JP2009015924A - Magnetic tape device and logical volume allocating method thereof, magnetic tape cartridge, and computer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic tape device capable of effectively using a recording area of a mass-storage magnetic tape, a logical volume allocating method thereof, a magnetic tape cartridge, and a computer system. <P>SOLUTION: The magnetic tape device divides a magnetic tape 24 of one volume into partitions 241 of fixed capacity in advance to handle the magnetic tape 24 of one volume as a virtual magazine 30 stored with a plurality of logical volumes, and has a management table 242 for allocating a plurality of partitions 241 to a logical volume. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic tape device, a logical volume allocation method thereof, a magnetic tape cartridge, and a computer system, and more particularly to a magnetic tape device capable of effectively using a large-capacity magnetic tape, a logical volume allocation method thereof, and a magnetic tape cartridge. , Relating to computer systems.

  One of the utilization forms of the magnetic tape device is a magnetic tape device with a changer.

  A magnetic tape device with a changer is a device that stores multiple volumes of magnetic tape in a magazine, mounts the magazine in the device, and loads the magnetic tape in the magazine into the drive with the changer according to instructions from the host computer. It is. Note that the changer-equipped magnetic tape device is defined as Removable Medium Devices with an Attached Medium Changer in SCSI Primary Commands 3 (ANSI INCITS 408-2005).

  In the magnetic tape unit with changer, the software uses the magnetic tapes in the storage order without regard to the magazine slots, or the software associates the magazine slots with the magnetic tapes and selects and uses the magnetic tapes. There are operations. These operational designs take into account the recording capacity of the magnetic tape.

  In recent years, the capacity of magnetic tape has been increased. However, if a magnetic tape device with a changer is operated using a large capacity magnetic tape based on the existing operation design, the large capacity magnetic tape will not use the full recording capacity. Therefore, the changer-equipped magnetic tape device makes many unused and empty magnetic tapes in the recording area and cannot effectively use the large capacity of the magnetic tape.

  In addition, the design for changing the operation in accordance with the large capacity of the magnetic tape requires reviewing many software created based on the operation of the existing magnetic tape, JCL (Job Control Language), and the like. Reviewing and changing the operational design requires a great deal of man-hours and costs and cannot be performed easily.

  Thus, techniques for efficiently handling a large-capacity magnetic tape include those described in Patent Documents 1 and 2.

  In Patent Document 1, when a magnetic tape of one volume is divided by a variable-length logical volume according to the data capacity and data is written to a logical volume in which data has already been written, the entire logical volume is stored on the magnetic tape. Rewrite from the end of valid data.

  In Patent Document 2, one volume of magnetic tape is divided in advance into equal fixed-capacity recording areas, each recording area is treated as an independent logical volume, and the logical volume is associated with a magazine slot. Therefore, when data is written again to the logical volume to which data has been written, it becomes unnecessary to rewrite the entire logical volume from the end position of the data, so that invalid data does not remain on the magnetic tape.

  Further, as a technique for emulating as a magazine without changing software or JCL that uses a magnetic tape device with a changer, there is one described in Patent Document 3.

  In Patent Document 3, a single magnetic tape is divided by a variable-length logical volume according to the data capacity, and a load command from the host computer is replaced with a command for accessing the logical volume.

JP 09-069028 A Japanese Patent Application Laid-Open No. 09-050351 JP 2005-122433 A

  The techniques of Patent Documents 1 and 3 described above divide a magnetic tape into variable-length logical volumes. FIG. 10 is a diagram showing the magnetic tape 124 divided into variable-length logical volumes (L-VOL1, L-VOL2, and L-VOL3).

  In a magnetic tape device (not shown) for writing to and reading from the magnetic tape 124 shown in FIG. 10, when writing data to a logical volume to which data has already been written, the entire logical volume is valid for the magnetic tape 124. Data is rewritten from the data end position 130. Accordingly, invalid data remains on the magnetic tape (L-VOL2 in FIG. 10). When this operation is repeated, many invalid areas remain. In order to effectively use the recording area of the magnetic tape, there is a problem that it is necessary to rearrange data, such as rewriting only valid data on another magnetic tape 124.

  Further, the technique disclosed in Patent Document 2 cannot use a logical volume assigned to a slot position that exceeds the usable range when used with a host computer that has a limited usable slot range. There is.

  For example, as shown in FIG. 11, the usable range of the host computer (not shown) is 10 slots (slot 0 to slot 9). At this time, even if the host computer divides the magnetic tape 125 into fixed areas corresponding to 16 slots (slot 0 to slot 15) (L-VOL1 to L-VOL16), the remaining 6 slots (slot 10 to slot) 15) The divided areas (L-VOL11 to L-VOL16) cannot be used.

  An object of the present invention is to provide a magnetic tape device that can effectively use a recording area of a large-capacity magnetic tape, a logical volume allocation method thereof, a magnetic tape cartridge, and a computer system.

  A magnetic tape device according to the present invention is a magnetic tape device that divides a magnetic tape into fixed-capacity recording areas in advance and handles a single magnetic tape as a virtual magazine storing a plurality of logical volumes. It has a management table for allocating recording areas.

  According to the logical volume allocation method of the magnetic tape device of the present invention, the magnetic tape is divided into recording areas of a fixed capacity in advance, and the logical volume allocation of the magnetic tape device which handles one volume of magnetic tape as a virtual magazine storing a plurality of logical volumes. A method is characterized in that a correspondence relationship between a recording area and a logical volume is managed by a management table, and a plurality of recording areas are allocated to the logical volume.

  A magnetic tape cartridge of the present invention is a magnetic tape cartridge in which a magnetic tape contained in a cartridge case is divided into recording areas of a fixed capacity in advance, and the magnetic tape is handled as a virtual magazine storing a plurality of logical volumes. A management table that allocates a plurality of recording areas and manages the correspondence between the recording areas and the logical volumes, and the management table includes a slot number of the virtual magazine, a logical volume number of the logical volume installed in the slot, and It has a first table for storing the first recording area number of the first recording area to be allocated to the logical volume, and a second table for storing the link state between the recording areas.

  The computer system of the present invention includes a host computer and a magnetic tape device that makes the host computer appear as a plurality of logical volumes in which a single magnetic tape divided into a plurality of fixed-capacity recording areas is virtually stored in a magazine. The magnetic tape device has a management table for assigning a plurality of recording areas to the logical volume.

  The magnetic tape device, the logical volume allocation method, the magnetic tape cartridge, and the computer system of the present invention effectively use a large-capacity magnetic tape even when the number of usable magazine slots and the number of recordable recording areas do not match. There is an effect that can be done.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

[Example 1]
A first embodiment of the magnetic tape device 20 of the present invention will be described with reference to the drawings.

  1 is a schematic block diagram showing a first embodiment of a magnetic tape device 20 according to the present invention, FIG. 2 is a block diagram showing a schematic configuration of a computer system 80 using the magnetic tape device 20, and FIG. 3 is a magnetic tape cartridge. FIG. 4 is a schematic configuration perspective view showing the virtual magazine 30.

  Referring to FIG. 1, the magnetic tape device 20 performs a magnetic tape 24, a drive 22 for writing / reading data to / from the magnetic tape 24, control of the drive 22, and processing of instructions from the host computer 90. It comprises with the control part 21 to perform.

  Referring to FIG. 2, the computer system 80 includes a host computer 90 and the magnetic tape device 20 shown in FIG.

  Referring to FIG. 3, the magnetic tape cartridge 23 includes a magnetic tape 24, a cartridge case 25 containing the magnetic tape 24, and a cartridge memory 26. The magnetic tape cartridge 23 includes a large capacity magnetic tape 24. The cartridge memory 26 that is a non-volatile memory may not be provided in the magnetic tape cartridge 23.

  Referring to FIG. 4, the virtual magazine 30 has a plurality of slots 31 and a magnetic tape cartridge 230 is mounted in the slots 31. The virtual magazine 30 assigns a slot number 400 (“0” to “N”: where N is an integer) to each slot 31. The storage capacity of the magnetic tape cartridge 230 installed in the slot 31 of the virtual magazine 30 is smaller than the storage capacity of the magnetic tape cartridge 23 shown in FIG. For example, the magnetic tape cartridge 23 contains a magnetic tape 24 of 400 GB (gigabyte) to 800 GB, and the magnetic tape cartridge 230 contains a magnetic tape (not shown) of 1.6 GB to 30 GB.

  1-4, the magnetic tape 24 includes a management table 242 for allocating a plurality of partitions 241 to a plurality of recording areas (hereinafter referred to as partitions 241) and a logical volume (magnetic tape cartridge 230). Is provided. The partition 241 is a plurality of fixed capacity recording areas obtained by equally dividing one magnetic tape 24.

  When the magnetic tape 24 is handled as the virtual magazine 30, the management table 242 stores the relationship between the slot 31 and the logical volume (magnetic tape cartridge 230) mounted in the slot 31 and the link state between the logical volume and the partition 241. To do. The management table 242 includes a first table 40 and a second table 41, details of which will be described later.

  The management table 242 may be recorded as data in the specific partition 241 of the magnetic tape 24 or may be recorded in the cartridge memory 26. FIG. 1 shows a case where the management table 242 is recorded on the magnetic tape 24.

  The magnetic tape device 20 creates the management table 242 at the same time as the partition 241 of the magnetic tape 24 is created, and can edit it arbitrarily.

  The control unit 21 refers to the management table 242 and associates the logical volume with the slot 31 instructed from the host computer 90 to control the drive 22.

  Since the host computer 90 and the drive 22 are both well known to those skilled in the art, their configurations are omitted.

  Next, the operation of the magnetic tape device 20 configured as described above will be described with reference to the drawings.

  In this embodiment, the magnetic tape 24 has already been divided into 16 partitions 241, and it looks like the virtual magazine 30 of 10 slots 31 in which logical volumes are mounted in each slot 31 (N = 9 in FIG. 4). ). In general, when the magnetic tape 24 is divided into partitions 241, the magnetic tape 24 is divided by a power of two. It is assumed that the magnetic tape 24 is divided by 2 to the 4th power and divided into 16 partitions 241.

  In addition, it is assumed that the six volumes of logical volumes installed in the slots 31 having the slot numbers 400 of 1 to 6 of the virtual magazine 30 allocate the capacity of two partitions 241.

  Based on the above-mentioned preconditions, first, details of the management table 242 will be described with reference to the drawings.

  FIG. 5A and FIG. 5B are diagrams for explaining the first table 40 and the second table 41, respectively.

  Referring to FIG. 5A, the first table 40 stores a slot number 400, a logical volume number 401, and a head partition number 402 of the virtual magazine 30.

  The slot number 400 indicates each slot 31 of the virtual magazine 30. The logical volume number 401 indicates the number of the logical volume (magnetic tape cartridge 230) installed in the slot 31. The head partition number 402 indicates the first partition 241 assigned to the logical volume.

  Referring to FIG. 5B, the second table 41 stores a bidirectional link state between the partitions 241. The second table 41 stores a partition number 410 indicating the partition 241, a NEXT 412 indicating the next partition number 410 to be allocated, and a PREV 411 indicating the partition number 410 before the allocation.

  Here, PREV 411 and NEXT 412 indicate link states between partitions 241. The second table 41 records the partition number 410 in the NEXT 412 if there is a next partition 241 and in the PREV 411 if there is a previous partition 241.

  Referring to FIGS. 5A and 5B, the logical volumes with the logical volume numbers 401 to 9 are stored in the slots 31 with the slot numbers 400 to 9. Partitions 241 with 0-9 as the first partition number 402 are first assigned to logical volumes with logical volume numbers 401-0-9. In particular, the logical volumes having logical volume numbers 401 to 1 to 6 indicate a state in which the partitions 241 having partition numbers 410 to 10 to 15 are allocated next to the partitions 241 having partition numbers 410 to 1 to 6 respectively.

  Next, the operation of the magnetic tape device 20 when the host computer 90 issues a write command to the magnetic tape device 20 will be described with reference to the drawings.

  FIG. 6 is a flowchart for explaining the operation of the magnetic tape device 20.

  Referring to FIG. 6, when receiving a write command from the host computer 90, the magnetic tape device 20 first performs a write process (S500).

  The control unit 21 of the magnetic tape device 20 determines whether or not the writing process is normally completed (S501). If the writing is normally completed, the writing is reported (S504), and the process for the command is terminated.

  If the writing is abnormally terminated due to overflow, the control unit 21 refers to the second table 41 and determines whether or not there is a record of the partition 241 in the NEXT 412 corresponding to the partition number 410 of the partition 241 being used ( S502).

  If there is a record in the NEXT 412, the control unit 21 performs the writing process by positioning it at the head of the next partition 241 (S 503), reports the completion of writing (S 504), and ends the process.

  Specific examples of the above (S502) and (S503) will be described with reference to the second table 41 in FIG. For example, it is assumed that a magnetic head for writing (not shown) is positioned at the end of the partition 241 whose partition number 410 is “1”. NEXT 412 of the partition 241 whose partition number 410 is “1” has a record of “10”. The control unit 21 can control the feeding of the magnetic tape 24 so that the magnetic head is positioned at the head of the partition 241 whose partition number 410 is “10”, and can perform the writing process with the magnetic head (S503).

  If there is no record in NEXT 412 in the above (S502), the control unit 21 reports an overflow error and ends the process (S505).

  As described above, the magnetic tape device 20 according to the first embodiment can effectively use the partition 241 by connecting the two partitions 241 using the management table 242.

[Example 2]
Next, a second embodiment of the magnetic tape device 20 of the present invention will be described with reference to the drawings.

  7 and 9 are diagrams showing the management table 252 of the second embodiment, and FIG. 8 is a flowchart for explaining the operation of the second embodiment. FIGS. 7A and 9A show the first table 40, and FIGS. 7B and 9B show the second table 43.

  The second embodiment is different from the first embodiment in which the link state of the partition 241 is dynamically generated, except that the link state is generated in advance. Explained. In addition, the same component as 1st Example is displayed with the same code | symbol.

  A management table 252 shown in FIG. 7 shows an initial state.

  The magnetic tape 24 has already been divided into 16 partitions 241. The magnetic tape 24 is handled as a virtual magazine 30 of 10 slots 31 in which a logical volume (magnetic tape cartridge 230) is stored in each slot 31.

  The first table 40 shown in FIG. 7A is the same as that in FIG. 5A of the first embodiment, and a description thereof will be omitted.

  The second table 43 shown in FIG. 7B manages an unused (remaining) partition 241 by linking it to the partition 241 of the FREE 620.

  The second table 43 provides FREE620 data indicating that it is in an unused state as a partition number 610, and records the link head of an unused partition 241.

  Therefore, referring to FIGS. 7A and 7B, the logical volumes having the logical volume numbers 401 to 9 are stored in the slots 31 having the slot numbers 400 to 9. Partitions 241 with 0-9 as the first partition number 402 are first assigned to logical volumes with logical volume numbers 401-0-9. The partition 241 whose partition number 610 is 10 to 15 is linked to the partition 241 of the FREE 620.

  Next, the operation of the second embodiment when the host computer 90 issues a write command to the magnetic tape device 20 will be described with reference to the drawings.

  Referring to FIG. 8, when receiving a write command from the host computer 90, the magnetic tape device 20 first performs a write process (S700).

  The control unit 21 of the magnetic tape device 20 determines whether or not the writing process is normally completed (S701). If the writing is normally completed, the writing is reported (S704), and the process for the command is terminated.

  If the writing is abnormally terminated due to overflow, the control unit 21 refers to the second table 43 and determines whether or not there is a record of the partition 241 in the NEXT 612 corresponding to the partition number 610 of the partition 241 being used ( S702).

  If there is a record in NEXT 612, the control unit 21 positions the head of the next partition 241 to perform the writing process (S703), reports the completion of writing (S704), and ends the process.

  If there is no recording in NEXT 612 in the above (S702), the control unit 21 determines whether there is a free partition 241 (S705). The control unit 21 determines whether or not there is a free partition 241 depending on whether or not there is a record of the partition number 610 in the NEXT 612 corresponding to the FREE 620 provided in the partition number 610.

  If there is an empty partition 241, the control unit 21 secures the empty partition 241 (S 706) and performs positioning writing at the head of the reserved partition 241 (S 703).

  If there is no free partition 241, the control unit 21 reports an overflow error and ends the process (S707).

  Specific examples of the above (S705) and (S706) will be described with reference to the second table 43 in FIG.

  For example, it is assumed that a magnetic head for writing (not shown) is positioned at the end of the partition 241 whose partition number 610 is “1”.

  Since NEXT 612 corresponding to the partition number 610 corresponding to the FREE 620 is recorded as “10”, the control unit 21 determines that there is a free partition 241. The control unit 21 secures the partition 241 whose partition number 610 is “10”.

  In the securing process, the control unit 21 records “11” in the NEXT 612 corresponding to the partition number 610 corresponding to the FREE 620 and removes it from the link of the FREE 620. After removing from the link, the control unit 21 records “10” in the NEXT 612 of the partition 241 whose partition number 610 is “1”, and records “1” in the PREV 611 of the partition 241 whose partition number 610 is “10”. . In this way, the control unit 21 links the partition 241 whose partition number 610 is “10” behind the partition 241 whose partition number 610 is “1”.

  As a result of performing the above securing process, the management table 252 changes from the state of FIG. 7 to the state shown in FIG.

  As described above, in the second embodiment of the magnetic tape device 20, in addition to managing the link state between the partitions 241, the large-capacity magnetic tape 24 is further effectively used by dynamically changing the link state. be able to.

1 is a schematic block diagram showing a first embodiment of a magnetic tape device according to the present invention. It is a schematic block diagram of a computer system of the present invention. It is a schematic block diagram which shows the magnetic tape cartridge of this invention. It is a schematic structure perspective view which shows a virtual magazine. It is a figure which shows the management table of 1st Example. It is a flowchart for demonstrating operation | movement of 1st Example of a magnetic tape apparatus. It is a figure which shows the initial state of the management table of 2nd Example. It is a flowchart for demonstrating operation | movement of 2nd Example of a magnetic tape apparatus. It is a figure which shows the state after the partition reservation process of the management table of 2nd Example. It is a figure which shows the magnetic tape divided | segmented into the variable-length logical volume. It is a figure for demonstrating that there is a limit in the number of the fixed length logical volumes which a host computer can use.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Magnetic tape apparatus 21 Control part 22 Drive 23 Magnetic tape cartridge 230 Magnetic tape cartridge 24 Magnetic tape 124 Magnetic tape 125 Magnetic tape 130 Data end position 241 Partition 242 Management table 252 Management table 25 Cartridge case 26 Cartridge memory 30 Virtual magazine 31 Slot 40 First table 41 Second table 43 Second table 80 Computer system 90 Host computer 400 Slot number 401 Logical volume number 402 First partition number 410 Partition number 411 PREV
412 NEXT
610 Partition number 611 PREV
612 NEXT
620 FREE

Claims (18)

In a magnetic tape apparatus that divides a magnetic tape into recording areas of a fixed capacity in advance and treats one magnetic tape as a virtual magazine storing a plurality of logical volumes, management that allocates a plurality of recording areas to the logical volumes A magnetic tape device comprising a table. 2. The magnetic tape device according to claim 1, wherein the management table has means for managing a correspondence relationship between the recording area and the logical volume. The management table includes a first table that stores a slot number of the virtual magazine, a logical volume number of the logical volume installed in the slot, and a first recording area number of a first recording area to be allocated to the logical volume; 3. The magnetic tape device according to claim 2, further comprising a second table for storing a link state between the recording areas. 4. The magnetic tape device according to claim 3, wherein the second table includes a recording area number indicating the recording area, the next recording area number to be assigned, and the recording area number before being assigned. 5. The magnetic tape device according to claim 3, wherein the second table generates the link state in advance. 5. The magnetic tape device according to claim 3, wherein the second table dynamically generates the link state. 7. The magnetic tape according to claim 4, wherein the second table is provided with the recording area number indicating an unused state, and stores the recording area linked with the unused recording area as a head. apparatus. The magnetic tape device according to claim 1, wherein the management table is stored in a memory mounted in a cartridge case containing the magnetic tape or in the magnetic tape. A logical volume allocation method for a magnetic tape device that divides a magnetic tape into recording areas of a fixed capacity in advance and handles one volume of the magnetic tape as a virtual magazine storing a plurality of logical volumes, the recording area and the logical volume A logical volume allocation method for a magnetic tape device, wherein a plurality of recording areas are allocated to the logical volume by managing a correspondence relationship with the logical volume. The management table stores the slot number of the virtual magazine, the logical volume number of the logical volume installed in the slot, and the first recording area number of the first recording area allocated to the logical volume in the first table, 10. The logical volume allocation method for a magnetic tape device according to claim 9, wherein the link state between the recording areas is stored in a second table. 11. The magnetic tape device according to claim 10, wherein the second table stores a recording area number indicating the recording area, the next recording area number to be assigned, and the recording area number before being assigned. Logical volume allocation method. The second table provides the recording area in the unused state in the recording area number before allocation, stores the recording area number by connecting the recording area in the unused state to the link, and stores the link state. 12. The logical volume allocation method for a magnetic tape device according to claim 11, wherein the logical volume allocation method is dynamically generated. When the logical volume write command is received and the write process is abnormally ended, it is determined whether or not the next recording area number to be allocated corresponding to the recording area number being used for writing is recorded by the management table. 12. If there is a record of the next recording area number, write processing is performed while positioning to the next recording area number, and if there is no recording of the next recording area number, error processing is performed. A logical volume allocation method for the magnetic tape device as described. When the logical volume write command is received and the write process is abnormally ended, it is determined whether or not the next recording area number to be allocated corresponding to the recording area number being used for writing is recorded by the management table. If there is a record of the next recording area number, the recording process is performed by positioning it to the next recording area number, and if there is no recording of the next recording area number, the recording area in the unused state by the management table 2. If there is an unused recording area, the unused recording area is secured, and writing processing is performed by positioning the secured recording area in the secured recording area. 11. A logical volume allocation method for a magnetic tape device according to 11 or 12. A magnetic tape cartridge in which a magnetic tape contained in a cartridge case is divided in advance into a fixed-capacity recording area, and the magnetic tape is handled as a virtual magazine storing a plurality of logical volumes, wherein a plurality of the recordings are recorded on the logical volumes. A management table that allocates an area and manages a correspondence relationship between the recording area and the logical volume, the management table including a slot number of the virtual magazine, a logical volume number of the logical volume installed in the slot, and A magnetic tape cartridge comprising: a first table for storing a first recording area number of the first recording area to be allocated to the logical volume; and a second table for storing a link state between the recording areas. 16. The magnetic tape cartridge according to claim 15, wherein the second table stores a recording area number indicating the recording area, the next recording area number to be assigned, and the recording area number before being assigned. 17. The magnetic tape cartridge according to claim 15, wherein the management table is stored in a memory mounted on the cartridge case or the magnetic tape. A host computer, and a magnetic tape device that pretends to the host computer as a plurality of logical volumes in which a single volume of magnetic tape divided into a plurality of fixed-capacity recording areas is virtually stored in a magazine, A computer system comprising a management table for allocating a plurality of the recording areas to the logical volume.

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