JP2017049817A - Storage device and control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly resume access to a recording medium.SOLUTION: Drives 1a, 1b can store a cartridge 3, and can access a recording medium 3a with a block number larger than an upper limit of a block number by a bit number managed by an information processor 2. When the drive 1a performs write to a block number larger than the upper limit in the recording medium 3a, a control part 1c stores management information showing that the write is performed in a memory 3b. The control part 1c executes access to the recording medium 3a on the basis of the management information stored in the memory 3b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a storage apparatus and a control program.

  Storage devices that record data handled by an information processing apparatus such as a computer on a recording medium that can be taken out of the information processing apparatus are used. For example, a recording medium in which data is written can be stored and used as a backup of the data. Examples of the recording medium include a magnetic tape medium and an optical disk medium. The recording medium is often stored in a case called a cartridge for convenience of handling. The amount of data that can be recorded on the recording medium may be limited by the specifications of the recording processing software executed by the information processing apparatus in addition to the capacity of the recording medium itself.

  By the way, in a storage device, an error may occur in data write / read access to a recording medium due to an abnormal operation. Therefore, a method has been considered that allows access to continue even if an access error occurs.

  For example, a recovery method called dynamic device reconfiguration (DDR) has been proposed for writing data to a magnetic tape medium. In DDR, when an error occurs in the magnetic tape device while data is being written to the magnetic tape medium, the magnetic tape device reports the block number indicating the write position at the time of the error to the host device. For example, when the magnetic tape medium is moved to a normal drive by an operator or the like, the higher-level device appends unwritten data to the magnetic tape medium using the reported block number as the starting point using the destination drive. To do.

  In this proposal, it is also considered that the magnetic tape device writes data in a block number larger than the block number manageable by the host device. Then, the usable capacity of the magnetic tape medium can be increased even if all the storage areas of the magnetic tape medium cannot be recognized by the upper apparatus side due to the software specification of the upper apparatus side. At the time of DDR, the magnetic tape device associates a plurality of block numbers managed by itself with one block number that can be managed by the host device. When an error occurs, the magnetic tape device reports block numbers within a range that can be managed by the host device to the host device. Thereby, it is possible to perform DDR while suppressing the influence on the host device side during DDR.

  Proposal that the cassette has a tape-shaped recording medium and a semiconductor memory, and information (information such as recording program name and address number for searching) recorded on the tape stored in the cassette is recorded in the semiconductor memory provided in the cassette There is.

International Publication No. 2012/042661 JP-A-5-258528

  As described above, for example, the storage device writes data to a block number that is larger than the block number that can be managed by the host device, thereby relaxing the restriction on the usage capacity of the recording medium caused by the software of the host device. obtain. At this time, as described above, the storage apparatus may perform DDR by associating a plurality of block numbers that can be managed by the storage apparatus with one block number that can be managed by the host apparatus. However, this method depends on the correspondence relationship between the block numbers held on the storage device side, and the storage device that does not hold the correspondence relationship cannot properly resume the access to the recording medium by DDR. Therefore, there is a problem of how to realize a mechanism that can appropriately resume the access to the recording medium without depending on the information held on the storage device side.

  In one aspect, an object of the present invention is to provide a storage apparatus and a control program that can appropriately resume access to a recording medium.

  In one aspect, a storage apparatus connected to an information processing apparatus that manages a block number indicating a position of an access destination for a recording medium with a predetermined number of bits is provided. This storage control device has a drive and a control unit. The drive can store a cartridge including a recording medium and a memory different from the recording medium, and can access the recording medium with a block number larger than the upper limit of the block number according to the number of bits. When writing to the block number larger than the upper limit for the recording medium by the drive, the control unit stores management information indicating that the writing has been performed in the memory, and based on the management information stored in the memory The recording medium is accessed.

  In one aspect, a control program executed by a computer is provided. The control program stores a recording medium and a memory different from the recording medium in a computer included in a storage apparatus connected to an information processing apparatus that manages a block number indicating a position of an access destination for the recording medium with a predetermined number of bits. If writing to a block number larger than the upper limit is performed on the recording medium by a drive that can store the cartridge provided and can access the recording medium by a block number larger than the upper limit of the block number by the number of bits, the writing The management information indicating that the recording has been performed is stored in the memory, and based on the management information stored in the memory, the process of accessing the recording medium is executed.

  In one aspect, it is possible to appropriately resume access to the recording medium.

It is a figure which shows the storage apparatus of 1st Embodiment. It is a figure which shows the example of the information processing system of 2nd Embodiment. It is a figure which shows the hardware example of a tape apparatus. It is a figure which shows the hardware example of a server. It is a figure which shows the function example of a tape apparatus. It is a figure which shows the parameter example of the command used for DDR. It is a figure which shows the example of the upper limit of the block number which can be accessed. It is a figure which shows the example of a mode management table. It is a figure which shows the example of the information stored in CM. It is a flowchart which shows the example of a mode report process. It is a flowchart which shows the example of a block number management process at the time of writing. It is a flowchart which shows the example of the block number management process at the time of reading. It is a flowchart which shows the example of an error time block number report process. FIG. 10 is a diagram illustrating an example of cartridge confirmation processing. It is a figure which shows the example of the positioning process. It is a figure which shows the example of a sequence at the time of the writing in EX36TRK mode. It is a figure which shows the other example of DDR.

Hereinafter, the present embodiment will be described with reference to the drawings.
[First Embodiment]
FIG. 1 illustrates a storage apparatus according to the first embodiment. The storage device 1 is connected to the information processing device 2. The storage device 1 may be connected to the information processing device 2 via a network. The storage device 1 can store the cartridge 3. The cartridge 3 has a recording medium 3a and a memory 3b.

  In response to an instruction from the information processing device 2, the storage device 1 accesses the recording medium 3a (data writing or data reading). The recording medium 3a is, for example, a magnetic tape medium. For example, by recording data used for processing of the information processing apparatus 2 in the recording medium 3a, the recorded data can be used as a backup of business data. The memory 3b is a rewritable nonvolatile storage device such as a flash memory, for example. Since the memory 3b is provided in the cartridge 3, it may be called a cartridge memory.

  Here, the information processing apparatus 2 manages the block number indicating the position of the access destination for the recording medium 3a with the first number of bits. For ease of explanation, the first number of bits is assumed to be 4 as an example. Then, the manageable block number range is from “0b0000” to “0b1111” (that is, from “0” to “7”). Here, the prefix “0b” indicates that the subsequent numerical value or numerical value sequence is expressed in binary (when there is no prefix, it is expressed in decimal). For example, the size of data that can be recorded per block number (block size) is 32 KB (kilobytes). In this case, the total storage capacity of the recording medium 3a that can be recognized by the information processing apparatus 2 is 32 KB × 8 = 256 KB.

  The storage device 1 includes drives 1a and 1b and a control unit 1c. The drives 1 a and 1 b can store the cartridge 3. The drive 1a can also be called a first drive, and the drive 1b can be called a second drive. For example, the drive 1a can access the recording medium 3a when the cartridge 3 is accommodated. The drives 1a and 1b can access the recording medium 3a with a block number represented by a second bit number larger than the first bit number. That is, in the drives 1a and 1b, the access position of the recording medium 3a can be specified by the block number exceeding the upper limit of the block number range managed by the information processing apparatus 2.

  For example, the second number of bits is 6. Then, the manageable block number range is from “0b000000” to “0b111111” (ie, “0” to “31”). As described above, when the block size is 32 KB, the size that can be recorded on the recording medium 3 a by the drives 1 a and 1 b is 32 KB × 32 = 1024 KB. That is, the storage device 1 can handle a larger area (1024 KB area) than the area recognizable by the information processing apparatus 2 (256 KB area) for the recording medium 3a.

  The controller 1c may include a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), and the like. The control unit 1c may be a processor that executes a program. As used herein, the “processor” may include a set of multiple processors (multiprocessor).

  The control unit 1c controls access by the information processing apparatus 2 to the recording medium 3a of the cartridge 3 stored in the drive 1a or the drive 1b. For example, normally, when the access position of the recording medium 3a reaches a position corresponding to the upper limit block number of the first bit number, the control unit 1c reports to the information processing apparatus 2 that the block number has reached the upper limit. And stop access. However, the drives 1a and 1b can specify the access position by a block number larger than the upper limit block number of the first bit number. For this reason, even if the block number reaches the upper limit block number of the first number of bits, the control unit 1c causes the information processing apparatus 2 to continue access without performing the above report. In this example, the control unit 1c does not report to the information processing device 2 that the upper limit of the block number has been reached even if the position corresponding to the block number “0b1111” is reached, and reaches the block number “0b111111”. Report that the upper limit has been reached. Then, it is possible to position the recording medium 3a at a position corresponding to a block number larger than the upper limit block number of the first bit number. For this reason, the restriction caused by the number of blocks that can be managed by the software of the information processing apparatus 2 can be relaxed with respect to the available storage capacity of the recording medium 3a.

  However, in this case, an error may occur at the timing when the block number exceeding the upper limit of the block number that can be recognized by the information processing apparatus 2 is accessed. For example, a head for reading / writing with respect to the recording medium 3a included in the drive 1a or a scratch on the tape may cause an error. In a recovery process such as DDR, even if a block number exceeding the upper limit of a block number that can be recognized by the information processing apparatus 2 is reported, the information processing apparatus 2 cannot properly recognize the block number. For this reason, the control part 1c performs a recovery process as follows. First, when the cartridge 3 is stored in the drive 1a, if an error occurs when accessing the recording medium 3a, the control unit 1c performs the processing shown in FIG.

  First, when writing to the recording medium 3a using the drive 1a, the controller 1c writes to the recording medium 3a to a block number larger than the upper limit of the first number of bits. Is stored in the memory 3b. It can also be said that the management information is a flag indicating that writing to a block number larger than the management upper limit block number of the information processing apparatus 2 has been performed.

  Thereafter, when an access error occurs during access to the recording medium 3a by the drive 1a, the drive 1a notifies the control unit 1c that the error has occurred. The control unit 1c detects that an error has occurred in access to the first block number (block number at the time of error) that is larger than the upper limit of the block number by the first number of bits (FIGS. 1A and 1). ). For example, the first block number is “0b11110”. In FIG. 1, the block number is abbreviated as “BLK (BLocK)” (in FIG. 1, the value of BLK is expressed in binary). The control unit 1c can acquire the first block number “0b11110” from the drive 1a (FIGS. 1A and 2).

The control unit 1c generates a second block number represented by the first number of bits from the first block number and transmits the second block number to the information processing device 2. For example, the control unit 1c uses the first bit number “4”.
Is generated from the first block number “0b11110”. More specifically, the control unit 1c extracts the lower 4 bits (for the first number of bits) of the first block number “0b1111010” and sets it as the second block number “0b1010”. The control unit 1c transmits the second block number “0b1010” to the information processing apparatus 2 (FIGS. 1A and 3). The control unit 1c may transmit the second block number to the information processing device 2 at a timing requested from the information processing device 2 after reporting the occurrence of the error, or may send the second block number together with the report that the error has occurred. May be transmitted to the information processing apparatus 2.

  The control unit 1c stores the offset value corresponding to the first bit number and the first block number in the memory 3b (the offset value may be included in the management information). For example, the control unit 1c stores the offset value “0b110000” in the memory 3b. More specifically, the control unit 1c acquires the upper 2 bits of the first block number “0b1111010” (the number of upper bits excluding the first bit number), and sets all the lower 4 bits to “0”. As a result, the offset value “0b110000” is generated and stored in the memory 3b (FIGS. 1A and 4). In FIG. 1, the offset value is expressed as “Offset”. In FIG. 1, the offset value is expressed in binary. In addition, the order of each step of FIG. 1 (A) (3) and FIG. 1 (A) (4) may be reversed, and may be performed in parallel.

  Thereafter, the cartridge 3 is transferred from the drive 1a to the drive 1b. The transfer may be performed by a system administrator or a robot, for example. The information processing device 2 notifies the administrator of the transfer of the cartridge 3 from the drive 1a to the drive 1b, or receives the cartridge movement, when receiving the report of the block number at the time of error from the control unit 1c. You may give instructions to other robots. The drive 1b may be a drive newly installed in the slot in which the drive 1a is provided after the drive 1a is removed from the storage device 1. Thereafter, the control unit 1c performs the process shown in FIG.

  When detecting that the cartridge 3 has been transferred to the drive 1b, the control unit 1c reports that fact to the information processing device 2. In response to the report, the information processing apparatus 2 notifies the control unit 1c of the second block number (“1010” in the above example) indicating the access resume position of the recording medium 3a. The control unit 1c receives the second block number from the information processing device 2 (FIGS. 1B and 5).

  The control unit 1c detects management information stored in the memory 3b. Thereby, the control part 1c can confirm that the data is written in the recording medium 3a by the block number larger than the upper limit of the first number of bits managed by the information processing apparatus 2. And the control part 1c acquires the offset value memorize | stored in the memory 3b. For example, the offset value stored in the memory 3b is “0b110000” (FIGS. 1B and 6). The control unit 1c outputs the first block number to the drive 1b based on the second block number and the offset value. For example, the control unit 1c generates the first block number by performing an OR operation between the second block number and the offset value. More specifically, when the second block number is “0b1010” and the offset value is “0b110000”, the control unit 1c takes the first block by ORing the same digits of each bit. The number “0b1111010” is generated. The process of restoring the first block number is a process of generating the first block number by correcting the second block number acquired from the information processing device 2 with an offset value (so-called correction value). You can also. The control unit 1c outputs the generated first block number “0b1111010” to the drive 1b (FIGS. 1B and 7).

  Then, the drive 1b can be positioned with respect to the recording medium 3a by the first block number “0b1111010”. The first block number “0b1111010” is the block number accessed at the time of the error. That is, the access can be resumed by directly specifying the block number accessed at the time of the error. For example, the information processing apparatus 2 instructs the storage apparatus 1 to resume access from data at the timing when an error occurs. Then, the storage apparatus 1 resumes access from the position corresponding to the first block number (FIGS. 1B and 8).

  Thus, according to the storage apparatus 1, after the cartridge 3 is transferred from the drive 1a to the drive 1b, the access resuming position of the recording medium 3a can be appropriately determined based on the information recorded in the memory 3b. The storage device 1 records information used to determine a block number when resuming access in the memory 3b included in the cartridge 3. For this reason, by moving the cartridge 3, the information for determining the block position when the access is resumed can also be moved. This makes it possible to appropriately determine the block number without depending on the information held on the storage device side.

  In the method according to the first embodiment, when the access is resumed, the first block number (block number at the time of error) can be restored, and the block number at which the access is resumed can be directly designated. For this reason, recovery processing such as DDR can be performed efficiently. For example, a method in which the storage device associates a plurality of block numbers managed by itself with a single block number that can be managed by the host device side is also conceivable. However, this method cannot directly specify a block number for resuming access. Because there is. Specifically, an inefficient access (so-called “empty writing”) such as reporting to the higher-level device (for example, the information processing device 2) that the data has been normally written without actually writing occurs when the access is resumed. obtain. On the other hand, according to the method of the first embodiment, the block number at the time of resuming access can be directly specified, and inefficient access such as “blank writing” is not required.

  Here, the offset value recorded in the memory 3b may be a value that does not include the lower 4 bits that are clearly “0”. For example, in FIG. 1 (A) (4), instead of the offset value “0b110000”, only the offset value “0b11” may be stored in the memory 3b. In this case, after the cartridge 3 is moved to the drive 1b, the control unit 1c performs an OR operation between the value obtained by adding the lower 4 bits to the offset value “0b11” and the block number “0b1010” acquired from the information processing device 2. Thus, the first block number “0b11110” can be restored. In this way, the storage capacity of the memory 3b can be saved.

  In the example of the first embodiment, the memory 3b is provided in the cartridge 3 to store the offset value. However, the offset value is stored in a memory (not shown in FIG. 1) provided in the storage device 1. May be. In that case, the memory may be a nonvolatile memory or a volatile memory. However, a nonvolatile memory is preferable. This is because there is a possibility that the storage apparatus 1 is powered off due to a power failure or the like, and in this case, the offset value can be held.

  Further, if the offset value is stored in the memory 3b of the cartridge 3, the cartridge 3 is transferred to a drive provided in another storage device other than the storage device 1, and the other value is determined based on the offset value stored in the memory 3b. Recovery processing can be performed by the storage device. For example, even when the storage apparatus has one drive, DDR can be efficiently executed by transferring the cartridge 3 to a drive of another storage apparatus.

[Second Embodiment]
FIG. 2 is a diagram illustrating an example of an information processing system according to the second embodiment. The information processing system according to the second embodiment includes tape devices 100 and 100a and a server 200. The tape devices 100 and 100a are connected to the server 200. The server 200 is connected to the network 10. The network 10 is, for example, a LAN (Local Area Network).

  The tape devices 100 and 100 a are storage devices that write data to a recording medium stored in the cartridge 300. The tape devices 100 and 100a may be called a library device or a changer device that can store a plurality of cartridges 300 in a housing. The tape devices 100 and 100a are an example of the storage device 1 according to the first embodiment.

  The cartridge 300 includes a magnetic tape 310 and a cartridge memory (CM: Cartridge Memory) 320. The magnetic tape 310 is a magnetic tape medium. The magnetic tape 310 has a larger storage area size than the CM 320 and can store a large amount of data. Data is written to and read from the magnetic tape 310 by sequential access. For example, a backup of data handled by the server 200 is stored in the magnetic tape 310. CM 320 is a semiconductor memory. The CM 320 stores data used for DDR processing. The cartridge 300 is an example of the cartridge 3 according to the first embodiment. Here, the cartridge 300 is a medium compliant with the LTO (Linear Tape-Open, registered trademark) standard. The tape devices 100 and 100a can write and read data to and from the LTO type cartridge 300 (the magnetic tape 310 in the cartridge). In the LTO type magnetic tape 310, for example, a storage capacity of several hundred GB to several TB can be used. On the other hand, the CM 320 has a smaller storage capacity than the magnetic tape 310.

  The server 200 is a server computer that provides a predetermined business service to other server devices or client devices (not shown). The server 200 uses the tape devices 100 and 100a to back up business data used for the processing of the server 200. Here, the server 200 has a DDR function. The server 200 may be called a host computer that executes processing for input from a terminal device. The server 200 is an example of the information processing apparatus 2 according to the first embodiment.

  Here, the access method for the magnetic tape 310 of the server 200 has a plurality of modes depending on the number of tracks accessed to the magnetic tape 310. For example, there are an 18 track (TRK: TRacK) mode, a 36 TRK mode, and a 128 TRK mode. In each mode, the range of block numbers that the server 200 can use for DDR processing is different.

For example, in the 18 TRK mode and the 36 TRK mode, the server 200 manages the block number with 22 bits. In this case, the server 200 can manage ²²² (about 4 million) block numbers. For example, since one block size is 32 KB, the total size of the magnetic tape medium that can be used by a block number represented by 22 bits is approximately 128 GB (= 32 KB × 4 million). An example of the magnetic tape medium used in the 18TRK mode is an OPEN type. Since the capacity per tape of the OPEN type magnetic tape medium is about 1.2 GB, it is sufficient to manage the block number with 22 bits. Similarly, a magnetic tape medium used in the 36TRK mode includes, for example, a CMT (Cartridge Magnetic Tape) type. Since the capacity per tape of the CMT type magnetic tape medium is about 2.4 GB, it is sufficient to manage the block number with 22 bits.

On the other hand, in recent years, the above-mentioned LTO type is often used as a magnetic tape medium. The LTO has a plurality of generations (LTO1 to LTO5, etc.), and depending on the generation, the capacity per volume can be written up to 200 GB to 1.6 TB (terabyte). However, when the block size is 32 KB and the block number is managed with 22 bits, only 128 GB can be used. Therefore, the above-described 128 TRK mode is usually used for accessing the LTO. In the 128 TRK mode, the block number is managed with 32 bits. In this case, it is manageable the block number of 2 ^{to 32} (about 400 million). The total size of the magnetic tape medium that can be used by the block number represented by 32 bits is 128 TB (= 32 KB × 400 million), and the total capacity of the LTO type magnetic tape medium can be fully utilized.

  Here, even though the tape devices 100 and 100a support writing to the LTO type magnetic tape medium, the OS (Operating System) on the server 200 side and software such as a driver are compatible with the 18TRK / 36TRK mode. However, it may not support 128 TRK mode. For example, the tape device may be replaced with the new tape device 100 while continuing to use the existing server 200 (the same applies to the tape device 100a). In this case, the tape device 100 emulates the operation of the 18TRK mode or the 36TRK mode according to the server 200, and enables writing to the LTO type magnetic tape medium.

  In the 18TRK / 36TRK mode, when the access destination block number of the magnetic tape 310 exceeds the upper limit manageable by 22 bits, the block number upper limit used in the DDR processing by the server 200 is exceeded. Therefore, the tape device 100 reports a logical EOT (End Of Tape) error to the server 200 when the block number of the access destination exceeds the upper limit represented by 22 bits in the above emulation processing, and performs further access. Will be deterred.

However, in this case, despite the handle LTO in 2 ³² or more block number it will not be available to 2 ²² or more block number. Then, the capacity of the magnetic tape 310 cannot be fully utilized. In the example of the second embodiment, the server 200 does not support the 128 TRK mode. Therefore, the tape devices 100 and 100a provide a function of making the capacity of the magnetic tape 310 fully usable while suppressing the influence on the DDR processing even when the server 200 does not support the 128 TRK mode.

  FIG. 3 is a diagram illustrating a hardware example of the tape device. The tape device 100 includes a processor 101, a RAM 102, a nonvolatile memory (NVRAM: Non-Volatile Random Access Memory) 103, a connection interface 104, and drives 105 and 106. Each unit is connected to the bus of the tape device 100. The tape device 100a can also be realized by the same hardware as the tape device 100.

  The processor 101 is a processor that controls information processing of the tape device 100. The processor 101 may be a multiprocessor. The processor 101 is, for example, a CPU, DSP, ASIC, or FPGA. The processor 101 may be a combination of two or more elements of CPU, DSP, ASIC, FPGA, and the like.

  The RAM 102 is a volatile memory that temporarily stores firmware programs executed by the processor 101 and various data. The RAM 102 may be used as a buffer that temporarily holds data stored in the magnetic tape 310 or the CM 320.

  The NVRAM 103 stores a firmware program executed by the processor 101. The NVRAM 103 stores data used for processing executed by the processor 101.

  The connection interface 104 is a communication interface connected to the server 200 via a predetermined cable. As the connection interface 104, for example, SAS (Serial Attached SCSI, SCSI is an abbreviation for Small Computer System Interface), OCLINK (Optical Channel LINK, registered trademark), or the like can be used.

  The drives 105 and 106 can store the cartridge 300. The drive 105 writes / reads data to / from the stored cartridge 300 in accordance with instructions from the processor 101. The drive 105 includes a tape recording unit 105a and a memory recording unit 105b. The tape recording unit 105a writes / reads data to / from the magnetic tape 310. The memory recording unit 105b writes / reads data to / from the CM 320. The drive 106 includes a tape recording unit 106a and a memory recording unit 106b. The function of the tape recording unit 106a is the same as that of the tape recording unit 105a. The function of the memory recording unit 106b is the same as that of the memory recording unit 105b.

  Here, each of the tape recording units 105 a and 106 a includes a magnetic head for writing / reading data to / from the magnetic tape 310. When the tape recording units 105 a and 106 a access a position corresponding to a certain block number of the magnetic tape 310, the magnetic head moves the magnetic tape 310 so that the magnetic head is disposed at the corresponding position of the magnetic tape 310. . As described above, the process of aligning the position of the magnetic tape 310 with respect to the magnetic head may be referred to as “positioning of the magnetic tape 310” or simply “positioning”.

  FIG. 4 is a diagram illustrating a hardware example of the server. The server 200 includes a processor 201, a RAM 202, an HDD (Hard Disk Drive) 203, a connection interface 204, an image signal processing unit 205, an input signal processing unit 206, a medium reader 207, and a communication interface 208. Each unit is connected to the bus of the server 200.

  The processor 201 controls information processing of the server 200. The processor 201 may be a multiprocessor. The processor 201 is, for example, a CPU, DSP, ASIC, or FPGA. The processor 201 may be a combination of two or more elements among CPU, DSP, ASIC, FPGA, and the like.

  The RAM 202 is a main storage device of the server 200. The RAM 202 temporarily stores at least part of an OS program and application programs to be executed by the processor 201. The RAM 202 stores various data used for processing by the processor 201.

  The HDD 203 is an auxiliary storage device of the server 200. The HDD 203 magnetically writes data to and reads data from a built-in magnetic disk. The HDD 203 stores an OS program, application programs, and various data. The server 200 may include other types of auxiliary storage devices such as a flash memory and an SSD, and may include a plurality of auxiliary storage devices.

The connection interface 204 is a communication interface connected to the tape devices 100 and 100a via a predetermined cable.
The image signal processing unit 205 outputs an image to the display 11 connected to the server 200 in accordance with an instruction from the processor 201. As the display 11, a CRT (Cathode Ray Tube) display, a liquid crystal display, or the like can be used.

  The input signal processing unit 206 acquires an input signal from the input device 12 connected to the server 200 and outputs it to the processor 201. As the input device 12, for example, a pointing device such as a mouse or a touch panel, a keyboard, or the like can be used.

  The medium reader 207 is a device that reads programs and data recorded on the recording medium 13. As the recording medium 13, for example, a magnetic disk such as a flexible disk (FD) or an HDD, an optical disk such as a CD (Compact Disc) or a DVD (Digital Versatile Disc), or a magneto-optical disk (MO) is used. Can be used. Further, as the recording medium 13, for example, a non-volatile semiconductor memory such as a flash memory card can be used. For example, the medium reader 207 stores the program and data read from the recording medium 13 in the RAM 202 or the HDD 203 in accordance with an instruction from the processor 201.

  The communication interface 208 communicates with other computers via the network 10. The communication interface 208 may be a wired communication interface or a wireless communication interface.

  FIG. 5 is a diagram illustrating an example of functions of the tape device. The tape device 100 includes an RW (Read / Write) control unit 110 and a storage unit 120. The RW control unit 110 is realized by the processor 101 executing a program stored in the RAM 102. The storage unit 120 is realized by a storage area secured on the RAM 102 or the NVRAM 103.

  The RW control unit 110 controls the writing and reading of data by the drives 105 and 106. For example, when the cartridge 300 is stored in the drive 105, the RW control unit 110 writes the data instructed by the server 200 to the magnetic tape 310 of the cartridge 300. Further, the RW control unit 110 reads the data instructed to be read from the server 200 from the magnetic tape 310 of the cartridge 300 and provides it to the server 200.

When an access error occurs in the drive 105 or the drive 106 when accessing a certain block number, the RW control unit 110 notifies the server 200 of the error occurrence. After that, when receiving a block number notification instruction at the time of access from the server 200, the RW control unit 110 reports the corresponding block number to the server 200. However, if the block number in which the access error has occurred is equal to or greater than the upper limit (2 ²² ) of the block number managed by the server 200, the RW control unit 110 generates a 22-bit block number from the block number, Report to server 200. The RW control unit 110 stores the offset value of the original block number with respect to the generated 22-bit block number in the CM 320.

  Thereafter, when the RW control unit 110 detects that the cartridge 300 has been moved to a normal drive (the drive 106 if an error occurs in the drive 105), the 22-bit block number reported at the time of the error is received from the server 200. get. Based on the 22-bit block number and the offset value stored in the CM 320, an access resumption position to the magnetic tape 310 is determined.

  The storage unit 120 stores information used for processing by the RW control unit 110. The storage unit 120 may be used as a buffer that temporarily stores data to be written received by the RW control unit 110 from the server 200 and data read from the magnetic tape 310.

  In the above description, the function of the tape device 100 has been described, but the tape device 100a also has the same function. The DDR process may be executed across the tape devices 100 and 100a (for example, when an error occurs in access by the tape device 100, the access is recovered using the tape device 100a).

  The server 200 includes a DDR processing unit 210 and a storage unit 220. The DDR processing unit 210 is realized by the processor 201 executing a program stored in the RAM 202. The storage unit 220 is realized by a storage area secured on the RAM 202 or the HDD 203.

  The DDR processing unit 210 controls DDR processing. Specifically, it is assumed that an access error occurs while the tape device 100 is accessing the magnetic tape 310 of the cartridge 300 accommodated in the drive 105. Then, the DDR processing unit 210 receives a block number at the time of error from the tape device 100 together with an access error notification from the tape device 100. The DDR processing unit 210 notifies the operator to transfer the cartridge 300 to the drive 106. For example, the DDR processing unit 210 may perform the notification by causing the display 11 to display a message that prompts the transfer of the cartridge 300. Alternatively, the DDR processing unit 210 may transmit the message to a terminal device used by the operator, or may notify the message by voice from a speaker connected to the server 200.

  Thereafter, the DDR processing unit 210 receives a notification from the tape device 100 that the cartridge 300 has been transferred to the drive 106. The DDR processing unit 210 instructs the tape device 100 to resume access from the position corresponding to the block number, together with the block number that received the report at the time of the error.

  The storage unit 220 stores information used for processing by the DDR processing unit 210. For example, the storage unit 220 stores block number information at the time of error received from the tape device 100.

  FIG. 6 is a diagram illustrating a parameter example of a command used for DDR. In DDR, two types of commands are mainly used. The first command is “RDBID (ReaD Block ID)”. ID is an abbreviation for IDentifier. “BID” indicates a block number. The RDBID command is a command issued to the tape device 100 by the server 200 after an access error is notified from the tape device 100 to the server 200, and is a command for instructing notification of a block number at the time of an error. The second command is “LOCATE”. The LOCATE command is a command issued to the tape device 100 by the server 200, and is a command for instructing the tape device 100 on the position of the magnetic tape 310 when access is resumed.

  Both the RDBID command and the LOCATE command specify a block number as a parameter. FIG. 6A shows the number of bits used in a parameter for specifying a block number in the RDBID command. In the 18TRK mode and the 36TRK mode, the number of bits used for specifying the block number in the RDBID command is 22 (corresponding to the 0th to 21st bits in FIG. 6A). On the other hand, in the 128 TRK mode, the number of bits used to specify a block number in the RDBID command is 32 (corresponding to the 0th to 31st bits in FIG. 6A).

  FIG. 6B shows the number of bits used in a parameter for specifying a block number in the LOCATE command. In the 18TRK and 36TRK modes, the number of bits used to specify the block number in the LOCATE command is 22 (corresponding to the 0th to 21st bits in FIG. 6B). On the other hand, in the 128 TRK mode, the number of bits used to specify the block number by the LOCATE command is 32 (corresponding to the 0th to 31st bits in FIG. 6B).

FIG. 7 is a diagram illustrating an example of the upper limit of accessible block numbers. In FIG. 7, the logical storage area of the magnetic tape 310 is schematically represented by one band. The block number of the beginning (BOT: Beginning Of Tape) of the storage area of the LTO type magnetic tape 310 is “0”. The block number of the end (EOT) is “2 ³² −1”. At the position of the block number “0”, a VOL ID (VOLume ID) for identifying the magnetic tape 310 is written. User data is sequentially written in subsequent blocks. The block size is 32KB.

For example, in the 36TRK mode, since the block number is managed with 22 bits as described above, the maximum value of the block number is 2 ²² -1. On the other hand, in the 128 TRK mode, since the block number is managed with 32 bits as described above, the maximum value of the block number is 2 ³² -1.

The EX36TRK mode (extended 36TRK mode) has been newly added as an operation mode of the tape device 100 in order to make the storage area of the magnetic tape 310 fully available even from the server 200 that supports the 36TRK mode but not the 128TRK mode. Provided. In the EX36TRK mode, the server 200 recognizes that the tape device 100 is accessing the magnetic tape 310 in the 36TRK mode, but in the tape device 100, the magnetic tape 310 is accessed in a manner equivalent to the 128TRK mode. . In the EX36TRK mode, the tape device 100 does not report a logical EOT error to the server 200 even if the block number reaches ²²² . Then, in the EX36TRK mode, the tape device 100 is positioned by a block number represented by 32 bits as in the 128TRK mode. For this reason, in the EX36TRK mode, the storage area of the magnetic tape 310 can be fully utilized as in the 128TRK mode.

  FIG. 8 is a diagram illustrating an example of the mode management table. The mode management table 121 is stored in the storage unit 120. The mode management table 121 includes items of tape device operation classification, operation mode, SNS I / O (SeNSe Input / Output) command, and block management bit number.

  Information indicating the operation category of the tape device is registered in the item of the tape device operation category. Information indicating the operation mode of the tape device is registered in the operation mode item. In the SNS I / O command item, a response code for the SNS I / O command corresponding to the operation mode is registered. Here, the SNS I / O command is a command issued by the server 200 and a command for confirming the operation classification of the tape device 100. In response to the SNS I / O command, the tape device 100 responds to the server 200 with a response code corresponding to the operation mode currently used by the tape device 100, thereby setting the operation classification of the tape device 100 to the server 200. Report. In the item of block management bit number, the number of bits used for block number management is registered.

  For example, information indicating that the tape device operation classification is “CMT type”, the operation mode is “36TRK”, the SNS I / O command is “FF17E236647036”, and the number of block management bits is “22” is registered in the mode management table 121. .

  This is because when the operation classification of the tape device 100 is “CMT type” and the operation mode is 36TRK mode, the SNS I / O is notified to notify the server 200 that it is “CMT type (36TRK mode)”. Indicates that the command response code “FF17E236647036” is to be reported. In the 36TRK mode, the number of bits available for block number management is 22 bits.

  Further, for example, in the mode management table 121, information that the tape device operation classification is “LTO type”, the operation mode is “EX36TRK”, the SNS I / O command is “FF17E236647036”, and the number of block management bits is “32”. Is done.

  This is because when the operation classification of the tape device 100 is “LTO type” and the operation mode is EX36TRK mode, the server 200 is notified of “CMT type (36TRK mode)” instead of “LTO type”. The SNS I / O command response code “FF17E236647036” (36TRK mode response code) is reported. This report is for making the server 200 recognize that the operation classification of the tape device 100 is “CMT type”. In the EX36TRK mode, the number of bits that can be used for block number management is 32 bits.

  FIG. 9 is a diagram illustrating an example of information stored in the CM. The CM 320 stores an EX36TRK use flag 321 (FIG. 9A) and an offset value 322 (FIG. 9B). The EX36TRK use flag 321 is a management in which “true” is set when the EX36TRK mode is used for access to the magnetic tape 310 and access is performed with a block number exceeding the upper limit of the block number of the 36TRK mode. Information. When the EX36TRK mode is not used for access to the magnetic tape 310, or when the block number of the access destination does not exceed the upper limit of the block number of the 36TRK mode, the EX36TRK use flag 321 is set to “false”. Even if the EX36TRK mode is not used for accessing the magnetic tape 310 and the access destination block number does not exceed the upper limit of the block number of the 36TRK mode, the EX36TRK use flag 321 is set to “false”. . It can also be said that the EX36TRK use flag 321 is management information indicating that the block number of the access destination for the magnetic tape 310 exceeds the upper limit of 22 bits.

  The offset value 322 is an offset value generated by the RW control unit 110 when an access error occurs on the magnetic tape 310. The offset value 322 is the upper 10 bits from which the lower 22 bits of the 32-bit block number accessed at the time of error are removed. The offset value 322 may be a value in which the lower 22 bits are all set to “0” without removing the lower 22 bits of the 32-bit block number. Saves space).

  For example, it is assumed that an access error has occurred at the block number “0xA0000100” of the magnetic tape 310 (the prefix “0x” indicates that the subsequent numerical value or numerical value string is expressed in hexadecimal). The block number “0xA0000100” exceeds the upper limit block number that can be managed by 22 bits. In this case, for example, the upper 10 bits “0b1010000000” are recorded in the CM 320 as the offset value 322 (the offset value in FIG. 9 is expressed in binary). Information including both the offset value 322 and the EX36TRK use flag 321 may be considered as management information.

  Next, a processing procedure in the tape device 100 configured as described above will be described. Here, in the tape device 100, which operation mode is set in advance (an operation mode consistent with the operation mode on the server 200 side) is set in advance by the system administrator. For example, information on a preset operation mode is stored in the NVRAM 103.

FIG. 10 is a flowchart illustrating an example of mode report processing. In the following, the process illustrated in FIG. 10 will be described in order of step number.
(S11) The RW control unit 110 receives a mode confirmation command (SNS I / O command) from the server 200. The RW control unit 110 refers to the NVRAM 103 and acquires the operation mode set in the tape device 100. The RW control unit 110 performs the following determinations in steps S12, S14, S16, and S18 based on the acquired operation mode.

  (S12) The RW control unit 110 determines whether or not the set operation mode is the 18TRK mode. If it is the 18TRK mode, the process proceeds to step S13. If not 18TRK mode, the process proceeds to step S14.

  (S13) The RW control unit 110 reports a response code “FF175118647018” indicating the 18TRK mode to the server 200. Then, the process ends. The response code to be reported for the operation mode can be acquired from the mode management table 121. The server 200 confirms from the response code that the operation mode of the server 200 matches the operation mode of the tape device 100. In addition, the server 200 accesses the cartridge 300 stored in the tape device 100 (the same applies to other modes).

  (S14) The RW control unit 110 determines whether or not the 36TRK mode is set. If it is 36TRK mode, the process proceeds to step S15. If not in the 36TRK mode, the process proceeds to step S16.

(S15) The RW control unit 110 reports to the server 200 a response code “FF17E236647036” indicating that it is in the 36TRK mode. Then, the process ends.
(S16) The RW control unit 110 determines whether or not the EX36TRK mode is set. If it is in the EX36TRK mode, the process proceeds to step S17. If not in the EX36TRK mode, the process proceeds to step S18.

(S17) The RW control unit 110 reports to the server 200 a response code “FF17E236647036” indicating that it is in the 36TRK mode. Then, the process ends.
(S18) The RW control unit 110 determines whether or not the 128 TRK mode is set. If it is the 128 TRK mode, the process proceeds to step S19. If not 128TRK mode, the process proceeds to step S20.

(S19) The RW control unit 110 reports a response code “FF17E27F64837F” indicating the 128 TRK mode to the server 200. Then, the process ends.
(S20) The RW control unit 110 reports a mode unmatch error to the server 200. This is because no mode is set and the mode cannot be confirmed.

  In this way, the server 200 confirms the mode of the tape device 100. In particular, when the EX36TRK mode is set, the tape device 100 reports to the server 200 that the 36TRK mode is set. Note that the server 200 may notify the system administrator of an error when the received operation mode does not match the operation mode of the server 200.

  FIG. 11 is a flowchart illustrating an example of a block number management process at the time of writing. In the following, the process illustrated in FIG. 11 will be described in order of step number. The following procedure is executed each time the block number is incremented when data is written to the magnetic tape 310 using the drive 105 or the drive 106 (data is written sequentially in ascending order of the block number).

  (S21) The RW control unit 110 determines whether the operation mode of the tape device 100 is either 18TRK or 36TRK mode. If it is either 18TRK or 36TRK mode, the process proceeds to step S22. If neither the 18TRK mode nor the 36TRK mode is selected, the process proceeds to step S24.

(S22) The RW control unit 110 determines whether or not the block number to be written (write block number) is ²²² or more. In the case of ²²² or more, the process proceeds to step S23. If it is not ²² or more, the processing is terminated (writing in 18TRK or 36TRK mode is continued).

  (S23) The RW control unit 110 reports a logical EOT detection error to the server 200. Then, the process ends. After reporting the logical EOT detection error, the write process will be interrupted.

  (S24) The RW control unit 110 determines whether or not the operation mode of the tape device 100 is either the 128TRK mode or the EX36TRK mode. If it is either 128TRK or EX36TRK mode, the process proceeds to step S26. If neither the 128TRK mode nor the EX36TRK mode is selected, the process proceeds to step S25.

  (S25) The RW control unit 110 reports a mode unmatch error to the server 200. Then, the process ends. After the mode unmatch error is reported, the writing process is interrupted.

(S26) The RW control unit 110 determines whether the write block number is 2 ³² or more. If it is 2 ³² or more, the process proceeds to step S27. If it is not 2 ³² or more, the process proceeds to step S28.

  (S27) The RW control unit 110 reports a logical EOT detection error to the server 200. Then, the process ends. After reporting the logical EOT detection error, the write process will be interrupted.

  (S28) The RW control unit 110 determines whether or not the operation mode of the tape device 100 is the EX36TRK mode. If it is in the EX36TRK mode, the process proceeds to step S29. If it is not in the EX36TRK mode, the process is terminated. If it is not in the EX36TRK mode, it means that it is in the 128TRK mode (writing in the 128TRK mode is continued).

(S29) The RW control unit 110 determines whether the write block number is ²²² or more. In the case of ²²² or more, the process proceeds to step S30. If not ²² or greater, the process proceeds to step S31.

  (S30) The RW control unit 110 sets the EX36TRK use flag 321 to “true”. Then, the processing is terminated (writing in the EX36TRK mode (corresponding to the 128TRK mode) is continued).

  (S31) The RW control unit 110 sets the EX36TRK use flag 321 to “false”. Then, the processing is terminated (writing in the EX36TRK mode (corresponding to the 128TRK mode) is continued).

  Note that when sequential writing is sequentially performed on a plurality of block numbers, the mode check in steps S21, S24, and S28 may be executed once and then not executed after the second (after the second time). Because the judgment result will be the same). In that case, the RW control unit 110 determines the block number in the same procedure as the procedure executed for the first time (for example, if Yes in step S21 for the first time, step S21 for the second and subsequent times). The block number is determined based on the determination in step S22 without needing to be determined). Further, the RW control unit 110 may skip steps S30 and S31 if there is no change from the contents of the set flag after the second time (for example, overwriting when “true” is already set, “ You may skip without setting "true").

  FIG. 12 is a flowchart illustrating an example of a block number management process at the time of reading. In the following, the process illustrated in FIG. 12 will be described in order of step number. The following procedure is executed each time the block number is incremented when data is read from the magnetic tape 310 using the drive 105 or the drive 106 (data is read sequentially in ascending order of the block number).

  (S41) The RW control unit 110 determines whether the operation mode of the tape device 100 is either 18TRK or 36TRK mode. If it is either 18TRK or 36TRK mode, the process proceeds to step S42. If it is not in 18TRK or 36TRK mode, the process proceeds to step S44.

(S42) The RW control unit 110 determines whether the block number to be read (read block number) is ²²² or more. In the case of ²²² or more, the process proceeds to step S43. If not ²² or more, the process ends (reading in 18TRK or 36TRK mode is continued).

  (S43) The RW control unit 110 reports a logical EOT detection error to the server 200. Then, the process ends. After reporting a logical EOT detection error, the read process will be interrupted.

  (S44) The RW control unit 110 determines whether or not the operation mode of the tape device 100 is either the 128TRK mode or the EX36TRK mode. If it is either 128TRK or EX36TRK mode, the process proceeds to step S46. If neither the 128TRK mode nor the EX36TRK mode is selected, the process proceeds to step S45.

  (S45) The RW control unit 110 reports a mode unmatch error to the server 200. Then, the process ends. After reporting the mode unmatch error, the reading process will be interrupted.

(S46) The RW control unit 110 determines whether the read block number is 2 ³² or more. If it is 2 ³² or more, the process proceeds to step S47. If it is not equal to or greater than ³² , the process ends (reading in 128 TRK mode or EX36 TRK mode (corresponding to 128 TRK mode) is continued).

  (S47) The RW control unit 110 reports a logical EOT detection error to the server 200. Then, the process ends. After reporting a logical EOT detection error, the read process will be interrupted.

  Note that when sequential reading is sequentially performed on a plurality of block numbers, the mode confirmation in steps S41 and S44 may be performed once and then not performed after the second time (the second and subsequent times are also determined). Because the result will be the same). In that case, the RW control unit 110 determines the block number in the same procedure as the procedure executed for the first time (for example, if Yes in step S41 for the first time, the step S41 for the second and subsequent times). The block number is determined based on the determination in step S42 without having to perform the determination).

FIG. 13 is a flowchart illustrating an example of an error block number reporting process. In the following, the process illustrated in FIG. 13 will be described in order of step number.
(S51) The RW control unit 110 detects that an error has occurred in accessing the magnetic tape 310 of the cartridge 300 accommodated in the drive 105. The RW control unit 110 reports an error occurrence to the server 200. At this time, the VOL ID stored in the magnetic tape 310 of the cartridge 300 is also reported to the server 200. The reported VOL ID is held by the server 200. Thereafter, the RW control unit 110 receives an RDBID command from the server 200.

(S52) The RW control unit 110 acquires from the drive 105 the block number of the access destination at the timing when the access error occurs (block number at the time of error).
(S53) The RW control unit 110 acquires the EXT36TRK use flag 321 from the CM 320 of the cartridge 300 mounted on the drive 105.

  (S54) The RW control unit 110 determines whether or not the EXT36TRK use flag 321 is “true”. If it is “true”, the process proceeds to step S55. If it is not “true” (that is, “false”), the process proceeds to step S57. When the EXT36TRK use flag 321 is “true”, the EXT36TRK mode is used, and the error block number exceeds the upper limit of the block number represented by 22 bits. On the other hand, when the EXT36TRK use flag 321 is “false”, the EXT36TRK mode is not used, or the EXT36TRK mode is used but the block number at the time of error is below the upper limit of the block number represented by 22 bits. Become.

  (S55) The RW control unit 110 records the upper 10 bits (offset value) obtained by removing the lower 22 bits of the error block number in the CM 320. For example, when the error block number is “0b10100000000000000000000100000000”, the offset value 322 is “0b1010000000”.

  (S56) The RW control unit 110 reports the lower 22 bits (dummy block number) of the block number at the time of error to the server 200 (host). For example, the dummy block number reported to the server 200 for the error block number in step S55 is “0b0000000000000100000000”. Then, the process ends.

  (S57) The RW control unit 110 reports the error block number to the server 200 (host). In this case, the server 200 recognizes only the lower 22 bits as the block number at the time of error (since the upper 10 bits are all “0”, there is no problem even if the upper 10 bits are discarded on the server 200 side). Then, the process ends.

  When the server 200 acquires the error block number from the tape device 100 in response to the RDBID command, the server 200 notifies the operator to move the cartridge 300 to another drive. The operator transfers the cartridge 300 from the drive 105 to the drive 106.

FIG. 14 is a diagram illustrating an example of the cartridge confirmation process. In the following, the process illustrated in FIG. 14 will be described in order of step number.
(S61) The RW control unit 110 mounts the cartridge 300 stored in the drive 106 (another drive). As a result, access to the magnetic tape 310 and the CM 320 using the drive 106 becomes possible. The RW control unit 110 notifies the server 200 that the cartridge 300 is mounted on the drive 106.

  (S62) The RW control unit 110 receives a VOL ID report instruction from the server 200. The RW control unit 110 acquires the VOL ID stored in the magnetic tape 310 and reports it to the server 200.

  The server 200 determines from the VOL ID that the cartridge 300 mounted on the drive 106 is the same as the cartridge that has caused the access error in the drive 105. For example, the server 200 acquires and holds the VOL ID of the cartridge 300 from the tape device 100 when an error occurs (step S51 in FIG. 13). Therefore, the server 200 can determine that the cartridge 300 mounted on the drive 106 is a DDR target if the held VOL ID matches the VOL ID acquired in step S62. On the other hand, if both VOL IDs do not match, the cartridge 300 mounted on the drive 106 is not a DDR target.

  When the server 200 determines that the cartridge 300 mounted on the drive 106 is a DDR target, the server 200 notifies the tape device 100 of a block number for resuming access to the magnetic tape 310 using a LOCATE command. The tape device 100 positions the magnetic tape 310 based on the block number specified by the LOCATE command.

FIG. 15 is a diagram illustrating an example of the positioning process. In the following, the process illustrated in FIG. 15 will be described in order of step number.
(S71) The RW control unit 110 receives a LOCATE command specifying a block number from the server 200 (host). The RW control unit 110 records the block number received from the server 200 in the storage unit 120.

(S72) The RW control unit 110 acquires the EXT36TRK use flag 321 from the CM 320 of the cartridge 300 mounted on the drive 106.
(S73) The RW control unit 110 determines whether or not the EXT36TRK use flag 321 is “true”. If it is “true”, the process proceeds to step S74. If it is not “true” (that is, “false”), the process proceeds to step S80.

  (S74) The RW control unit 110 determines whether or not the operation mode of the tape device 100 (self tape device) is the EXT36TRK mode. If it is in the EXT36TRK mode, the process proceeds to step S77. If not in the EXT36TRK mode, the process proceeds to step S75.

  (S75) The RW control unit 110 determines whether the operation mode of the tape device 100 (self tape device) is the 18TRK or 36TRK mode. If it is 18TRK or 36TRK mode, the process proceeds to step S76. If it is not the 18TRK or 36TRK mode (that is, the 128TRK mode), the process proceeds to step S77. The reason for proceeding to step S77 in the 128 TRK mode is that, in the 128 TRK mode, positioning with all block numbers in the EX36TRK mode is possible.

  (S76) The RW control unit 110 reports to the server 200 that the magnetic tape 310 cannot be positioned (cannot be positioned). Then, the process ends. In this case, the tape device 100 cannot continue the DDR process.

  (S77) The RW control unit 110 performs an OR operation on the block number received from the server 200 (host) and the offset value 322 stored in the CM 320. Here, the offset value 322 is obtained by extracting the upper 10 bits of the error block number and removing the lower 22 bits. Therefore, the RW control unit 110 performs an OR operation on the value obtained by adding “0” for 22 bits to the lower order of the offset value 322 and the block number acquired from the server 200. More specifically, when the offset value 322 is “0b1010000000”, first, an offset value “0b10100000000000000000000000000” for 22 bits of “0” is added to the lower order. Then, an OR is performed between each digit of the block number “0b0000000000000100000000” acquired from the server 200 and each digit of the offset value for the OR operation. As a result, the RW control unit 110 obtains the error block number “0b10100000000000000000000100000000”.

(S78) The RW control unit 110 clears the offset value 322 recorded in the CM 320. As a result, the offset value 322 is not set.
(S79) The RW control unit 110 instructs the drive 106 to position with the block number (block number at the time of error) obtained by the OR operation in step S77. As a result, the magnetic head of the drive 106 is arranged at a position corresponding to the error block number of the magnetic tape 310. Then, the process ends.

  (S80) The RW control unit 110 instructs the drive 106 to position with the block number received from the server 200 (host). This is because when the EXT36TRK use flag is “false”, the block number received from the server 200 matches the error block number (more precisely, the lower 22 bits of the error block number) (the upper 10 of 32 bits). All bits may be “0”). As a result, the magnetic head of the drive 106 is arranged at a position corresponding to the error block number of the magnetic tape 310.

  Steps S74, S75, and S76 are cases in which the magnetic tape 310 accessed beyond the upper limit of the 22-bit block number is stored in the tape device 100 for DDR in a tape device different from the tape device 100. This is an assumed mode confirmation process. The magnetic tape 310 accessed with a block number larger than 22 bits can be correctly positioned by the destination tape device when the operation mode of the destination tape device is the EXT36TRK mode or the 128TRK mode. On the other hand, when the destination tape device is in the 18TRK mode or the 36TRK mode, a block number larger than 22 bits cannot be used, so that it cannot be positioned. In the latter case, if access is resumed from the block number designated by the server 200, data of an inappropriate block number may be overwritten or read out. Accordingly, the RW control unit 110 reports that the positioning is impossible to the server 200 in step S76 and performs control so that such a problem does not occur.

  However, even when DDR is performed using only the tape device 100, after the cartridge 300 is removed from the drive 105, the mode of the tape device 100 is changed from the EX36TRK mode to the 36TRK mode, and then the cartridge 300 is moved to the drive 106. It can also be considered. In consideration of such a case, the processes in steps S74, S75, and S76 are useful for avoiding the above-described problem even when performing DDR using only the tape device 100.

  Next, a specific example of the processing flow in the EX36TRK mode between the tape device 100 and the server 200 according to the above procedure will be described. Hereinafter, as an example, a case where data is written to the magnetic tape 310 of the cartridge 300 will be described.

FIG. 16 is a diagram showing a sequence example at the time of writing in the EX36TRK mode. In the following, the process illustrated in FIG. 16 will be described in order of step number.
(ST1) The server 200 transmits a write command to the tape device 100 together with data to be written. The RW control unit 110 receives a write command and write target data from the server 200. The RW control unit 110 starts writing data to the magnetic tape 310 of the cartridge 300 housed in the drive 105 in accordance with the received write command. Data is written sequentially in ascending order of block numbers. For example, the RW control unit 110 continuously receives data to be written from the server 200 and stores it in the storage unit 120, acquires the data from the storage unit 120, and writes the data to the magnetic tape 310.

(ST2) The RW control unit 110 writes data at a position corresponding to a block number larger than the upper limit represented by 22 bits (indicated as BLK number in FIG. 16).
(ST3) The RW control unit 110 sets the EX36TRK use flag 321 to “true”.

(ST4) The RW control unit 110 detects that a write error has occurred in the drive 105.
(ST5) The RW control unit 110 notifies the server 200 that a write error has occurred. The RW control unit 110 may notify the server 200 of the VOL ID stored in the magnetic tape 310 together with the write error. The server 200 receives a write error notification. The server 200 records information indicating in which part of the data to be written an error has occurred in the storage unit 220. When the server 200 resumes writing by DDR, the server 200 resumes writing from the data portion indicated by the information.

(ST6) The server 200 transmits an RDBID command to the tape device 100. The tape device 100 receives the RDBID command.
(ST7) The RW control unit 110 acquires from the drive 105 an error block number represented by 32 bits.

  (ST8) The RW control unit 110 extracts the upper 10 bits from the block number at the time of error, and records the upper 10 bits as the offset value 322 in the CM 320 of the cartridge 300.

  (ST9) The RW control unit 110 extracts the lower 22 bits from the block number at the time of error, and reports the lower 22 bits (dummy block number) to the server 200. The server 200 notifies the operator to transfer the cartridge 300 from the drive 105 to another drive.

  (ST10) The cartridge 300 is transferred from the drive 105 to the drive 106. When taking out the cartridge 300 from the drive 105, the RW control unit 110 performs an unmount process of the cartridge 300 by the drive 105. Further, when the cartridge 300 is stored in the drive 106, the RW control unit 110 performs the mounting process of the cartridge 300 by the drive 106. The RW control unit 110 notifies the server 200 that the mounting process of the cartridge 300 by the drive 106 has been completed.

(ST11) The RW control unit 110 acquires the VOL ID stored in the magnetic tape 310 from the drive 106.
(ST12) The RW control unit 110 communicates with the server 200 to mutually confirm that the cartridge 300 has been transferred from the drive 105. Specifically, it is confirmed that the VOL ID reported to the server 200 at the time of the error matches the VOL ID acquired from the cartridge 300 transferred to the drive 106.

  (ST13) The server 200 transmits a LOCATE command to the tape device 100. The LOCATE command includes designation of a block number represented by 22 bits received in step ST9. The RW control unit 110 receives the LOCATE command.

(ST14) The RW control unit 110 acquires the offset value 322 stored in the CM 320 of the cartridge 300 from the drive 106.
(ST15) The RW control unit 110, based on the block number acquired in step ST13 (dummy block number reported to the server 200) and the offset value acquired in step ST14, the error block number (32 bits) Is generated.

(ST16) The RW control unit 110 designates the 32-bit error block number generated in step ST15 and instructs the drive 106 to position the magnetic tape 310.
(ST17) The RW control unit 110 reports positioning completion to the server 200. Server 200 receives the positioning completion report.

  (ST18) The server 200 transmits a write command to the tape device 100 together with data to be written. Here, the server 200 may transmit to the tape device 100 from the data location where writing was interrupted due to an error. For example, as shown in step ST5, if the server 200 records the location where writing was interrupted due to an error in the storage unit 220, the writing is interrupted due to the information stored in the storage unit 220 in step ST18. Can be identified. The RW control unit 110 receives a write command and write target data from the server 200.

(ST19) The RW control unit 110 resumes data writing to the magnetic tape 310 from the position corresponding to the error block number in response to the write command.
As described above, according to the tape device 100, after the magnetic tape 310 is transferred from the drive 105 to the drive 106, an access resuming position for the magnetic tape 310 can be appropriately determined. Therefore, the drive 106 does not need to perform inefficient access to the magnetic tape 310 (for example, “blank writing” processing for reporting to the server 200 that normal writing has been performed without actually writing). Therefore, the recovery process by DDR can be efficiently performed while the storage area of the LTO type magnetic tape 310 can be fully utilized.

  FIG. 17 is a diagram illustrating another example of the DDR. As described above, in addition to the tape device 100, the tape device 100a is also connected to the server 200. In this case, the tape devices 100 and 100a can perform DDR processing in the EX36TRK mode, as described above. Specifically, a case where an access error occurs when the cartridge 300 is stored in the tape device 100 and the magnetic tape 310 is accessed will be considered. At this time, if the block number at the time of error exceeds the upper limit of 22 bits, an EX36TRK use flag 321 (“true”) and an offset value 322 are stored in the CM 320 of the cartridge 300.

  Then, the tape device 100a can acquire the EX36TRK use flag 321 and the offset value 322 from the CM 320 by transferring the cartridge 300 to the drive included in the tape device 100a. Therefore, the tape device 100a can execute the procedure in FIG. 15 based on the EX36TRK use flag 321 and the offset value 322 acquired from the CM 320 (the processing after step ST11 in the procedure in FIG. 16 is executed by the tape device 100a. ). In this way, by storing the EX36TRK use flag 321 and the offset value 322 in the CM 320, DDR can be executed using a plurality of tape devices. For example, even when the tape devices 100 and 100a have one drive, DDR can be executed using a plurality of tape devices.

  By the way, for example, as described above, the storage device (for example, the tape device 100) writes data to a block number larger than the block number that can be managed by the higher-level device (for example, the server 200). It is possible to relax the usage capacity limitation of the magnetic tape due to the above. At this time, it is conceivable that the storage apparatus performs recovery processing such as DDR by associating a plurality of block numbers that can be managed by the storage apparatus with one block number that can be managed by the host apparatus (this method is referred to as “ Referred to as “Comparative Method”). However, in the method of the comparative example, resumption of access to the magnetic tape 310 after the cartridge 300 is transferred to a normal drive becomes a problem.

  For example, the consecutive block numbers “A1”, “A2”, “A3” (A1 <A2 <A3) managed by the storage device are associated with the block number “B1” managed by the host device, and the block number “ Consider reporting B1 ″ to the host device. In this case, for example, after the transfer of the cartridge 300, the storage apparatus starts the block numbers “A1”, “A2”, and “A3” managed by the storage apparatus with respect to the block number “B1” specified by the upper apparatus. "A1" is determined as the access resuming position. However, for example, after the block numbers “A1” and “A2” are normally accessed before the error occurs, an error may occur when accessing the block number “A3”. If the block number “B1” is simply designated by the host device, it cannot be positioned directly at the block number “A3” at the time of error after the drive is transferred to a normal drive.

  Therefore, after the cartridge 300 is transferred to a normal drive, the storage apparatus first positions the block number “A1” with respect to the block number “B1” designated by the host apparatus. After that, the storage device performs pseudo access again to the block numbers “A1” and “A2” that have been normally accessed (for example, reports to the host device that normal writing has been performed without actually writing). The “blank writing” process such as the above) reaches the block number “A3” where the access is resumed. As described above, in the method of the comparative example, after the cartridge 300 is transferred to a normal drive, inefficient access such as “empty writing” may occur on the magnetic tape 310.

  On the other hand, according to the method of the second embodiment, after the cartridge 300 is transferred to a normal drive, the block number indicated by the server 200 is corrected based on the offset value recorded in the CM 320, and an error is detected. Can be positioned directly on the block number. For this reason, generation | occurrence | production of inefficient access like "empty writing" can be suppressed.

  Further, according to the method of the second embodiment, the EXT 36 use flag 321 and the offset value 322 are recorded in the CM 320 provided in the cartridge 300. Therefore, as long as the cartridge 300 is transferred to a normal drive, the DDR process can be continued by appropriately specifying the access resuming position based on the information recorded in the CM 320 by the transfer destination storage apparatus.

  Note that the information processing of the first embodiment can be realized by causing a processor used as the control unit 1c to execute a program. The information processing according to the second embodiment can be realized by causing the processor 101 to execute a program. The tape device 100 can be considered to include a computer including a processor 101 and a RAM 102. The program can be recorded on a computer-readable recording medium 13.

  For example, the program can be distributed by distributing the recording medium 13 on which the program is recorded. Alternatively, the program may be stored in another computer and distributed via a network. For example, the computer stores (installs) a program recorded in the recording medium 13 or a program received from another computer in a storage device such as the RAM 102 or the NVRAM 103, and reads and executes the program from the storage device. Good. For example, the computer included in the tape device 100 may acquire the program acquired by the server 200 via the recording medium 13 or the network 10 from the server 200 and store it in a storage device such as the RAM 102 or the NVRAM 103.

DESCRIPTION OF SYMBOLS 1 Storage apparatus 1a, 1b Drive 1c Control part 2 Information processing apparatus 3 Cartridge 3a Recording medium 3b Memory

Claims (9)

A storage device connected to an information processing device that manages a block number indicating a position of an access destination for a recording medium with a predetermined number of bits,
A drive capable of storing a cartridge including the recording medium and a memory different from the recording medium, and accessible to the recording medium by a block number larger than an upper limit of a block number by the number of bits;
When writing to the block number larger than the upper limit for the recording medium by the drive, management information indicating that the writing has been performed is stored in the memory,
A control unit that executes the access to the recording medium based on the management information stored in the memory;
A storage device. A plurality of the drives;
When an error occurs in access to the recording medium by the first drive, the control unit stores an offset value corresponding to the number of bits and a block number at the time of error in the memory, and the cartridge is in the second drive. When the management information stored in the memory is detected, the block number for restarting the access to the recording medium is assigned to the second drive based on the offset value stored in the memory. Output,
The storage apparatus according to claim 1.   When an error occurs in an access to a first block number larger than the upper limit, the control unit generates a second block number represented by the number of bits from the first block number, and sends it to the information processing apparatus. The storage apparatus according to claim 2, which transmits.   When the controller receives the second block number from the information processing apparatus after the cartridge is moved to the second drive, the control unit receives the second block number and the offset value stored in the memory. The storage apparatus according to claim 3, wherein the first block number is generated based on the data and output to the second drive.   When the control unit detects the management information stored in the memory after the cartridge is moved to the second drive, the control unit operates in a mode in which the own storage device can manage the block number exceeding the upper limit. The storage according to any one of claims 2 to 4, wherein it is determined whether or not resumption of access to the recording medium by the information processing apparatus can be accepted in response to confirmation of whether or not apparatus.   The control unit stores, in the memory, an offset value corresponding to the number of bits and a block number at the time of error when an error occurs in access to the recording medium after storing the management information in the memory. Item 4. The storage device according to Item 1.   The control unit detects that the management information of the recording medium is recorded in the memory after an error occurs in access to the recording medium by another storage device and the cartridge is moved to the drive. The storage apparatus according to claim 1, wherein a block number for resuming the access to the recording medium is output to the drive based on the offset value stored in the memory.   The control unit responds to the inquiry about the operation mode from the information processing apparatus that it is a mode for reporting an error when the access destination block number for the recording medium reaches the upper limit, The storage apparatus according to claim 1, wherein even if a block number of an access destination for the recording medium by a drive reaches the upper limit, the storage apparatus continues to access the block number exceeding the upper limit without reporting the error. A computer provided in a storage device connected to an information processing device that manages a block number indicating a position of an access destination for a recording medium with a predetermined number of bits
The recording medium and a cartridge having a memory different from the recording medium can be stored, and the recording medium can be accessed by the drive that can access the recording medium by a block number larger than the upper limit of the block number by the bit number When writing to a block number larger than the upper limit, management information indicating that the writing has been performed is stored in the memory,
Performing the access to the recording medium based on the management information stored in the memory;
A control program that executes processing.

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