JP2000067527A - Magnetic tape and magnetic tape device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability of the reading of data by making data not to disappear even when there are the run-out of a tape and a burst error. SOLUTION: This magnetic tape device is provided plural blocks which are defined in the advancing direction of a magnetic tape 10 and in which data to be recorded by the device are stored by every constant quantity and subblocks provided in an adjacent relation with these blocks. Moreover, subblocks have redundant data of the data of an Nth block in blocks separated by k blocks (|k|>1) in the advancing direction of the tape with respect to a subblock.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape and a magnetic tape device, and more particularly to a magnetic tape and a magnetic tape device requiring high reliability such as data backup.

[0002]

2. Description of the Related Art Conventionally, a magnetic tape device has been used as a data backup application for data such as a magnetic disk device, and is a device which is required to have extremely high reliability. However, a reading error may occur in the magnetic tape device due to a change in the state of the magnetic tape or an increase in the density of the magnetic tape. Error code processing has been conventionally performed on such a read error. For example, Japanese Patent Application Laid-Open No. 7-57401 discloses a method of logically arranging three error codes as a three-dimensional array.

[0003]

However, in the above-mentioned conventional example, even if a small number of errors can be corrected, when a tape is cut or a burst error occurs, the data cannot be corrected or restored. There was the inconvenience of disappearing.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to improve the disadvantages of the prior art, and in particular to improve the reliability of data reading without erasing data even when a tape break or a burst error occurs. It is an object of the present invention to provide a magnetic tape and a magnetic tape device that can perform the same.

[0005]

SUMMARY OF THE INVENTION Therefore, according to the present invention, in a magnetic tape on which data is recorded and reproduced by a magnetic tape device, data defined by a traveling direction of the magnetic tape and recorded by the magnetic tape device is fixed. It comprises a plurality of blocks stored for each quantity and sub-blocks provided adjacent to the blocks. The sub-block is an N-th block (N is 1 or more and a finite natural number) which is k blocks (| k |> 1) away from the position of the sub-block in the tape advancing direction. Has redundant data. This aims to achieve the above-mentioned object.

When reproducing a magnetic tape having such a data structure by a magnetic tape device, if there is no error, the blocks are continuously reproduced. If an error occurs in this reproduction, for example, if an error occurs in the reproduction of the N-th block data in the tape traveling direction, the redundant data of the N-th block data is k blocks in the tape traveling direction. (| K |> 1) because the data is recorded in a distant block,
The data recorded in the N-th block is corrected using the data (sub-data) stored in the sub-block after the block.

In a preferred embodiment, the sub-blocks are arranged at both ends of the block in a direction perpendicular to the direction in which the tape advances. Then, a configuration is adopted in which the data of the N-th block is dispersedly recorded as the redundant data in a sub-block at one end which is k blocks away from the N-th block and a sub-block at the other end which is −k blocks away. If you have this data structure, N
Even if the data of the third block cannot be completely read, N
Since the same data as that of the Nth block is stored in subblocks located at positions apart by ± k blocks, the data of the Nth block is reproduced by synthesizing the data in these subblocks.

As described above, the magnetic tape according to the present invention and the magnetic tape device for recording or reproducing data on or from the magnetic tape improve reliability when reading data by adding redundant data to the recording format. Things. According to the present invention, since the same data is divided into arbitrary block data and distributed and recorded as sub-block data, it is possible to enhance recovery processing when an error occurs during data reading.
In the related art, even when a tape portion has a defective portion and data cannot be recovered, the present recording method has a possibility of recovering more data.

Further, the magnetic tape device according to the present invention has means for recording data transmitted from a higher-level device in such a data structure. The magnetic tape device according to the present invention has means for reproducing data recorded in such a data structure or recovering lost information.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the data structure of a magnetic tape according to the present invention. A magnetic tape 10 on which data is recorded / reproduced by a magnetic tape device includes a plurality of blocks each storing data, which is defined in a traveling direction of the magnetic tape 10 and recorded by the magnetic tape device, at fixed intervals, and includes a plurality of blocks. And sub-blocks provided adjacent to each other. In addition, the sub-block has the redundant data of the N-th block in a block that is k blocks (| k |> 1) away from the position of the sub-block in the tape advancing direction.

As described above, since the storage destination of the redundant data is a sub-block of a block distant by k blocks (| k |> 1), even if a failure occurs in a certain block, it is separated from the block in which the failure has occurred. Since there is a high possibility that the failure has not occurred in the redundant data at the position, even if a failure such as a tape break occurs, the possibility of losing the data decreases. Thereby, the reliability of the magnetic tape is improved.

That is, in the example shown in FIG. 1, for each block on the recording format of the magnetic tape, the block data portion 12 and the width direction of the tape sandwiching the block in a direction orthogonal to the tape traveling direction are shown. Are provided at both ends. Redundant data is recorded in this sub-block data portion. At the time of reading data, data is normally read from the block data section 12. However, when reading from the block data section 12 fails, data distributed and recorded in the sub-block data sections 11 and 13 of another block is read. reading,
Performs recovery processing when reading data. For example, N
When reading from the block data section 12 of the second block 16 fails, it is one block away.

Further, in the example shown in FIG. 1, a sub-block at one end indicated by reference numeral 11 which is k blocks (here, one block) away from the N-th block, and the other end indicated by reference numeral 13 which is -k blocks away And the data of the N-th block are distributedly recorded in the sub-blocks. By changing the position where the same data is recorded in this way, the possibility of recovery in the event of a failure is increased.

When N is a finite natural number and the N-th block data is considered as an arbitrary place, the sub-block data portion of the (N-1) -th block before and after the N-th block data and N +
Distributed recording is performed on the contents of the N-th block data in the sub-block data portion of the first block. here,
It is assumed that each of the distributedly recorded sub-block data has a content that allows the content of the N-th block data to be restored by the recording content obtained by combining the two sub-block data. Also,
For the first block data, only the sub-block data is recorded immediately before, and for the last block data, only the sub-block data is recorded thereafter.

FIG. 1 shows an example in which k = 1 and redundant data is stored in a sub-block located one block away. However, if the value of k is a natural number of 1 or more, it depends on the design. Can be selected appropriately. For example, when the sub-block data of the N-th block data is recorded at the (N ± 2) -th, the (N−1), N-th block data or N, N +
Even when the two block data of the first block data cannot be read, the data recovery of the two block data that could not be read becomes possible by using the block in which the sub-block data is recorded.

When recording the sub-block data of the N-th block data in the N ± 3rd block,
Even when the (N-1, N, N + 1) th three block data cannot be read, the data recovery of the three unreadable block data becomes possible by using the sub-block data. As described above, it can be confirmed that the redundancy is increased by separating the recording position of the sub-block data from the position of the base block data. At this time, the sub-block data is read out after an error occurs, or the contents of the sub-block data are always reproduced, and the sub-block corresponding to the N-th block data is normally read out. According to the configuration of the magnetic tape device such as the configuration for erasing the data of
May be appropriately selected.

The magnetic tape shown in FIG. 1 is expected to be reproduced by a magnetic tape device (magnetic tape reproducing device) whose schematic structure is shown in FIG. The magnetic tape device shown in FIG. 2 includes a magnetic head 9 for reproducing in parallel a plurality of data recorded according to the width of the magnetic tape 10 in a direction perpendicular to the traveling direction of the magnetic tape 10, Driver 18 for amplifying the reproduction current generated in 9
And a control unit 1 for controlling the operation of the head driver 18.
9 is provided. The control unit 19 includes a CPU and this C
It is realized by a program executed by the PU or an electronic circuit.

The control section 19 has the function of a block 12 arranged at the center in the width direction of the magnetic tape 10.
If there is an error in the reproduction of the data of sub-block 1, the sub-block 1 defined at the end in the width direction of the magnetic tape 10
1 and 13, a sub-data extracting means 20 for extracting data recorded in a sub-block separated by a predetermined natural number k from the block in which the error occurred, and a sub-data extracted by the sub-data extracting means 20. Data generating means 21 for generating data of the block having the error based on the data.

The sub-data extracting means 20 may be a means for running the magnetic tape 10 to a target sub-block to obtain sub-block data when a read error occurs, depending on the configuration of the magnetic tape device. The sub-block data that has already been read and the sub-block data that is to be read may be specified.

The magnetic tape device shown in FIG.
By reproducing the magnetic tape with the data structure shown in the above, even if a failure occurs in a specific part of the magnetic tape,
This can be restored based on redundant data at a position separated by k blocks, and the possibility that reading becomes impossible when reading data is reduced.

FIG. 3 is a block diagram showing the configuration of a magnetic tape device (magnetic tape recording device) for recording data on a magnetic tape in the data structure (format) shown in FIG. The magnetic tape device shown in FIG. 3 includes a magnetic head 9 that records a plurality of data in parallel in a direction perpendicular to the direction of travel of the magnetic tape according to the width of the magnetic tape, and the plurality of data stored in the magnetic head 9. And a control unit 19 for controlling the operation of the head driver 18 according to data transmitted from the host device.

The control unit 19 has a function of a data dividing unit 22 for dividing data transmitted from a higher-level device into a plurality of blocks, and for each data divided by the data dividing unit 22, Data generating means 2 for generating sub data having redundancy by means of
3 and sub-data for recording sub-data of N-th data among the data divided into blocks at a position k blocks (| k |> 1) away from the N-th block in the tape traveling direction. Recording timing control means 24. This makes it possible to control the generation of redundant data and the storage position of the redundant data.

In a preferred embodiment, the control unit 19
The sub-data recording position control means 25 for recording the sub-data generated by the sub-data generation means 23 at positions at both ends in the width direction of the tape may be provided. Thereby, the sub-blocks can be positioned at both ends in the width direction of the magnetic tape.

[0025]

FIG. 4 shows the configuration of a magnetic tape device according to the present embodiment. In the example shown in FIG.
U3, a sub-data generating circuit that generates sub-data that is redundant data of data input from a higher-level device via a data bus, and temporarily stores data output to the magnetic head or reproduced by the magnetic head. Memory 4
And a memory controller 5 for controlling the memory 4. Further, as the head driver 18, a read / write circuit for amplifying a current input from the read / write head is used.
It comprises a write head amplifier 7, a servo motor 8 for providing a driving force for advancing a magnetic tape to a tape drive mechanism (not shown), and a servo controller 6 for controlling the servo motor. The magnetic tape device shown in FIG. 4 includes a read / write head (magnetic head) 9 and a bus controller 1 for controlling a data bus.

The magnetic tape device transfers the data transferred from the data bus to the sub-data generating circuit 2 under the control of the CPU 3 and the bus controller 1. The sub-data generation circuit 2 generates a block data portion and a sub-block data portion for each block to be recorded on the magnetic tape, and the generated data is stored in the memory 4 under the control of the memory controller 5. When positioning of the servo motor 8 is controlled by the control of the servo controller 6 and writing is ready, the read / write head amplifier 7 and the read / write head 9 are synchronized with the read / write head 9 via the write head on the magnetic tape. Write data.

At the time of reading, the servo controller 6 is controlled by a command from the CPU 3, and data is read from the read / write head 9 by positioning from the servo motor 8.

The data sent from the host computer is sent to the sub data generation circuit 2 via the bus controller 1.
The block data is divided into block data and sub-block data generated from the data for each block of the format recorded on the magnetic tape. Here, the sub-block data is data generated by dividing the original block data. The sub-block data has data that can generate the contents of the original block data.

At the time of data writing, read-after-write, in which data is written by the write head 9 and then read by the read head, is used. When reading during read-after-write,
Data is read from both the block data section and the sub-block data section, and it is confirmed that the block data section and the sub-block data section are correctly written.

In read-after-write, either in the case where reading from the block data portion fails or in the case where reading from the sub-block data portion fails, the data recording state becomes unstable in the corresponding block portion. It is determined that the data has been skipped, the corresponding block is skipped, and rewriting is performed from the next block onward. Only when normal recording is confirmed in both the block data section and the sub-block data section by read-after-write, the magnetic tape device determines that the writing to the block has been completed normally.

In normal data reading, data is read only from the block data section. When reading from the block data section is successful, the read data is stored in the memory 4 under the control of the memory controller 5.
Then, the data is transferred through the memory controller 5, the sub data generation circuit 2, and the bus controller 1.

When reading data from the block data portion of a certain block during data reading fails,
Data is read from the sub-block data recorded in the preceding and following blocks. The read data is stored in the memory 4 under the control of the memory controller 5. Then, through the sub-block data read by the sub-data generation circuit 2 through the memory controller 5,
Data generation is executed for the block data that could not be read. Thereafter, the data is transferred through the bus controller 1. In this case, when data is transferred to the host, the recording state is unstable, and a report to the effect that the block data has been recovered from the sub-block data is also sent to the host.

As described above, according to the present embodiment, the following effects can be obtained. The first effect is that if a tape break or a burst error occurs during data reading, the range is 1
If it is within the block, the use of the sub-block data makes it possible to recover the block data of the block where the error has occurred. The second effect is that when data is read during read-after-write, data is read from both the block data portion and the sub-block data portion and the write status is checked, so that the status check at the time of writing is strengthened, thereby improving reliability. The improvement of the property can be expected.

[0034]

Since the present invention is constructed and functions as described above, according to this, when reproducing a magnetic tape having the data structure (format) of the present invention with a magnetic tape device, the reproduction of the N-th block is performed. Even if an error occurs, since the redundant data of the data of the N-th block is recorded in a block separated by k blocks (| k |> 1) in the traveling direction of the tape, the sub-block or k blocks before the k-th block The data recorded in the N-th block can be corrected using the data (sub-data) stored in the subsequent sub-block, and the redundant data is k blocks in the traveling direction from the block in which the error has occurred. Because of the separation, even in the case of an error such as a tape break, it is possible to recover the data in the portion where the error occurred based on the redundant data. Excellent it is possible to provide a magnetic tape and a magnetic tape apparatus is not in.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a data structure of a magnetic tape according to the present invention.

FIG. 2 is a block diagram showing a configuration of a magnetic tape device according to the present invention suitable for reproducing the magnetic tape shown in FIG.

FIG. 3 is a block diagram showing a configuration of a magnetic tape device according to the present invention suitable for recording data on a magnetic tape with the data structure shown in FIG. 1;

FIG. 4 is a block diagram showing a configuration of a magnetic tape device according to one embodiment of the present invention.

[Description of Signs] 9 Magnetic head (read / write head) 18 Head driver 19 Control unit 20 Sub-data extraction unit 21 Data generation unit 22 Data division unit 23 Sub-data generation unit 24 Sub-data recording timing control unit 25 Sub-data recording position Control means

Claims (7)

[Claims] 1. A magnetic tape on which data is recorded / reproduced by a magnetic tape device, a plurality of blocks each storing data, which is defined in a traveling direction of the magnetic tape and recorded by the magnetic tape device, for each fixed amount, And a sub-block provided adjacent to the block, wherein the sub-block is an N-th block away from the position of the sub-block by k blocks (| k |> 1) in the tape traveling direction. A magnetic tape having redundant data of block data. 2. The sub-block is disposed at both ends of the block in a direction perpendicular to the tape moving direction, and the sub-block at one end and a -k block apart from the N-th block by k blocks. 2. The magnetic tape according to claim 1, wherein data of an N-th block is dispersedly recorded as the redundant data in a sub-block at the other end that is separated. 3. A magnetic head for recording a plurality of data in parallel in a direction orthogonal to a traveling direction of a magnetic tape according to a width of the magnetic tape, and a recording current corresponding to the plurality of data to the magnetic head. A magnetic tape device comprising: a head driver to generate the data; and a control unit that controls the operation of the head driver in accordance with data transmitted from the higher-level device. Data dividing means for dividing data into blocks, sub-data generating means for generating sub data having redundancy for the data for each data divided into blocks by the data dividing means, and data divided into blocks. Of the N-th data in the k blocks (|
k |> 1) A magnetic tape device comprising: a sub data recording timing control means for recording data at a remote position. 4. The control unit includes a sub-data recording position control unit that records the sub-data generated by the sub-data generation unit at positions at both ends in the width direction of the tape. The magnetic tape device according to claim 3. 5. The sub-data generating unit has a function of dispersing the data into two sub-data units, and the sub-data recording timing control unit transmits the sub-data to one end sub-block which is −k blocks away from the N-th block. A function of recording the one sub data that is distributed and a function of recording the other sub data that is distributed to the other sub block that is k blocks away from the Nth block. The magnetic tape device according to claim 4, wherein 6. The head driver has a read-after-write function of reproducing data immediately after recording data on the magnetic tape and comparing the reproduced data with data to be recorded. 4. A function for determining that the recording operation is normal when read-after-write is normal for both data to be recorded in a block and data to be recorded in the sub-block. 6. The magnetic tape device according to 4 or 5. 7. A magnetic head for reproducing a plurality of data recorded in parallel with a width of the magnetic tape in a direction orthogonal to a traveling direction of the magnetic tape, and amplifying a reproducing current generated in the magnetic head. In a magnetic tape device including a head driver and a control unit for controlling the operation of the head driver, the control unit includes an error in reproducing data of a block disposed at a center in a width direction of the magnetic tape. In this case, among the sub-blocks defined at the end in the width direction of the magnetic tape, data recorded in a sub-block separated by a predetermined natural number k from the block having the error is extracted. Sub-data extraction means, and data generation for generating data of the block having the error based on the sub-data extracted by the sub-data extraction means Magnetic tape apparatus is characterized in that a stage.