JP3078862B2 - High-speed positioning device for magnetic tape storage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-speed positioning instrumentation magnetic tape storage device to locate the data blocks on the magnetic tape to be accessed in the head by a high speed tape running
About the installation . In a magnetic tape storage device, there are provided some means for positioning at an arbitrary recorded data block or a tape mark. However, magnetic tapes need to be read and written sequentially from the beginning of the medium due to their properties, and cannot be positioned at an arbitrary position on the medium at high speed.

In order to locate an arbitrary data block on a magnetic tape, it is necessary to position the data while actually reading the data on the medium. Therefore, the positioning can be performed only at the same speed as ordinary reading and writing. Therefore, as the data on the medium increases, it takes an enormous amount of time to locate the data block at the end of the medium. With the improvement in recording density, the amount of data that can be written on one roll of medium is expected to further increase in the future, and a high-speed positioning means is required.

[0003]

2. Description of the Related Art Conventional high-speed positioning apparatuses for magnetic tape storage devices all perform high-speed positioning based on physical position information on a medium. FIG. 16 shows an example of a conventional system, in which the physical position of the magnetic tape is obtained from the ratio (Rf / Rm) of the radius between the machine reel 100 and the file reel 102. That is, the magnetic tape is wound from the file reel 100 to the machine reel 102 side.

Therefore, the medium is expressed by using an equation that expresses the ratio of the radius Rf of the magnetic tape wound on the file reel 100 to the radius Rm of the magnetic tape wound on the machine reel 102 by an integer within a certain range. With the above physical position, rough high-speed positioning is performed based on this value, and then accurate positioning is performed by ordinary reading.

As a further refinement of the system of FIG. 16, there is a system in which a control track 104 is provided in addition to a data recording track 110 on a magnetic tape as shown in FIG. In this method, a control head 108 is provided on a magnetic tape in addition to the data recording head 106. Control track 104 written by control head 108
Is written in the field at a value that increases by +1 at every fixed distance. The recording frequency of the control track 104 is changed so that the control track 104 can be read at a higher speed than normal reading / writing.

Accordingly, high-speed positioning is performed by reading the information of the control track 104 at high speed.

[0007]

However, such conventional high-speed positioning devices have common drawbacks. The drawback is that there is no way to actually manage the physical location of the data blocks on the media. That is, in order to locate a data block on a magnetic tape or a tape mark attached to the end of a data file composed of one or more data blocks, the physical position of the data block or the tape mark is stored. Need to be kept.

[0008] Such storage of the physical position of the data block or tape mark must rely on the management of the host CPU, and it is sufficient if the medium has several tens of volumes. Not practical due to memory location issues.
Also, due to the nature of the magnetic tape, the medium can be exchanged, there is virtually no means for managing the physical position of the medium written by another CPU, and the conventional high-speed positioning method is hardly used at present. .

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and appropriately manages a physical position on a medium without burdening a host, thereby quickly positioning an arbitrary data block. It is an object of the present invention to provide a high-speed positioning device for a magnetic tape storage device which enables the above.

[0010]

1 SUMMARY OF THE INVENTION The Ru principle illustration der of the present invention.

[Basic Invention] First, a high-speed positioning apparatus for a magnetic tape storage device according to the present application
The basic invention of the present invention relates to positional information on a magnetic tape 1 and a magnetic tape.
Creates a correspondence table 2 with data delimiter information on 1
Table recording means 3 for writing on the magnetic tape 1 by means of
It is characterized by positioning control with reference to this table 2.
And

[First invention] A first invention of the present application is a logical number of a data block and a tape mark 6 on the magnetic tape 1 and a physical number indicating a physical position of the data block and the tape mark 6 on the magnetic tape. And table recording means 3 for creating the table 2 of FIG. 1B and associating it with flag information indicating whether or not the data block is a tape mark 6 and writing it on the magnetic tape 1.

The table reading means 4 for reading the table 2 recorded on the magnetic tape 1 into the apparatus and the table reading means 4 for positioning a data block or a tape mark 6 corresponding to an arbitrary logical number. With reference to the table 2 read into the apparatus, the physical number of the target data block or the tape mark 6 on the magnetic tape is obtained from the logical number, the tape mark 6 or the flag information, and up to the target data block or the tape mark 6. High-speed positioning means 5 for positioning at high speed.

Here, the high-speed positioning means 5 performs high-speed positioning up to a position just before the target data block, switches to normal speed, and positions the target data block.

[Second Invention] A second invention according to the present invention is directed to a logical number of a tape mark 7 indicating the end position of a data file on the magnetic tape 1 composed of one or a plurality of data blocks, A table recording means 2 for creating a table shown in FIG. 1C and associating it with a physical number indicating a physical position on the magnetic tape 1 and writing the table on the magnetic tape 1, and a table recorded on the magnetic tape 1 Table reading means 4 for reading the read table 2 into the apparatus, and, when positioning the data block in an arbitrary data block, referencing the table 2 read by the table reading means 4 to the logical number of the tape mark 7 closest to the target data block. Corresponding magnetic tape 1
After the above physical number is obtained and positioned at the tape mark 7, the high speed positioning means 5 for switching to the normal speed and positioning the target data block is provided.

[Common Items of the First Invention and the Second Invention] Here, in both the first invention and the second invention, the table reading means 4 uses the table 2 when the magnetic tape 1 is loaded.
Is read into the memory in the apparatus, and the table recording means 3 reads the table 2 in the memory in response to the access to the magnetic tape 1.
Is updated and the table 2 in the memory is written on the magnetic tape 1 when the magnetic tape 1 is unloaded, or only the changed points of the table 2 are added.

Further, the high-speed positioning of the first and second inventions
In addition to the device , a flag recording means for setting a management flag indicating update of the table 2 at the time of unloading and recording the information in a table management block 7 area following the recording area of the table 2 on the magnetic tape 1; Reset means for resetting the management flag of the table management block 7 at the time of loading, and if the management flag is in a set state before the reset at the time of loading, it is determined that the table has been updated normally at the time of the previous unloading, A flag judging means for judging that the table has not been updated properly when the management flag has been reset is provided.

[0018]

According to the high-speed positioning apparatus for a magnetic tape storage device of the present invention having the above-described structure, the following effects can be obtained.

[Operation of the First Invention] First, in the first invention, a table 2 shown in FIG. 1B is created and recorded on the magnetic tape 1. The table 2 of FIG. 1B includes a logical number of a data block on the magnetic tape 1, a physical number (a value obtained from a control track) indicating a physical position of the data block on the magnetic tape, and a data block. Whether or not the mark is a tape mark 6 is associated with flag information.

When the magnetic tape 1 is loaded into the apparatus, the table 2 is read into a memory in the apparatus, and thereafter, the operation is performed with reference to the table 2 stored in the memory.
Reference and update of Table 2 are performed on the memory. That is, each time there is a data block or tape mark write command, the table 2 on the memory is updated to the latest information.
The update of the table 2 for the magnetic tape 1 is performed on the magnetic tape 1
Is performed at the time of unloading.

[Operation of the Second Invention] On the other hand, in the second invention, a table shown in FIG. 1C is created and stored on a magnetic tape. The table 2 in FIG. 1C includes a logical number of the tape mark 6 indicating the end position of the data file on the magnetic tape 1 composed of one or a plurality of data blocks, and a physical number of the tape mark 6 on the magnetic tape. And a physical number indicating a typical position.

Since the positioning of an arbitrary data block in the second invention cannot be performed directly as in the first invention, high-speed positioning is performed at the physical number of the tape mark closest to the target data block, and then the data is read while switching to the normal speed. Position to the target block. For this reason, although the efficiency is lower than that of the first invention, the configuration of the table 2 is simple and the memory capacity can be reduced.

The reading at the time of loading and the updating of the table on the memory and the updating of the table on the magnetic tape 1 at the time of unloading are the same as those of the first invention.

[Overall Operation] As a result, the magnetic tape storage device of the present invention refers to Table 2 by itself if only the logical number of the data block (logical block ID) or the logical number of the tape mark is given. High-speed positioning can be performed by obtaining a physical position. Also, there is a command such as "locate to the next tape mark" which is frequently used in the magnetic tape storage device. By referring to Table 2 also in this command, the position of the tape mark closest to the current position is obtained, and high-speed Can be positioned.

Further, in the conventional method, there is no means for knowing how many tape marks are written on the magnetic tape and at what position, and therefore, there is no instruction of "position to the next tape mark" once. However, the tape mark is usually written as a data file delimiter, and when there are a plurality of files on the magnetic tape 1, the "next tape mark" In many cases, the command "Position at the position" is issued a plurality of times in succession.

At this time, the loss of the time required for starting and stopping the tape, which is performed each time a plurality of instructions are performed, has been a factor of reducing the speed of the file search. However, according to the present invention, since the positions of all the tape marks on the medium can be known by retrieving the table 2, it is necessary to execute a plurality of "position to the next tape mark" commands collectively. Is also possible.

Thus, the time required for starting and stopping the tape can be minimized. Therefore, when used in combination with high-speed positioning, the speed of file search can be further increased. If a special command is prepared and the contents of the table are transferred to the host CPU, the position of the block / tape mark on all media can be known on the CPU side, so that a higher-speed search can be performed. It is.

[Operation of Table Update Flag] In both the first invention and the second invention, since the table 2 in the memory is updated between the loading and unloading of the magnetic tape 1, an accident such as a power failure occurs. Therefore, if normal unloading cannot be performed, there is a possibility that the table in the memory does not match the information actually written on the magnetic tape 1.

Therefore, a table management block 7 is written on the magnetic tape 1 separately from the table 2. When the table 2 on the magnetic tape 1 is updated, that is, the table update flag set at the time of unloading is recorded in the table management block 7. The table update flag is reset when the magnetic tape 1 is loaded. Therefore, if the table update flag was not recorded at the time of loading,
In other words, if the table has been reset, it can be determined that the table on the magnetic tape 1 has not been updated normally at the time of the previous unloading, and an incorrect position is determined by using the table that has not been updated due to the occurrence of a power failure or the like. Can be prevented beforehand.

In order to recover the table in this case, a special table reconfiguration support command is prepared, or the table is automatically reconfigured when the magnetic tape storage device is loaded or unloaded. Good. If the table is not updated, or if a positioning instruction is received before the table reconfiguration processing, the positioning is performed while reading the data as in the related art without referring to the table.

[0031]

FIG. 2 is a block diagram showing an embodiment of a magnetic tape storage device to which the high-speed positioning device of the present invention is applied. 2, the magnetic tape storage device of the present invention is roughly divided into a magnetic tape storage control device 110 and a magnetic tape drive device 112. Magnetic tape drive 112
Has a drive controller 132 and a drive 134.

The drive controller 132 receives a command from the magnetic tape storage controller 110 to
4 is operated to directly perform operations such as loading, writing, reading, and unloading on the magnetic tape. For this reason, as shown in FIG. 16, the drive 134 pulls out the magnetic tape housed in the cassette case having the file reel (delivery reel) 100 and the machine reel (take-up reel) 102 at the time of loading as shown in FIG. Make contact. .

For the magnetic tape loaded in the drive 134, a read / write head and a control track read / write head for obtaining the physical position of the magnetic tape are provided. this house,
For the data recording / reproducing head, a rotary head is used to increase the recording density.

The magnetic tape storage controller 110 analyzes and processes commands and data received from the host computer, controls the operation of the magnetic tape drive 112, and reads or writes data after positioning the magnetic tape. This magnetic tape storage controller 1
The microprocessor 10 is provided with a microprocessor (MPU) 114 for centrally controlling the entire control device.

The exchange with the host computer is performed by the host interface 116, and the exchange with the magnetic tape drive 112 is performed by the drive interface 118. The data buffer 120 is a buffer used at the time of data transfer accompanying reading / writing of a magnetic tape, and data transfer using the data buffer 120 is directly managed by the DMA controller 122.

The control storage 124 expands a microprogram executed by the microprocessor 114 and is also used as a temporary storage area such as a register and a pointer necessary for control of the microprogram including the high-speed positioning control of the present invention. . A dip switch 126 is used to set the hardware version of the magnetic tape storage controller 110 at the time of factory shipment.

FIG. 3 is a functional block diagram showing the magnetic tape storage device shown in FIG. 2 in which parts necessary for the high-speed positioning device of the present invention are extracted. In FIG. 3, first, a write head 17 for writing data using a rotary head, a read head 18 for reading data, and a control track for obtaining a physical position on a magnetic tape are provided on the magnetic tape drive 112 side. , A control track write head 15 and a control track read head 16 are provided.

Further, a high-speed / low-speed switch 22 for switching the tape drive speed in a plurality of stages is provided for the tape drive motor 23 for driving the magnetic tape. Here, the low speed means a running speed at the time of writing or reading of a normal magnetic tape. On the other hand, the microprocessor 14 and the data buffer 10 are provided on the magnetic tape storage controller 110 side. In the data buffer 10, a table recorded on a magnetic tape is developed as will be described later.

On the magnetic tape storage controller 110 side, a physical block ID generator 9 and a logical block ID
A register 11, a physical block ID register 12, a table update flag register 13, a pointer 21, and a register 24 are provided. These generators, registers and pointers are stored in the control storage 12 shown in FIG.
4 is implemented.

Further, switches 19 and 20 are provided on the data lines from the write head 17 and the read head 18, and the switch 19 is a write head for write data from any of the host, the data buffer 10 and the table update flag register 13. Switch the route to 17. The switch 20 switches the path of the read data from the read head 18 to the host data buffer 10 or the table update flag register 13.

FIG. 4 is an explanatory diagram showing a format of a magnetic tape used in the high-speed positioning apparatus of the present invention.
In FIG. 4, a table 2 used for the high-speed positioning method of the present invention is recorded at the head of the magnetic tape 1,
Following the table 2, a table management block 7 for recording a management flag indicating whether or not the table has been updated is recorded.

The area of the magnetic tape 1 on which the table 2 and the table management block 7 are recorded is a system area that can be accessed only by the magnetic tape storage device and cannot be accessed by the user. The user area starts from the table management block 7 and data blocks are recorded in order as shown in the figure.

In this embodiment, one file is composed of three data blocks from the head of the user area, and a tape mark 6 is recorded after the third data block at the end of the file. Subsequent to the tape mark 6, two data blocks forming the = 2 file are recorded, and the tape mark 6 is similarly recorded after the data block at the end of the = 2 file.

Further, a control track 104 is recorded on the magnetic tape 1 in parallel with the data area. As shown in FIG. 17, the control track 104 is written with a value which increases by +1 at every fixed distance, and is normally written. The recording frequency is changed so that the magnetic tape 1 can be read at a higher speed than the read / write of the magnetic tape 1.
Can be identified.

FIG. 5 is an explanatory diagram showing the structure of the table 2 recorded at the head of the magnetic tape 1 used in the first invention of the present application. In FIG. 5, in Table 2 of the first invention, three correspondences of a tape mark flag, a physical block ID (physical number) of a data block, and a logical block ID (logical number) of a data block are recorded.

FIG. 6 shows a recording state on the magnetic tape 1 corresponding to the contents of the table 2 in FIG. First, the tape mark flag in FIG. 5 is set to 1 for the tape marks TM1, TM2, and TM3 at the end of the data file, and is reset to 0 for data blocks other than the tape mark. The physical block ID of each data block is an ID determined by the count value of the control track 104. For example, as shown in FIG. Registered in.

In this case, the tape mark flag of each data block is the first, second and third physical block ID1,
The tape mark flag is reset to 0 for 2 and 3, and the tape mark flag is set to 1 for the physical block ID 4 of the fourth tape mark TM1. The flag indicating the presence or absence of the tape mark on the magnetic tape 1 and the physical block ID of each block correspond to the logical block ID of each data block used for data access on the magnetic tape storage controller. Have been done.

Referring again to FIG. 4, a management flag indicating whether or not the table has been updated is recorded in the table management block 7 provided subsequent to the table 2. That is, in the present invention, when the magnetic tape 1 is loaded into the apparatus, the leading table 2 of the magnetic tape 1 is read and developed in the data buffer 10 shown in FIG.
The high-speed positioning of the magnetic tape is performed using, for example, the table 2 shown in FIG.

When writing to a new magnetic tape 1 is performed, the table 2 in the data buffer 10 is updated each time. On the other hand, when the magnetic tape 1 is unloaded, the table is expanded by recording the table 2 developed in the data buffer 10 in the area of the table 2 at the head of the magnetic tape 1.

However, when the magnetic tape is unloaded due to a power failure or the like, it is impossible to update the recording of the table 2 in the memory on the magnetic tape 1. A management flag is recorded in the table management block 7 to determine whether the update of the table 2 at the time of unloading has been performed normally. That is, at the time of updating when the recording of the table 2 on the magnetic tape 1 is normally performed, the management flag is set to 1 and written in the table management block 7. On the other hand, at the time of loading, the management flag of the table management block 7 is reset to 0.

For this reason, if the table 2 cannot be updated due to unloading due to a power failure or the like, the management flag of the table management block 7 of the magnetic tape 1 remains reset to 0, and the next time the table is loaded. Even if the table management block 7 is read, the management flag remains reset to 0, so it can be determined that the table 2 of the magnetic tape 1 was not updated normally at the time of the previous unloading.

The management flag of the table management block 7 of the magnetic tape 1 is set and reset using the table update flag register 13 shown in FIG. That is, when the magnetic tape is loaded, the table management block 7 of the magnetic tape 1 is read by the write head 17 and stored in the table flag update register 13 to notify the microprocessor 14 of the set and reset states of the management flag.

If the management flag is reset to 0 at the time of loading, the microprocessor 14 determines that the table 2 of the magnetic tape 1 was not updated normally at the time of the previous unloading, and for example, re-executes a special table. Execute the command at the time of configuration to automatically perform table reconfiguration at the time of loading or unloading. Further, when a positioning command is received from the host computer before this table reconfiguration processing, the positioning is performed while reading the data of the magnetic tape 1 with the read head 18 without using the table 2 developed in the data buffer 10. Will do.

Next, with reference to the flowcharts of FIGS. 7, 8, 9 and 10, a processing operation according to the first invention of the present application using the table 2 shown in FIG. 5 will be described with reference to FIG. 5 is a flowchart showing a data block write operation and a tape mark write operation. First, in step S1, the high speed / low speed switch 22 is set to the normal speed side, and in step S2, the tape drive motor 23 is started.

Subsequently, in step S3, it is determined whether or not the command from the host computer is a "write tape mark". Here, as shown in FIGS. 4 and 6, since the tape mark 6 is added to the end of a file composed of a plurality of blocks, the first command is not a “write tape mark” but a write command of a data block. Therefore, the process proceeds to step S4 to write a data block on the magnetic tape.

Subsequently, in step S5, the tape mark flag at the table position indicated by the pointer 21 is reset because no tape mark has been written. The pointer 21 is initialized to 0 each time the pointer 21 reaches the head position of the tape.
Subsequently, in step S6, the physical block ID register 12 and the logical block ID 11 are copied to the position of the table 2 indicated by the pointer 21 at that time, whereby the 1 shown in FIG.
The correspondence relationship between two tape mark flags, physical block IDs and logical block IDs is registered.

Subsequently, the physical block ID register 11 is incremented in step S7, the pointer 21 is similarly incremented in step S8, and thereafter, every time a write command of block data is received, the same processing is performed through steps S9 and S10. repeat. When writing of the last block consisting of multiple data blocks is completed,
The host computer issues a command “write tape mark”, and step S3 proceeds to step S11 to write the tape mark on the magnetic tape.
Then, the tape mark flag at the position of the table 2 indicated by the pointer 21 at that time is set to 1.

The following processing is the same as the data block write operation. If it is determined in step S9 that the command chain has been interrupted during such a data block write operation or a tape mark write operation, the flow advances to step S13 to stop the tape drive motor 23.
FIG. 8 is a flowchart showing a processing operation of a high-speed positioning instruction according to an instruction of a logical block ID from the host computer.

In FIG. 8, when a high-speed positioning command is received from the host computer, the high-speed / low-speed switch 22 is set to a high-speed value in step S1, and the logical block ID specified in step S2 is changed to the current logical block ID. Check if it is equal to the value of register 11,
If they are equal, a series of processing ends because the tape has been positioned.

If it is determined in step S2 that the two do not match, the flow advances to step S3 to check whether the designated logical block ID is larger than the logical block ID register 11. If smaller, the tape drive motor 2 is determined in step S4.
3 is started in reverse, and if larger, the tape drive motor 23 is advanced in step S5 to start. Subsequently, in step S6, the logical block ID designated by the host computer is set in the pointer 21. In step S7, the physical block ID obtained from the control track running at high speed is the logical block ID set in the pointer 21.
A predetermined value i from the physical block ID of table 2 corresponding to
Checks whether it is equal to the value obtained by subtracting.

The value of i is determined based on the switching time from high speed to normal speed. If it is determined in step S7 that the value of the physical block ID register 12 matches the value obtained by subtracting a predetermined value i from the physical block ID at the table position indicated by the pointer 21, the high / low speed switch 22 is set to the normal speed in step S8. , And reading of data blocks by normal tape running is started from step S9.

That is, the logical block ID is read from the tape in step S10, the read logical block ID is set in the logical block ID register 11 in step S11, and the physical block ID register 1 is set in step S12.
When the value of 2 matches the value specified in the logical block ID register 11, it is determined that the positioning to the target data block has been completed, and the tape drive motor 23 is stopped in step S13.

FIG. 9 is a flowchart showing a processing operation when a positioning command for a next tape mark is received from the host computer. In FIG. 9, first, the high-speed / low-speed switch 22 is set to a high-speed value in step S1, and a forward or backward search is determined in step S2. If the search is forward, the process proceeds to step S3, the pointer 21 is incremented, and the tape flag at the table position indicated by the pointer 21 is checked in step S4.

Since the tape mark flag is off at the end of the file and is on at the end of the file, if it is determined at step S4 that the tape mark flag at the end of the file is on, the process proceeds to step S5, where the tape drive motor 23 To start. On the other hand, if the backward search is determined in step S2, the pointer 21 is decremented in step S6, and similarly, the tape mark flag at the table position pointed to by the pointer is checked in step S7, and the pointer 21 whose tape mark flag is turned on is checked. When the value is obtained, the tape drive motor 2
Start with 3 in reverse.

When the tape drive motor 23 is started in step S5 or S8, the value of the physical block ID register 12 and the value obtained by subtracting the predetermined value i from the physical block ID at the table position indicated by the pointer 21 match in step S9. The high speed / low speed switch 22 is set to the normal speed, the data block is read as the normal tape running in step S11, and the logical block from the tape is read in step S12. The block ID is read, the logical block ID is stored in the logical block ID register 11 in step S13, and when the value of the logical block ID register 11 matches the designated logical block ID in step S14, the tape drive motor is determined in step S15. Stop 23 and position To completion.

FIG. 10 shows a case where a plurality of "positioning commands to the next tape mark" are received from the host computer.
9 is a flowchart illustrating a processing operation for executing a plurality of instructions at a time. In FIG. 10, the pointer 21 is first saved in the register 24 in step S1.

Next, a forward or backward search is checked in step S2. If the search is forward, the pointer 21 is incremented in step S3, and the pointer 21 is incremented in step S4 until the tape mark flag at the table position indicated by the pointer is turned on. Repeat the increment. On the other hand, if it is a backward search, the pointer 21 is decremented in step S4, and the decrement of the pointer 21 is repeated in step S6 until the tape mark flag at the table position indicated by the pointer is turned on.

Subsequently, in step S7, a command termination process is executed, and in step S8, the presence or absence of the next command chain is checked. If a plurality of instructions are consecutive, a command chain is determined in step S8, and a step S9 is executed.
Then, it is checked whether or not the next command is a command of "position to the next tape mark". If this command is issued, the process returns to step S2 and repeats the same process.

If the command chain is broken in step S8 or if the received instruction is another instruction in step S9, the process proceeds to step S10, where the value of the register 24 in which the value of the first pointer 21 has been saved is compared with the value in step S3 or S3. The value of the pointer 21 changed in step S5 is compared, and if they match, the tape drive is not performed at all, so the process proceeds to step S14 to stop the tape and terminate the command.

On the other hand, if the tape running is not performed normally, the two do not match in step S10, so the process proceeds to step S11, where the pointer 21 saved in the register 24 is read.
Is compared with the current value of the pointer 21. If the initial value of the pointer is smaller than the current value, the tape drive motor 23 is moved forward in step S12 to start the high-speed feeding of the magnetic tape. .

On the other hand, if the pointer initial value is larger than the current pointer value in step S11, the tape drive motor 23 is moved backward in step S13 to start, so that the backward tape high-speed feeding is similarly performed. Subsequently, the process jumps to step S9 in FIG. 9, and the physical block ID of the table indicated by the pointer 21 based on a plurality of tape marks, similarly to the processing operation of the single “positioning instruction to the next tape mark”
The tape is positioned at a high speed up to a position obtained by subtracting a predetermined value i from the tape, and is positioned to the target block by normal reading.

FIG. 11 is an explanatory diagram showing the structure of the table 2 used in the second invention of the present application. In FIG.
In Table 2, the correspondence between the physical block ID corresponding to the tape mark indicating the end of the file of the magnetic tape and the logical block ID corresponding to the tape mark is registered.

FIG. 12 shows the recording state of the magnetic tape 1 corresponding to the table 2 of FIG. 11, and the user area following the table 1, the table 2 and the table management block 7 is composed of a plurality of data blocks = 1. File, = 2
.. Are recorded, and tape marks TM1, TM2, TM are provided at the end of each file.
3 is recorded.

In the table 2 in FIG. 11, the correspondence between the physical block ID3 of the first tape mark TM1 in FIG. 10 and the corresponding logical block ID3 is registered. The same applies to the tape marks TM2 and TM3. Thus, the second invention of the present application does not have the correspondence table of all data blocks on the table 2 as in the first invention,
It is simplified by having a correspondence table with only tape marks.

In the high-speed positioning using the table 2 shown in FIG. 11, the physical block ID of the tape mark closest to the target data block is obtained from the table 2 and the high-speed positioning is performed. You have to look for the actual data block. Therefore, the first
Although the efficiency is lower than that of the present invention, the configuration of the table 2 is simple, and the capacity of the table occupied by the data buffer 10 when it is read into the apparatus can be greatly reduced.

FIGS. 13, 14 and 15 are flowcharts showing the processing operation of the second invention of the present application using the tape mark table 2 shown in FIG. First, FIG.
FIG. 9 is a flowchart showing the processing operation of writing block data and writing a tape mark to the end of a file in the second invention of the present application. In FIG. 13, the high speed / low speed switch 22 is set to the normal speed in step S1, and the tape drive motor 23 is set in step S2.
Start.

Subsequently, in step S3, a write command for the data block is first determined, and the flow advances to step S4 to write the data block. Subsequently, in step S5, the logical block ID register 11 is incremented. In step S6, the presence or absence of the next command is determined. If there is a command, in step S7 it is determined whether the command is a data block write command or a tape mark write command. S3
And the same process is repeated until a write command for the tape mark is obtained.

When the end of the file is reached in step S3 and a write command for a tape mark is determined, step S8 is performed.
Is used to write a tape mark. At step S9, the physical block ID register 12 and the logical block ID
The register 11 is copied to the table position indicated by the pointer 21 to create a correspondence table of the physical block ID of the tape mark and the ID of the logical block of the tape mark shown in FIG.

Thereafter, the same processing is repeated each time the file data is received. If the command chain is cut off in step S6 or if the command is a command other than the data block or tape mark write command in step S7, the flow advances to step S11 to execute tape drive. The motor 23 is stopped. FIG. 14 is a flowchart showing a processing operation when a high-speed positioning instruction is received from a host computer according to an instruction of a logical block ID in the second invention of the present application.

In FIG. 14, first, in step S1, the high speed / low speed switch 22 is set to a high speed value. In step S2, it is determined whether the logical block ID specified in step S2 matches the value of the logical block ID register 11 at that time. It is checked, and if they match, a series of processes is terminated because the tape has been positioned. If a mismatch is determined in step S2, the process proceeds to step S3, where the designated logical block ID is specified.
Is larger than the value of the logical block ID register 11, and the pointer 21 is decremented until the logical block ID at the table position indicated by the pointer becomes larger than the logical block ID specified in steps S4 and S5.

Subsequently, in step S6, the pointer 21 is incremented by one to return to the tape mark immediately before the target block.
Start with the reverse. On the other hand, if the value of the logical block ID specified in step S3 is larger than the value of the logical block ID register 11, steps S8 and S9
The logical block ID designated by the processing of
The pointer 21 increments until it becomes larger than the logical block ID at the table position indicated by No. 1, and the pointer 21 is decremented by one in step S10, and the tape mark immediately before the target block is indicated by the pointer 21. In S11, the tape drive motor 23 is advanced to start.

When the high-speed feeding in step S7 or S11 is started, the value of the logical block ID pointed to by the pointer 21 is set in step S12, and the value of the physical block ID register 12 obtained from the control track is set in step S13. Until the value of the physical block ID at the table position indicated by the pointer 21 is less than the predetermined value i.

Subsequently, in step S14, the high / low speed switch 22 is set to the normal speed.
By performing the processing in steps S18 to S18, the tape drive motor 23 is stopped in step S19 after positioning is performed for the target logical block ID while reading the data block of the tape. FIG. 15 shows the second embodiment of the present application.
FIG. 4 is a flowchart showing a processing operation when a “position to next tape mark” command is received from the host computer in the present invention.

In FIG. 15, first, the high / low speed switch 22 is set to a high speed value in step S1, and a forward and backward search is performed in step S2. If it is a forward search, the pointer 21 is incremented in step S3 and step S3 is executed.
At 4, the tape drive motor 23 is started forward. If it is a backward search, the pointer 21 is decremented in step S5, and the tape drive motor 23 is started in reverse in step S6.

Subsequently, in step S7, the physical block ID register 12 obtained from the control track by running the tape
The high-speed feed is performed until the value of coincides with the value obtained by subtracting the predetermined value i from the physical block ID at the table position indicated by the pointer 21, and if they match, the high / low speed switch 22 is set to the normal speed in step S8. In steps S9 to S12, the data block is read to the target logical block while being read in the normal running, and finally the tape drive motor 23 is stopped in step S13.

The processing operation when a plurality of "positioning commands to the next tape mark" are received from the host computer and executed collectively is the same as that of the first invention shown in FIG.

[0087]

As described above, according to the present invention, the correspondence between the logical block ID and the physical block ID on the magnetic tape can be obtained without requiring the storage load on the host side. By using the physical block ID, the positioning to the data block or the tape mark, which has been performed at the same speed as the normal reading and writing, can be performed at a high speed, and the access performance of the magnetic tape storage device can be greatly improved. .

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an explanatory view of an embodiment functionally showing a main part of the present invention in FIG. 2;

FIG. 4 is an explanatory diagram of a format of a magnetic tape used in the present invention.

FIG. 5 is a table configuration diagram used in the first invention of the present application.

FIG. 6 is an explanatory diagram of the contents recorded on a magnetic tape corresponding to the table configuration of FIG. 5;

FIG. 7 is a flowchart showing a write operation involving table creation of a data block and a tape mark according to the first invention;

FIG. 8 is a flowchart showing a high-speed positioning operation according to an instruction of a logical block ID according to the first invention;

FIG. 9 is a flowchart showing the operation according to the “positioning command for next tape mark” of the first invention;

FIG. 10 is a flowchart showing an operation according to a plurality of “positioning commands to the next tape mark” of the first invention;

FIG. 11 is a table configuration diagram used in the second invention of the present application.

FIG. 12 is an explanatory diagram of the contents recorded on a magnetic tape corresponding to the table configuration of FIG. 11;

FIG. 13 is a flowchart showing a write operation involving table creation of a data block and a tape mark according to the second invention;

FIG. 14 is a flowchart showing a high-speed positioning operation according to an instruction of a logical block ID according to the second invention;

FIG. 15 is a flowchart showing an operation according to a “positioning command for the next tape mark” of the first invention;

FIG. 16 is an explanatory diagram showing an example of a conventional method.

FIG. 17 is an explanatory diagram showing another example of the conventional method.

[Description of Signs] 1: Magnetic tape 2: Table 3: Table recording means 4: Table reading means 5: High-speed positioning means 6: Tape mark (TM) 7: Table management block 10: Data buffer 11: Logical block ID register 12 : Physical block ID register 13: table update flag register 14: microprocessor (MPU) 15: control track write head 16: control track read head 17: write head 18: read head 19, 20: switch 21: pointer 22: high speed / Low speed switching switch 23: Tape drive motor 24: Register 110: Magnetic tape storage controller 112: Magnetic tape drive 116: Host interface 118: Drive interface 122: DMA controller 124: Cement Roll Storage 126: DIP switch 128: a control bus 130: DMA bus 132: the drive controller 134: Drive

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-246075 (JP, A) JP-A-2-195575 (JP, A) JP-A-50-99525 (JP, A) JP-A-60-1985 47268 (JP, A) JP-A-5-54551 (JP, A) Sadao Yabuki, "Application of DAT Technology to External Storage System", Interface, CQ Publishing Co., Ltd., July 1, 1989, No. 146, July issue, pp. 253-264 (58) Fields investigated (Int. Cl. ⁷ , DB name) G06F 3/06 303 G11B 20/12

Claims (8)

(57) [Claims] A table recording means for creating a correspondence table (2) between positional information on a magnetic tape (1) and delimiter information of data on the magnetic tape (1) and writing the table on a magnetic tape (1). 3) A high-speed positioning apparatus for a magnetic tape storage device, wherein the positioning is controlled with reference to the table (2). 2. A logical number of a data block and a tape mark (6) on a magnetic tape (1), a physical number indicating a physical position of the data block and a tape mark (6) on the magnetic tape, and the data Table recording means (3) for creating a table (2) in which flag information indicating whether or not the block is a tape mark (6) and writing the table on a magnetic tape (1); and a magnetic tape (1) A table reading means (4) for reading the table (2) recorded thereon into the apparatus; and a table reading means (4) for positioning a data block or a tape mark (6) corresponding to an arbitrary logical number. referring to the read filled-in table in the device (2) in), the logical number, magnetic tape of a tape mark (6) or from the flag information desired data block or tape mark (6) To obtain a physical number on flop, and high-speed positioning means (5) for positioning at high speed until the data block or tape mark object (6); fast positioning device of a magnetic tape storage device, characterized in that provided. 3. The high-speed positioning apparatus for a magnetic tape storage device according to claim 2 , wherein said high-speed positioning means (5) switches to a normal speed after positioning to a position immediately before a target data block, and switches to a normal speed. A magnetic tape storage device high-speed positioning device characterized by positioning. 4. A high-speed positioning apparatus for a magnetic tape storage device according to claim 2 , wherein said table reading means reads said table into a memory when said magnetic tape is loaded, and records said table. The means (3) updates the table (2) in the memory in response to the access of the magnetic tape (1) and, when the magnetic tape (1) is unloaded, transfers the table (2) in the memory to the magnetic tape (1). A high-speed positioning apparatus for a magnetic tape storage device, wherein writing is performed or only a changed point of a table (2) is added. 5. A high-speed positioning apparatus for a magnetic tape storage device according to claim 2 , further comprising: setting a management flag indicating an update of said table (2) at the time of unloading; Flag recording means for recording in the area of the table management block (7) following the area; reset means for resetting the management flag of the table management block (7) when loading the magnetic tape (1); before reset by the reset means If the management flag is in the set state, it is determined that the table has been updated normally at the time of the previous unloading, and if the management flag has been reset, it is determined that the table has not been updated properly. A high-speed magnetic tape storage device positioning apparatus . 6. The logical number of a tape mark (6) indicating the end position of a data file on a magnetic tape (1) composed of one or a plurality of data blocks, and the tape mark (6) on the magnetic tape A table recording means (3) for creating a table (2) in correspondence with a physical number indicating a physical position and writing the table on a magnetic tape (1); and the table recorded on the magnetic tape (1) A table reading means (4) for reading (2) into the apparatus; when positioning an arbitrary data block, referencing the table (2) read by the table reading means (4) and closest to the target data block After obtaining the physical number on the magnetic tape (1) corresponding to the logical number of the tape mark (6) and positioning it on the tape mark (6), switching to normal speed and positioning on the target data block Fast positioning means (5) and; magnetic tape apparatus comprising the. 7. The magnetic tape storage device high-speed positioning apparatus according to claim 6 , wherein said table reading means reads said table into a memory when loading said magnetic tape, and records said table. The means (3) updates the table (2) in the memory in response to the access of the magnetic tape (1) and, when the magnetic tape (1) is unloaded, transfers the table (2) in the memory to the magnetic tape (1). A high-speed positioning apparatus for a magnetic tape storage device, wherein writing is performed or only a changed point of a table (2) is added. 8. A magnetic tape storage device high-speed positioning apparatus according to claim 6 , further comprising: setting a management flag indicating update of said table (2) at the time of unloading; Flag recording means for recording in the area of the table management block (7) following the area; reset means for resetting the management flag of the table management block (7) when loading the magnetic tape (1); before reset by the reset means If the management flag is in the set state, it is determined that the table has been updated normally at the time of the previous unloading, and if the management flag has been reset, it is determined that the table has not been updated properly. A high-speed magnetic tape storage device positioning apparatus .