JP3368378B2 - Storage content management method and data processing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage content management method and a data processing device, and more particularly to a method useful for online recovery / expansion of multiplexed storage content and its method. A data processing apparatus suitable for implementation is provided.

[Prior Art] FIG. 7 shows an example of a multi-computer system in which a plurality of computers α, β, γ, ...
Are connected to each other so that they can exchange data with each other. Each computer α, β, γ, ... Has an external storage device 11α, 11β, 11γ, ... For accumulating data. In each of the external storage devices 11α, 11β, 11γ, ..., files A, B, C, D, ... In which data is stored with an index, for example, are defined, and there are multiplexed files (for example, files A, file C).

In this multi-computer system, for example, one of the conventional methods performed when recovering the file A of the computer β is to prohibit the access to the file A at all and then copy the file A of the computer α to the computer β side. This is a method of permitting access after completion of copying. In this method, since the access to the file A is prohibited at all, the current data of the file A does not occur during the recovery, and the processing becomes simple.

However, since it is inconvenient that the file A cannot be accessed at all, a file recovery method improved so that the file A of the computer α can be accessed even during recovery is proposed in Japanese Patent Laid-Open No. 62-102342, for example. .

This recovery method is a method in which a sequential file is applied, and as shown in FIG.
File A is copied to the computer β side, current data A ⁺ generated after the start of copying is added as usual on the computer α side and stored in the current data buffer b on the computer β side. When the file A has been copied to the contents at the start of copying, the current data stored in the buffer b as shown in FIG. 8 (b).
Add A ⁺ . As a result, the file A including the current data A ⁺ is restored.

[Problems to be Solved by the Invention] In the above recovery method, a current data buffer that temporarily stores current data is required on the recovery side during recovery, but the amount of current data generated during this recovery period is You cannot choose an appropriate buffer size because it is unpredictable. Therefore, for the sake of safety, there is no choice but to provide a current data buffer larger than the actually required capacity, and there is a problem that an inefficient equipment load is imposed.
Further, even if a large-capacity current data buffer is provided, there is no guarantee that the current data amount will not exceed it, and at that time there is a problem that the stored contents cannot be recovered.

Therefore, it is an object of the present invention to allow access to stored contents even during recovery, does not require a large capacity buffer, and does not make the stored contents unrecoverable even if the amount of current data increases. It is to provide a method for recovering contents and a device therefor.

Another object of the present invention is to provide a storage content management method related to the storage content recovery method and an apparatus therefor.

[Means for Solving the Problems] In the first aspect, the present invention is configured so that a plurality of data processing devices are connected via a transmission path so that data can be exchanged with each other, and storage in each data processing device. In a system in which contents are multiplexed, a data processing device that supports recovery / expansion of stored contents sends the stored contents to be recovered / expanded to the transmission path as recovery / expansion data,
A data processing device that requires recovery / expansion of storage contents temporarily erases the storage contents to be recovered / expansion, identifies and receives both the current data and the recovery / expansion data from the transmission line, and receives the current data. When receiving the recovery / expansion data, when the corresponding data is stored, the received recovery / expansion data is discarded, and the corresponding data is stored. If not, the received recovery / expansion data is stored, and thereby the online storage / expansion of the multiplexed storage contents is performed, thereby providing a storage content management method.

In addition, the reason why “recovery / expansion” is used in the above description is that the present invention is applicable to “expansion” as well as “recovery”.

According to a second aspect, the present invention provides a system in which a plurality of data processing devices are connected via a transmission line so that data can be exchanged with each other and the storage contents of each data processing device are multiplexed. The data processing device that supports the recovery / expansion of the stored contents sends the stored contents to be recovered / expanded to the transmission line as recovery / expansion data,
A data processing device that requires recovery / expansion of stored contents should not return a response to access to the stored contents that need recovery / expansion, erase the stored contents that need recovery / expansion once, and Both the current data and the recovery / expansion data are identified and received from, and when the current data is received, first access in update mode, and if the corresponding data does not exist and an error occurs, Next, when the recovery / expansion data is converted and accessed and the recovery / expansion data is received, the recovery / expansion data received is accessed if the corresponding data already exists and an error occurs. Provided is a method of managing stored contents, which is characterized by discarding use data.

According to a third aspect of the present invention, the present invention is connected via a transmission line so that data can be exchanged with another data processing device, and storage contents are multiplexed with another data processing device. When the managed storage device is physically accessible from the inaccessible state or when it is desired to expand the stored content, the updated data indicating the freshness of the updated stored content. Update information sending means for sending information to the transmission line, and receiving the update information sent by another data processing device from the transmission line and comparing it with its own update information to recover / expand the stored contents of the other data processing device. When it is determined to support the recovery / expansion of the storage contents of another data processing device and the update information comparison / determination means for determining whether or not to support and transmitting the determination result to the transmission path, the recovery / expansion is performed. Recovery / expansion data sending means for sending the stored contents to the transmission path as recovery / expansion data, and the judgment result sent by the other data processing device to the transmission path, and recovery / expansion from the judgment result. When the necessary storage contents are found, response limiting means for preventing a response to the access to the storage contents found necessary for the recovery / expansion, and the storage contents requiring the recovery / expansion from the judgment result A storage content erasing means for once erasing the storage content that is found to be necessary for recovery / expansion when it is determined,
A data receiving unit that receives both the current data and the recovery / expansion data by identifying them from the transmission line, and when the current data is received, first access in the update mode, and if the corresponding data does not exist, an error occurs. In the case of, the update / additional mode conversion access means for converting to the additional mode and accessing the data, and when the recovery / expansion data is received, the data is accessed in the additional mode and the corresponding data already exists. In the case of an error due to the error, a data processing device is provided which comprises recovery / expansion data processing means for discarding the received recovery / expansion data.

[Operation] In the present invention according to the first aspect described above, the data processing device that supports the recovery / expansion of the storage content sends the storage content to be recovered / expanded as recovery / expansion data to recover / store the storage content. In a data processing device that requires expansion, both the current data and the recovery / expansion data are identified and received, and when the current data is received, it is stored preferentially and the recovery / expansion data is stored. When received, the received recovery / expansion data is stored only when the corresponding data is not stored. In other words, the current data can be written even during recovery / expansion, and a large current data buffer becomes unnecessary. In addition, the problem of irrecoverability due to insufficient buffer capacity is solved.

In the present invention according to the second aspect, since the data processing device that needs to restore / expand the stored content does not return a response to access to the stored content that needs to be restored / expanded, the data processing device has the corresponding stored content. Conflict does not occur with the response of the data processing device. In addition, since the stored contents that need to be restored / expanded are deleted, unnecessary stored contents do not remain. further,
When an access command for the erased stored contents in the update access mode is received, the access command is converted to the additional access mode and the access command is executed, so that no access error occurs.

In the present invention according to the third aspect, the first aspect
From the point of view of the above, the present invention according to the second aspect is integrated into a device.

[Examples] The present invention will be described in more detail with reference to the examples shown in the drawings. The present invention is not limited to this.

FIG. 1 shows the configuration of a computer 10 according to an embodiment of the present invention, which is connected to another computer 10 by a transmission line L as in the configuration shown in FIG. It also has an external storage device 11.

The computer 10 includes a transmission control device 101 and an information processing device 104.

The transmission control device 101 has a selective reception management unit 102 and a selective reception table 103. In the selective reception table 103, content codes indicating many types of data that can be processed by the computer 10 are registered.

The information processing device 104 includes a reception buffer 105 and a transmission buffer 1.
It has 06, a processing unit 107, a content code table 108, and an external storage management unit 109.

The processing unit 107 includes a current data management unit 43.
And a recovery / extension management unit 44.

The current data management unit 43 has a self-opening unit 431.
And an update / addition conversion unit 432 and a response limiting unit 434.

Further, the recovery / extension management unit 44 includes an update information sending unit 44
1, an update information comparison / determination unit 442, and a stored content deletion unit 443.
And a recovery / expansion data sending unit 444 and a recovery / expansion data receiving unit 445.

As shown in FIG. 2, the content code table 108 has a buffer area divided by content codes of many kinds of data that can be processed by the computer 10. Each buffer area has a content code 401, a check flag 402, a message storage area 403, and a recovery flag 40.
Made of 4

FIG. 3 shows the format of the message 200 flowing on the transmission line L, 201 is a flag indicating the beginning and end of the message 200, 202 is a content code indicating the type of content of the data body 206, and 203 is the message 200. The address of the sender computer 10, 205 is an event number, 206 is a data body, and 207 is a frame check sequence for checking a transmission error of the message 200.

The event number 205 is composed of an event number that identifies an event of data driving when the program is data driven, and a serial number of data that occurs.

The data body 206 is composed of a file client list 206a and information 206b for data for accessing a file and for its response. The file client list 206a includes data necessary for accessing a file, such as access mode (read, update, add, etc.), record length, block length, key length, key position, self-open flag, etc. ing.

Now, access to a file starts with an open instruction and ends with a close instruction, and if it is accessed without an open instruction, an instruction issue order error occurs. For this reason, when the computer 10 having a file already opened in the system starts up later, there is a problem that an instruction issue order error occurs in the computer 10.

Therefore, the system of the present invention avoids the problem that an instruction issue order error occurs as follows.

That is, each computer 10 sets the self-open flag in the file client list 206a to “Self-open flag” in the message 200 including the current data regarding the file until the close command is issued when the open command to open the file is successful. 1 ”. On the other hand, the self-opening part 431 of each computer 10
Message 200 when an instruction issue order error occurs.
Check the self-open flag in the file client list 206a of. If the self-open flag is "1", the file is opened by itself and the access command is executed again.

As a result, it is possible to avoid an instruction issuance order error for a file that has risen during a series of file access instructions that start with an open instruction and end with a close instruction.

Regarding the processing such as the update mode access in which the reading processing and the writing processing are paired, even if the self-open processing is performed, if the processing is started from the data requesting the writing processing at the start-up, An instruction issue order error may occur. Therefore, in this case, similarly to the self-open processing described above, a flag that also indicates whether or not the read processing paired with the write processing that resulted in the instruction issue order error is successful is set in the message. Based on this, the reading process may be performed before the writing process.

Now, the processing in the normal time, which is not the recovery / expansion time, is performed as follows.

That is, when the message 200 flows on the transmission line L,
The selective reception management unit 102 looks at the content code 202 in the message 200 and checks whether the content code is registered in the selective reception table 103. If it is not registered, the message 200 is ignored. If registered, the flag 201 indicating the beginning and end of the message 200 and the frame check sequence 207 are removed, and the message 200 is passed to the reception buffer 105.

The message 200 passed to the reception buffer 105 is buffered in the message storage area 403 of the corresponding buffer area of the content code table 108 based on the content code 202. When the message is buffered in the message storage area 403, the check flag 402 is set to "1".

The processing unit 107 receives the message 20 by first-in / first-out from the message storage area 403 of the buffer area in which the check flag 402 is “1”.
0 is taken out and the data is passed to the user program for processing based on the content code 401, or the external storage management unit
A file in the external storage device 11 is accessed via 109.

On the other hand, the message sent from the user program and the response message to the file access request message are generated from the processing unit 107, passed to the transmission buffer 106, and sent to the transmission line L via the transmission control device 101. Be done.

The same event number 205 is attached to the file access request message and the response message.

Since the files are multiplexed, a plurality of response messages may flow on the transmission line L for one file access request message. At this time, the computer requesting the file access accepts the message by selecting, for example, the first-come-first-served basis or the majority decision.

  Next, processing related to recovery / expansion will be described.

Now, one external storage device 11 is, for example, the external storage device.
If the file in the external storage device 11 is temporarily inaccessible due to a failure or power off of the corresponding computer 11, a failure or power off of the corresponding computer 10, etc., the file in the external storage device 11 is not accessible and is not updated. Unmatching between encrypted files may occur. Therefore, when the external storage device 11 becomes physically accessible (when the external storage device 11 starts up), the occurrence of unmatching is first examined.

That is, when the external storage device 11 becomes physically accessible, the response limiting unit 433 of the processing unit 107 sets the recovery flag 404 of the buffer area having the content code 401 meaning access to the file of the content code table 108. Set to "1" to suppress the response to the access request to the file existing in the external storage device 11.

After setting the recovery flag 404 to “1”, the processing unit 107
The update information sending unit 441 sends the file start-up message on the transmission line L. This file start-up message has a content code 202 indicating a file start-up message, and a data body 206 includes a file name, a content code indicating access to the file, and a file event number. I'm out.

The file event number is update information of a file existing for each file, and when the file is accessed based on the received message, the event number 205 of the message is updated as the file event number. However, the file event number is not updated in the access in the read mode where the contents of the file do not change even if accessed. In addition to such an updating method, a method of updating only when the file is opened / closed may be used.

When the file start-up message flows on the transmission line L, all the computers 10 fetch it and determine whether the content code included in the data body 206 exists in the content code 401 in the content code table 108 ( In other words, check whether you have the file). If it does not exist, do nothing. If it exists, it is judged whether or not the file is being recovered by the recovering flag 404 in the buffer area of the content code 401, and if it is being recovered, nothing is done. If not being recovered, the update information comparison / judgment unit 442 of the processing unit 107 checks the file event number of the file, and determines the data body of the file startup message.
The file event number contained in 206 is compared, and if there is a match, a recovery necessity message indicating that recovery is not necessary and if recovery is necessary is sent on the transmission line L. The recovery necessity message has a content code 202 indicating that it is a recovery necessity message, and the data body 206 indicates the file name, the content code indicating access to the file, and the recovery necessity of the file. It includes four flags and file definition information of the file, that is, information about the processing method and attributes of the file.

The computer 10 which has transmitted the start-up message fetches this recovery necessity message, and if it is determined that the recovery is unnecessary, the recovery flag 404 of the buffer area having the content code 401 meaning access to the file in the content code table 108. Is returned to "0". If you find it necessary to recover,
The storage content erasing unit 115 of the processing unit 107 erases the file (this is because the data that has been present on the recovery target side but has already been erased on the recovery support side is not recovered even after the recovery process is completed). This is to prevent the recovery side from remaining). Then, the data body 206 of the recovery necessity message
The file is redefined on the basis of the file definition information included in the file, and a recovery preparation completion message is broadcast on the transmission line L. The recovery preparation completion message has a content code 202 indicating that it is a recovery preparation completion message, and the data body 206 includes a file name and a content code meaning access to the file.

If you want to expand the file, follow the procedure above. That is, during online processing, the same file that already exists in the system is defined, the recovery flag 404 for that file is set to "1", the file event number is set to blank, and the file startup message is transmitted. Shed on the road L. Since the file event number is blank, the recovery necessity message that the recovery is necessary is returned. After receiving this, the completely same processing as described above is performed, and the recovery preparation completion message is sent on the transmission line L.

Now, when the recovery preparation completion message flows on the transmission line L, the computer (hereinafter, referred to as this computer and the recovery / extension support side computer) 10 that has notified the recovery necessity message captures it.

Then, as shown in FIG. 4, the recovery / expansion data transmission unit 117 of the processing unit 107 uses the record of the file 31 (hereinafter, recovery / expansion support file) 31 read from the external storage device 11 to support the recovery / extension. Message 200
Is created and sent as recovery / expansion data 2 on the transmission line L. The recovery / expansion support message 200 has a content code 202 indicating that it is the recovery / expansion data 2, and the data body 206 has a file name, a content code meaning access to the file, a record, and a recovery.・ File event number 4 which is the update information of the extended support file 31
Including one. The number of records is arbitrary and can be set to one record. Therefore, the records of the recovery / expansion support file 31 are divided into the number of records included in one recovery / expansion data 2 and are sent in order from the first record.

The computer 10 that has notified the recovery preparation completion message (hereinafter referred to as the recovery / expansion required computer) 10 retrieves the recovery / expansion data 2.

Then, the recovery / expansion data receiving unit 445 accesses the recovery / expansion file 41 in the addition mode for the acquired data. That is, if there is no record with the same key, write it, and if there is no record, do nothing. Since the storage content erasing unit 443 erases the file as described above, in many cases, there is no record with the same key, and writing is performed. However, as described below, if the record of the current data 1 has already been written, the record of that key already exists, and the writing is not performed. That is, the current data 1 has priority over the recovery / expansion data 2.

As an example, FIG. 4 shows a case where the recovery / expansion support side receives the data for updating the m + 1th record 312 as the current data 1 immediately after sending the mth record 311 as the recovery / expansion data 2. .

At this time, on the recovery / extension support side, the m + 1th record 312 is accessed in the update mode by the current data 1 and updated, and the response message is returned to the update data transmission source.

On the other hand, on the side requiring recovery / expansion, data for recovery / expansion 2
The m-th record is accessed and added in the add mode by. That is, it is recovered. Next is the current data 1
Thus, the m + 1th record is accessed in the update mode, but since the m + 1th record does not yet exist in the recovery / expansion required file 41, an access error occurs. However, at this time, since the update / addition conversion unit 432 converts the mode to the addition mode and accesses again, the m + 1th record 312 is eventually added.

Next, the m + 1st record is sent from the recovery / expansion support side as the recovery / expansion data 2 and the recovery / expansion necessary file 41 is accessed in the addition mode. Since there is an m + 1 record added by data 1, an access error occurred and m + 1 sent as recovery / expansion data 2
Number record is discarded.

Next, when the data for updating the m-th record 311 is received as the current data 1, since this is accessed in the update mode, the recovery / extension support side and the recovery / extension necessary side can perform the update without any problem.

After all, the current data 1 is always the recovery / expansion data 2
Will be given priority over.

As described above, when the recovery / expansion support side sends the final record and the recovery / expansion need side adds or discards the final record, the multiplexed files are matched.

Thereafter, the processing unit 107 on the recovery / expansion required side resets the in-recovery flag 404 related to the file in the content code table 108 to “0”, and recovers the online storage content.
The extension processing ends.

In the above embodiment, the computer 10 is provided with a current data buffer capable of accumulating the current data to some extent, and the recovery / expansion required side accumulates the current data in the current data buffer during the recovery. When it's full, or when all the recovery / expansion data has been processed,
The data in the current data buffer may be fetched and updated by first-in first-out. The role of the current data buffer in this case is different from that of the current data buffer described in the prior art, and the problem of irrecoverability due to insufficient capacity does not occur at all.

Further, in the above embodiment, the transmission method is not limited to the content code, but may be the transmission method using the destination address. At this time, the message 20 shown in FIG.
The 0 format replaces the content code 202 with the destination address and the computer 10 of FIG. 1 has the address and will receive the message based on the destination address in the message. Further, the computer 10 has information as to which other computer 10 the file managed by itself is multiplexed.

Further, the target file may be of any type and may be a database. Further, these files may be present not only in the external storage device 11 but also in the internal storage device of the computer 10.

Further, not only files, but also stored contents such as screen buffers, memories of other input / output devices, buffers, and the like are targeted.

  An embodiment in which the target is a screen buffer is shown in FIG.

5, the computers 10, 10, ...
Connected to each other and exchange data with each other. Each of the computers 10, 10, ... Has a terminal 120, 120 ,. The terminals 120, 120, ... Respectively have screen buffers 130, 13
It has 0, ...

At the time of recovery / expansion of the terminals 120, 120, ..., The recovery / expansion support side divides the information in the screen buffer based on the screen definition information and sends it. On the recovery / expansion required side, by prioritizing the current data over the recovery / expansion data,
You can recover and expand the screen buffer online as well as recover and expand files.

  Next, FIG. 6 shows still another embodiment of the present invention.

In this embodiment, the recovery / expansion support storage content 311 and the recovery / expansion required storage content 411 may be different in content, or may be different in type / attribute and the like.

Recovery / expansion Required memory contents 411 recovery / expansion when recovery / expansion
Recovery / expansion data 2 is sent from the expansion support side. On the recovery / expansion required side that has received this recovery / expansion data 2, the recovery / expansion data receiving unit 445 passes the recovery / expansion data 2 to the user program 45. The user program 45 returns the processing result to the recovery / expansion data receiving unit 445. On the other hand, for the current data 1 as well, the current data management unit 43 sets the user program
The current data is passed to 44, and the processing result is returned. Then, the recovery / expansion data receiving unit 445 and the current data management unit 43 perform the recovery / expansion process in the same manner as described with reference to FIG. 4 based on the returned processing results.

According to this embodiment, it becomes possible to restore / expand the stored contents with the support of the stored contents of different contents possessed by the other computer 10.

[Effects of the Invention] According to the present invention, the current data and the data for recovery / expansion are received together, and the stored contents are recovered / expanded while keeping the consistency between the two. Therefore, it is necessary to suppress the processing of the current data. Recovery without system interruption
Expansion can be realized. Further, it is not necessary to prepare a large current data buffer for accumulating the current data. Furthermore, no matter how big the memory contents are,
It will be possible to expand.

Further, since the recovery / extension is started after the necessity of recovery / extension is judged based on the update information of the stored content, it is possible to prevent waste of the recovery of the stored content which does not need to be recovered.

Further, since the open process is performed by itself, even if the stored contents are already opened in the system, the stored contents can be accessed without causing an error even when the system is started up later.

[Brief description of drawings]

FIG. 1 is a block diagram of a computer according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of the structure of a content code table, FIG. 3 is a message format diagram, and FIG. 4 is a data flow at the time of recovery / extension. 5 is a block diagram showing a multi-computer system according to another embodiment of the present invention, FIG. 6 is a view corresponding to FIG. 4 of still another embodiment of the present invention, and FIG. 7 is a multiplexed file. FIG. 8A and FIG. 8B are block diagrams of a multi-computer system that is provided, which are conceptual diagrams for explaining a conventional file recovery / expansion method. (Description of symbols) 1 ... Current data 2 ... Recovery / expansion data 10 ... Computer 11 ... External storage device 43 ... Current data management unit 431 ... Self-opening unit 432 ... Update / addition conversion unit 433 ...... Response limiting unit 44 ...... Recovery / expansion management unit 441 ...... Update information sending unit 442 ...... Update information comparison / decision unit 443 ...... Memory content deletion unit 444 ...... Recovery / expansion data sending unit 445 ...... Recovery Expansion data receiving part L ... Transmission line.

Front page continued (72) Inventor Masayuki Orishige 1099 Ozenji, Aso-ku, Kawasaki-shi, Kanagawa Hitachi Systems Development Laboratory, Ltd. In software factory (72) Inventor Masuyuki Takeuchi 5030 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi Ltd. Software factory (56) Reference JP-A-63-174148 (JP, A) JP-A-59- 75349 (JP, A) JP-A-57-141763 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06F 12/00 G06F 12/16 G06F 3/06

Claims (4)

(57) [Claims] 1. In a system in which a plurality of data processing devices are connected via a transmission path so that data can be exchanged with each other and the storage contents of each data processing device are multiplexed, the recovery of the storage contents -The data processing device that supports expansion sends the storage contents to be recovered / expanded to the transmission path as recovery / expansion data, and the data processing device that needs to recover / expand the storage contents is the storage to be expanded / expanded. Once the contents are erased, both the current data and the recovery / expansion data are identified and received from the transmission line, when the current data is received, it is stored, and when the recovery / expansion data is received If the corresponding data is stored, the received recovery / expansion data is discarded, and if the corresponding data is not stored, it is received. Storing recovery and extended data management method of a storage content thereby and performing online recovery and expansion of multiplexed memory contents. 2. A data processing device having a storage device that has changed from a physically inaccessible state to an accessible state or a data processing device for which the storage content is to be expanded is updated to indicate the freshness at the time of updating the storage content. Information is sent to the transmission line, and the update information is received by another data processing device having a multiplexed storage content and compared with the update information indicating the freshness at the time of updating the corresponding storage content stored by the user. Then
When the update information does not match, the other data processing device becomes a data processing device that supports the recovery / expansion of the stored content, and the data processing device that has sent the update information to the transmission path restores / expands the stored content. The storage content management method according to claim 1, which is a required data processing device. 3. In a system in which a plurality of data processing devices are connected via a transmission path so that data can be exchanged with each other and the storage contents of each data processing device are multiplexed, the recovery of the storage contents -A data processing device that supports expansion sends the stored contents to be recovered / expanded to the transmission line as recovery / expansion data, and a data processing device that needs to recover / expand the stored contents needs recovery / expansion. In addition to not returning a response to the access to the stored contents, once erased the stored contents that need to be restored / extended, and receive and identify both the current data and the restoration / extended data from the transmission line. When the current data is received, first access it in update mode, and if the corresponding data does not exist and an error occurs, then convert it to append mode. When accessing and receiving the recovery / expansion data, it is accessed in the addition mode, and when the corresponding data already exists and an error occurs, the received recovery / expansion data is discarded. And how to manage the stored contents. 4. A data processing apparatus which is connected via a transmission line so that data can be exchanged with another data processing apparatus and whose stored contents are multiplexed with another data processing apparatus. In the above, when the storage device under management changes from the physically inaccessible state to the accessible state or when it is desired to expand the storage content, update information indicating the freshness at the time of updating the multiplexed storage content is transmitted to the transmission line. Whether or not the update information sending means for sending and the update information sent by another data processing device are received from the transmission line and compared with own update information to support recovery / expansion of the storage contents of the other data processing device. Whether or not the update information comparison / determination means determines whether or not the determination result is transmitted to the transmission line, and the storage / restoration to be expanded / restored when it is determined to support recovery / expansion of the storage content of another data processing device. Recover the contents -
Recovery / expansion data sending means for sending to the transmission path as expansion data, and the judgment result sent by another data processing device to the transmission path, and the storage contents that need recovery / expansion are found from the judgment results. Sometimes, a response limiting unit that does not return a response to an access to a storage content that is found to need recovery / expansion; and when the storage content that needs recovery / expansion is found from the determination result, the recovery is performed.・ Memory content erasing means for once erasing the memory content that has been determined to require expansion, data receiving means for receiving and identifying both the current data and the recovery / expansion data from the transmission line, and the current data received In this case, first access in update mode, and if there is no corresponding data and an error occurs, then convert to additional mode and access Additional mode conversion access means, and when the recovery / expansion data is received, access is performed in the additional mode, and if the corresponding data already exists and an error occurs, the received recovery / expansion data is discarded. A data processing device comprising: