JP2010271952A - Data management device for distributed control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To immediately refer to a data content updated by another computer by a self computer, and to flexibly change a computer which includes an update authority with respect to respective data items constituting a database. <P>SOLUTION: Respective computers in a data management device of a distributed control system connected via a network includes: a shared data processing means which updates shared data and transmits differential data of an update result to another computer when an access request to the shared data from a self computer is an update request and the means includes an update authority; and an update authority processing means which makes an acquisition request of the update authority of the respective computers for data that the self computer does not own the update authority, and updates a update authority data content of the self computer and transmits a response of a update authority transfer to the requesting computer when the acquisition request of a update authority transfer is received by another computer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a data management apparatus for a distributed control system that manages data of a distributed control system in which a plurality of computers are connected via a network.

  In an industrial system (power, gas, water, public transportation, etc.) that is said to be the lifeline that forms the backbone of modern cities, the database used to monitor and control the industrial system must be huge and accessible at high speed Is required. When the state of the industrial system changes, the database is updated, and the data contents of the computers at various places are required to be kept equal. By keeping the data contents of the computers in each place equal, data is not obtained via the network at each place, and high-speed access is possible.

  In addition, when operating the most important computer as a server, a dual (or multiple) industrial system that backs up the server function so that the function of the industrial system is not lost even if this server is stopped. It is usual to compose. By adopting a multi-system configuration, even if the server is stopped, the server function is immediately transferred to another computer so that the function of the industrial system is not impaired. In this case, even if the server function is moved, it is necessary that the data can be accessed and accessed as before, and the other remaining computers are also kept in the same state.

  In a data management system for a distributed control system for maintaining the same data contents among multiple computers, common data is stored in multiple computers connected to the network, and data is updated by each computer. On the other hand, the updated data change content is transmitted to other computers, and the computer that has received the change content keeps the data content of each computer the same by reflecting the change content in the data held by the own computer.

  If the same data item is updated at the same time by multiple computers, a conflict of data update results will occur and the data contents of each computer cannot be kept the same. In order to prevent this, the computer having the database update authority is limited to one computer, and the data update is performed only by the computer having the authority.

  A control system that is geographically distributed due to the advancement of industrial systems is connected by a network, and an object that is monitored and controlled by a certain control system can be monitored by another control system, or an accident can occur in a certain control system. There is a need for a more flexible distributed control system, such as granting monitoring control authority to other control systems to reduce the work load when the work load becomes high due to, etc. Similarly, a more flexible data management method is required for the management method.

  In a distributed database system having the same design data, there is a distributed database synchronization method capable of updating a collaborative work area at an arbitrary timing (see, for example, Patent Document 1). Patent Document 1 provides a collaborative work area for the own computer and other computers in the computer, the data update in the own computer is reflected in the collaborative work area for the own computer, and the change contents are transmitted to the other computer. . The update data received from other computers is reflected in the collaborative work area for other computers. After that, the data contents of a plurality of computers are kept the same by merging the data contents of the collaborative work area for other computers and the collaborative work area for the own computer.

  In addition, there is one that maintains the consistency of common data between databases in a distributed system in real time and is managed in a distributed manner according to the system configuration (for example, see Patent Document 2). In Patent Document 2, a computer having update authority is uniquely assigned to each data item in the database, and when performing data update, it is determined whether the own computer has update authority for the data item to be updated, Updating is performed only when the user has update authority, thereby preventing conflicts in updating the same data item and keeping the data contents the same during the calculation period.

JP 2007-58769 A JP-A-5-225027

  However, in Patent Document 1, the update information updated in another computer is reflected in the collaborative work area for the other computer and then merged into the collaborative work area for the own computer. It takes time to refer to the result with its own computer. When the number of computers increases, each computer needs to have a cooperative work area for the number of computers, and a large-capacity data storage area is required. In addition, when the same data is updated on multiple computers at the same time, the order of merging the contents of the changed data into the collaborative work area of the own computer may be different for each computer, and the same merge result must be maintained. It is difficult.

  In addition, since the thing of patent document 2 has the computer which has update authority for every data item fixedly, the computer which has update authority about a certain data item cannot be changed dynamically.

  An object of the present invention is to provide a data update responsiveness that allows data contents updated by other computers to be immediately referred to by the own computer, and to flexibly change a computer having update authority for each data item constituting the database. The present invention is to provide a data management apparatus for a distributed control system.

  A data management apparatus of a distributed control system according to the present invention is a data management apparatus of a distributed control system in which a plurality of computers are connected via a network, and each computer has shared data to be shared between computers, Update authority management data that records computer information with update authority for each data item of the shared data, and if the access request to the shared data from the local computer is a reference request, return the data stored in the shared data In the case of an update request, if you have update authority for the data contents to be updated, update the shared data and send the difference data of the update result to the other computer, when you receive the update difference data from the other computer The shared data processing means for updating the shared data and an access request from the own computer to the update authority management data are required to check whether the update authority is possessed. If the data is a request to obtain update authority and the data for which the local computer does not have update authority, the update authority acquisition request is sent to each computer. After receiving the transfer response, update the update authority data of the local computer, send the update result data to the other computer, and receive the update authority transfer acquisition request from the other computer, the local computer will update For the authorized data, update the update authority data contents of the own computer, send the update authority transfer response to the request destination computer, and receive the update result data update data contents from other computers, Update authority processing means for updating the contents of update authority data of the own computer is provided.

  According to the present invention, data update responsiveness is good, and data contents updated by other computers can be immediately referred to by the own computer, and a computer having update authority can be flexibly changed for each data item constituting the database. it can.

The block diagram which shows an example of the data management apparatus of the distributed control system which concerns on embodiment of this invention. Explanatory drawing which shows an example of the table file which comprises the shared data in embodiment of this invention. Explanatory drawing which shows an example of the update authority management data which uses the table in embodiment of this invention as a unit item. Explanatory drawing which shows an example of the update authority management data which makes a table and a column name the unit item in embodiment of this invention. Explanatory drawing which shows an example of the update authority management data which makes a table, a column name, and a row number a unit item in embodiment of this invention. Explanatory drawing which shows an example of the update authority management data which stored the IP address as a computer which has the table, the column name, and the row number in embodiment of this invention as a unit item, and has an update authority. The flowchart which shows an example of the processing content of the shared data processing means in embodiment of this invention. The flowchart which shows an example of the processing content of the update authority process means in embodiment of this invention. The flowchart which shows another example of the processing content of the shared data processing means in embodiment of this invention. The flowchart which shows another example of the processing content of the update authority process means in embodiment of this invention. The block diagram which shows another example of the data management apparatus of the distributed control system which concerns on embodiment of this invention. Explanatory drawing which shows an example of the file structure of IP address data in embodiment of this invention. The flowchart which shows the processing content of the computer address management means in embodiment of this invention. Explanatory drawing which shows an example of the judgment table which defined the IP address of the other computer which the own computer takes over when the failure of the other computer occurs in the embodiment of the present invention. Explanatory drawing which shows another example of the update authority management data in embodiment of this invention. The flowchart which shows another example of the processing content of the update authority process means in embodiment of this invention.

  Hereinafter, embodiments of a data management device of a distributed control system according to the present invention will be described. FIG. 1 is a configuration diagram showing an example of a data management apparatus of a distributed control system according to an embodiment of the present invention.

  The plurality of computers 11 </ b> A to 11 </ b> Z are connected to each other via the communication network 12. Each of the computers 11A to 11Z includes shared data 13 for sharing among the computers 11A to 11Z, update authority management data 14 in which computer information having update authority is recorded for each data item of the shared data 13, and shared data 13. It has a shared data processing means 15 for processing, an update authority processing means 16 for processing the update authority management data 14, and an application 17 for executing the shared data processing means 15 and the update authority processing means 16.

  The shared data 13 is shared data shared by the computers 11A to 11Z, and stores a plurality of table files. The table file is stored in a storage device (hard disk or memory) (not shown) of the computers 11A to 11Z. The table file is a tabular file having rows and columns as shown in FIG. 2, and one table file is specified by the table name. The table file update and reference processing is performed by specifying a table name and specifying one data by the column name and row name of the table. The column name and the row name are designated by numerical values or character strings.

  The update authority management data 14 is data for storing whether or not the own computer has the authority to update a row or column in the table file or table file to be updated when the shared data 13 is updated. The data 13 is stored in the storage devices of the computers 11A to 11Z in the same manner as the data 13 file. The update authority management data 14 is managed as a tabular file as shown in FIGS.

  FIG. 3 is an example of the update authority management data 14 when the computers 11A to 11Z having the update authority are given for each table, and FIG. 4 is an example having the computers 11A to 11Z having the update authority for each column of the table. FIG. 5 is an example having update authority for each data item specified by the column and row number of the table. Further, as shown in FIG. 6, the update authority management data 14 may be divided and managed for each table, and the IP address of the computer may be stored as computer information. 192.168.2.1 in FIG. 6 is the IP address of the computer 11A, for example, 192.168.2.2 is the computer 11B, 192.168.2.3 is the computer 11C, 192.168.8.2. 4 is the IP address of the computer 11D.

  The application 17 operates on the computers 11 </ b> A to 11 </ b> Z, and executes reference / update processing for the data items of the shared data 13 using the common data processing means 15. Further, the application 17 uses the update authority processing means 16 to acquire update authority for any data item of the shared data 13.

  Next, means for referring to and updating the shared data 13 from the own computer and reflecting update difference data from other computers will be described. FIG. 7 is a flowchart showing an example of the processing content of the shared data processing means for referring to and updating the shared data 13 from the application 17 and reflecting the updated differential data from other computers on the shared data 13. Assume that the own computer is the computer 11A. First, it is determined whether the request is from the application 17 of the own computer 11A or the update difference data reflection request from the other computers 11B to 11Z (S701). If the received request is a request from the application 17 of the own computer 11A, it is determined whether the request content is a reference request or an update request (S702). If it is a reference request, reference is made to the shared data 13 (S703), and the reference result is returned to the application 17 (S704).

  If it is determined in step S701 that the request is not from the application 17 of the own computer 11A, the difference data of the update results in the other computers 11B to 11Z is reflected in the shared data 13 (S705).

  If it is determined in step S702 that the request is from the application 17 of the own computer 11A and the request content is an update request, the update authority processing means 16 determines whether the data item updated by the update request has an update authority. Using this, the update authority management data 14 is collated (S706), and it is determined whether or not the user has update authority (S707). If the user does not have update authority, an error is returned to the application 17 (S708). On the other hand, if it is determined in step S707 that the user has update authority, the shared data 13 is updated (S709), and the update difference data is transmitted to the other computers 11B to 11Z (S710).

  Next, means for acquiring and verifying update authority for an arbitrary data item of the shared data 13 will be described. FIG. 8 shows an update authority process for acquiring update authority from the application 17, checking update authority performed when updating shared data from the application 17, and reflecting the update authority acquisition result on the update authority management data 14 in other computers. 10 is a flowchart showing an example of processing contents of means 16.

  First, it is determined whether it is a request from the own computer 11A or a request for reflecting an update authority acquisition result from the other computers 11B to 11Z (S801). Note that the request from the own computer 11 </ b> A is an update request from the application 17 and an update authority collation described in the shared data processing means 15.

  If it is determined in step S801 that the request is from the computer 11A, it is determined whether the received request is a request from the application 17 of the computer 11A (S802). If it is a request from the application 17 of the own computer 11A, the update authority management data 14 is referred to (S803). If it is determined in step S802 that the update authority acquisition request is from the own computer 11A, the update authority management data 14 is collated for the data item requested to be acquired (S804), and the own computer 11A has the update authority. It is determined whether or not it has (S805). If the user has update authority, a completion notice is returned to the application 17 (S806).

  If the own computer 11A does not have update authority, an update authority acquisition request is transmitted to the other computers 11B to 11Z (S807). A notification of transfer of update authority from the other computer 11K having update authority for the requested update authority is received (S808). When a notification of transfer of update authority from the other computer 11K having update authority is received, the update authority management data 14 of the own computer 11A is updated (S809), and the update authority acquisition result is transmitted to the other computers 11B to 11Z. (S810), a completion notice is returned to the application 17 (S811).

  Here, in the own computer 11A, the acquisition request transmitted as the update authority acquisition request from the other computers 11B to 11Z is received and processed in step S801. That is, the own computer 11A that has received the update authority acquisition request determines that it is a request from the other computers 11B to 11Z, not a request from the own computer 11A, based on the determination in step S801 (NO in S801).

  Then, it is determined whether or not the request from the other computers 11B to 11Z is an update authority acquisition result (S812). Since the request is an update authority acquisition request, the process advances to step S813. In step S813, the update authority management data 14 is referred to the data item for which an acquisition request has been made, and further, it is determined whether or not the own computer 11A is a data item having an update authority (S814).

  If the own computer is a data item that does not have the update authority 11A, the process ends. On the other hand, if the own computer 11A is a data item having update authority, the update authority owning computer of the corresponding data item in the update authority management data 14 of the own computer 11A is changed to the requesting computer (S816). ), An update authority transfer notification of the data item is transmitted to the request source computer (S817).

  Here, in the own computer 11A, the update authority transfer notification transmitted from the other computers 11B to 11Z is received in step S808. Further, the acquisition result of the update authority transmitted from the other computers 11B to 11Z is subjected to reception processing in step S801.

  That is, in the own computer 11A, in step S801, in each computer that has received the update authority acquisition result, it is determined that the request is not from the own computer by determining whether or not the request is from the own computer (S801). NO). Then, in step S812, it is determined whether or not it is an update authority acquisition result, and since it is an update authority acquisition result (YES in S812), an update process to the update authority management data 14 (S818) is performed.

  In this way, when the own computer 11A updates the data item having the authority to update the data, confirmation to the other computers 11B to 11Z is unnecessary, so that the responsiveness of the data update is good, and the updated data Since the changed contents are immediately reflected in the other computers 11B to 11Z, the changed data contents can be referred to immediately in the other computers 11B to 11Z. Further, since the computer having update authority can be changed for each data item constituting the database, flexible operation is possible.

Next, another example of the processing content of the shared data processing means in the embodiment of the present invention will be described. FIG. 9 is a flowchart showing another example of the processing content of the shared data processing means in the embodiment of the present invention. For the example shown in FIG.
For updating data items that do not have update authority, a data update request is made to an authorized computer.

  In FIG. 9, as in the example of FIG. 7, it is first determined whether the request is from the application 17 of the own computer 11A or the update difference data reflection request from the other computers 11B to 11Z (S901). If the received request is a request from the application 17 of the own computer 11A, it is determined whether the request content is a reference request or an update request (S902). If the request is a reference request, the shared data 13 is referred to (S903), and the reference result is returned to the application 17 (S904).

  If it is determined in step S901 that the request is not from the application 17 of the own computer 11A, it is determined whether the difference data is an update result in the other computers 11B to 11Z or an update request from the other computers 11B to 11Z. (S905). If the difference data is an update result in the other computers 11B to 11Z, it is reflected in the shared data 13 (S906). On the other hand, when it is not the difference data of the update results in the other computers 11B to 11Z but the update request from the other computers 11B to 11Z, the update processing is performed on the shared data 13 of the own computer 11A (S907). Data is transmitted to the other computers 11B to 11Z (S908).

  If it is determined in step S902 that the request is from the application 17 of the own computer 11A and the request content is an update request, the update authority processing unit 16 determines whether the data item updated by the update request has an update authority. The update authority management data 14 is collated using it (S909), and it is determined whether or not it has the update authority (S910). If the user does not have update authority, an update request is made to the computer having update authority for the data item (S911).

  If it is determined in step S910 that the user has update authority, the shared data 13 is updated (S912), and the update difference data is transmitted to the other computers 11B to 11Z (S913).

  Next, another example of the processing contents of the update authority processing means in the embodiment of the present invention will be described. FIG. 10 is a flowchart showing another example of the processing contents of the update authority processing means 16 in the embodiment of the present invention. The difference from the example shown in FIG. 8 is that the processing (S1007) in the case where the own computer 11A does not have the update authority for the data item requested to acquire the update authority from the application 17 is added. If the computer 11A does not have update authority (NO in S1005), an update authority acquisition request is transmitted only to a computer that has update authority for the data item requested in the update authority management data 14 (S1007). Since the rest is the same, the description is omitted.

  In this way, even in the case of a data item for which the own computer 11A does not have the update authority for data update, by requesting the data update to the computer having the update authority, the data can be updated without changing the update authority. Updates can be made. In addition, by making an update authority acquisition request only to a computer that currently has an update authority for a data item that is subject to change of the update authority, the other computers 11B to 11Z that do not have the update authority. Therefore, it is possible to efficiently acquire the update authority.

  Next, another example of the data management apparatus of the distributed control system according to the embodiment of the present invention will be described. FIG. 11 is a configuration diagram illustrating another example of the data management device of the distributed control system according to the embodiment of the present invention. In another example, in contrast to the example shown in FIG. 1, each of the computers 11A to 11Z has the IP address data 18 storing the IP address of the computer having update authority, and the computer having update authority has failed. In addition, when the IP address of the computer is taken over, a computer address management means 19 for updating the IP address data 18 is added to the IP address data 18. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 11, IP address data 18 is a data file in which the computers 11 </ b> A to 11 </ b> Z are associated with IP addresses and computers used when communicating via the communication network 12, and are stored in a storage device (not shown) of the computers. It is remembered. The IP address data 18 is a tabular data file as shown in FIG. 12, and the IP addresses (192.168.2.1, 192.168.2.2...) Owned by each computer are described. ing. The computer address management means 19 determines whether or not each other's computers are operating via the communication network 12 and updates the IP address data 18.

  Next, the computer address management means 19 will be described. The computer address management means 19 confirms whether the other computers 11B to 11Z are operating, and updates the IP address data 18 when a failure occurs in the other computers 11B to 11Z. FIG. 13 is a flowchart showing the processing contents of the computer address management means 19.

  First, it is determined whether or not the IP address change result has been received from the other computers 11B to 11Z (S1301). If the change result has been received, the IP address data 18 of the own computer 11A is updated (S1302). ).

  On the other hand, when the IP address change result has not been received from the other computers 11B to 11Z, the operation states of the other computers 11B to 11Z are confirmed (S1303). As an operation state confirmation means, for example, a means for confirming packet reachability to a partner computer on the Internet represented by ping (packet internet groper) is used. As a result of checking the operation status, it is determined whether there is a computer that does not respond (S1304). If there is a computer that does not respond, it is determined whether the own computer 11A takes over the IP address. (S1305).

  There is a method of giving a takeover scenario in advance as a method of determining whether or not the own computer 11A takes over the IP address. FIG. 14 is an example of a determination table that defines in advance which own computer will take over the IP address when a failure occurs in the other computers 11B to 11Z.

  In the example of FIG. 14, for example, when a failure occurs in the computer A, the computer B with the takeover order 1 takes over the IP address, and when both the computer A and the computer B fail, the takeover order is 2. This shows a case where the computer C takes over the IP address. Hereinafter, similarly, when a failure occurs in the computer B, the computer A whose takeover order is 1 takes over the IP address, and when both the computer B and the computer A fail, the computer whose takeover order is 2 When C takes over the IP address and a failure occurs in the computer C, the computer A whose takeover order is 1 takes over the IP address, and when both the computer C and the computer A fail, the takeover order is 2. A computer B takes over the IP address.

  It is determined whether or not the own computer 11A takes over the IP address (S1305). When the IP address is taken over, the IP address data 18 is updated (S1306), and the change result is transmitted to the other computers 11B to 11Z ( S1307).

  When it is determined whether or not the own computer 11A has update authority for a certain data item, the IP address described in the update authority management data 14 is described in the IP address data 18 as a search key. The update authority is verified by confirming the computer name of the IP address.

  As described above, when a failure occurs in the computer, it is necessary to change the data item owned by the computer in which the failure has occurred in the update authority management data 14 by changing the computer having the IP address. Therefore, it is possible to immediately change the computer having update authority, and it is possible to shorten the operation switching time when a failure occurs.

  Next, a case will be described in which update authority data is exchanged between computers by using a plurality of files as the update authority management data 14 and switching the pattern file according to the combination.

  FIG. 15 is an explanatory diagram showing another example of update authority management data according to the embodiment of the present invention. As shown in FIG. 15, the update authority management data 14 has two or more update authority patterns for one data item. The update authority management data 14 shown in FIG. 6 is used as the pattern 1 update authority management data 14, and the pattern 2 update authority management data 14 is a data item in which the IP address 192.168.2.1 has the update authority in the pattern 1. For data items for which 192.168.2.4 has update authority and the IP address 192.168.2.4 has update authority, 192.168.2.1 has update authority for data items Management data 14.

  FIG. 16 is a flowchart showing another example of the processing content of the update authority processing means in the embodiment of the present invention. Steps S1601 to S1618 are the same as steps S1001 to S1018 in FIG.

  In step (S1619), it is determined whether or not it is an update authority data pattern switching request, and if it is a request from the application 17 and the request content is an update authority pattern change request (YES in S1619), an update is performed. The pattern of authority data 14 is switched (S1620).

  Pattern switching will be described with reference to FIG. A pattern number is assigned to each pattern of the update authority data 14, and an update authority pattern change request is made from the application 17 together with the pattern number. By storing the pattern number of the change result, it becomes possible to determine the update authority data 14 to be accessed in referring to and updating the update authority data 14.

  Next, the result of the pattern switching of the update authority data 14 is transmitted to the other computers 11B to 11Z (S1621). The information to be transmitted is notified together with the pattern number in the same manner as the request from the application 17. After the transmission to the other computers 11B to 11Z is completed, the application 17 is notified of completion (S1622).

  When the pattern switching of the update authority data 14 is received from the other computers 11B to 11Z (YES in S1623), the pattern is switched for the update authority data 14 of the own computer 11A (S1624).

  As described above, the update authority switching process may be performed by switching the update authority pattern prepared in advance. Therefore, when the update authority pattern can be determined in advance, the update authority can be immediately changed.

DESCRIPTION OF SYMBOLS 11 ... Computer, 12 ... Communication network, 13 ... Shared data, 14 ... Update authority management data, 15 ... Shared data processing means, 16 ... Update authority processing means, 17 ... Application, 18 ... IP address data, 19 ... Computer address management means

Claims (6)

  In a data management apparatus of a distributed control system in which a plurality of computers are connected via a network, each computer has shared data for sharing between computers, and computer information having update authority for each data item of the shared data The update authority management data that records and the data stored in the shared data is returned when the access request to the shared data from the local computer is a reference request, and the updated data contents are updated when the update request is received Update the shared data when authorized, send the difference data of the update result to another computer, and receive the updated difference data from the other computer; If the access request to the update authority management data from the computer is an update authority ownership confirmation request, check with the update authority management data, If the data is a request to acquire a new authority and the computer does not have the update authority, the update authority acquisition request is sent to each computer, and after receiving a response to transfer the update authority, the update authority data contents of the computer are Update, send the update result data to another computer, and when it receives a request to transfer update authority from another computer, update the update authority data of the own computer for data for which the own computer has update authority When the update authority transfer response is transmitted to the request destination computer, and the update authority data content update result data is received from another computer, the update authority processing means for updating the update authority data content of the own computer A data management device for a distributed control system.   2. The data management apparatus for a distributed control system according to claim 1, wherein the update authority processing means makes an update authority acquisition request only to a computer that currently has an update authority.   If the access request to the shared data from the local computer is an update request, the shared data processing means updates the shared data when the local computer has an update authority and transmits the difference data of the update result to the other computer. When the own computer does not have update authority, it sends a request for updating shared data to another computer with update authority, and when it receives an update request for shared data from another computer, 3. The data management apparatus for a distributed control system according to claim 2, wherein the shared data is updated when update difference data is received from another computer.   Each computer has IP address data storing an IP address of a computer having update authority, and the update authority processing means identifies a computer having update authority with reference to the IP address data. The data management apparatus of the distributed control system of any one of Claims 1 thru | or 3.   Each computer has computer address management means for updating the IP address data to the IP address data when taking over the IP address of the computer when a failure occurs in the computer having the update authority, and the update authority processing 5. The data management apparatus for a distributed control system according to claim 4, wherein the means uses the IP address data when the computer determines that the data has update authority.   In the update authority management data, IP addresses of a plurality of computers having an update authority are recorded in advance for each data item of the shared data, and the update authority processing means receives an access request to the update authority management data. If the content is an update authority management data switch request, the update authority management data of the local computer is switched, an update authority management data switch request is sent to each computer, and the update authority management data is transferred from another computer. 6. The data management apparatus for a distributed control system according to claim 1, wherein when the switching request is received, the update authority management data of the own computer is switched.

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