JPH02114337A - Dual computer system - Google Patents

Abstract

PURPOSE:To check the mounting of a different ROM by collating respective check sum values in a dual system by a check sum value collating program stored in a ROM, and when the values are different, setting up a check sum value collated result flag in a RAM and stopping data tracking between com puter systems. CONSTITUTION:The check sum value collating program detects respective check sum values in the dual system, collates both the values by a dual system commu nication equipment 4, and when both the values are different from each other, displays an alarm to an alarm display device 6 and sets up a discrepancy flag in the RAM 2 as a check sum value collated result flag 10. At the time of generating discrepancy in the check sum value collated result, a dual system communication program 8 stops data tracking between respective computer systems A and B, and stops communication between respective systems. Conse quently, the mounting of a different ROM can be checked and the generation of process disturbance can be prevented.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a duplex computer system that controls data tracking between computer systems while checking the program contents of the duplex system.

[Conventional technology]

FIG. 3 is a block connection diagram showing a conventional redundant computer system. In the figure, l represents each computer system A, B.
2 is a random access memory (hereinafter referred to as RAM), and 3 is a read-only memory (hereinafter referred to as R).
(referred to as OM) 4 is a dual system communication device for computer systems A and B, 5 is a checksum value storage area for storing the checksum value of the contents of ROM 3, 6 is an alarm display device, and 7 is a checksum value storage area for checking the checksum value. Checksum check program that checks whether the contents of ROM3 are normal or not, 8 is 2
This is an ffl-based communication program. Next, the operation will be explained. First, the checksum value storage area 5 of the ROM3 stores a pre-calculated checksum value of the contents of the ROM3, and the checksum check program 7 calculates the result of adding up all the contents of the ROM3 and the above-mentioned pre-calculated checksum value. By comparing the calculated checksum value, it is checked whether the contents of the ROM 3 are normal or not, that is, whether or not they have been destroyed. Also, 2
The duplex communication program 8 uses the duplex communication device 4 to perform data tracking between computer systems in which process control data is converted into 2FFI, and prevents process disturbance from occurring when switching the duplex system.

[Problem to be solved by the invention]

Since the conventional redundant computer system is configured as described above, not only is there no way to check when different ROMs 3 are installed in each computer system A and B, but also there is no way to check the data tracking between each computer system A and B. Even when this method is used to prevent process disturbances from occurring when dual system switching occurs, there is a problem in that tracking data mismatch may conversely cause process disturbances. Incidentally, as an approximation technique, there is one described in Japanese Patent Laid-Open No. 56-68843. This invention was made to solve the above-mentioned problems by detecting discrepancies in ROM contents between dual computer systems and stopping data tracking between each computer system when this discrepancy occurs. The object of the present invention is to obtain a redundant computer system that can prevent process disturbances from occurring.

[Means to solve the problem]

The duplex computer system according to the present invention is provided with a checksum value verification program in the read-only memory of each computer system in the duplex system, thereby collating each checksum value in the duplex system, and randomizing when there is a mismatch. A checksum value verification result flag is set in the access memory to stop data tracking.

[For use]

The checksum value matching program in this invention detects whether or not the checksum values of each computer system in the dual system match, and when there is a mismatch, stops data tracking between the computer systems to prevent process disturbances from occurring. Acts to prevent.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. In Figure 1, 9 is a checksum (1α verification program) that verifies the double system checksum value using a dual system communication device, and is provided in ROM3. This is a sum value verification result flag.Next, the operation will be explained with reference to the flowchart in Fig. 2.First, the checksum value storage area 5 of the ROM 3 stores a checksum value calculated in advance. This checksum value can be calculated in advance at the time of burning the ROM and burned into the ROMa, or
The contents of M3 are calculated by the checksum check program 7 at the initial time and generated on the RAM 2. In addition, the checksum value verification program first detects each checksum value of the duplex system (Step 5TI), and verifies it using the dual system communication device 4 (Step 5T2). As a result of this verification, each checksum value does not match. When , alarm display device 6
(Step 5T3) and RAM2
sets a discrepancy flag as the checksum value verification result flag lO (step 5T4), whereby the duplex communication program 8 performs data tracking between each computer system A and B when the checksum value verification result does not match. and stop communication between each system (step 5T5
). On the other hand, if the entire area of ROM 3 is divided into multiple areas and the checksum value for each divided area is registered in the checksum value storage area 5, the checksum value verification program 9 will check each area. Sam match,
By setting the checksum value verification result flag lO for each of the above areas, the 2fi system communication program 8
Accordingly, it is possible to execute/stop a specific area of data tracking for each area, and thereby, when a specific program does not match, it is possible to execute/stop only the data tracking related to that program. Note that in the above embodiment, ROM3 and RAM are used as storage devices.
2 is shown, however, a magnetic disk, magnetic tape, magnetic valve memory, floppy disk, etc. may also be used. Further, in the above embodiment, a case has been described in which various programs are provided on the ROMa, but the programs may be provided on the RAM 2, and the same effects as in the above embodiment can be obtained.

【Effect of the invention】

As described above, according to the present invention, each checksum value of the double system is verified by a checksum value verification program provided in the ROM, and when there is a discrepancy, a checksum value verification result flag is set in the RAM, and the computer system Since the configuration is configured to stop data tracking in between, it is possible to check whether a different ROM is installed in the computer system, and to prevent unnecessary process disturbances when switching between dual systems. There are benefits to be gained.

[Brief explanation of the drawing]

Fig. 1 is a block connection diagram showing a redundant computer system according to an embodiment of the present invention, Fig. 2 is a flowchart showing the procedure for process disturbance prevention processing in this invention, and Fig. 3 is a conventional duplex computer system. It is a block connection diagram showing a computer system. 1 is a calculation unit, 2 is random access memory (RAM)
, 3 is a read-only memory (ROM), 4 is a duplex communication device, 5 is a checksum value storage area, 7 is a checksum check program, 8 is a duplex communication program,
9 is a checksum value verification program, and 10 is a checksum value verification result flag. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 1 10:%-t')%iiIIL9j%i陀%-)”
77-1, Indication of the case, Patent Application No. 63-267053, 2, Name of the invention Duplicate computer system 3, Representative 6 of the person making the amendment, Contents of the amendment (1) In the second line of page 6 of the specification The phrase "first detect the checksum value" should be corrected to "first calculate the checksum value". (2) "By program" on page 7, line 16 of the specification
Correct the statement to "by program." (3) Correct Figure 2 as shown in the attached sheet. 7. Document containing Figure 2 after the revised catalog of attached documents l Continuous kite top

Claims (1)

[Claims] A checksum value storage area that stores a pre-calculated checksum value of the contents of the read-only memory is compared with the result of adding all the contents of the read-only memory and the checksum value. a checksum check program for checking the contents of the read-only memory; and a checksum check program provided in the read-only memory for performing data tracking between dual computer systems using a dual system communication device. In a redundant computer system comprising a redundant communication program and an arithmetic unit that processes data of each of the computer systems, each check of the redundant system is stored in the read-only memory of each of the redundant computer systems. A redundant computer system comprising a checksum value verification program that verifies sum values and stops the data tracking when there is a discrepancy.