Tape media management server, system, tape media management method and program

Abstract

To provide a tape medium management server or the like which implements data arrangement that enables access efficiently to data scattered in content data.SOLUTION: Provided is a tape medium management server including: a content data acquisition unit for acquiring content data to be recorded on a tape medium; a digest information acquisition unit for acquiring digest information that specifies a portion constituting a digest, which is a part of the content data; a position acquisition unit for predicting and acquiring the position on which the tape medium of the portion constituting the digest when the tape medium has a plurality of lengths, based on the content data and the digest information; a travel distance calculation unit for calculating the travel distance of the tape medium required to access the digest based on the position; and an efficiency calculation unit for calculating efficiency when accessing the digest using the travel distance and the length of the plurality of media.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tape media management server, a system, a tape media management method, and a program. [Background technology]

[0002] When renting out video content, due to the large volume of video content, the data is generally transported on magnetic tape. Since magnetic tape generally stores not just one video content but multiple contents, when renting out, only the requested content is often copied onto a separate tape and rented out.

[0003] Generally, when using video content, the borrower may want to view the entire video or only a digest video, so the lender may prepare the entire video and a digest video and provide them to the borrower.

[0004] Therefore, in cases where the entire video and the digest video are recorded separately and the data is provided to the requester, or if the digest video is considered to be part of the entire video, one method is to make a list of the playback times that make up the digest video and communicate this to the lender (the list can also be stored on magnetic tape), and the borrower can then check the digest portion of the entire video content.

[0005] However, when the lender records both the entire video and a digest video and lends the data to the requester, in addition to the entire video, the digest video must also be written to magnetic tape, which creates the problem of unnecessarily lengthening the duplication time.

[0006] Furthermore, when digest footage is considered as part of the entire video, the method of listing the playback times that make up the digest footage, communicating this to the lender, and then having the borrower check the digest portion poses the problem that, because the data portions that make up the digest footage are scattered throughout the magnetic tape, it takes the borrower time to extract the digest version from the entire video content.

[0007] Patent Document 1 discloses an invention that improves read efficiency by consolidating the positions where data is written. Specifically, in a tape drive that moves a tape back and forth in the longitudinal direction of the tape, data is written to specific areas within multiple wraps to improve read efficiency.

[0008] Patent Document 2 discloses an invention that speeds up the reading of catalog information by shifting the timing of recording catalog information for each lap. Specifically, the catalog information recorded on the data tape is arranged in a continuous staircase pattern from the beginning of the tape in the tape feed direction, making it possible to read the catalog information without fast-forwarding or rewinding the tape.

[0009] Patent Document 3 discloses a method for improving efficiency by providing segment header portions at predetermined intervals on a tape in order to efficiently locate user data stored on a magnetic tape medium.

[0010] Patent Document 4 discloses a method of shortening the time required for tape positioning when reading or writing additional data by using dummy data.

[0011] Patent Document 5 discloses a recording method in which the tape medium is divided in the longitudinal direction to efficiently access desired data. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-191259 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-257523 [Patent Document 3] Japanese Patent Application Publication No. 10-011908 [Patent Document 4] Japanese Patent Application Laid-Open No. 2009-99207 [Patent Document 5] Japanese Patent Application Publication No. 11-306690 Summary of the Invention [Problem to be solved by the invention]

[0013] The disclosures of the above-mentioned prior art documents are incorporated herein by reference. The following analysis has been carried out by the present inventors.

[0014] However, the above-disclosed methods require special processing by the writing control side, such as changing the order in which data is written or writing special data such as dummy data, etc. Therefore, they are not methods for efficiently extracting data scattered within video content, such as digest video.

[0015] The main object of the present invention is to provide a tape media management server, system, tape media management method and program that realizes data placement that allows efficient access to data scattered throughout content data stored on tape media. [Means for solving the problem]

[0016] According to a first aspect of the present invention and disclosure, there is provided a tape media management server having a content data acquisition unit that acquires content data to be recorded on tape media, a digest information acquisition unit that acquires digest information that identifies a portion of the content data that constitutes a digest, the portion being a part of the content data, a position acquisition unit that predicts and acquires the position on the tape media of the portion that constitutes the digest when multiple tape media lengths are taken based on the content data and the digest information, a running distance calculation unit that calculates the running distance of the tape media required to access the digest based on the position, and an efficiency calculation unit that calculates the efficiency when the digest is accessed using the running distance and multiple tape media lengths.

[0017] According to a second aspect of the present invention or disclosure, there is provided a system having a tape drive and a tape media management server, the tape media management server further having a tape drive control unit that controls reading and writing of tape media by the tape drive.

[0018] According to a third aspect of the present invention or disclosure, there is provided a tape media management method including the steps of: acquiring content data to be recorded on tape media; acquiring digest information that identifies a portion of the content data that constitutes a digest; predicting and acquiring, based on the content data and the digest information, the position on the tape media of the portion that constitutes the digest when multiple tape media lengths are taken; calculating, based on the position, a running distance of the tape media required to access the digest; and calculating efficiency when accessing the digest using the running distance and multiple tape media lengths.

[0019] According to a fourth aspect of the present invention or disclosure, there is provided a program for causing a computer to execute the following processes: a process for acquiring content data to be recorded on tape media; a process for acquiring digest information that identifies a portion of the content data that constitutes a digest; a process for predicting and acquiring, based on the content data and the digest information, the position on the tape media of the portion that constitutes the digest when multiple tape media lengths are used; a process for calculating, based on the position, the running distance of the tape media required to access the digest; and a process for calculating the efficiency of accessing the digest using the running distance and multiple tape media lengths. The program can be recorded on a computer-readable storage medium. The storage medium can be a non-transient medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present invention can also be embodied as a computer program product. [Effects of the Invention]

[0020] According to each aspect of the present invention and disclosure, a tape media management server, system, tape media management method and program are provided that realize data placement that allows efficient access to data scattered throughout content data stored on tape media. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 illustrates an example of the configuration of a tape media management server according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a configuration of a position acquisition unit according to an embodiment. [Figure 3] 1 is a diagram illustrating an example of the configuration of a system including a tape media management server according to a first embodiment. [Figure 4] 6 is a flowchart showing an example of the operation of the system including the tape media management server and tape drives according to the first embodiment. [Figure 5] FIG. 2 is a schematic diagram showing the hardware configuration of a tape media management server according to the first embodiment. [Figure 6] FIG. 10 is a diagram illustrating an example of a configuration of a system according to a second embodiment. [Figure 7] FIG. 2 is a schematic diagram of a table stored in a video data digest management DB. [Figure 8] FIG. 2 is a schematic diagram of a table stored in a video data digest management DB. [Figure 9] 10 is a flowchart showing the operation of the system of the second embodiment for determining the physical positions of the components of the digest for each tape media length. [Figure 10] FIG. 11 is a diagram showing an example of a table showing the physical location of a digest for each tape media length calculated by the operation of the system of the second embodiment. [Figure 11] FIG. 10 is a diagram showing an example of a table showing travel distances and efficiencies calculated by the operation of the system of the second embodiment. [Figure 12] FIG. 10 is a diagram showing a tape image when video data is written by the operation of the system of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] First, an overview of one embodiment will be described. Note that the reference numerals in the drawings attached to each element in this overview are added for convenience as an example to facilitate understanding, and the description of this overview is not intended to be limiting in any way. Furthermore, the connection lines between blocks in each figure include both bidirectional and unidirectional. Unidirectional arrows are used to schematically indicate the flow of the main signal (data) and do not exclude bidirectionality. Furthermore, although not explicitly shown in the circuit diagrams, block diagrams, internal configuration diagrams, connection diagrams, etc. shown in this disclosure, input ports and output ports exist at the input and output ends of each connection line. The same applies to input / output interfaces.

[0023] 1 is a diagram showing an example of the configuration of a tape media management server according to an embodiment. As shown in this diagram, the tape media management server according to an embodiment includes a content data acquisition unit 11, a digest information acquisition unit 12, a location acquisition unit 13, a travel distance calculation unit 14, and an efficiency calculation unit 15.

[0024] The content data acquisition unit 11 acquires content data to be recorded on a tape medium.

[0025] "Tape media" refers to a storage medium consisting of a long strip of tape on which data is recorded. Magnetic tape is an example, but is not limited to this. Tape media does not allow random access, but is instead sequential access. Tape media may also be configured to record data in multiple wraps on the tape, with the tape running back and forth in the longitudinal direction to record or read data. That is, the tape media management server may be configured to run the tape from the beginning, write or read data on one wrap, and when the end of the tape is reached, reverse the tape running direction and write or read data on another wrap toward the beginning of the tape. The present invention is particularly suitable for configurations employing multi-wrap tape media that reads and writes data by running back and forth as described above.

[0026] The present invention can be applied to any type of "content data," but is particularly suitable for data with a time axis, such as audio or video.

[0027] "Acquisition" here refers to the tape media management server receiving content data via a network or another storage medium such as tape media, and temporarily storing it in a storage medium such as memory. The acquired content data is passed to the position acquisition unit 13, which will be described later.

[0028] The digest information acquisition unit 12 acquires digest information that identifies a portion that constitutes a digest, which is a part of the content data.

[0029] A "digest" is data that is constructed by joining together one or more parts of the content data.

[0030] "Digest information" is information for identifying the parts of the content data that make up the digest. For example, if the content data is video data, the digest information may be information that lists the start and end points of the content data of each part that makes up the digest in order on the time axis. The digest information may be provided together with the content data, or may be provided and acquired separately.

[0031] Based on the content data and the digest information, the position acquisition unit 13 predicts and acquires the positions on the tape media of the parts that make up the digest when multiple tape media lengths are used. Specifically, the position acquisition unit 13 acquires the length of the content on the tape from the content data, and uses the acquired length to identify the positions on the tape of the elements that make up the digest. This is done for multiple tape lengths, and the position on the tape of each digest element is determined.

[0032] FIG. 2 is a diagram illustrating an example of the configuration of a position acquisition unit in an embodiment. Assume that there is content data with a length of 110 on a tape. The length of the recording portion per lap on Tape A is 120, and on Tape B is 60. Based on the digest information, the portions that make up the digest are located at positions 10-20, 45-55, and 80-95 on the tape. If Tape A is used, the portions that make up the digest are located at positions 10-20, 45-55, and 80-95 on the tape. If Tape B is used, the portions at positions 10-20 and 45-55 are located on the forward lap, but the portion at 80-95 is folded back at the end and located in the reverse direction at position 25-40. Therefore, if Tape B is used, the portions that make up the digest are located at positions 10-20, 25-40, and 45-55 on the tape. In this way, the position acquisition unit in an embodiment acquires the positions on the tape of the elements that make up the digest according to the length of the tape.

[0033] Based on the position, the running distance calculation unit 14 calculates the running distance of the tape media required to access the digest. In this invention, "running distance" refers to the distance the tape is advanced to "cue" each element of the digest, which is necessary to access each element. Therefore, it does not include the distance the tape is advanced when actually reading or writing the content. Referring to Figure 2, when referring to tape A, to access the digest, the tape is first advanced 10 increments starting from the beginning to reach the first digest portion. The digest element portion is read there, and then the tape is advanced 25 increments from position 20 to position 45. The digest is again read there, and the tape is advanced 25 increments from position 55 to position 80. Therefore, the running distance for tape A is 60 increments. In contrast, for tape B, the tape is advanced 10 increments from the beginning, then 25 increments, and then the tape is reversed from position 55 and advanced 15 increments to position 40 in order to read the final portion of the digest. Therefore, the running distance for tape B is 50 increments. In this way, the running distance calculation unit 14 in one embodiment calculates the running distance required to access all digests according to the length of the tape.

[0034] The efficiency calculation unit 15 calculates the efficiency of accessing the digest using the travel distance and multiple tape media lengths. In the present invention, "efficiency" refers to an index of how much travel distance has been saved relative to the rate at which the tape media length has been shortened (lengthened). The reason for using efficiency relative to the rate at which the tape media has been shortened, rather than simply the length of the travel distance, is that simply shortening the tape media length to shorten the travel distance for accessing the digest reduces the travel distance. However, shortening the tape increases the number of wraps, and when attempting to access the entire content data, the frequency of tape wraps increases. This has the disadvantage of increasing damage to the tape, the tape drive's travel mechanism, the read head, etc. Therefore, in the present invention, a tape media length that allows digest data to be allocated in a way that allows for more efficient tape use is determined through optimization.

[0035] In this way, the tape media management server in one embodiment acquires content data and uses digest information to acquire the position of the digest on the tape. This is done for multiple lengths of tape to calculate the running distance. The server further calculates the efficiency based on the calculated running distance and the corresponding tape media length, and then uses the tape media length with the highest efficiency to write the content data.

[0036] According to one embodiment of the tape media management server, it is possible to efficiently access digest data. For example, when you want to extract only digest video from tape media, if you use a highly efficient tape media length, you can quickly extract the digest data.

[0037] Specific embodiments will be described in more detail below with reference to the drawings. Note that the same components in each embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0038] [First embodiment] The first embodiment will be described in more detail with reference to the drawings.

[0039] 3 is a diagram showing an example of the configuration of a system including a tape media management server 10 according to the first embodiment. As shown in this diagram, the system according to the first embodiment has a tape media management server 10 and a tape drive 20. The tape media management server 10 has a content data acquisition unit 11, a digest information acquisition unit 12, a position acquisition unit 13, a travel distance calculation unit 14, and an efficiency calculation unit 15. These components have been explained above, so further description will be omitted. In the system of this embodiment, the tape media management server 10 further has a selection unit 16 and a tape drive control unit 17.

[0040] The selector 16 selects, from among the multiple tape media lengths, the tape media length that has the highest efficiency calculated by the efficiency calculation unit and that can efficiently save travel distance. Specifically, the selector 16 receives the efficiency value for each tape media length from the efficiency calculation unit 15, and selects and outputs the tape media length with the smallest value.

[0041] The tape drive control unit 17 controls the reading and writing of tape media by the tape drive. "Control" refers to sending read and write commands to the tape drive. In addition, it sends commands to advance or reverse the tape for "cueing."

[0042] In the first embodiment, the position acquisition unit 13 of the tape media management server 10 acquires the predicted logical position of the digest on the tape media based on the digest information acquired by the digest information acquisition unit 12, and acquires the predicted physical position of the digest on the tape media when multiple tape media lengths are taken based on the logical position.

[0043] A "logical position" is a position on a tape if the tape is assumed to be infinitely long, and can take on values ​​from 0 to infinity. For example, if there is video content data, this logical position may be associated with a position on a time axis such as a time code. That is, if there is 120 minutes of content data, the start time may be set to logical position 0 and the end time to logical position 120.

[0044] A "physical position" is a position on a tape of finite length. It takes a value ranging from 0 to a length that depends on the length of the tape media. The physical position may include position information that specifies not only the longitudinal position but also the wrap, which is the lateral position. In Figure 2, the logical position of the end of the content data recorded on Tape A and Tape B is 110. Meanwhile, the physical position of the end of the content data on Tape A is 110, and the physical position of the end of the content data on Tape B is 10. Note that the values ​​of the physical position and logical position in Figure 2 are shown as examples and may be selected as appropriate according to need and convenience.

[0045] The physical location of the digest for each tape media length is calculated based on the remainder obtained by dividing the logical location by the round-trip length of each tape media. If this value is shorter than the tape media length, the physical location is located forward on the tape, and the remainder is the physical location. If this value is longer than the tape media length, the physical location is located backward on the tape, and the physical location is the round-trip length minus the remainder.

[0046] The logical and physical positions of the digests on the tape acquired by the position acquisition unit 13 are output to the travel distance calculation unit 14 .

[0047] The travel distance calculation unit 14 calculates the travel distance of the tape media required to access the digest for each of the plurality of tape media lengths based on the logical position and the physical position. The calculated travel distance is output to the efficiency calculation unit 15.

[0048] The efficiency calculation unit 15 calculates the efficiency as the degree of increase or decrease in the calculated running distance relative to the degree of shortening of the tape media length for each of the multiple tape media. In other words, it calculates the ratio of the saving rate of the tape media length to be calculated relative to the reference tape media length to the saving rate of the running distance when the tape media length to be calculated is used relative to the running distance when the reference tape media length is used. In other words, by calculating this ratio, it is possible to calculate the tape media length that can most efficiently shorten the running distance for accessing digests when the tape media length is shortened.

[0049] [Explanation of operation] An example of the operation of the system of this embodiment will be described with reference to FIG. 4. FIG. 4 is a flowchart showing an example of the operation of a system including the tape media management server 10 and the tape drive 20 according to the first embodiment. When the tape media management server starts operation, the tape media management server 10 acquires content data (step S41). This content data may be data recorded on a tape medium installed in the tape drive and acquired from the tape drive. Next, the tape media management server 10 acquires digest information (step S42). After acquiring the digest information and content data, the tape media management server 10 predicts and acquires the positions on the tape medium of the portions that constitute the digest based on the acquired digest information, content data, and tape media length (step S43). Next, the tape media management server 10 calculates the running distance of the tape medium for each tape media length based on the positions of the portions that constitute the acquired digest (step S44). Next, the tape media management server 10 uses the calculated running distance and tape media length to calculate efficiency, which is calculated from the degree of reduction in running distance relative to the degree of reduction in tape media length (step S45). Next, the tape media management server 10 selects the tape media length with the highest efficiency (smallest efficiency value) from the calculated efficiencies (step S46). Next, the tape media management server 10 controls the tape drive 20 to write the content data at the selected tape media length, and the tape drive 20 executes the write process in accordance with the control (step S47).

[0050] [Hardware configuration] The tape media management server 10 can be configured using an information processing device (computer), and has the configuration shown in Fig. 5. For example, the tape media management server 10 includes a CPU (Central Processing Unit) 51, memory 52, an input / output interface 53, and a NIC (Network Interface Card) 54 as a communication means, which are interconnected by an internal bus 55.

[0051] However, the configuration shown in Fig. 5 is not intended to limit the hardware configuration of the tape media management server 10. The tape media management server 10 may include hardware not shown, and may not include the input / output interface 53 as necessary. Furthermore, the number of CPUs and other components included in the tape media management server 10 is not intended to be limited to the example shown in Fig. 5; for example, the tape media management server 10 may include multiple CPUs.

[0052] The memory 52 is a RAM (Random Access Memory), a ROM (Read Only Memory), or an auxiliary storage device (such as a hard disk).

[0053] The input / output interface 53 is a means for interfacing with a display device and an input device (not shown). The display device is, for example, a liquid crystal display. The input device is, for example, a device that accepts user operations such as a keyboard or a mouse. Content data is exchanged with the tape drive 20 via the input / output interface, and the content data is read from and written to tape media in the tape drive 20.

[0054] The functions of the tape media management server 10 are realized by a group of programs stored in memory 52, such as a content data acquisition program, a digest information acquisition program, a location acquisition program, a travel distance calculation program, an efficiency calculation program, a selection program, and a tape drive control program, and a group of data, such as content data and digest information data. The processing modules are realized, for example, by the CPU 51 executing each program stored in memory 52. ​​The programs can be downloaded via a network or updated using a storage medium that stores the programs. Furthermore, the processing modules may be realized by semiconductor chips. That is, it is sufficient if the functions performed by the processing modules are executed by some kind of hardware and / or software.

[0055] [Hardware operation] When the tape media management server 10 starts operation, a content data acquisition program is called from the memory 52, is put into execution by the CPU 51, and acquires content data via the input / output interface 53, the NIC 54, etc. Next, a digest information acquisition program is called from the memory 52, is put into execution by the CPU 51, and acquires digest information data similarly via the input / output interface 53, the NIC 54, etc. The acquired data is temporarily stored in an area reserved in the memory 52.

[0056] Next, one or more tape media length values ​​are input from the input / output interface 53 or the like and stored in the memory 52. ​​The position acquisition program is executed by the CPU 51, and the position of each digest component in each tape media length is calculated using the tape media length values, content data, and digest information data. The calculated position values ​​are temporarily stored in the memory 52.

[0057] Next, the running distance calculation program is executed by the CPU 51. This program reads the tape media length value stored in the memory 52 and the calculated position value, and calculates the running distance for each tape media length. The calculated running distance is associated with the tape media length and temporarily stored in the memory 52.

[0058] Next, the efficiency calculation program is executed by the CPU 51. This program reads the tape media length value and the associated travel distance value stored in the memory 52, and calculates the efficiency. The calculated efficiency value is associated with the tape media length value and temporarily stored in the memory 52.

[0059] Next, the selection program is executed by the CPU 51. This program compares the efficiency values ​​stored in the memory 52 to select the smallest value, and outputs the tape media length associated with this value.

[0060] Next, the tape drive control program is executed by the CPU 51. This program writes the content data to the tape medium according to the tape medium length output by the selected program.

[0061] When creating a digest video or the like, the tape drive control program first reads the position data of the portion that constitutes the digest, which corresponds to the tape media length of the currently stored tape media, stored in memory 52. ​​Next, by accessing the portion of the content data that corresponds to the read position data, the portion that constitutes the digest of the content data stored in memory 52 is read, and that portion is output and written to the tape drive.

[0062] [Second embodiment] The second embodiment will be described in more detail with reference to the drawings.

[0063] 6 is a diagram showing an example of the configuration of a system according to the second embodiment. This system comprises a management server 100 (corresponding to the tape media management server 10 in the first embodiment) and a tape drive 200 (corresponding to the tape drive 20). The management server 100 has a digest creation unit 101, a video data digest management DB 102, a data read / write control unit 103, a tape position acquisition unit 104, a tape media length change processing unit 105, and an appropriate tape media length determination unit 106.

[0064] The digest creation unit 101 is a mechanism for creating (extracting) a digest portion from video content, and this portion is configured using existing technology.

[0065] The video data digest management DB 102 is a DB that records a list of digest parts of video data.

[0066] The data read / write control unit 103 is a control unit that reads and writes video data from and to a magnetic tape, and connection to a tape drive is generally realized by a SAS (Serial Attached SCSI) interface or an FC (Fibre Channel) interface.

[0067] The tape position acquisition unit 104 is a control unit that issues a command to acquire information about the current position on the tape.

[0068] The tape media length change processing unit 105 is a control unit that issues a command to the tape drive to change the longitudinal length of the tape media, and this command changes the usable longitudinal length of the magnetic tape stored in the tape drive.

[0069] The appropriate tape media length determination unit 106 is a part that determines to which tape media length the data should be changed in order to efficiently read the digest portion of specific video data.

[0070] The tape drive 200 is a device that reads and writes data from and to a loaded magnetic tape, and performs reading and writing in response to commands from the data read / write control unit 103. A plurality of pieces of video data are stored on the magnetic tape.

[0071] Figure 7 is a schematic diagram of a table stored in the video data digest management DB 102. As shown in the table in this figure, after the video content is completed, a digest of the video data is created using existing technology. After this, which parts of the video data correspond to the digest are listed and recorded in the video data digest management DB.

[0072] 8 is a schematic diagram of a table stored in the video data digest management DB 102. As shown in the table in this figure, after the video content is completed, when the video content data is recorded onto magnetic tape, the management server acquires the tape position at the timing of recording data at the start of the digest portion and at the timing of recording data at the end of the digest portion, and records this in the video data digest management DB.

[0073] When a request to lend video content is received (for example, video data α existing on Tape α), the system copies only the relevant data α onto a tape for lending in preparation for lending. As a preliminary step to the copying, the system calculates where on the tape the digest video portion of the relevant data will be physically recorded if the length of the tape is adjusted.

[0074] If the start point of the relevant data in the copy source is not logical position 0 on the tape, the logical position is recalculated as if starting from logical position 0. After that, the physical position of the digest is calculated when the tape media length is changed in increments of 10 from 10 to 100.

[0075] Here, the tape logical position of the digest αx is assumed to be LT_αx, and the physical position is assumed to be RT_αx. The physical position RT_αx when the tape media length is N is calculated using the following formula. When Mod(LT_αx,kN)≦N:RT_αx=Mod(LT_αx,kN) When Mod(LT_αz,kN)>N: RT_αx=kN-Mod(LT_αx,kN) Here, k is an arbitrary predetermined number greater than 1, which is appropriately determined by taking into consideration the accuracy and efficiency of the calculation. For example, it can be set to 2 to 3.

[0076] [System operation: from obtaining physical location to calculating mileage] Here, the operation of the system from obtaining the physical position to calculating the traveled distance will be explained using the figures. Figure 9 is a flowchart showing the operation of the system of the second embodiment for determining the physical position of the components of the digest for each tape media length. Here, the direction from the start of the magnetic tape to the end is called "forward," and the direction from the end of the magnetic tape to the start is called "backward." 1. At the data start point closest to the beginning of the tape, digest data is read in order starting from the forward digest data (step S91). 2. The digest data that is the closest data start point in the forward direction from the data end point of the digest data that was read immediately before to the end of the tape is positioned as the data to be read next, and then the data is read (step S92). 3. It is determined whether data exists in the forward direction (step S93), and if data exists (Yes), the process returns to step S92 in 2. If data does not exist (No), the running direction changes to the backward direction and the process proceeds to the next step 4, step S94. 4. At the data start point nearest to the end of the tape, digest data is read in order starting from the digest data in the backward direction (step S94). 5. The digest data that is closest in the backward direction from the end point of the digest data that was read immediately before to the beginning of the tape is determined as the data to be read next, and then the data is read (step S95). 6. It is determined whether data exists in the backward direction (step S96), and if data exists (Yes), the process returns to step S95 in 5. If data does not exist (No), the process proceeds to the next step 7, step S97. 7. Excluding the data that has already been read (step S97), steps 1 to 6 are repeated (step S98) to calculate the traveled distance (step S99).

[0077] Figure 10 shows an example of a table showing the physical location of digests for each tape media length calculated by performing the above operations. Using the information in this table, the tape running distance is calculated for each tape media length, and combined with the percentage by which the tape media length is shortened, the length at which the tape running distance is most efficient is determined. Here, "relative distance" refers to the physical distance at which data can actually be written, a value that depends on the tape media length.

[0078] After calculating the tape running distance as described above, calculate the efficiency of the reduction in tape media length using the following formula: (Distance traveled when tape media length is N / Distance traveled when tape media length is 100) / (Tape media length N / Tape media length 100) Fig. 11 shows the travel distance and efficiency calculated using the above formula. Check the tape media length condition that is most efficient (lowest number) (70 in this example). Before writing the video data for which a lending request has been made onto the duplication tape, the tape media length change processing unit 105 issues a command to the tape drive to adjust the tape media length to 70%.

[0079] After changing the tape media length, the video data is written to the duplication tape. Figure 12 shows an image of the tape after video data has been written. As can be seen from this figure, changing the tape media length makes it possible to efficiently access the data that constitutes the digest. When writing video data to tape, the management server obtains tape position information for the digest portion and records it in a list. (Tape position information is obtained at the timing of data recording for the start and end of the digest portion.)

[0080] The tape for duplication is then transported to the source of the video data lending request, and the data is lent out. The list of tape position information of the digest video may be shared separately by e-mail or by other means.

[0081] After receiving the magnetic tape on which the video data has been copied, the video data borrower can extract the digest portion in accordance with the digest video configuration list, thereby enabling efficient extraction of the digest portion.

[0082] [Effect description] According to this embodiment, by obtaining the positions on the tape media of the parts that make up the digest data and calculating the tape running distance required to access the parts that make up the digest data, it is possible to optimize the tape media length and provide a system that can efficiently create digest data.

[0083] Some or all of the above embodiments can also be described as follows, but are not limited to the following: stomach. [Form 1] This is the same as the tape media management server according to the first aspect described above. [Form 2] Preferably, the tape media management server of form 1 further comprises a selection unit that selects, from among a plurality of tape media lengths, the tape media length that has the highest efficiency calculated by the efficiency calculation unit and that can efficiently save on running distance, wherein the position acquisition unit acquires the predicted logical position of the digest on the tape media based on the digest information, and acquires the predicted physical position of the digest on the tape media when a plurality of tape media lengths are taken based on the logical position, and the running distance calculation unit calculates the running distance of the tape media required to access the digest for each of the plurality of tape media lengths based on the logical position and the physical position. [Form 3] Preferably, the tape media management server of aspect 1 or 2, wherein the efficiency calculation unit calculates, as efficiency, the degree of increase or decrease in running distance relative to the degree of reduction in the length of each of the plurality of tape media. [Form 4] The position acquisition unit acquires the predicted physical position of the digest on the tape media based on the remainder calculated by dividing the length of the digest based on its logical position on the tape media by a value that is k times the length of the multiple tape media (k is any number greater than 1), preferably a tape media management server of form 2 or 3. [Form 5] The content data acquisition unit acquires content data including at least one of video and audio, and including data for identifying the position of the data on the time axis, preferably a tape media management server of any one of forms 1 to 4. [Form 6] This is the same as the system according to the second aspect described above. [Form 7] Preferably, the system of form 6 is such that the tape drive magnetically reads and writes data from and to the tape medium. [Form 8] Preferably, the system is of form 6 or 7, wherein the tape drive records data by running the tape medium back and forth in the longitudinal direction thereof. [Form 9] This is the same as the tape media management method according to the third aspect described above. [Form 10] This is the same as the program related to the fourth perspective mentioned above. Note that, like mode 1, mode 9 and mode 10 can be expanded into modes 2 to 5.

[0084] The disclosures of the above-cited patent documents and other documents are incorporated herein by reference. Modifications and adjustments of the embodiments and examples are possible within the scope of the entire disclosure of the present invention (including the claims), and further based on the basic technical concepts thereof. Furthermore, various combinations and selections (including partial deletions) of various disclosed elements (including elements of each claim, each element of each embodiment or example, each element of each drawing, etc.) are possible within the scope of the entire disclosure of the present invention. In other words, the present invention naturally includes various modifications and alterations that would be possible by a person skilled in the art in accordance with the entire disclosure and technical concepts, including the claims. In particular, with regard to the numerical ranges set forth herein, any numerical value or subrange included within the range should be construed as specifically set forth, even if not otherwise specified. [Explanation of symbols]

[0085] 10 Tape Media Management Server 11 Content data acquisition unit 12 Digest information acquisition unit 13 Position acquisition part 14. Travel distance calculation unit 15 Efficiency calculation section 16 Selection section 17 Tape drive control unit 18 Validity period information acquisition unit 20, 200 tape drives 51 CPU(Central Processing Unit) 52 memory 53 Input / Output Interface 54 NIC(Network Interface Card) 55 Internal Bus 100 Management Server 101 Digest Generation Unit 102 Video Data Digest Management DB 103 Data read / write control unit 104 Tape position acquisition unit 105 Tape media length change processing unit 106 Appropriate tape media length determination unit

Claims

1. a content data acquisition unit that acquires content data to be recorded on a tape medium; a digest information acquisition unit that acquires digest information that identifies a portion that constitutes a digest video that is a part of the content data; a position acquisition unit that predicts and acquires positions on the tape medium of portions that constitute the digest video when multiple lengths of the tape medium are taken based on the content data and the digest information; a travel distance calculation unit that calculates a travel distance for accessing data portions constituting the digest video scattered throughout the video content for each length of a plurality of tape media based on the position; an efficiency calculation unit that uses the running distance and the lengths of the plurality of tape media to calculate an increase or decrease in the running distance relative to a degree of shortening of the length of each of the plurality of tape media as an efficiency; a selection unit that selects, from the lengths of the plurality of tape media, the length of tape media that has the highest calculated efficiency and that can efficiently save the running distance; A tape media management server having:

2. the position acquisition unit acquires a predicted logical position of the digest video on the tape medium based on the digest information, and acquires a predicted physical position of the digest video on the tape medium based on the logical position when a plurality of lengths of the tape medium are taken into account; the running distance calculation unit calculates a running distance of the tape media required to access the digest video for each length of the plurality of tape media based on the logical position and the physical position; 2. The tape media management server of claim 1.

3. the position acquisition unit acquires a predicted physical position of the digest video on the tape media based on a remainder calculated by dividing a length of the digest video based on a logical position on the tape media by a value that is k times the length of the plurality of tape media (k is an arbitrary number greater than 1); 3. The tape media management server according to claim 1.

4. the content data acquisition unit acquires content data including at least one of video and audio, and including data for identifying a position of the data on a time axis; 4. The tape media management server according to claim 1.

5. A tape drive; a tape media management server according to any one of claims 1 to 4; and The tape media management server further includes a tape drive control unit that controls reading and writing of tape media by a tape drive.

6. 6. The system of claim 5, wherein the tape drive magnetically reads and writes to tape media.

7. 7. The system according to claim 5, wherein the tape drive records data by running the tape medium back and forth in the longitudinal direction thereof.

8. obtaining content data to be recorded on a tape medium; acquiring digest information that identifies a portion of the content data that constitutes a digest video; a step of predicting and acquiring positions on a tape medium of portions that constitute the digest video when a plurality of lengths of the tape medium are taken based on the digest information; calculating a travel distance for accessing data portions constituting the digest video scattered throughout the video content for each length of a plurality of tape media based on the position; using the running distance and the lengths of the plurality of tape media, calculating an increase or decrease in the running distance relative to a degree of shortening of the length of each of the plurality of tape media as an efficiency; selecting a length of tape media that has the highest calculated efficiency and can efficiently save travel distance from among the lengths of the plurality of tape media; A tape media management method comprising:

9. A process of acquiring content data to be recorded on a tape medium; A process of acquiring digest information that identifies a portion that constitutes a digest video that is a part of the content data; a process of predicting and acquiring positions on a tape medium of portions that constitute the digest video when a plurality of lengths of the tape medium are taken based on the digest information; a process of calculating a travel distance for accessing data portions constituting the digest video scattered throughout the video content for each length of a plurality of tape media based on the position; a process of calculating, as an efficiency, a degree of increase or decrease in the running distance relative to a degree of shortening of the length of each of the plurality of tape media, using the running distance and the lengths of the plurality of tape media; A process of selecting, from among the lengths of the plurality of tape media, a length of tape media that has the highest calculated efficiency and can efficiently save travel distance; A program for causing a computer to execute the above.

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