JP2005182870A - Magnetic tape device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To add tape information to a magnetic tape by holding the tape information in an erase gap pattern while maintaining compatibility with the conventional device. <P>SOLUTION: A significant erase gap pattern is constituted by the arrangement of an erase gap and an ALLZERO pattern and the erase gap pattern is written in the BOT of a magnetic tape and other arbitrary parts. In another embodiment, tape information having contents indicating that the relevant region is an error frequently occurring region is written into the erase gap pattern which is to be written into the error frequently occurring region and the tape is skipped to the next region when the tape is read. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic tape device and a control method thereof, and more particularly, to a magnetic tape device and a control method thereof that add tape information that does not cause a read error in other devices to the magnetic tape.

  2. Description of the Related Art Conventionally, there is a magnetic tape device that stores tape information as control information on a magnetic tape. For example, in Patent Document 1, tape information such as the tape format date, the last access date, and the number of accesses is recorded in the head portion or other portion of the tape, and this tape information is read when the magnetic tape is loaded. An apparatus for retaining a magnetic tape when a predetermined period has elapsed since the last access date is disclosed. In the embodiment, the tape information is written in a predetermined area immediately after the load / unload area provided from the tape start point (FIG. 3).

Patent Document 2 describes an erase pattern of a magnetic tape. When a data write error occurs, the tape is rewound to the location where the error occurred, the erase pattern is written, the area is skipped, and the next area is rewritten.
Japanese Patent Laid-Open No. 3-156705 JP 2001-135041 A (paragraphs 0002-0003)

  In the conventional tape information storage system such as Patent Document 1, since tape information is written in a device-specific format, when this tape area is read by another magnetic tape device, it is recognized as just illegal data. End up. Some devices end in error if there is data that cannot be recognized normally even after several reading retries, and there is a problem that reading of user data cannot be achieved. That is, the conventional tape information storage method has a problem that compatibility with other magnetic tape devices cannot be maintained.

  Further, since the conventional device of Patent Document 2 is configured to simply write a plurality of erase gaps in an error-prone area, data is written again in the same area when data is overwritten thereafter, and several retries and erase gaps are performed. It may be necessary to perform a series of operations such as writing and skipping again. This has a problem that processing time is delayed and reliability of the apparatus is lowered.

  In view of the above problems, the present invention provides a magnetic tape device and a control method thereof that can add tape information while maintaining compatibility with a conventional device by providing the erase gap pattern with tape information. With the goal.

  A magnetic tape device according to the present invention is a magnetic tape device that records and reproduces tape information as control information at an arbitrary location on a magnetic tape, wherein the tape information is configured using an erase gap pattern. .

  In a preferred embodiment, the erase gap pattern constituting the tape information is constituted by an arrangement of an erase gap and an ALLZERO pattern.

  Here, the apparatus includes a conversion table for converting a predetermined erase gap pattern arrangement into significant data, creates tape information to be written on the magnetic tape based on the conversion table, and reads the tape from the magnetic tape. Get information.

  The tape information can be composed of two information blocks each having eight erase gap patterns.

  The method according to the present invention is a method of controlling a magnetic tape device that records and reproduces tape information at an arbitrary location on a magnetic tape, and is characterized in that the tape information is configured using an erase gap pattern.

  In this method, it is effective to write the tape information into a BOT (Beguining of Tape) portion of the tape when the magnetic tape is demounted, and to read the BOT portion and acquire the tape information when the magnetic tape is mounted. .

  In addition, the tape information having the content of the error occurrence area is written in the location where the error frequently occurs when writing data to the magnetic tape, and the tape information having the content of the error occurrence location is read when reading the data on the magnetic tape. In this case, the tape may be advanced to the next area and the data reading may be continued.

  Further, the tape information may be written at predetermined intervals when data is written to the magnetic tape.

  By adding tape information to the BOT portion using an erase gap pattern, information on the tape can be obtained when the magnetic tape is loaded or read. Since the erase gap pattern is skipped by other devices, no read error occurs in other devices, and tape information can be added while maintaining compatibility with conventional devices.

  In addition, by incorporating tape information indicating whether or not an error-prone area is included in the erase pattern, the magnetic tape apparatus can grasp this and avoid using an error-prone area.

  Best modes for carrying out the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic block diagram showing the configuration of a magnetic tape device according to the present invention. As shown in FIG. 1, the magnetic tape device 10 is connected to the host device 20 by, for example, a SCSI interface, and user data sent from the host device 20 is written to the magnetic tape 11 or user data read from the magnetic tape 11 is read. It is sent to the host device 20.

  The magnetic tape device 10 includes a recording / reproducing unit 12 for writing / reading data to / from the magnetic tape 11, a control unit 13 for controlling the operation of the entire device, and a user for processing user data recorded / reproduced on the magnetic tape 11. A data processing unit 14, a tape information processing unit 15 for processing various control information recorded and reproduced on the magnetic tape 11, a tape mount / demount mechanism 16 for mounting / demounting the magnetic tape 11 on the apparatus 10, and the magnetic tape 11 And a tape drive unit 17 for performing the traveling drive. Although not shown, the tape information processing unit 15 has an internal memory that temporarily stores read tape information and updated tape information.

  The tape information processing unit 15 of the present invention records tape information on the magnetic tape 11 using an erase gap pattern. 2 to 4 are diagrams for explaining the procedure. In the preferred embodiment, the tape information processing unit 15 secures a tape information area 30 in a BOT (Beguining Of Tape) portion of the magnetic tape 11 as shown in FIG. 2, and prepares two information blocks there (information block). 31a, 31b). Then, eight erase gap patterns 32 are written in each information block 31. An example of the erase gap pattern 32 is shown in FIG.

  As shown in FIG. 3, in the present invention, the erase gap and the ALLZERO pattern are used to form 9-digit 2-bit data with the erase gap = 1 and the ALLZERO pattern = 0. Here, the tape information processing unit 15 has a contrast table as shown in FIG. 4 in advance, and each erase gap pattern 32 is significant data indicating any one of a total of 16 characters of 0 to 9 and A to F, respectively. And is written in the information block 31. A margin area 33 for countermeasure against write error is provided behind the information blocks 31a and 31b. As shown in FIG. 2, the tape information area 30 is followed by a data area according to a conventional format composed of tape marks and data blocks.

  By providing 8 character hexadecimal data in one information block by the procedure as described above and defining significant tape information for this combination of data, significant data can be obtained using the erase pattern in the tape information area 30. Tape information can be written. The tape information written in the information block is not particularly limited. For example, the last update date and the number of times of writing to the magnetic tape can be considered.

  The operation of the thus configured magnetic tape apparatus will be described below. FIG. 5 is a flowchart for explaining the operation when the magnetic tape is mounted. When the tape is mounted by the tape mount / demount mechanism 16 of the magnetic tape device 10 (step 101), the recording / reproducing unit 12 reads one block of data (step 102), and whether or not the data block is an erase gap. Is determined (step 103). If the read data is not an erase gap, the tape is rewound by the read amount to enter an idling state (steps 107 to 108).

  If the read data is an erase gap, the recording / reproducing unit 12 reads the two information blocks 31a and 31b and sends them to the tape information processing unit 15 (step 104). The tape information processing unit 15 analyzes the erase gap pattern, and if it is not an illegal pattern (step 105), converts it into tape information using the conversion table shown in FIG. (Step 106). If the erase gap pattern is not defined in the conversion table, it is determined that the erase gap is merely an erase gap (incorrect pattern) that is not tape information, and the rewind is performed for the read amount to set the idle state (steps 107 to 108).

  Next, a flow during normal operation of the magnetic tape device 10 will be described with reference to FIG. When data is written to the magnetic tape 11, it is necessary to update tape information such as the last update date of the tape and the number of times of writing. Therefore, when the head is located in the BOT portion (step 201) and the write command is received from the host device 20 (step 202), the magnetic tape device 10 determines the two information blocks 31a and 31b in the BOT portion as “ Initialization is performed with a 0 "character (step 203), and then a reception command is executed (step 204). Here, when writing to the magnetic tape 11, the tape information processing unit 15 updates the tape information stored in the device memory. As will be described later, the tape information stored in the memory of the tape information processing unit 15 is written again in the BOT portion when the tape is demounted. On the other hand, if the command from the host device 20 is not a write command (step 202: NO), that is, if it is a read command, the command is executed as it is (step 204).

  Next, the demounting operation of the magnetic tape device 10 will be described with reference to FIG. When there is a demount request by an operator or the like, the control unit 13 checks whether or not the head is at the BOT position (step 301). If the head is not at the BOT, tape rewinding is performed to position the head at the BOT ( Step 302). Next, it is confirmed whether the tape information stored in the tape information processing unit 15 has been updated. If the tape information has not been updated, the demount process is performed as it is (step 303). Further, here, when the tape information does not exist in the memory of the tape information processing unit 15, that is, when the tape information cannot be obtained by the above-described mounting process, the demounting process is performed as it is. On the other hand, if the tape information has been updated, the tape information is read from the memory and written into the tape information area 30 (step 304), and the demounting process is performed after the tape information is updated (step 305). Here, the writing of the tape information is performed according to the above-described procedure of FIGS. Thereafter, the apparatus 10 returns to the idling state (step 306).

  As described above, by using the tape information using the erase gap pattern, it is possible to write the tape information in the BOT portion by a method not conventionally used.

  Next, another embodiment of the present invention will be described. Conventionally, when a write error occurs in data write, there is a technique for writing an erase pattern at an error occurrence location and writing it in a subsequent area. In this embodiment, an error occurrence location is indicated at an error occurrence location. The erase gap pattern is written, and the information is written in the BOT tape information area so that it can be grasped thereafter.

  FIG. 8 is a flowchart for explaining the data write operation of this embodiment. In the data writing operation of the magnetic tape device 10 (step 401), if data can be normally written to the tape (step 402: NO), it is confirmed whether all user data related to the write command from the host device 20 has been written. If the writing is completed, the process returns to idle (step 407). If the writing is not completed, the tape data writing is continued (to step 401).

  On the other hand, when data cannot be normally written to the tape and errors frequently occur (step 402), the tape is rewound to the location where the error occurred (step 403), and an erase gap pattern indicating that the error occurs frequently is written (step S404). . Here, in step 402, for example, the controller 13 counts the number of retries when an error occurs in the read-after-write in which the write data is read and verified immediately, and the number of errors equal to or greater than a predetermined number of times with a predetermined tape length. When it becomes, it determines with it being an error frequent occurrence area | region. When the writing of the tape information is completed, the next area is erased (step 405). Thereafter, it is confirmed whether or not the writing is finished (step 406). If the writing is finished, the process returns to the idle (step 407). If the writing is not finished, the data writing is resumed (to step 401). Information such as the location and length of the error-prone area is stored as tape information in the memory of the tape information processing unit 15 and registered in the tape information area of the BOT unit at the time of demounting (the process of FIG. 7).

  FIG. 9 shows the flow of the data reading operation of this embodiment. The magnetic tape device 10 that has received a read command from the host device 20 starts reading tape data (step 501). In this data reading, the recording / reproducing unit 12 determines whether or not the read data is an erase gap pattern (step 502), and if it is not an erase gap, sends the read data to the user data processing unit 14. The control unit 13 confirms whether all the data related to the read command from the higher-level device 20 has been read (step 508), and sets the idle state if the read is completed (step 509).

  On the other hand, when the read data is an erase gap (step 502), the recording / reproducing unit 12 reads the information block and sends it to the tape information processing unit 15 (step 503). The tape information processing unit 15 refers to the erase gap pattern and acquires the tape information composed of the characters shown in FIG. 4 (step 505). At this time, if the erase gap is not the tape information, the process proceeds to step 508. If the data reading is completed, the process returns to the idle (step 509), and if not completed, the data reading is resumed (to step 501).

  Further, when the read tape information is a content indicating that it is an error-prone area (step 506), the tape is advanced to the end of the error-prone area (step 507), and it is confirmed whether the reading is completed (step 507) 508), if it is finished, return to idle (step 509). If not completed, data reading is resumed (to step 501). In this way, by incorporating tape information indicating whether or not an error-prone area is included in the erase pattern, the magnetic tape apparatus can grasp this and avoid using an error-prone area.

  In the magnetic tape device of this embodiment, since the presence or location of the error occurrence area is determined in advance based on the tape information read at the time of tape mounting, writing can be performed while avoiding the error occurrence area from the beginning when writing data. it can. As a result, it is possible to avoid a situation where an error occurs again when data is written to the area, thereby reducing the writing time and improving the reliability.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said Example, It can implement | achieve as various other Examples. In particular, the format and definition method of tape information, the amount of information, etc. are not limited to the above example, and other configurations may be used as long as significant data is defined by the arrangement of the erase gap and the ALLZERO pattern. Further, the content of the tape information constituted thereby is not limited to the above example, and other data can be included as necessary.

  Further, in the above embodiment, the tape information area is provided in the BOT or error occurrence area, but the tape information area is provided on the magnetic tape with an erase gap pattern at regular intervals so that the tape information can be obtained periodically. It is good also as a structure.

  According to the first embodiment of the present application, the tape information can be obtained when the magnetic tape is loaded by adding the tape information to the BOT portion by using the erase gap pattern. Since the erase gap pattern is skipped by other devices, no read error occurs in other devices, and tape information can be added while maintaining compatibility with conventional devices.

  According to the second embodiment of the present application, by incorporating tape information indicating whether or not an error-prone area is included in the erase pattern, the magnetic tape apparatus can grasp this and avoid using the error-prone part.

It is a general | schematic functional block diagram which shows the structure of a magnetic tape apparatus. It is an image figure which shows the data structure of the magnetic tape produced with a magnetic tape apparatus. It is an image figure which shows the structure of an erase gap pattern. It is a figure which shows the example of a character defined by an erase gap pattern. It is a flowchart explaining the operation | movement at the time of tape mounting of a magnetic tape apparatus. It is a flowchart explaining the operation | movement at the time of writing of a magnetic tape apparatus. It is a flowchart explaining the operation | movement at the time of tape demounting of a magnetic tape apparatus. It is a flowchart explaining the operation | movement at the time of the tape data writing in another Example. It is a flowchart explaining the operation | movement at the time of the tape data reading in another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic tape apparatus 11 Magnetic tape 12 Recording / reproducing part 13 Control part 14 User data processing part 15 Tape information processing part 16 Tape mount / demount mechanism 17 Tape drive part 20 Host apparatus 30 Tape information area 31 Information block 32 Erase gap pattern 33 Margin area

Claims (8)

  A magnetic tape device for recording and reproducing tape information as control information at an arbitrary location on a magnetic tape, wherein the tape information is configured using an erase gap pattern.   2. The magnetic tape device according to claim 1, wherein the erase gap pattern constituting the tape information is constituted by an arrangement of an erase gap and an ALLZERO pattern.   3. The magnetic tape device according to claim 2, further comprising a conversion table for converting a predetermined erase gap pattern arrangement into significant data, and generating tape information to be written on the magnetic tape based on the conversion table. A magnetic tape device for acquiring tape information read from the magnetic tape.   4. The magnetic tape device according to claim 1, wherein the tape information is composed of two information blocks each having eight erase gap patterns.   A method of controlling a magnetic tape device that records and reproduces tape information at an arbitrary location on a magnetic tape, wherein the tape information is configured using an erase gap pattern when the tape information is written. Control method.   6. The method of controlling a magnetic tape device according to claim 5, wherein the tape information is written to a BOT (Beguining of Tape) portion of the tape when the magnetic tape is demounted, and the BOT portion is read when the magnetic tape is mounted. And acquiring the tape information.   7. The method of controlling a magnetic tape device according to claim 6, wherein the tape information having the error occurrence area is written at a location where an error frequently occurs when writing data to the magnetic tape, and an error occurs frequently when reading data from the magnetic tape. A method of controlling a magnetic tape device, comprising: when tape information having a content as a location is read, the tape is advanced to the next area and the data reading is continued.   6. The method of controlling a magnetic tape device according to claim 5, wherein the tape information is written at predetermined intervals when data is written to the magnetic tape.

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