JPH04359187A - Computer clock system - Google Patents

Abstract

PURPOSE:To automatically set the time of a common clock to a computer inner clock while confirming the healthiness of the common clock by judging the common clock normal when the time difference between the common clock and computer inner clock is within a specified value. CONSTITUTION:A time comparison section 6 reading the time of a common clock 2 and the computer inner clock 3 of a computer 1(1) respectively calculates the time difference and stores 5 it as epsilon1. A common clock healthiness confirmation section 7 judges whether the read time difference epsilon1 is within a specified value epsilon or not, judges the clock 2 normal if epsilon1 is within the specified value epsilon, and outputs a correction instruction to a computer inner clock time setting section 4. The setting section 4 sets the time of the clock 2 to that of the clock 3 according to the instruction. The time of the clock 2 or clock 3 is judged abnormal if epsilon1 is not within the specified value epsilon, and the time difference epsilon2 between a computer 1(2) and the clock 2 is calculated like for the computer 1(l). The clock 2 is judged normal if epsilon2 is within the specified value epsilon, and the time is set to the clock 3. The clock is judged abnormal if epsilon2 is not within the specified value epsilon, and the time is not set. The computer 1(2) is likewise processed.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer clock system for adjusting the time of computers in a complex computer system.

0002

2. Description of the Related Art Generally, in a complex computer system, each computer is equipped with an internal clock, and each computer operates with the time of its own internal clock as positive. in this case,
A common clock that can be read from a plurality of computers is installed to synchronize the internal clocks of each computer, and the time of the common clock is set to the internal clock of each computer at the request of an operator.

FIG. 3 shows a computer clock system in a conventional complex computer system.

[0004] This computer clock system has a computer 1 (1
) and the computer 1 (2) are connected to a common clock 2. Each computer 1 includes a computer internal clock 3 and a computer internal clock time setting section 4.

When the operator inputs a time adjustment command to the computer 1 ( 1 ), the computer internal clock time setting section 4 reads the time from the common clock 2 and sets the time in the computer internal clock 3 . Furthermore, in the same way, regarding the computer 1 (2), the computer internal clock time setting section 4 sets the time in the computer internal clock 3 from the common clock 2 in response to the input of the operator's time adjustment command. In this way, in a composite computer system, similar processing is performed on each computer to make the time on the internal clocks of all the computers coincide with the time on the common clock.

[0006]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional system, in order to manually input a time adjustment command when the operator notices it, the internal clocks of the computers 1 (1) and 1 (2) are There may be a time difference of 3.

[0007] If a time lag occurs in the computer internal clock 3 of each computer 1, the relationship between the time and plant data in the output of each computer 1 will deviate in a process where the values of plant data etc. change moment by moment, and the consistency of the data will be affected. There is a problem in that it is not possible to obtain the required data, and the reliability of the data further deteriorates.

In this case, it is possible to automatically set the time of the common clock 2 to the computer's internal clock 3 on a regular basis to eliminate the above-mentioned time deviation. However, if the time on the common clock 2 was incorrect, the time on all computers would be incorrect, so this could not be carried out.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a computer clock system that automatically sets the time of a common clock in a computer's internal clock periodically while checking the soundness of the common clock. [Structure of the invention]

0010

[Means for Solving the Problems] The present invention provides a plurality of computers, a common clock for setting the internal clocks of each of the plurality of computers to the same time, and a time adjustment command for each of the computers to adjust the time to the same time. Read the time of the common clock,
and a computer clock system having a computer internal clock time setting unit for setting the time of the common clock in the computer internal clock, which periodically reads out the time of the common clock and the time of each of the computer internal clocks. a time comparison unit provided in each of the computers that calculates the time difference between both times; a storage device that stores each of the time differences calculated by these time comparison units; The time difference and a specified value stored in advance in the storage device are periodically read and compared in sequence, and when any of the time differences is within the specified value, a time correction command is output to the computer internal clock time setting section. A common clock health confirmation section provided in each of the computers is provided.

[0011]

[Operation] With the above configuration, the common clock health confirmation unit determines that the common clock time is normal when any of the time differences between the common clock time and the computer internal clock is within the specified value stored in advance in the storage device. It is determined that The computer internal clock time setting section reads out the time of the common clock according to the time adjustment command, and sets this time in the computer internal clock. Thereby, each computer internal clock of the plurality of computer systems is synchronized with the time of the common clock, and the times of all the computer internal clocks can be made to match.

0012

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a computer clock system showing one embodiment of the present invention. In the figure, the same reference numerals as in FIG. 3 indicate the same or corresponding parts. The difference from Figure 3 is that
The computer 1 is provided with a storage device 5 and is connected to the computers 1 (1) and 1 (2), while each computer 1 is provided with a time comparison section 6 and a common clock health confirmation section 7.

The storage device 5 writes the time difference between the common clock 2 and the computer internal clock 3 and a predetermined specified value.

The time comparator 6 calculates the time difference between the time of the common clock 2 and the time of the computer internal clock 3, and writes the time difference to the storage device 5.

The common clock health checking unit 7 determines whether the time difference written in the storage device 5 is within a specified value,
If it is within the specified value, the common clock 2 is considered normal and the computer internal clock time setting section 4 outputs a time correction command.

Next, the operation will be explained along the processing procedure shown in FIG.

First, it is assumed that processing is performed on computer 1 (1). First, the time comparator 6 reads the time of the common clock 2 (101). Subsequently, the time comparator 6 reads the time of the computer internal clock 3 (102). Further, the time comparator 6 calculates the difference between the time of the common clock 2 read by the time comparator 6 and the time of the computer internal clock 3, and writes the time difference as ε1 to the shared memory of the storage device 5 (1
03).

The common clock health checking unit 7 reads out the time difference ε1 calculated by the time comparison unit 6 and written into the storage device 5, and determines whether the time difference ε1 is within the specified value ε (10
4).

That is, it is determined whether the following conditional expression (1) holds.

[0021]

[Math 1] ε1<(|α1|+|α2|)×T=ε……(1)

0
[022] Here, α1: Accuracy of the common clock 2 α2: Accuracy of the computer internal clock 3 T: Period of time adjustment

If the above conditional expression (1) is satisfied, the common clock 2 is considered to be normal and the common clock health check section 7 outputs a time adjustment command to the computer internal clock time setting section 4. The computer internal clock time setting section 4 reads the time from the common clock 2 according to the time correction command and sets it in the computer internal clock 3 (105) (106).

On the other hand, if the above conditional expression (1) is not satisfied, the time of the common clock 2 or the computer internal clock 3 of the computer 1 (1) is determined to be abnormal and the following processing is performed.

First, regarding the next computer 1 (2), the difference between the time of the common clock 2 and the time of the computer internal clock 3 of the computer 1 (2), which has been processed in the same manner as the above computer 1 (1), that is, the memory The common clock health confirmation unit 7 of the computer 1 (1) reads out the time difference ε2 written in the device 5 (107
). Next, the common clock health check unit 7 of the computer 1 (1) determines whether the following conditional expression (2) is satisfied (108).

[0026]

[Math 2] ε2<ε...(2)

If the condition of the above equation (2) is satisfied in this judgment, the common clock health check section 7 of the computer 1 (1) outputs a time adjustment command to the computer internal clock time setting section 4. As a result, the computer internal clock time setting unit 4 reads the time of the common clock 2 (105). Then, the time of the common clock 2 is set in the computer internal clock 3 of the computer 1 (1) (10
6).

Regarding the computer 1 (2), the computer internal clock time setting section 4 reads the time of the common clock 2 through the same process. Then, the time of the common clock 2 is set in the computer internal clock 3 of the computer 1 (2). The above processing is repeatedly performed at regular intervals. Further, if the above conditional expression (2) is not satisfied, the common clock 2 is considered to be abnormal and does not set the time. In such a case, for example, a warning is output.

The specified value ε for determining the health of the common clock 2 is calculated in advance and written in the shared memory of the storage device 5.

[0030] In this way, it is possible to synchronize the times of two computer clock systems by adjusting the time of the computer internal clock to the common clock while checking the soundness of the common clock without requiring any operation by an operator. .

[0031] In the above embodiment, a computer clock system having a configuration of two computers was explained. However, even if the number of computers increases, it is possible to increase the number of computers for comparing time differences and to check whether one of them is normal. For example, it is possible to perform time adjustment assuming that the common clock is normal so that the times of each computer in the complex computer system match.

[0032]

[Effects of the Invention] As explained above, according to this embodiment,
The time of the computer's internal clock can be adjusted to the common clock while checking the health of the common clock. Therefore, the time difference between each computer in the composite computer system can be corrected accurately.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a computer clock system showing one embodiment of the present invention.

FIG. 2 is a flowchart showing the processing procedure of the device.

FIG. 3 is a block configuration diagram of a computer clock system showing a conventional example.

[Explanation of symbols]

1(1), 1(2) Calculator 2 Common clock 3. Computer internal clock 4. Computer internal clock time setting section 5. Storage device 6 Time comparison section 7 Common clock health confirmation section

Claims (1)

[Claims] 1. A plurality of computers, a common clock for setting the internal clocks of each of the plurality of computers to the same time, and a time correction command for each of the computers to read the time of the common clock, and , in a computer clock system having a computer internal clock time setting unit for setting the time of the common clock in the computer internal clock, periodically reading out the time of the common clock and the time of each of the computer internal clocks; a time comparison unit provided in each of the computers that calculates a time difference; a storage device that stores each of the time differences calculated by these time comparison units; and each of the times stored in this storage device. The difference and a specified value stored in advance in the storage device are periodically read out and compared in sequence, and when any of the time differences is within the specified value, a time correction command is output to the computer internal clock time setting section. A computer clock system comprising: a common clock health confirmation section provided in each of the computers.