JPH0580940A - Dual system for auxiliary storage device - Google Patents

Abstract

PURPOSE:To maintain the system on an on-line basis. CONSTITUTION:This dual system consists of a control bus 11 and a control bus 12, and a controller 18 and a controller 19 of two systems, a device 13, a device 14, and a device 15 for connecting a fixed disk 16, a fixed disk 17, and a backup cassette M/T device to those buses, a bus control circuit and a bus switching circuit for setting which of the control bus 11 and control bus 12 those buses are connected to, an arithmetic part which processes data, and an input/output device which outputs the data processed by the arithmetic part to a plant or inputs data from the plant to the arithmetic part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a computer having two systems of controllers and a control bus controlled by the controllers, and having a program for executing processing independently of each other. The present invention relates to an auxiliary storage dual system in the system.

[0002]

2. Description of the Related Art In a monitoring device for monitoring and controlling an industrial plant or the like, it is required that a real-time process be executed at high speed and that the system be highly reliable.

FIG. 2 is a schematic block diagram of an example of a conventional monitoring device.

Reference numeral 1 denotes a plant which is monitored and controlled by a monitoring device, and 3 denotes a processing device which processes data for controlling the plant 1 via an input / output device 2. Programs and data for performing arithmetic processing at this time are mainly stored in the fixed disk 1 and the fixed disk 2. The fixed disk 1 and the fixed disk 2 are
Only the information to recognize each other's devices is different,
Everything else is the same, which makes up a dual system.

In the conventional monitoring device, when the data from the plant 1 is arithmetically processed and written to the fixed disk 1 and the fixed disk 2, the data is taken into the arithmetic unit 4 in the processing device 3 via the input / output device 2. , Executes arithmetic processing, and through the controller 5 and the control bus 7,
The same data is written on each of the fixed disk 1 and the fixed disk 2.

At this time, if a writing error occurs in the fixed disk 1, the processing device 3 recognizes that the fixed disk 1 is abnormal in the arithmetic unit 4 via the control bus 7 and the controller 5. And fixed disk 1
Is separated from the system, the process is switched to the fixed disk 2, and the operation of the monitoring device is continued by the auxiliary storage device single system.

The fixed disk 1 which has become abnormal as described above is replaced by stopping the monitoring device. At this time, in order to make the auxiliary storage device dual system, the system program and data are transferred to the replaced fixed disk. Although it is downloaded from the backup cassette M / T device 8, there is a problem that the control bus 7 is occupied during the execution of this process, and the monitoring device must be stopped for a long time.

[0008]

The above-mentioned conventional techniques have the following problems.

In order to replace an abnormal fixed disk and operate it as an auxiliary storage dual system, a system bus and a system program and data for the replaced fixed disk are transferred from the backup cassette M / T unit 8 to the control bus. 7 must be occupied and downloaded, the fixed disk cannot be accessed during this process, and the monitoring device must be stopped for a long time.

The present invention is a backup cassette M / T.
The purpose is to shorten the occupied time of the control bus 7 when executing non-steady-state processing such as downloading from the device 8 to a fixed disk, and to achieve high speed of the system.

[0011]

In the present invention, in order to separately and independently process the above-described steady processing and non-steady processing, a controller and a control bus for connecting a fixed disk and a processing device have been conventionally used. The system that was once the system is provided in two systems, and each system is made to carry out the steady process and the non-steady process.

Further, in order to reduce the occupied time of the control bus in the unsteady processing, one of the above-mentioned two control buses is used. Also, in order to reduce the load on the processing device due to non-steady-state processing, the execution priority of the program that executes non-steady-state processing is set lower than the execution priority of the program that executes non-steady-state processing. The non-steady-state process is executed by utilizing the idle time of the processing device due to the access of the device or the like.

[0013]

In the present invention, since the two systems of the controller and the control bus connecting the fixed disk and the processing device separately execute the steady process and the unsteady process in the monitoring device, respectively, the unsteady process is being executed. However, since the steady process can be executed by the other control bus, by setting the execution priority of the program that executes the non-steady process lower than the execution priority of the program that executes the steady process. The load can be reduced by the non-steady-state processing in the processing device. Also, by making the program that executes the non-steady-state processing resident in the controller on the fixed disk as firmware, the processing device activates the firmware, and the processing device determines the subsequent processing based on the processing result of the firmware and continues. By doing so, it is possible to reduce the load due to the unsteady processing in the processing device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a schematic block diagram of an auxiliary storage device dual system in a monitoring device for controlling and monitoring an industrial plant or the like.

In this embodiment, the plant 1 to be controlled is
The fixed disk 1 is operated by an arithmetic unit 4 for arithmetically processing the control data, an input / output device 2 for outputting the control data to the plant 1 or inputting / outputting the control data from the plant 1, and a command from the arithmetic unit 4. Control bus 1, control bus 2, control bus 2, device bus 1, device bus for connecting controller 1, controller 2, processing device 3 for controlling fixed disk 2 and fixed disk 1, fixed disk 2, backup cassette M / T device 8 2, a device bus 3, a control bus 1 and a control bus 2 are connected to a bus switching circuit 10 for switching which of the device bus 1, the device bus 2 and the device bus 3 is connected, and a bus control circuit for controlling the bus switching circuit 10. It is composed of 9.

Next, the operation of this embodiment will be described with reference to the block diagram of FIG. The processing device 3 delivers data for controlling the plant 1 to the plant 1 via the arithmetic unit 4 and the input / output device 2. The fixed disk 1 and the fixed disk 2, which are the auxiliary storage devices of the system, operate in a dual system to improve the reliability of the system. That is, the fixed disk 1 and the fixed disk 2 are
Only the information for recognizing each other's devices is different, and the other contents have the same content.
Thus, the device bus 1 and the device bus 2 are connected to the control bus 1, respectively, and the fixed disk 1 and the fixed disk 2 are connected to the buses of the same system to form an auxiliary storage device dual system. Here, when the fixed disk 1 becomes inoperable due to some abnormality, the processing device 3 causes the bus switching circuit 1 via the bus control circuit 9.
0 disconnects the device bus 1 from the control bus 1. After that, the system continues to operate by the degenerate operation of only the fixed disk 2. The fixed disk 1 that has become abnormal is promptly replaced with a normal fixed disk 1. Further, in order to configure the dual system again, the cassette M / T device 8 for backing up the system program and data to the newly connected fixed disk 1
Need to download more. Therefore, the processor 3 connects the device bus 1 and the device bus 3 to the control bus 2 by the bus switching circuit 10 via the bus control circuit 9. After this, the system uses the control bus 2 different from the control bus 1 that executes the steady process during the degenerate operation by the fixed disk 2.
Unsteady processing such as downloading from the backup cassette M / T device 8 to the fixed disk 1 is executed online. Fixed disk 1 for which download processing has finished
Can operate as a dual system by waiting for a state where the control bus 1 becomes bus-free and switching the connection of the device bus 1 from the control bus 2 to the control bus 1. According to the present embodiment, in a dual system of fixed disks as an auxiliary storage device, one fixed disk becomes abnormal and only the other fixed disk is performing the degenerate operation,
It is possible to replace the abnormal fixed disk with a normal fixed disk and reconfigure the dual system online, so the system down time can be shortened and the plant cannot be stopped for a long time. Effective for control.

In this embodiment, human error can be reduced by only artificially changing the fixed disk and performing most of the processing by the program.

[0019]

According to the present invention, in an auxiliary storage dual system in a computer system, by providing two bus systems for connecting a processing device and an auxiliary storage device, program reading, data reading,
Since it becomes possible to separately and independently execute steady processing such as writing and non-steady processing such as restoration processing to the dual system when the auxiliary storage device is replaced, the system is conventionally stopped when executing non-steady processing. Although it had to be done before, the non-steady-state processing can be executed online, and the system down time can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an auxiliary memory dual system according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of an auxiliary memory dual system according to the related art.

[Explanation of symbols]

1 ... Plant, 2 ... Input / output device, 3 ... Processing device, 4 ... Arithmetic unit, 5 ... Controller, 6 ... Cassette M / T controller, 7 ... Control bus, 8 ... Backup Y cassette M / T device, 9 ... Bus Control circuit, 10 ... Bus switching circuit, 11 ... Control bus 1, 12 ... Control bus 2, 13 ... Device bus 1, 14 ... Device bus 2, 15 ... Device bus 3, 16 ... Cottage disk 1, 17 ... Cottage disk 2 , 18 ... Controller 1,
19 ... Controller 2.

Claims (2)

[Claims] 1. A computer system has two control buses for connecting a processing device and a fixed disk as an auxiliary storage device, and a controller for controlling the control bus is provided on the processing device. An auxiliary storage dual system having a system and characterized in that these control buses operate independently of each other. 2. A routine process for reading or writing a program or data for controlling a system,
Monitoring the status of a fixed disk that is an auxiliary storage device
2. The program according to claim 1, wherein the control bus of the two systems has a program for separately and independently executing an unsteady process of downloading the contents of the fixed disk to a cassette M / T device or the like. Auxiliary storage dual system.