorate the user experience and make tape storage unusable in scenarios with high data real-time requirements.
  • the embodiment of the present disclosure proposes an improved tape storage solution.
  • the improved solution by changing the number of tape layers from a single layer to multiple layers and correspondingly arranging multiple sets of magnetic heads in the drive, parallel reading and writing operations can be performed on the multi-layer tape.
  • the length of each layer of the tape can be reduced by multiples, thereby greatly shortening the time required to read or write data without increasing the reading speed or writing speed, and also reducing the positioning time required to read a file in the tape.
  • FIG. 2 shows a schematic diagram of the structure of a tape storage system 1000 according to an embodiment of the present disclosure.
  • the tape storage system 1000 uses a magnetic tape as a storage medium and is capable of accessing data in the magnetic tape.
  • the tape storage system 1000 is used, for example, as an auxiliary memory or main memory of a computing device or a processing device, and is suitable for scenes such as sequentially reading and writing a large amount of data, and offline archival storage.
  • the tape storage system 1000 includes a drive 100 and a tape device 200.
  • the tape device 200 is loaded in the drive 100 and can be separated from the drive 100 for separate storage.
  • the drive 100 can perform data read and write operations on the tape device 200.
  • FIG. 3 shows a schematic diagram of the structure of a magnetic tape device 200 according to an embodiment of the present disclosure.
  • the magnetic tape device 200 includes a reel 210 and a magnetic tape 220.
  • the magnetic tape 220 includes a tape base and a magnetic surface layer covering the surface of the tape base.
  • the tape base is made of polyester film or other suitable materials, and the magnetic surface layer includes a magnetizable medium or a magnetic medium such as ⁇ -Fe 2 O 3 and CrO 2.
  • the magnetic tape device 200 is a single reel structure, that is, there is only one reel 210.
  • the magnetic tape device 200 is also a double reel structure. It can be understood that other components not shown in the figure can also be provided in the magnetic tape device 200 as needed, such as a shell for protecting the magnetic tape 220.
  • the magnetic tape 220 of the magnetic tape device 200 includes a multi-layer magnetic tape wound in parallel on the reel 210.
  • a multi-layer magnetic tape wound in parallel on the reel 210.
  • three magnetic tape layers 220-1, 220-2 and 220-3 are wound in parallel on the reel 210.
  • the number of layers of the magnetic tape is not limited thereto, but can be other appropriate numbers of layers, such as 2 layers, 4 layers or more layers.
  • the length of the magnetic tape of the LTO-9 of a single magnetic tape layer is 1035 meters, and if the magnetic tape is constructed in a multi-layer magnetic tape manner, the length of each layer of magnetic tape of the same capacity is reduced to 1/N of the length of 1035 meters, where N is the number of layers of the multi-layer magnetic tape.
  • N is the number of layers of the multi-layer magnetic tape.
  • FIG. 4 shows an enlarged stereoscopic view of a partial section of a multi-layer magnetic tape 220-1, 220-2, and 220-3 according to an embodiment of the present disclosure
  • FIG. 5 shows an enlarged top view of a partial section of a magnetic tape layer 220-1 according to an embodiment of the present disclosure.
  • each layer of magnetic tape 220-1, 220-2, or 220-3 includes a plurality of tracks parallel to each other, and the plurality of tracks include a plurality of data tracks 221 suitable for storing data.
  • the data tracks 221 are tracks for recording data, and in order to maximize the use of the width of the magnetic tape, the number of data tracks 221 can be as high as several thousand, for example, as high as more than 8,000.
  • These data tracks 221 can be formed, for example, by extending in a serpentine manner, that is, extending from the beginning to the end of each layer of magnetic tape. end, and then extend from the end to the beginning.
  • each layer of magnetic tape 220-1, 220-2 or 220-3 may also include at least one servo track 222, and at least one servo track 222 is suitable for storing information for assisting the positioning of the magnetic head.
  • the servo track 222 may be located on both sides or either side of the data track 221 in the width direction of the magnetic tape, and a single servo track 222 may, for example, be composed of a plurality of straight line segment patterns with an inclined angle (see FIG. 5 ).
  • the magnetic head of the drive 100 may determine the position of the magnetic head as a whole by reading the data on the servo track 222.
  • the implementation of the servo track 222 is not limited thereto, for example, the servo track 222 may also be arranged between the data tracks without being arranged on both sides of the data tracks, or the servo track 222 may include patterns of other shapes suitable for positioning.
  • FIG6 shows a schematic block diagram of a drive 100 according to an embodiment of the present disclosure.
  • the drive 100 of the tape storage system 1000 may include a first drive mechanism 110, which is suitable for driving the tape 220 in the tape device 200 to roll between the two reels 150 and 210.
  • the first drive mechanism 110 may include a motor or other actuator suitable for driving the reels to rotate. After the tape device 200 is loaded into the drive 100, the end of the tape 220 may be adsorbed and pulled to the other reel 150. Then, the motor or other actuator of the first drive mechanism 110 drives at least one of the reels 150 and 210 to rotate, thereby rolling the tape 220 from the reel 210 to the other reel 150, or from the other reel 150 to the reel 210.
  • the drive 100 includes a reel 150 of two reels 150 and 210.
  • the drive 100 may provide another reel 150 for rolling the magnetic tape 220, so that the magnetic tape 220 can roll between the reel 210 of the tape device 200 and the reel 150 of the drive 100.
  • the drive 100 may not be provided with a reel, but only provide a first drive mechanism 110 for driving the reel, which can also implement the embodiments of the present disclosure.
  • the first drive mechanism 110 of the drive 100 may provide one or two engaging elements such as a shaft body to engage with one or two reels of the tape device 200.
  • the reel of the tape device 200 can be sleeved and fixed on the engaging element (e.g., shaft body) of the first drive mechanism 110.
  • the engaging element can drive the reel of the magnetic tape device 200 to rotate under the drive of the motor or other actuator of the first driving mechanism 110 .
  • the drive 100 includes a space for storing a magnetic tape, and a plurality of groups of magnetic heads corresponding to multiple layers of magnetic tape, for example, groups of magnetic heads 120-1, 120-2, and 120-3 corresponding to the magnetic tape layers 220-1, 220-2, and 220-3.
  • Each group of magnetic heads 120-1, 120-2, or 120-3 is suitable for reading or writing data for the corresponding layer of magnetic tape 220-1, 220-2, and 220-3 during the rolling of the magnetic tape 220.
  • each group of magnetic heads 120-1, 120-2, or 120-3 includes at least a write head and a read head, wherein the write head records data by magnetizing and changing the magnetic field of the magnetic medium, and the read head reads data on the magnetic medium by sensing the magnetic field of the magnetic medium.
  • the magnetic head in the magnetic head group 120-1 reads or writes data to the magnetic tape layer 220-1
  • the magnetic head in the magnetic head group 120-2 reads or writes data to the magnetic tape layer 220-2
  • the magnetic head in the magnetic head group 120-3 reads or writes data to the magnetic tape layer 220-3. Since multiple groups of magnetic heads read or write multiple layers of magnetic tape in parallel, the actual speed of data reading or writing is greatly accelerated, thus shortening the time required to read or write data by multiples compared to conventional solutions.
  • the drive 100 also includes multiple groups of shafts 130-1, 130-2 and 130-3 corresponding to the multiple groups of heads, each group of shafts is adjacent to the corresponding group of heads and is suitable for positioning the to-be-read or to-be-written section of the corresponding layer of magnetic tape located between the two reels 150 and 210 near the corresponding group of heads during the winding of the magnetic tape 220, wherein the multiple groups of shafts are arranged to eliminate the travel difference between the multiple layers of magnetic tape.
  • the shaft groups 130-1, 130-2 and 130-3 may correspond to the head groups 120-1, 120-2 and 120-3, respectively.
  • the shaft group 130-1 is adjacent to the head group 120-1, and two or more shafts are provided on both sides of the head group 120-1 along the direction in which the magnetic tape extends, thereby positioning a partial section of the magnetic tape layer 130-1 near the top of the head group 120-1, so that the magnetic head in the head group 120-1 performs a read operation or a write operation on the partial section.
  • the shaft groups 130-2 and 130-3 may include a plurality of shafts, respectively, and are arranged near the head groups 120-2 and 120-3, respectively, so that the magnetic head groups 120-2 and 120-3 perform a read operation or a write operation on the magnetic tape layers 220-2 and 220-3, respectively. Since the magnetic tape layers 220-1, 220-2 and 220-3 roll on different paths, there is inevitably a travel difference between them. For example, since the magnetic head group 120-1 is farther away from the two reels 150 and 220 than the magnetic head groups 120-2 and 120-3, the magnetic tape layer 220-1 corresponding to the magnetic head group 120-1 will have a longer travel between the two reels than the magnetic tape layers 220-2 and 220-3.
  • the magnetic tape layer 220-2 has a longer travel between the two reels than the magnetic tape layer 220-3. This travel difference will affect the parallel reading operation or writing operation of the magnetic head groups 120-1, 120-2 and 120-3. For this reason, the rotating shaft groups 130-1, 130-2 and 130-3 can be designed or arranged to eliminate the travel difference between the magnetic tape layers 220-1, 220-2 and 220-3.
  • the spindle group 130-2 can be provided with more spindles, and the magnetic tape layer 220-2 can travel along a more tortuous path between the multiple spindles, thereby increasing the stroke of the magnetic tape layer 220-2 between the two reels to eliminate the stroke difference between the magnetic tape layer 220-2 and the magnetic tape layer 220-1.
  • the spindle group 130-3 can be designed and arranged to allow the magnetic tape layer 220-3 to have a longer stroke between the two reels, thereby eliminating the stroke difference between the magnetic tape layer 220-3 and the magnetic tape layers 220-1 and 220-2.
  • multiple sets of shafts 130-1, 130-2 and 130-3 may also be provided in the tape device 200, wherein the multiple sets of shafts 130-1, 130-2 and 130-3 correspond to the multiple layers of magnetic tape 220-1, 220-2 and 220-3 in the tape device 200, respectively, and similarly help to achieve positioning between each layer of magnetic tape and the corresponding head group, and eliminate the travel difference between the multiple layers of magnetic tape.
  • the drive 100 further includes a second drive mechanism 140, which is coupled to the plurality of heads 120-1, 120-2, and 120-3 and is adapted to drive each head group 120-1, 120-2, or 120-3 to move over different tracks of the corresponding layer of magnetic tape 220-1, 220-2, or 220-3.
  • the second drive mechanism may include a voice coil motor (VCM) or other actuators to drive the plurality of heads 120-1, 120-2, and 120-3 to move. Since each layer of magnetic tape may have up to thousands of parallel tracks, the number of heads in each head group is usually only a few or dozens (e.g., 8 or 32), and a single head can only perform a write or read operation on a single track.
  • VCM voice coil motor
  • each group of magnetic heads can first perform a read or write operation along a portion of the tracks, and after completing the read or write operation of this portion of the tracks, the second drive mechanism 140 drives the group of magnetic heads to move to the top of another portion of the tracks to continue to perform the read or write operation.
  • each group of magnetic heads can read the data of the first portion of the tracks of each layer of the magnetic tape, and after the magnetic tape 220 is completely wound onto the reel 150, each group of magnetic heads can be moved to the top of the second portion of the tracks by the second drive mechanism 140, and then as the magnetic tape 220 is rewound from the reel 150 to the reel 210, each group of magnetic heads continues to read the data of the second portion of the tracks of each layer of the magnetic tape. In this way, as the magnetic tape rolls back and forth between the two reels, each group of magnetic heads can complete data reading or data writing for all the tracks of each layer of the magnetic tape.
  • multiple groups of magnetic heads 120-1, 120-2 and 120-3 are driven independently of each other by the second driving mechanism 140.
  • the number of tracks on the magnetic tape is large and the width of a single track is small.
  • the width of a single track is only a few microns. Therefore, a slight deviation in the position of each layer of magnetic tape may cause the magnetic head to deviate from the corresponding track.
  • the second driving mechanism 140 By driving multiple groups of magnetic heads 120-1, 120-2 and 120-3 independently of each other, it is helpful to adjust each group of magnetic heads separately to eliminate position deviations and accurately position each group of magnetic heads to the corresponding track, thereby reducing or eliminating the risk of failure to read or write data.
  • multiple VCMs can be set to control each group of magnetic heads separately, or a single VCM can be set to drive each group of magnetic heads to move in sequence.
  • the second driving mechanism 140 can also uniformly drive multiple groups of magnetic heads 120-1, 120-2 and 120-3 to move. In this way, the drive control of the head group can be achieved in a simpler way, thereby simplifying the control process.
  • Each group of magnetic heads 120-1, 120-2 or 120-3 includes at least one data head 121 and at least one servo head 122, at least one data head 121 is suitable for reading or writing data tracks 221 of the corresponding layer of magnetic tape 220-1, 220-2 or 220-3, and at least one servo head 122 is suitable for reading head position information from the servo tracks 222 of the corresponding layer of magnetic tape 220-1, 220-2 or 220-3 for controlling the second driving mechanism 140.
  • each group of magnetic heads 8 data heads 121 or any other appropriate number of data heads (for example, 32 data heads) can be set, and these data heads 121 are arranged in sequence along a direction parallel to the width direction of the magnetic tape.
  • One or more servo heads 122 may be arranged on both sides of the data head 121, or one or more servo heads 122 may be arranged on one side of the two sides of the data head 121.
  • the arrangement of the data head 121 and the servo head 122 may correspond to the arrangement direction of the data track 221 and the servo track 222 of the magnetic tape, so as to align the data head 121 with the target data track and align the servo head 122 with the servo track 222 when performing data reading or data writing.
  • the servo track 222 usually has a specific pattern that is easy to locate, such as a straight line segment with an inclined angle, so that when the head group moves over different data tracks, the servo head 122 of the head group will align with different positions of the inclined straight line segment of the servo track 222 and read the corresponding position information, so that the position of the head group as a whole can be determined.
  • the drive 100 may also be provided with a support 125 for supporting and arranging multiple groups of heads 120-1, 120-2 and 120-3.
  • a support 125 for supporting and arranging multiple groups of heads 120-1, 120-2 and 120-3.
  • the support body 125 shown in FIG. 7 is merely exemplary and not restrictive, and the support body 125 may have any appropriate shape and structure.
  • three support bodies separated from each other may be provided for three groups of magnetic heads.
  • multiple groups of magnetic heads 120-1, 120-2, and 120-3 are sequentially arranged along a direction perpendicular to the traveling direction of the magnetic tape between the two reels 150 and 210, and are arranged to read or write data in parallel to the same offset address of the same track of the multi-layer magnetic tape 220-1, 220-2, and 220-3.
  • the multiple-level improvement of data reading and writing bandwidth can be achieved.
  • the bandwidth of the magnetic tape storage system 1000 will be N times that of a conventional single-layer magnetic tape system.
  • the drive 100 further includes a data transmission and control logic circuit 180.
  • the data transmission and control logic circuit 180 can be communicatively coupled to the multiple sets of magnetic heads 120, and transmit data that the multiple sets of magnetic heads 120 have read from the magnetic tape 220 or transmit data that will be written to the magnetic tape 220 via the multiple sets of magnetic heads 120.
  • the data transmission and control logic circuit 180 can be communicatively coupled to the first drive mechanism 110, and control the first drive mechanism 110 to drive the reels according to external instructions or a predetermined program so that the magnetic tape 220 rolls between the two reels.
  • the data transmission and control logic circuit 180 can also include a servo control processor 181 for controlling the second drive mechanism 140.
  • the servo heads 122 in each set of magnetic heads generate a servo signal indicating the position of the magnetic heads.
  • the servo signal can obtain the current position information of each set of magnetic heads after signal decoding and is provided to the servo control processor 181.
  • the servo control processor 181. Based on the comparison between the target track information and the current position information, the servo control processor 181 sends a control signal to instruct the second drive mechanism 140 to drive each group of magnetic heads to move to the target track where data reading or data writing is required, thereby quickly and accurately guiding the data head to the target track, and also timely calibrating when the position of the magnetic head or track deviates.
  • the data transmission and control logic circuit 180 can also coordinate the operations between each drive mechanism and the magnetic head group, for example, with the help of the main control chip.
  • the data transmission and control logic circuit 180 and the servo control processor 181 can be implemented in any appropriate manner.
  • the data transmission and control logic circuit 180 may include one or more processors or controllers, which can implement the functions of reading or writing data transmission and controlling the first drive mechanism, and at the same time provide the functions of the servo control processor 181, or the data transmission and control logic circuit 180 can additionally provide a processor or controller dedicated to implementing the functions of the servo control processor 181.
  • the servo control processor 181 can also be set independently instead of being set in the data transmission and control logic circuit 180, which can also implement the embodiments of the present disclosure. It is understood that in addition to the components or elements shown in Figures 2 and 6, other components and peripheral structures can be set in the driver as needed.
  • FIG8 shows a simplified schematic diagram of data distribution of multi-layer magnetic tapes 220-1, 220-2, and 220-3 according to an embodiment of the present disclosure.
  • continuous data is distributed at the same offset address of the same track of the multi-layer magnetic tapes 220-1, 220-2, and 220-3.
  • the drive 100 can be configured to write continuous data to the same offset address of the same track of the multi-layer magnetic tapes 220-1, 220-2, and 220-3 via multiple sets of magnetic heads 120-1, 120-2, and 120-3.
  • the storage space with the same offset position of the same track of the multi-layer magnetic tape 220-1, 220-2 and 220-3 can be defined as a continuous storage space, so that a piece of continuous data can be written and stored in such a continuous storage space.
  • the target data can be distributed at the same offset address of the same numbered track of the multi-layer magnetic tape through specific coding slices.
  • the target data can be divided into several fragments and stored at the same address of the same numbered track of the multi-layer magnetic tape.
  • These fragments can be distributed in the multi-layer magnetic tape according to certain rules or randomly, and when reading data, the fragments obtained by multiple groups of magnetic heads from the same address of the multi-layer magnetic tape can be immediately combined into the target data.
  • This storage method can facilitate multiple groups of magnetic heads to read available data from the multi-layer magnetic tape in parallel in less time, simplifying the subsequent processing of the data.
  • data distributed on the multi-layer magnetic tapes 220-1, 220-2, and 220-3 have a redundant protection relationship.
  • One implementation is that data on the same offset address of the same numbered tracks on different magnetic tapes form a redundant protection group.
  • the data when storing or writing data in the above continuous storage space, the data can be preprocessed according to a redundancy algorithm such as an erasure coding (EC) algorithm to generate a set of data blocks with redundant data or check data, and the set of data blocks are dispersedly stored in different layers of magnetic tapes.
  • the set of data blocks conforms to the EC check algorithm or other check algorithms.
  • the redundant array of independent disks (RAID) algorithm can be regarded as a type of EC algorithm. For example, RAID-5 is equivalent to the k+1 mode of EC, k data blocks + 1 check block; RAID-6 is equivalent to the k+2 mode of EC, k data blocks + 2 check blocks.
  • different data blocks of the same EC group are distributed in different tapes, so that even if one or a few layers of the multi-layer tape fail, all data can be restored through data from other layers.
  • the application of the redundancy algorithm effectively improves the data storage reliability of the storage system 1000 with multiple layers of tapes.
  • a 3+2 EC check group consisting of 5 layers of tapes, even if any one or two layers of the tape are damaged, the data lost due to the damage can be restored through data from other layers of tapes.
  • it can also support redundant protection of multiple copies, that is, storing different copies of the same data in different tapes of the same tape device.
  • the data blocks belonging to the same check group are stored in multiple layers of tapes in a dispersed manner. This data protection method is also called a check relationship between the multiple layers of tapes.
  • the time for reading or writing tape data can be reduced by multiples while the disk capacity and the reading speed or writing speed remain unchanged, and the positioning time for reading files from the tape is also reduced.
  • the scheme of the present disclosure effectively improves the real-time performance of data reading and writing of the tape storage system.

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Abstract

一种驱动器(100)、磁带装置(200)和磁带存储系统(1000)。驱动器(100)包括：第一驱动机构(110)，适于驱动磁带装置(200)中的磁带(220)在两个卷轴(150、210)之间卷动，磁带(220)包括并行卷动的多层磁带(220-1、220-2、220-3)；以及多组磁头(120-1、120-2和120-3)，分别与多层磁带(220-1、220-2、220-3)相对应，每组磁头(120-1、120-2和120-3)适于在磁带(220)卷动期间针对对应层磁带(220-1、220-2、220-3)进行数据的读取或写入。有益效果：可以有效减少磁带存储系统(1000)读取或写入磁带数据的时长，并且还可以减少从磁带(220)中读取文件的定位时长。

Description

驱动器、磁带装置和磁带存储系统 技术领域
本公开主要涉及存储技术领域，更具体地，涉及一种磁带驱动器、磁带装置以及磁带存储系统。
背景技术
磁带存储设备或存储器可以通过磁带来实现数据存储。作为一种非易失性存储介质的磁带由具有可磁化覆盖材料的带状物组成，并且通常采用卷绕的方式进行封装。磁带存储设备一般以顺序的方式存取数据，并且存储数据后的磁带能够单独保存并可以通过磁带驱动器读出数据。此外，磁带存储具有存储容量大、低成本、低能耗并且易于携带等特点，因此非常适合于传统的存储和备份。
随着信息技术的快速发展，为了存储海量的数据和信息，对存储容量的要求不断增加。然而，为了增大磁带存储的容量，磁带变得更薄并且更长，从而将整盘磁带写满或者读取整盘磁带所需耗费的时间也越来越长。例如，写满整盘磁带的时间可能会长达十小时以上。磁带存储设备使用过程中的过长的读写时间劣化了用户体验，并且对于数据实时性要求较高的很多场景是无法接受的，这严重限制了磁带存储的应用。
发明内容
本公开的提供了一种改进的磁带存储系统以及驱动器和磁带装置。
在本公开的第一方面，提供了一种驱动器，包括：第一驱动机构，适于驱动磁带装置中的磁带在两个卷轴之间卷动，磁带包括并行卷动的多层磁带；以及多组磁头，分别与多层磁带相对应，每组磁头适于在磁带卷动期间针对对应层磁带进行数据的读取或写入。
通过提供与多层磁带相对应的多组磁头，相比于单层磁带和单组磁头的常规方案，可以在存储容量不变的情况下以倍数级减少读取或写入磁带数据的时长，并且还减少了从磁带中读取文件的定位时长。
在第一方面的一种实现方式中，驱动器还包括：多组转轴，分别与多组磁头相对应，每组转轴邻近于对应组磁头并且适于在磁带卷动期间将对应层磁带的位于两个卷轴之间的待读取或待写入区段定位在对应组磁头附近，其中多组转轴被布置为消除多层磁带之间的行程差。通过这种实现方式，可以有效消除多层磁带的行进路径差异造成的行程差，从而改善磁头组的读取操作或写入操作。
在第一方面的一种实现方式中，多组磁头沿着与两个卷轴之间的磁带的行进方向垂直的方向依次布置，并且被布置为对多层磁带的相同磁道的相同偏移地址并行地进行数据的读取或写入。通过这种实现方式，可以在磁带存储系统中以倍数级提升数据读取和写入带宽。
在第一方面的一种实现方式中，驱动器被配置为经由多组磁头将连续数据写入多层磁带的相同磁道的相同偏移地址。通过这种实现方式，有助于多组磁头以并行的方式将数据写入多层磁带，从而提升操作速度。
在第一方面的一种实现方式中，每层磁带包括彼此平行的多个磁道，并且驱动器还包括：第二驱动机构，耦合到多组磁头，并且适于驱动每组磁头在对应层磁带的不同磁道上方移动。通过这种实现方式，可以准确地将磁头引导到目标磁道上方，并且有助于实时校准磁头相对于目标磁道的位置，从而避免数据读取或数据写入失败。
在第一方面的一种实现方式中，多组磁头彼此独立地或统一地被第二驱动机构驱动。通过这种实现方式，有助于针对各组磁头分别进行位置调整，从而消除各层磁头相对于各自目标磁道的位置偏差。
在第一方面的一种实现方式中，每组磁头包括至少一个数据磁头和至少一个伺服磁头，至少一个数据磁头适于针对对应层磁带的数据磁道进行读取或写入，并且至少一个伺服磁头适于从对应层磁带的伺服磁道读取磁头位置信息以用于控制第二驱动机构。通过这种实现方式，有助于将数据磁头准确地定位到目标磁道上方。
在第一方面的一种实现方式中，驱动器还包括两个卷轴中的一个卷轴。在这种实现方式中，驱动器可以适用于单卷轴的磁带装置。
在本公开的第二方面，提供了一种磁带装置，包括：卷轴；以及多层磁带，并行地卷绕在卷轴上。通过提供多层磁带，相比于单层磁带的方案，可以在存储容量不变的情况下以倍数级减少读取或写入磁带数据的时长，并且还减少了从磁带中读取文件的定位时长。
在第二方面的一种实现方式中，磁带装置还包括：多组转轴，分别与多层磁带相对应，每组转轴适于在磁带卷动期间将对应层磁带的待读取或待写入区段定位在与该对应层磁带相对应的一组磁头附近，其中多组转轴被布置为消除多层磁带之间的行程差。通过这种实现方式，可以有效消除多层磁带在两个卷轴之间的行进路径差异造成的行程差，从而改善磁带的数据读取操作或写入操作。
在第二方面的一种实现方式中，每层磁带包括彼此平行的多个磁道，多个磁道包括多个数据磁道和至少一个伺服磁道，多个数据磁道适于存储数据，并且至少一个伺服磁道适于存储用于辅助磁头定位的信息。通过这种实现方式，有助于将数据磁头准确地定位到目标磁道上方。
在第二方面的一种实现方式中，连续数据分布在多层磁带的相同磁道的相同偏移地址。通过这种实现方式，有助于并行读取多层磁带的数据以缩短读取时长。
在第二方面的一种实现方式中，分布在多层磁带的数据具有冗余保护关系。通过这种实现方式，有助于改善具有多层磁带的存储系统的数据存储可靠性。
在第二方面的一种实现方式中，多层磁带之间具有校验关系。通过这种实现方式，可以增强数据的存储可靠性，同时避免用于实现冗余保护的数据占用过多空间。
在本公开的第三方面，提供了一种磁带存储系统，包括：根据第一方面的驱动器；以及根据第二方面的磁带装置。
上述提供的根据第三方面的磁带存储系统包括根据第一方面的驱动器和根据第二方面的磁带装置。因此，关于第一方面和第二方面的解释或者说明同样适用于第三方面。此外，第三方面所能达到的有益效果可参考关于第一方面和第二方面的有益效果，此处不再赘述。
本发明的这些和其它方面在以下(多个)实施例的描述中会更加简明易懂。
附图说明
结合附图并参考以下详细说明，本公开各实施例的上述和其他特征、优点及方面将变得更加明显。在附图中，相同或相似的附图标注表示相同或相似的元素，其中：
图1示出了常规的磁带存储系统的结构示意图。
图2示出了根据本公开的实施例的磁带存储系统的结构示意图。
图3示出了根据本公开的实施例的磁带存储系统的磁带装置的结构示意图。
图4根据本公开的实施例的多层磁带的部分区段的放大立体视图。
图5示出了根据本公开实施例的磁带层的部分区段的放大俯视图。
图6示出了根据本公开的实施例的磁带存储系统的驱动器的示意框图。
图7示出了根据本公开的实施例的多组磁头的结构示意图。
图8示出了根据本公开的实施例的多层磁带的数据分布的简化示意图。
具体实施方式
下面将参照附图更详细地描述本公开的实施例。虽然附图中显示了本公开的某些实施例，然而应当理解的是，本公开可以通过各种形式来实现，而且不应该被解释为限于这里阐述的实施例，相反提供这些实施例是为了更加透彻和完整地理解本公开。应当理解的是，本公开的附图及实施例仅用于示例性作用，并非用于限制本公开的保护范围。
在本公开的实施例的描述中，术语“包括”及其类似用语应当理解为开放性包含，即“包括但不限于”。术语“基于”应当理解为“至少部分地基于”。术语“一个实施例”或“该实施例”应当理解为“至少一个实施例”。术语“第一”、“第二”等等可以指代不同的或相同的对象。下文还可能包括其他明确的和隐含的定义。
如前文所述，磁带存储具有低成本、低能耗等诸多优点，因此被广泛用于数据和资料的存储和备份。图1示出了常规的磁带存储系统1000’的结构示意图。如图1所示，磁带存储系统1000’包括磁头120’和卷绕在卷轴210’上的磁带220’。当需要对磁带220’中的数据进行读写时，磁带220’会在卷轴210’与另一卷轴140’之间卷动。在磁带220’从卷轴210’卷动到卷轴140’或从卷轴140’卷动到卷轴210’的过程中，磁带220’在磁头120’下方来回移动，从而由磁头120’将数据顺序写入磁带220’或者对磁带220’中的数据进行顺序读取。由此可见，对于磁带存储系统1000’而言，如果磁头120’对整盘磁带220’进行数据写入或读取，则磁头120’至少需要经过整盘磁带的全部长度。因此，磁带的数据读取或写入实际所需的时间与磁带的长度存在较强的关联性。图1的磁带装置中，磁带仅有一层(也就是磁带220’)，因此图1介绍的是一种单 层磁带装置。
随着磁带存储容量的提升，磁带正在变得越来越薄并且越来越长，因此读写整盘磁带耗费的时间也变得越来越长。以标准形态为傲群(Ultrium)的线性磁带开放(linear tape open，LTO)数据存储技术为例，LTO Ultrium在2000年发布了第一代产品LTO-1，到目前为止，已经发展到第九代LTO-9。下表列出了从第一代LTO-1到第九代LTO-9的一些参数对比。
表1
从表1可以看出，从第一代产品LTO-1到第九代产品LTO-9，磁带容量从0.1TB增大到高达18TB，但是磁带长度也随之从609米增加到1035米。随着磁带长度的增加，写满整盘磁带的时长从至少1小时23分增加到至少12小时30分。此外，从磁带中读取文件的平均定位时长也增加到45秒左右。漫长的读写时间和更长的定位时间劣化了用户体验，并且导致磁带存储无法应用于对数据实时性要求较高的场景。
本公开的实施例提出了一种改进的磁带存储方案。在改进方案中，通过将磁带层数由单层变为多层并且相应地在驱动器中设置多组磁头，可以对多层磁带进行并行的读写操作。由此，对于相同容量的磁带，磁带的每层长度可以倍数级地减少，因此在不用增加读取速度或写入速度的情况下大大缩短了读取或写入数据所需的时间，并且还减少了在磁带中读取文件所需的定位时间。
图2示出了根据本公开的实施例的磁带存储系统1000的结构示意图。磁带存储系统1000利用磁带作为存储介质，并且能够对磁带中的数据进行存取。磁带存储系统1000例如作为计算设备或处理设备的辅助存储器或主存储器，并且适用于顺序读写大量资料、离线归档存储等场景。如图2所示，磁带存储系统1000包括驱动器100和磁带装置200。作为示例，磁带装置200被装载在驱动器100中，并且能够与驱动器100分离以单独保存。当磁带装置200被装载在驱动器100中时，驱动器100能够对磁带装置200进行数据读写操作。
图3示出了根据本公开的实施例的磁带装置200的结构示意图。如图2和图3所示，磁带装置200包括卷轴210和磁带220。作为示例，磁带220包括带基和覆盖在带基表面的磁表面层。带基由聚酯薄膜或者其他适当材料制成，并且磁表面层包括诸如γ-Fe2O3和CrO2之类的可磁化介质或磁性介质。通过将磁带220完全卷绕在卷轴210上，将磁带220保持在磁带装置200中。磁带装置200是单卷轴结构，即仅有一个卷轴210。备选地，磁带装置200也是双卷轴结构。可以理解，在磁带装置200中还可以根据需要设置图中未示出的其他部件，例如用于保护磁带220的壳体。
根据本公开的实施例，磁带装置200的磁带220包括并行地卷绕在卷轴210上的多层磁带。作为示例，在卷轴210上并行地卷绕3个磁带层220-1、220-2和220-3。然而，磁带的层数并不受此限制，而可以是其他适当的层数，例如2层、4层或更多层。通过设置多层磁带，在存储容量不变的情况下大大减少每层磁带的长度。例如，单磁带层的LTO-9的磁带长度为1035米，而如果采用多层磁带的方式来构造磁带，相同容量磁带的每层磁带长度减小到长度1035米的1/N，其中N是多层磁带的层数。例如，2层磁带中的每层磁带长度减少到1035/2＝517.5米，并且3层磁带中的每层磁带的长度减少到1035/3＝345米。由于多层磁带并行卷绕在卷轴210上，并且以并行的方式进行读写操作，因此在读写速度不变的情况下，多层磁带的数据读写时长同样会呈倍数级减少。此外，每层磁带长度减少也相应地减少了从磁带220中读取文件的定位时长。
图4示出了根据本公开的实施例的多层磁带220-1、220-2和220-3的部分区段的放大立体视图，以及图5示出了根据本公开实施例的磁带层220-1的部分区段的放大俯视图。如图4和图5所示，每层磁带220-1、220-2或220-3包括彼此平行的多个磁道，多个磁道包括适于存储数据的多个数据磁道221。作为示例，数据磁道221是记录数据的轨迹，并且为了最大程度地利用磁带的宽度，数据磁道221的数目可以高达数千，例如高达8000多条。这些数据磁道221例如可以以蛇形方式延伸来形成，即从每层磁带的首端延伸到末 端，然后又从末端延伸到首端。
此外，每层磁带220-1、220-2或220-3的多个磁道还可以包括至少一个伺服磁道222，至少一个伺服磁道222适于存储用于辅助磁头定位的信息。作为示例，伺服磁道222可以在磁带的宽度方向上位于数据磁道221的两侧或者任一侧，并且单个伺服磁道222例如可以由若干个具有倾斜角度的直线段图案组成(参见图5)。由此，驱动器100的磁头通过读取伺服磁道222上的数据可以确定磁头整体的位置。可以理解，伺服磁道222的实现方式并不受限于此，例如，伺服磁道222也可以被设置在数据磁道之间而无需设置在数据磁道两侧，或者伺服磁道222可以包括适于定位的其他形状的图案。
图6示出了根据本公开的实施例的驱动器100的示意框图。如图2和图6所示，磁带存储系统1000的驱动器100可以包括第一驱动机构110，第一驱动机构110适于驱动磁带装置200中的磁带220在两个卷轴150和210之间卷动。作为示例，第一驱动机构110例如可以包括适于驱动卷轴转动的电机或其他致动器。当磁带装置200被装载到驱动器100之后，磁带220的端部可以被吸附并牵引到另一卷轴150。然后，第一驱动机构110的电机或其他致动器驱动卷轴150和卷轴210中的至少一个卷轴旋转，从而将磁带220从卷轴210卷动到另一卷轴150，或者从另一卷轴150卷动到卷轴210。
在本公开的一些实施例中，驱动器100包括两个卷轴150和210中的卷轴150。具体而言，对于单卷轴的磁带装置200，驱动器100可以提供用于卷动磁带220的另一卷轴150，以使磁带220能够在磁带装置200的卷轴210与驱动器100的卷轴150之间卷动。可以理解，在磁带装置200包括两个卷轴的情况下，驱动器100也可以不设置卷轴，而仅提供用于驱动卷轴的第一驱动机构110，这同样可以实现本公开的实施例。在一个实施例中，针对单卷轴或双卷轴的磁带装置200，驱动器100的第一驱动机构110可以提供诸如轴体之类的一个或两个接合元件，以与磁带装置200的一个或两个卷轴接合。例如，磁带装置200的卷轴可以套接并固定在第一驱动机构110的接合元件(例如轴体)上。由此，该接合元件可以在第一驱动机构110的电机或其他致动器的驱动下带动磁带装置200的卷轴转动。
根据本公开的实施例，驱动器100包括收纳磁带的空间，以及与多层磁带相对应的多组磁头，例如，与磁带层220-1、220-2和220-3相对应的磁头组120-1、120-2和120-3。每组磁头120-1、120-2或120-3适于在磁带220卷动期间针对对应层磁带220-1、220-2、220-3进行数据的读取或写入。作为示例，每组磁头120-1、120-2或120-3至少包括写磁头和读磁头，其中写磁头通过磁化改变磁性介质的磁场记录数据，而读磁头通过感应磁性介质的磁场读取磁性介质上的数据。在磁带220在两个卷轴之间卷动的过程中，磁头组120-1中的磁头对磁带层220-1进行数据的读取或写入，磁头组120-2中的磁头对磁带层220-2进行数据的读取或写入，并且磁头组120-3中的磁头对磁带层220-3进行数据的读取或写入。由于多组磁头并行地对多层磁带进行读取或写入，数据读取或写入的实际速度被大大加快，因此相比于常规方案以倍数级缩短了读取或写入数据所需的时长。
在本公开的一些实施例中，驱动器100还包括与多组磁头相对应的多组转轴130-1、130-2和130-3，每组转轴邻近于对应组磁头并且适于在磁带220卷动期间将对应层磁带的位于所两个卷轴150和210之间的待读取或待写入区段定位在对应组磁头附近，其中多组转轴被布置为消除多层磁带之间的行程差。
作为示例，转轴组130-1、130-2和130-3可以分别与磁头组120-1、120-2和120-3相对应。例如，转轴组130-1邻近于磁头组120-1，并且沿着磁带延伸的方向设置有位于磁头组120-1两侧的两个或更多个转轴，由此可以将磁带层130-1的部分区段定位在磁头组120-1的上方附近，以便磁头组120-1中的磁头对该部分区段进行读取操作或写入操作。类似地，转轴组130-2和130-3可以分别包括多个转轴，并且分别布置在磁头组120-2和120-3附近，以便由磁头组120-2和120-3分别对磁带层220-2和220-3进行读取操作或写入操作。由于磁带层220-1、220-2和220-3在不同的路径上卷动，因此它们之间不可避免地存在行程差。例如，由于磁头组120-1相比于磁头组120-2和120-3更远离两个卷轴150和220，因此相比于磁带层220-2和220-3，与磁头组120-1相对应的磁带层220-1会在两个卷轴之间具有更长的行程。类似地，磁带层220-2相比于磁带层220-3在两个卷轴之间具有更长的行程。这种行程差会影响到磁头组120-1、120-2和120-3的并行读取操作或写入操作。为此，可以对转轴组130-1、130-2和130-3进行设计或布置来消除磁带层220-1、220-2和220-3之间的行程差。例如，相比于转轴组130-1，转轴组130-2可以设置更多的转轴，并且使磁带层220-2沿着更加曲折的路径在多个转轴之间行进，从而增加磁带层220-2在两个卷轴之间的行程以消除磁带层220-2与磁带层220-1之间的行程差。类似地，可以对转轴组130-3进行设计和布置来使磁带层220-3在两个卷轴之间具有更长的行程，从而消除磁带层220-3与磁带层220-1和220-2的行程差。
备选地，多组转轴130-1、130-2和130-3也可以设置在磁带装置200中，多组转轴130-1、130-2和130-3在磁带装置200中分别与多层磁带220-1、220-2和220-3相对应，并且类似地帮助实现每层磁带与对应磁头组之间的定位、以及消除多层磁带之间的行程差。
在本公开的一些实施例中，驱动器100还包括第二驱动机构140，第二驱动机构140耦合到多组磁头120-1、120-2和120-3，并且适于驱动每组磁头120-1、120-2或120-3在对应层磁带220-1、220-2或220-3的不同磁道上方移动。作为示例，第二驱动机构可以包括音圈电机(voice coil motor,VCM)或其他致动器，以用于驱动多组磁头120-1、120-2和120-3移动。由于每层磁带可能具有高达数千个的平行磁道，而每组磁头的磁头数目通常仅有数个或数十个(例如8个或32个)，并且单个磁头仅能针对单个磁道执行写入或读取操作。因此，当从磁带读取数据或向磁带写入数据时，每组磁头可以先沿着部分磁道执行读取或写入操作，并在完成这部分磁道的读取或写入操作后由第二驱动机构140驱动该组磁头移动到另一部分磁道上方以继续执行读取或写入操作。例如，在每层磁带的磁道按照蛇形方式延伸的情况下，随着磁带220从卷轴210卷动到卷轴150，每组磁头可以读取各层磁带的第一部分磁道的数据，并且当磁带220完全卷绕到卷轴150上之后，每组磁头可以被第二驱动机构140移动到第二部分磁道上方，然后随着磁带220从卷轴150重新卷动到卷轴210，每组磁头继续读取各层磁带的第二部分磁道的数据。通过这种方式，随着磁带在两个卷轴之间的来回卷动，每组磁头可以针对每层磁带的所有磁道完成数据读取或数据写入。
在本公开的一些实施例中，多组磁头120-1、120-2和120-3彼此独立地被第二驱动机构140驱动。具体而言，磁带上的磁道数目较多并且单个磁道宽度较小，例如，对于宽度为12.65毫米并具有8000条磁道的磁带，单个磁道的宽度仅有数微米。因此，各层磁带的位置的微小偏差可能会导致磁头偏离对应的磁道。通过彼此独立地驱动多组磁头120-1、120-2和120-3，有助于针对各组磁头分别进行调整，以消除位置偏差并且将各组磁头准确地定位到对应磁道，从而降低或消除读取数据或写入数据失败的风险。作为示例，在第二驱动机构140中，可以设置多个VCM来对各组磁头分别进行控制，或者设置单个VCM依次驱动各组磁头移动。备选地，第二驱动机构140也可以统一地驱动多组磁头120-1、120-2和120-3移动。通过这种方式，可以以更简单的方式实现磁头组的驱动控制，从而简化控制过程。
图7示出了根据本公开的实施例的多组磁头120-1、120-2和120-3的结构示意图。每组磁头120-1、120-2或120-3包括至少一个数据磁头121和至少一个伺服磁头122，至少一个数据磁头121适于针对对应层磁带220-1、220-2或220-3的数据磁道221进行读取或写入，并且至少一个伺服磁头122适于从对应层磁带220-1、220-2或220-3的伺服磁道222读取磁头位置信息以用于控制第二驱动机构140。作为示例，在每组磁头中，可以设置8个数据磁头121或者任何其他适当数目的数据磁头(例如32个数据磁头)，这些数据磁头121沿着与磁带宽度方向平行的方向依次布置。在数据磁头121的两侧可以分别布置有一个或多个伺服磁头122，或者在数据磁头121的两侧中的一侧布置一个或多个伺服磁头122。换言之，数据磁头121和伺服磁头122的布置方式可以与磁带的数据磁道221和伺服磁道222的布置方向相对应，以便于在执行数据读取或数据写入时将数据磁头121与目标数据磁道对准，并且将伺服磁头122与伺服磁道222对准。如前文所述，伺服磁道222通常具有便于定位的特定图案，例如具有倾斜角度的直线段，由此，磁头组在不同数据磁道上方移动时，该磁头组的伺服磁头122会对准伺服磁道222的倾斜直线段的不同位置并读出对应的位置信息，从而可以确定该磁头组整体所处的位置。在一个实施例中，驱动器100还可以设置有支撑体125，以用于支撑和布置多组磁头120-1、120-2和120-3。可以理解，图7中所示出的支撑体125仅仅是示例性的而非限制性的，并且支撑体125可以具有任何适当的形状和构造，例如针对三组磁头可以分别设置彼此分离的三个支撑体。
在本公开的一些实施例中，多组磁头120-1、120-2和120-3沿着与两个卷轴150和210之间的磁带的行进方向垂直的方向依次布置，并且被布置为对多层磁带220-1、220-2和220-3的相同磁道的相同偏移地址并行地进行数据的读取或写入。通过这种方式，可以实现数据读取和写入带宽的倍数级提升。例如，在设置N层磁带的情况下，磁带存储系统1000的带宽将是常规的单层磁带系统的N倍。
返回到图6，驱动器100还包括数据传输和控制逻辑电路180。数据传输和控制逻辑电路180可以通信耦合到多组磁头120，并且传输多组磁头120已从磁带220读取的数据或者传输经由多组磁头120将向磁带220写入的数据。数据传输和控制逻辑电路180可以通信耦合到第一驱动机构110，并且根据外部指令或预定程序控制第一驱动机构110驱动卷轴，以使磁带220在两个卷轴之间卷动。数据传输和控制逻辑电路180还可以包括用于控制第二驱动机构140的伺服控制处理器181。各组磁头中的伺服磁头122生成指示磁头位置的伺服信号，伺服信号通过信号解码后可以获得各组磁头的当前位置信息并被提供给伺服控 制处理器181。基于目标磁道信息与当前位置信息的比较，伺服控制处理器181发出控制信号来指示第二驱动机构140驱动各组磁头移动到需要进行数据读取或数据写入的目标磁道上方，由此可以快速准确地将数据磁头引导到目标磁道上方，并且还可以在磁头或磁道的位置出现偏差时及时进行校准。此外，数据传输和控制逻辑电路180还可以例如借助于主控芯片来协调各个驱动机构和磁头组之间的操作。
可以理解，数据传输和控制逻辑电路180和伺服控制处理器181可以以任何适当的方式来实现。例如，数据传输和控制逻辑电路180可以包括一个或多个处理器或控制器，这些处理器或控制器可以实现读取或写入数据传输以及控制第一驱动机构的功能，并且同时提供伺服控制处理器181的功能，或者数据传输和控制逻辑电路180可以另外提供专用于实现伺服控制处理器181的功能的处理器或控制器。备选地，伺服控制处理器181也可以独立设置，而不设置在数据传输和控制逻辑电路180中，这同样可以实现本公开的实施例。可以理解，除了图2和图6中所示出的部件或元件之外，在驱动器中还可以根据需要设置其他部件和外围结构。
图8示出了根据本公开的实施例的多层磁带220-1、220-2和220-3的数据分布的简化示意图。如图8所示，连续数据分布在多层磁带220-1、220-2和220-3的相同磁道的相同偏移地址。此外，驱动器100可以被配置为经由多组磁头120-1、120-2、120-3将连续数据写入多层磁带220-1、220-2和220-3的相同磁道的相同偏移地址。
具体而言，可以将多层磁带220-1、220-2和220-3的相同磁道的具有相同偏移位置的存储空间定义为连续存储空间，由此一块连续数据可以被写入和存储在这样的连续存储空间中。例如，目标数据可以通过特定的编码切片而被分布在多层磁带的相同编号磁道的相同偏移地址。也就是说，可以将目标数据分成若干的片段而分别存储在多层磁带的相同编号磁道的相同地址处，这些片段可以按照一定规则或随机地分布在多层磁带，并且在读取数据时，多组磁头分别从多层磁带的相同地址处获取的片段能够立即组合成目标数据。这种存储方式可以方便多组磁头以更少的时间并行地从多层磁带读取可用数据，简化了数据的后续处理。
在本公开的一些实施例中，分布在多层磁带220-1、220-2、220-3的数据具有冗余保护关系。其中一种实现方式是：位于不同磁带的相同编号磁道的相同偏移地址的数据形成一个冗余保护组。
具体而言，在将数据存储或写入上述连续存储空间中，可以按照纠删码(erasure coding,EC)算法之类的冗余算法来对数据进行预处理，以生成一组带有冗余数据或校验数据的数据块，并把这一组数据块分散存储在不同层的磁带中，这一组数据块符合EC校验算法，或者其他校验算法。独立磁盘冗余阵列(redundant arrays of independent disks,RAID)算法可以视为EC算法的一种，例如：RAID-5相当于EC的k+1模式，k个数据块+1个校验块；RAID-6相当于EC的k+2模式，k个数据块+2个校验块。
在本公开的一些实施例中，同一个EC组的不同数据块分布在不同的磁带中，这样，即使多层磁带中的一层或少数层磁带出现故障，也可以通过其他层的数据恢复所有数据。冗余算法的应用有效改善了具有多层磁带的存储系统1000的数据存储可靠性。例如：由5层磁带组成3+2的EC校验组，即使任意一层或者两层磁带损坏，可以通过其他层磁带的数据对因为损坏而丢失的数据进行恢复。除了使用EC算法进行数据保护之外，还可以支持多副本的的冗余保护，也就是把相同数据的不同副本，保存在同一磁带装置的不同磁带中。把属于同一个校验组的数据块分散存储在多层磁带，这种数据保护方式也称为这多层磁带之间具有校验关系。
在本公开的实施例中，通过提供并行卷动的多层磁带与多层磁带相对应的多组磁头，可以在磁盘容量不变以及读取速度或写入速度不变的情况下以倍数级减少读取或写入磁带数据的时长，而且还减少了从磁带中读取文件的定位时长。本公开的方案有效改善了磁带存储系统的数据读取和写入的实时性。
通过以上描述和相关附图中所给出的教导，这里所给出的本公开的许多修改形式和其它实施方式将被本公开相关领域的技术人员所意识到。因此，所要理解的是，本公开的实施方式并不局限于所公开的具体实施方式，并且修改形式和其它实施方式意在包括在本公开的范围之内。此外，虽然以上描述和相关附图在部件和/或功能的某些示例组合形式的背景下对示例实施方式进行了描述，但是应当意识到的是，可以由备选实施方式提供部件和/或功能的不同组合形式而并不背离本公开的范围。就这点而言，例如，与以上明确描述的有所不同的部件和/或功能的其它组合形式也被预期处于本公开的范围之内。虽然这里采用了具体术语，但是它们仅以一般且描述性的含义所使用而并非意在进行限制。

Claims (15)

  1. 一种驱动器(100)，包括：
    第一驱动机构(110)，适于驱动磁带装置(200)中的磁带(220)在两个卷轴(150、210)之间卷动，所述磁带(220)包括并行卷动的多层磁带(220-1、220-2、220-3)；以及
    多组磁头(120-1、120-2、120-3)，分别与所述多层磁带(220-1、220-2、220-3)相对应，每组磁头(120-1、120-2、120-3)适于在磁带(220)卷动期间针对对应层磁带(220-1、220-2、220-3)进行数据的读取或写入。
  2. 根据权利要求1所述的驱动器(100)，还包括：
    多组转轴(130-1、130-2、130-3)，分别与所述多组磁头(120-1、120-2、120-3)相对应，每组转轴(130-1、130-2、130-3)邻近于对应组磁头(120-1、120-2、120-3)并且适于在磁带(220)卷动期间将对应层磁带(220-1、220-2、220-3)的位于所述两个卷轴(150、210)之间的待读取或待写入区段定位在所述对应组磁头(120-1、120-2、120-3)附近，其中所述多组转轴(130-1、130-2、130-3)被布置为消除所述多层磁带(220-1、220-2、220-3)之间的行程差。
  3. 根据权利要求2所述的驱动器(100)，其中所述多组磁头(120-1、120-2、120-3)沿着与所述两个卷轴(150、210)之间的磁带的行进方向垂直的方向依次布置，并且被布置为对所述多层磁带(220-1、220-2、220-3)的相同磁道的相同偏移地址并行地进行数据的读取或写入。
  4. 根据权利要求3所述的驱动器(100)，其中所述驱动器(100)被配置为经由所述多组磁头(120-1、120-2、120-3)将连续数据写入所述多层磁带(220-1、220-2、220-3)的相同磁道的相同偏移地址。
  5. 根据权利要求1所述的驱动器(100)，其中每层磁带包括彼此平行的多个磁道，并且所述驱动器还包括：
    第二驱动机构(140)，耦合到所述多组磁头(120-1、120-2、120-3)，并且适于驱动每组磁头(120-1、120-2、120-3)在对应层磁带(220-1、220-2、220-3)的不同磁道上方移动。
  6. 根据权利要求5所述的驱动器(100)，其中所述多组磁头(120-1、120-2、120-3)彼此独立地或者统一地被所述第二驱动机构(140)驱动。
  7. 根据权利要求5所述的驱动器(100)，其中每组磁头(120-1、120-2、120-3)包括至少一个数据磁头(121)和至少一个伺服磁头(122)，所述至少一个数据磁头(121)适于针对对应层磁带(220-1、220-2、220-3)的数据磁道(221)进行读取或写入，并且所述至少一个伺服磁头(122)适于从对应层磁带(220-1、220-2、220-3)的伺服磁道(222)读取磁头位置信息以用于控制所述第二驱动机构(140)。
  8. 根据权利要求1所述的驱动器(100)，还包括所述两个卷轴(150、210)中的一个卷轴(150)。
  9. 一种磁带装置(200)，包括：
    卷轴(210)；以及
    多层磁带(220-1、220-2、220-3)，并行地卷绕在所述卷轴(210)上。
  10. 根据权利要求9所述的磁带装置(200)，还包括：
    多组转轴(130-1、130-2、130-3)，分别与所述多层磁带(220-1、220-2、220-3)相对应，每组转轴(130-1、130-2、130-3)适于在磁带(220)卷动期间将对应层磁带(220-1、220-2、220-3)的待读取或待写入区段定位在与所述对应层磁带相对应的一组磁头(120-1、120-2、120-3)附近，其中所述多组转轴(130-1、130-2、130-3)被布置为消除所述多层磁带(220-1、220-2、220-3)之间的行程差。
  11. 根据权利要求9所述的磁带装置(200)，其中每层磁带(220-1、220-2、220-3)包括彼此平行的多个磁道，所述多个磁道包括多个数据磁道(221)和至少一个伺服磁道(222)，所述多个数据磁道(221)适于存储数据，并且所述至少一个伺服磁道(222)适于存储用于辅助磁头定位的信息。
  12. 根据权利要求9所述的磁带装置(200)，其中连续数据分布在所述多层磁带(220-1、220-2、220-3)的相同磁道的相同偏移地址。
  13. 根据权利要求9所述的磁带装置(200)，其中分布在所述多层磁带(220-1、220-2、220-3)的数据具有冗余保护关系。
  14. 根据权利要求13所述的磁带装置(200)，其中所述多层磁带(220-1、220-2、220-3)之间具有校验关系。
  15. 一种磁带存储系统(1000)，包括：
    根据权利要求1至8中任一项所述的驱动器(100)；以及
    根据权利要求9至14中任一项所述的磁带装置(200)。
PCT/CN2023/113420 2022-10-26 2023-08-16 驱动器、磁带装置和磁带存储系统 WO2024087820A1 (zh)

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CN1249840A (zh) * 1997-03-04 2000-04-05 伊美申公司 磁带伺服系统和方法,读写头,以及有关的伺服磁道结构
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