JPS63118860A - Back-up method for decentralized system - Google Patents

Abstract

PURPOSE:To immediately and automatically back up the breakdown of one processor by dividing terminals into groups together with addition of logical terminal numbers and providing a back-up data acquiring module to each data processor for each group. CONSTITUTION:An inter-data processor table 54 is stored in each data processor constituting a network so that any data processor can support the function of another data processor within the network. In the case of a data processor 20B, for example, the logical terminal numbers 301-303 are prepared for a processor number 20B. In the same way, the logical terminal numbers 304 and 305 are prepared for a data processor 20C. For instance, the terminal 301 or 302 is used when the processor 20B backs up the terminal 304 or 605 connected to the processor 20C having breakdown in terms of a table 54B corresponding to the processor 20B.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for backing up a distributed system using a network, and in particular, when the system has a redundant system, automatic backup is performed with high reliability using broadcast communication, and the system This invention relates to a backup method for a distributed system that can easily handle modifications.

[Conventional technology]

In recent years, with the development of microcomputers and local area networks, distributed data processing systems using microcomputers have become mainstream for equipment control.1 Distributed data processing systems are characterized by flexibility in system construction and low cost of the system. However, since the system is distributed, it is necessary to improve data continuity and system reliability.

To solve these problems, there is a system that duplicates the important processing devices in the system configuration and matches the data between the Tii processing devices (Special Publication No. 81-18786゜Special Publication No. 6).
1-19060), which realizes data continuity on the transmission path (see Hitachi internal G P2O-160014)
There is.

[Problem that the invention seeks to solve]

FIG. 7A shows a system in which a network having a broadcast communication function is used as the transmission line 10, and the transmission line 10 is connected to data processing apparatuses 20B and 20G as well as data processing apparatuses 20Az and 20Az having a dual system configuration. . Here, for example, if data Dz is sent from the data processing device 20B, and the data processing device! ! 20
When data D2 is sent from A1, the data is guaranteed and the data is also passed to terminal 401. However, when several dozen terminals 401 to 40n are connected to the network, from the viewpoint of terminal responsiveness, these terminals are connected to the data processing devices 20B to 2oz as shown in FIG. 7B, and the data processing devices are The load can be reduced. However, with this configuration, the data processing device! 20B is data D3
If the data processing device 20B goes down after receiving the data D8, there is a problem that the data D8 is lost and cannot be reproduced because the data processing device 20B is not duplicated. Furthermore, in distributed network processing systems, (1) it is possible to create software that is not aware of the physical location and status of terminals;
(2) There is a need to be able to flexibly respond to gradual construction and modification of the system, but conventional technology has not been able to meet these requirements.

An object of the present invention was to solve the problems of the prior art described above, and it is possible to immediately and automatically back up the functions of one processing device even if it goes down, and moreover, To provide a backup method for a distributed system that does not require awareness of the physical location of terminals and can flexibly respond to changes in the system.

[Means for solving problems]

The purpose of the above is to divide terminals into functional groups and give them logical terminal numbers, to have each data processing device have a backup data acquisition module for each functional group, and to use this functional module to back up data when broadcast communication is performed. This is achieved by acquiring data and, when an abnormality is detected in any data processing device, backing up the data and outputting it to a terminal that is not connected to another data processing device and has the same function.

[Effect]

A functional group of terminals is composed of one or more physical terminals connected to the same data processing device, and has a logical terminal number unique to the group (only one throughout the entire distributed network). If the application software specifies this logical terminal number according to the required function and the processing device assigns it to the actual terminal, the software does not need to be aware of the state of the physical terminal.

Furthermore, the backup data acquisition module is a function that realizes automatic backup of terminals within the same data processing device and automatic backup of data between other data processing devices, and is a function that realizes automatic backup of terminals within the same data processing device and automatic backup of data between other data processing devices. It is also a function that can support missing functions as automatic backup processing.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 2 shows an example of a distributed network to which the method of the present invention is applied, in which terminals are connected to each of the data processing devices 20B to 20Z, and these terminals have the same function (
301, 302, . . . , 30n are assigned to the groups surrounded by dotted lines. 40ia, 40i for terminals in each group 30i
b, -...

The physical terminal number is assigned as follows.

FIG. 1 is a diagram showing the software configuration 50 of the above-mentioned 2nd@I data processing device 20B, and the other data processing devices have the same configuration. Inside the software 50, a backup data acquisition module 55. A terminal function type table 52 that defines the correspondence between the logical terminal number and physical terminal number and the function pattern of the terminal displaying the data 51. Inter-data processing device table 54. Terminal backup table 5
3. Other software module groups 56 (this part is unrelated to the present invention) are included.

FIG. 3 shows a detailed example of the function type table 52, which is a definition table that facilitates system modification in accordance with the terminal status and increase/decrease in the number of terminals using application software. Application linkage is logical terminal number 301-30
3, and depending on the contents of the data 51, this table 52
Data output terminals can be determined by function types corresponding to the physical terminal numbers 401a to 403a with reference to . In other words, by grouping based on the functional classification of the terminal or the unit related to the arrangement of the terminal, without being aware of the physical terminal,
Data can be logically output to the terminal.

FIG. 4 is a flowchart of the processing of the backup data acquisition module 55. In step 100, the logical terminal number and function type in the data are taken in, and the corresponding physical terminal number is determined by referring to the table 52. In step 102, it is checked whether the terminal just determined is normal or not. If it is normal, data is output in step 103. If it is not normal, the terminal function type table 52 is referred to again in step 104, and the terminal has the corresponding function. Decide on another device,
In step 105, data is output to the terminal. With such a mechanism, even when the number of physical terminals increases or decreases, it can be handled simply by modifying the terminal function type table 52, and there is no need to modify the application software of a single distributed network system, making it possible to respond flexibly.

FIG. 5 shows the contents of the inter-data processing device table 54.
This table is stored in all data processing devices that make up the network, and is used to enable any data processing device in the network to support the functions of other data processing devices. Data processing device 20B
In this case, there are three logical terminal numbers 301 to 303 corresponding to the own processing device number 20B, and similarly, the data processing device 20G
In the case of , there are two logical terminal numbers 304 and 305, etc.
For example, the table 54B corresponding to the data processing device 20B indicates that when the data processing device 20B backs up the terminal 304 or 305 connected to the data processing device 20G when it goes down, 3
01 or 302. table 54
Other entries in B and other tables 54D, 542
etc. have the same meaning.

FIG. 6 is a flowchart of the backup process in the functional module 55, starting with steps 110 and 111.
In step 112, the data processing device number and the logical number of the terminal connected to the device are taken in, and then in step 112, the inter-data processing device table 54 is referred to based on the number of the data processing device to be backed up and the device number. , determine the logical number of the terminal to use for backup. As a result, even when the non-redundant data processing devices 20B to 20Z go down, backup can be performed by other devices. Even during the gradual construction of a zero-distributed network system, backup can be made to unset data processing devices.

〔Effect of the invention〕

According to the present invention, in a single distributed network processing system, there is an effect that automatic backup is possible when a data processing device goes down, it is also possible to easily cope with the gradual construction of a network system, and furthermore, the application software side This also has the effect of eliminating the need to be aware of the physical location and status of the device.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the software configuration of a data processing device for implementing the method of the present invention, Fig. 2 is a diagram showing an example of a distributed network to which the present invention is applied, and Fig. 3 is an example of a function type table. FIG. 4 is a flowchart of the function type processing section of the backup data acquisition function module,
FIG. 5 is a diagram showing an example of a table between data processing devices, and FIG.
Figures 7A and 7B are flowcharts of the logical terminal number acquisition processing section of the backup data acquisition function module.
The figure shows a conventional distributed network. 10... Transmission line, 20A-2oz... Data processing device, 301-30n... Logical terminal number, 401a-4
0nm...Physical terminal number, 51...Data, 52.
. . . Terminal function type table, 54 . . . Table between data processing devices, 55 . . . Backup data acquisition function module.

Claims (1)

[Claims] 1. A transmission path with a broadcast communication function, a plurality of data processing devices connected to the transmission path and exchanging data through broadcast communication, and a device connected to each data processing device and assigned a unique physical number. In a backup method for a distributed system consisting of a group of terminals, the group of terminals connected to each data processing device is divided into groups according to their functions, a logical number is assigned to each group, and each terminal connected to the own device is A first table showing the correspondence between the function and physical number of the terminal and the logical number assigned to the group to which the terminal belongs, and a terminal connected to any one data processing device to any other data processing device. Each data processing device is provided with a second table that indicates the correspondence between the backed-up terminal and the backup terminal when the data processing device is backed up by a terminal connected to the own device, using respective logical numbers. If a data processing device that should receive the transmitted data is abnormal or is not connected, one of the other data processing devices refers to the second table and updates its own data. When it is determined which terminal group with a logical number should be backed up, and the determined logical number and the function of the terminal to which the received data at that time should be given are specified, or by broadcasting from another data processing device to the own device. When the logical number of the terminal to be used and the function of the terminal to which the received data should be given are specified by the sent data, the terminal with the physical number to be used is determined by referring to the first table above. A method for backing up a distributed system, characterized in that the received data is output to the terminal.