JPH069042B2 - Sequential access control device for shared storage medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sequential access control device for a shared storage medium of a control device for a secondary storage medium that can be shared by a plurality of host computers.

[Conventional technology]

Conventionally, a control device for a secondary storage medium that can be shared by multiple host computers of this type needs to specify the physical address of a file existing on the secondary storage medium for access. It was necessary to manage the current address of the file to be accessed by the host computer and obtain the current address through communication between the host computers.

[Problems to be solved by the invention]

The above-described control device for a secondary storage medium that can be shared by conventional host computers, when files existing on the secondary storage medium are sequentially accessed by multiple host computers as a whole, the current that should be sequentially accessed between the host computers. It is said that an address must be obtained by a communication means, and the communication, acquisition, and input / output operations must be synchronized, and it takes a lot of processing time to access the secondary storage medium and perform the input / output operation. There was a flaw.

Further, since it is not possible to collectively block data from a plurality of host computers in a block which is an input / output unit of the host computer, there is a drawback that the capacity of the secondary storage medium cannot be effectively used.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sequential access control device for a shared storage medium which can eliminate the above-mentioned drawbacks and can perform sequential access at high speed and can effectively utilize the capacity of the secondary storage medium.

[Means for solving problems]

The configuration of the sequential access control device for the shared storage medium of the present invention is issued from each of the plurality of host computers in a sequential access control device for controlling access to a file on a secondary storage medium that can be shared by a plurality of host computers. Processing request analyzing means for receiving and analyzing a processing request, processing request response means for returning a response to the processing request to the requesting host computer, and provision for a sequential access control request issued from each of the plurality of host computers. Current address, file identifier, which is sequentially writing or reading to the file on the next storage medium,
A file address storage area for holding a block number and a relative position in the block, and a file address control means for controlling read / write control and update by a current address in the file address storage area in response to a request from the processing request analysis means. An input / output unit for performing input / output with the secondary storage medium; a data buffer area for temporarily storing the data in the file in block units in preparation for output of the data in the file; Data buffer control means for controlling input / output of data or data blocks to / from the next storage medium.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a system including a shared medium sequential access control device according to an embodiment of the present invention.

In FIG. 1, 2 is a secondary storage medium control device, 11 and 12 are host computers, and 31 and 32 are secondary storage media. The number of host computers in this embodiment is two, but it is possible to connect one, three or more host computers to the secondary storage medium control device 2. Also,
One host computer is a plurality of secondary storage medium control devices 2
Can be connected. Further, one host computer can be connected to a plurality of secondary storage medium control devices 2. Although there are two secondary storage media 2 in this embodiment, a plurality of secondary storage media can be connected to one secondary storage media control device 2. Further, the secondary storage medium control device 2 has therein a processing request analysis means 4, a processing request response means 5, a file address control means 6, a file address storage area 7, a data buffer control means 8, a data buffer area 9, Input / output means 1
Contains 0.

The processing request analysis means 4 is a means for receiving respective processing requests from a plurality of host computers, analyzing the processing request contents, and making it possible to access the same secondary storage medium, the operation of which is shown in FIG. Is shown in the flow chart of FIG.

The processing request response unit 5 is a unit that responds to the processing requests from the host computers 11 and 12 to the host computers 11 and 12 with a processing result based on the request processing failure or the completion of the request processing.

The file address control means 6 is a means for storing, reading and updating the address on the secondary storage medium and the current address required for sequential access for each file in the file address storage area 7, and its operation is This is shown in the flow chart of FIG.

The data buffer control means 8 searches for the requested data in the data buffer area 9 in accordance with the data input / output request from the processing request analysis means 5 and returns the data to the request source if there is data. When there is no data in 9, a new buffer area is secured and the control is passed to the input / output means 10 to access the secondary storage medium. Further, the updated flag held in the data buffer area 9 is managed, and when the buffer area is insufficient, the block in which the updated flag is set is written back to the file and the block in the buffer is released. The operation is shown in the flow chart of FIG.

The input / output means 10 is means for inputting / outputting data or the like to / from the secondary storage media 31, 32 in response to a request from the data buffer control means 9 or the file address control means 6.

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

In FIG. 1, the processing requests output from the host computers 11 and 12 to the secondary storage medium control unit 2 include a data or block unit sequential write request, a data or block unit sequential read request, and a block unit address. There is a specified write request, a block unit address specified read request, a file registration request, a file deletion request, and a file specified forced write request. The operation of each means in FIG. 1 in response to these requests will be described in detail.

When the file registration / deletion request is output from the host computer, the processing request analysis unit 4 analyzes the processing request, determines the corresponding medium (step 21 in FIG. 2), and determines whether the corresponding medium is accessible. (Step 22 in FIG. 2).
If the medium cannot be accessed by another host computer due to occupation, protection, or failure,
A notification that the processing request cannot be accepted is returned to the host computer (step 29 in FIG. 2). If the medium is accessible, the file address control means is notified of the processing request (step 24 in FIG. 2). File address control means 6
Checks the file registration deletion request (step 31 in FIG. 3), and if the file registration deletion request, updates the file address storage area 7 (step 3 in FIG. 3).
2) Notify the input / output unit 10 to update the secondary storage medium. The processing response is returned from the input / output unit 10 to the host computer via the file address control unit 6 and the processing request response unit 5.

When a sequential write request is issued from the host computer, the processing request analysis means 4 analyzes the request (step 2 in FIG. 2).
1) Then, it is checked whether the medium to be accessed is accessible (step 22 in FIG. 2), and if it is accessible, the processes in steps 23 and 25 in FIG. Control is passed to the address control means 6. The file address control means 6 carries out the processing with step 31 and step 34 in FIG.
At 5, the write address is obtained from the file address storage area 7.

File address storage 7 stores a table shown in Table 1, in accordance with the file identifier F _n, for sequentially write address W _{n (w n)} and sequentially read address R
₁ (r ₁ ) can be obtained. Here, W _n indicates the block number and w _n indicates the relative position within the block.
Similarly, R ₁ and r ₁ also indicate the block number and the relative position within the block.

Therefore, by receiving the medium identifier, the file identifier and the write data as parameters in the sequential access request, the file address control means 6 obtains the address to be written from the file address storage area 7 (step 35 in FIG. 3), The data buffer control means 8 is notified (step 36 in FIG. 3).

The data buffer control means 8 searches the data buffer area 9 to check whether or not the requested block exists therein (step 43 in FIG. 4). If it does not exist, the buffer area is secured in the data buffer area 9. (Step 44 in FIG. 4), notifies the input / output means 10 to read the data block from the file into the buffer (step 45 in FIG. 4),
Next, it is checked whether it is a writing process (step 46 in FIG. 4), and if it is a writing process, it is checked whether it is a block unit (step 48 in FIG. 4). If it is a block unit, the block unit is transferred to the data buffer area 9 (step 52). If it is not a block unit request, it is checked whether or not there is a space for writing in the corresponding block (step 49 in FIG. 4), and if not, the next block is acquired (step 50 in FIG. 4). Data is transferred from the host computer to the block in the data buffer area 9,
The data is divided into blocks (step 51 in FIG. 4), and an updated flag is set in the updated block (step 5 in FIG. 4).
2) Notify the address to the file address control means (step 55 in FIG. 4).

Then, via the processing request response means 5, the host computer 1
1 and 12 are notified of the completion of processing.

The operation in the case of the sequential read request is different from the operation in the case of the sequential write request by referring to the read processing and the sequential read address in the file address storage area.

When there is a writing or reading request from the host computer sequentially or with address designation, the processing request analysis means 4 analyzes the processing request and determines the medium (step 2 in FIG. 2).
1) If the medium is accessible, step 23,
The processes 25 and 26 are performed, and the data buffer control means 8 is notified in step 28. The data buffer control means 8 checks whether or not the requested block exists in the data buffer area 9 (step 43 in FIG. 4), and if the requested block does not exist, secures the area in the data buffer area 9 (fourth step). (Step 44 in FIG. 4), notifies the input / output means 10 to read the data block (step 45 in FIG. 4), and determines whether or not it is a writing process (step 46 in FIG. 4). The data in the block of the data buffer area 9 or the data in the block is transferred to the host computer, and the completion of the process is notified to the host computer via the process request response means 5. In the case of sequential access, the file address control means 6 is notified of the current address (steps 54 and 55 in FIG. 4). In the case of write processing (step 46), it is checked whether it is in block units (step 48 in FIG. 4). However, in the case of address designation other than sequential access processing, processing is in block units, so transfer of blocks is performed. (Step 52 in FIG. 4), the updated flag held in the data buffer area of the block is set (Step 53 in FIG. 4), and the completion of processing is notified to the host computer via the processing request response unit 5. .

A file specification compulsory write request is issued from the host computer by specifying a medium identifier and a file identifier. When the processing request analysis means 5 accepts the request, the request is analyzed (step 21 in FIG. 2), the step 22 is checked, the steps 23, 25, 26 and 27 are processed, and the data buffer is processed in the step 28. The control means 8 is notified, and the data buffer control means 8 searches the data buffer area 9 for a block corresponding to the specified medium identifier and file identifier, and outputs the block with the updated flag to the input / output means 10. Notifying and writing processing is performed in step 42 of FIG. The completion is notified to the host computer via the processing request response means. The writing of the block in which the updated flag is set is not limited to the case where the forced writing request is made. When the buffer area in the data buffer area is secured, the data buffer control means 8 may secure the space by writing back the block in which the updated flag is set to the file when the space in the buffer area is insufficient.

It is also possible to make a compulsory write request by using the host identifier and in-host task identifier in addition to the medium identifier and file identifier. In that case, when the updated flag is set, the host identifier and in-host task identifier are set. Also needs to be recorded. If a data block is found in the data buffer area in step 43 of FIG. 4,
If the host identifier for which the updated flag is set and the task identifier in the host are different from those of the processing request, write-back is performed and then processing is performed.

[Effects of the Invention] As described above, according to the present invention, a secondary storage medium control device that can be shared by a plurality of host computers is provided with sequential access, has a file address storage area, and handles files therein. By storing the current block number and relative address within the block, and by temporarily holding a data block in the data buffer area, the file existing on the secondary storage medium can be saved. There is an effect that it is possible to sequentially access without communicating between a plurality of hosts.

Further, as described above, data from a plurality of host computers can be mixed in a block that is an input / output unit of the host computer, and the capacity of the secondary storage medium can be effectively used.

[Brief description of drawings]

FIG. 1 is a block diagram of a system including a sequential access control device for a shared storage medium according to an embodiment of the present invention, FIG. 2 is a flow chart of a processing example of a processing request analysis unit 4 of the present invention, and FIG. Of the processing example of the file address control means 6 of
FIG. 4 is a flow chart of a processing example of the data buffer control means 8 of the present invention. 2 ... Secondary storage medium control device, 3 ... Secondary storage medium, 4 ... Processing request analysis means, 5 ... Processing request response means, 6 ... File address control means, 7 ... File address storage area, 8 ...
Data buffer control means, 9 ... Data buffer area, 10
... I / O means, 11, 12 ... Host computer.

Claims (1)

[Claims] 1. A processing request analysis for accepting and analyzing a processing request issued from each of the plurality of host computers in a sequential access control device for controlling access to a file on a secondary storage medium that can be shared by the plurality of host computers. Means, processing request response means for returning a response to the processing request to the requesting host computer, and sequential writing to a file on the secondary storage medium in preparation for a sequential access control request issued from each of the plurality of host computers, or A file address storage area that holds a current address, a file identifier, a block number, and a relative position within the block that are sequentially read out, and a read-out document by a current address in the file address storage area according to a request from the processing request analysis unit. File add that controls embedded and update Control means, an input / output means for performing input / output with the secondary storage medium, a data buffer area for temporarily storing the data in the file in block units in preparation for the output of the data in the file, and this data buffer area Or a sequential access control device for a shared storage medium, comprising: a data buffer control means for controlling input / output of data or data blocks to / from the secondary storage medium.