JPS6272038A - Testing method for program runaway detecting device - Google Patents

Abstract

PURPOSE:To test a watch dog timer itself without exerting any influence upon other parts by inputting a signal which is generated when the watch dot timer detects a runaway of a program to a computer through the switching of a switching device and confirming whether there is the input signal from the watch dot timer during the test. CONSTITUTION:When the watch dot timer WDT2 is normal, the runaway of the program is detected at latest 2 seconds after WDT in-test information is set and a WDT output signal 6 is inputted to the computer 1 through a signals input device 10. A WDT test program 8 checkes whether or not the WDT output signal 6 is inputted from a signal input device 10 after the delay and when the signal is inputted, the program decides that the WDT is normal, resets the WDT in-test information, and outputs a restart command to the WDT and a switching command to the switching device 9 through a switching command output device 11 to reset the switching state of the WDT output signal 6 to the state before the test, thereby performing delay operation until next execution. If the WDT 2 is abnormal, the WDT output signal 6 is not inputted after the delay, so the abnormality of the WDT is detected as a result.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a test method for a program runaway detection device, and particularly to a test method for a watchdog timer.

[Technical background of the invention]

A watchdog timer (VDT) is a device that monitors whether the software is operating normally.When the software is operating normally, the watchdog timer (VDT)
A restart signal is supplied, and when the software malfunctions such as runaway, the signal supply stops and an alarm is issued. Normally, a program periodically executes a command to output a restart signal. to confirm that the software is working properly.

FIG. 5 shows an example of the configuration of a conventional dual computer system.

Conventionally, the WDT restart grograms 7 and 7' of each computer 1 and 1' output a restart signal to the M)Ts 2 and 2' at regular intervals, and when this restart signal is no longer output, the WDT 2 and 7'2' outputs all signals 6 and 6' (hereinafter referred to as WDT output signals) which detect program runaway. The signals 6 and 6' are the automatic restart devices 4 and 4.
', and the computer was automatically restarted; it was passed to the computer status display 3, which notified the operator of the abnormality with a bell or lamp; and it was passed to the computer status input devices 5' and 5 of other systems. The data is then backed up by other computers.

That is, the VDT plays an important role in monitoring and controlling the operating conditions of the computer.

[Problems with background technology]

As mentioned above, although the VDT plays an important role, there has been no check to see if the WDT itself is normal. In order to test VDT,
■It is necessary to have T output a program runaway detection signal, and as a result, the operator is notified of a computer abnormality, the computer is automatically restarted, and in a compound computer system, backup by another computer is required. This is because the operating width calculator will be greatly affected.

Therefore, if the WDT itself becomes abnormal, there is a problem in that even if a program runaway occurs, it cannot be detected. Furthermore, in compound computer systems, even if a program runs out of control, it cannot be detected and backup cannot be performed, which prevents the advantages of compound computers from being utilized.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and its main object is to provide a test method for a program runaway detection device that can test the WDT itself without affecting the operating state of the computer.

[Summary of the invention]

In the present invention, the signal generated when the watchdog timer detects program runaway is switched by the switching device and inputted to the computer, and the presence or absence of the input signal from the watchdog timer during the test is confirmed. This allows tests to be carried out without affecting others.

[Embodiments of the invention]

Examples will be described below with reference to the drawings. FIG. M1 is a block diagram of an embodiment for explaining a test method for a program runaway detection device according to the present invention. First, an embodiment in a single computer system will be explained.

In FIG. 1, the symbols in the figure correspond to those in FIG. 8
9 is a WDT test program, 9 is a switching device, 10 is a signal input device, and 11 is a switching command output device. As the signal input device 10, for example, a digital input device of a process input/output device may be used, and as the switching command output device 11, a relay output device may be used.

FIG. 2 is a flowchart showing the operation of the WDT restart program, and FIG. 3 is a flowchart showing the operation of the VDT test program.

For convenience of explanation, we will assume that the time it takes for the WDT to detect a runaway program, that is, the time it takes for the M)T to receive a restart command, start counting the timer, and determine that the program is running out of control is 2 seconds. .

Furthermore, the execution cycle of WDT restart program 7 is 0,
The execution period of the WDT test program is 60 seconds. Of course, these times can be arbitrarily set with consistency.

First, the operation when the M)T test is not in progress (during normal operation) will be explained. Note that when the WDT is not being tested, it means that in FIG. M) refers to a state in which only the T restart program 7 is in the execution cycle.

Here, the WDT restart program a is executed every 0.1 seconds to determine whether or not the WDT test is in progress, and since the test is not in progress,
Output a restart command to the VDT and repeat the delayed operation until the next execution (Fig. 2, steps 21, 22.2)
3).

Therefore, when there is no program runaway, WDT 2
will repeat the count of 0.1 seconds from O. In addition, when a program runaway occurs, the M)T restart program 7 cannot be executed, so the program runaway is detected after 2 seconds, and the M)T output signal 6 is transmitted to the computer status display 3 or the automatic restart device 4. A warning is issued to the operator and an automatic restart is performed.

Next, the operation during the VDT test will be explained.

The WDT test program runs every minute (60 seconds),
First, a switching command is output to the switching device fIt9 via the switching command output device 11 (step 31 in FIG. 3). As a result, the 9 VDT output signal is not passed to the computer status display 3 or the automatic restart device 4, but to the signal input device 10. Next, the VDT test information is set and delayed for a certain period of time (Step 32 and 33 in Figure 3), where M) T2 is the time at which program runaway is detected.
It may be longer than seconds, for example about 3 seconds. In this case, the 1-T restart program 7 does not output the WDT restart command because the WDT test information is set (step 21.23 in FIG. 2). Therefore, if M)T2 is normal, runaway of the program will be detected at the latest two seconds after the VDT test information is set, and the WDT output signal 6 will be input to the computer IK via the signal input device IO. M) T test program 8 is the VDT after delay.
It is checked whether the output signal 6 can be inputted from the signal input device 10, and if it can be inputted, it is determined that the WDT is normal, and the WDT
Reset the information during the test, M) Output a restart command to T, output a switching command to the switching device 9 via the switching command output device 11, and return the switching state of the M) T output signal 6 to the state before the test. , will be delayed until the next execution (Step 3 in Figure 3)
4゜35.36.37.38).

If M)T2 is abnormal, since there is no input of the WDT output signal 6 after the delay, the VDT abnormality is detected based on this and the operation is notified (steps 34 and 39 in FIG. 3).

FIG. 4 shows another embodiment of the present invention, which is a block diagram of a dual computer system. In the dual computer system configuration of this embodiment, the WDT output signals 6 and 6' are passed to the fine needle calculator status input devices 5' and 5 for backup of the fine needle calculator. The other configurations are the same as those in FIG. 1. Further, the operations of the WDT restart programs 7 and 7' and the WDT test programs 8 and 8' are the same as those in the above-described embodiment and are shown in FIGS. 2 and 3, and therefore will not be described here.

〔Effect of the invention〕

As explained above, according to the present invention, the watchdog timer, which detects program runaway, is tested by switching the switching circuit. I was able to conduct my own tests, and when a runaway program occurred due to an abnormality in the watchdog timer, I was unable to notify the operator of the abnormality, I was unable to perform an automatic restart, and the combined THE machine system In this case, it is possible to solve problems such as the inability to perform backup using a thin needle calculator, and improve the reliability of the system.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the test method for a program runaway detection device according to the present invention, FIG. 2 is a flowchart showing the operation of the watchdog timer restart program, and FIG. 3 is a flowchart showing the operation of the watchdog timer restart program. FIG. 4 is a flowchart showing the operation of the test program, FIG. 4 is a configuration diagram of a dual system computer system as another embodiment, and FIG. 5 is a configuration diagram of a conventional computer system. 1.1'...Calculator 2.2'...Watchdog timer 3...Computer status display 4,4'...Automatic restart device 5.5'...Fine needle calculator status input Device 6.6'... Watchdog timer output signal 7.7'
...Watchdog timer restart program 8.8'...Watchdog timer meeting test program 9.9'...Switching device fl 10.10'...
Signal input device 11.11'...Switching command output device Patent Σ1 person Toshiba Corporation Representative Patent attorney Norio Ishii Figure 2 Figure 4

Claims (1)

[Claims] A computer that is equipped with a watchdog timer as a program runaway detection device, and uses a signal from which the watchdog timer detects a program runaway to notify other computers or operators of a computer abnormality, thereby automatically restarting or maintaining the computer. The system is characterized in that a signal detected by a watchdog timer to detect program runaway is inputted to a computer by being switched by a switching circuit, and the watchdog timer itself is tested by detecting the presence or absence of the input signal. A test method for a program runaway detection device.