JPH04284554A - Computer system - Google Patents

Abstract

PURPOSE:To provide the computer system to automatically inhibit data, which are transmitted from another system, from being written in a common memory device. CONSTITUTION:At the computer system to write the data, which are transmitted from another system 2, through a common memory interface 6 of an own system 1 to a common memory device 5, when the write of the data is not desired, a switch 15 is turned off by the software of a basic processor 3. Thus, a switch operation conventionally manually executed is omitted, and the data can be prevented from being erroneously reloaded by forgetting the operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system in which data sent from other systems via a common memory interface can be written into a common memory device.

0002

[Prior Art] Figure 3 shows, for example, Mitsubishi Electric MELCOM35.
This is a block diagram showing a computer system using the conventional common memory interface described in the 0-60 series BA236/BA238 common memory manual (published January 20, 1985). In FIG. 1, 1 indicates the own system. , 2 are other systems that communicate with the own system.

In the own system 1, 3 is a basic processing unit as a central processing unit, 4 is a raw storage device used for processing calculations, 5 is a common memory device for storing data of the own system 1 and other systems 2, and 6 is a common memory device. A common memory interface 7 communicates with other systems 2, and a memory bus 7 connects the above components.

[0004] In other system 2, 8, 9, 10, 1
1 and 12 correspond to 3, 4, 5, 6, and 7 of the own system 1. Reference numeral 13 denotes a common memory interface bus that connects the common memory interfaces 6 and 11 of the own system 1 and the other system 2.

FIG. 4 shows the common memory interface 6,
11 shows the switch that changes the state, ■Memory bus・
It is configured as a toggle switch that switches between three states: common memory interface bus enabled, common memory interface bus enabled, and common memory interface bus disabled.

Next, the operation will be explained.

In the own system 1, data can be read and written from the basic processing unit 3 to the raw storage device 4 and the common memory device 5 via the memory bus 7. In addition, when writing data from the basic processing unit 3 to the common memory device 5, the same data is transferred to the common memory of another system 2 via the common memory interface 6, common memory interface bus 13, common memory interface 11, and memory bus 12. The device 10 can also be written to. The same applies when reading and writing data from the basic processing unit 8 of another system 2.

As described above, the common memory devices 5, 10
Since the same data is written to the basic processing units 3 and 8,
can share data.

Furthermore, when it is not desired to write data from the other system 2 to the common memory device 5 of the own system 1, the switch 14 is set to a state in which the common memory interface bus is disabled.

0010

[Problems to be Solved by the Invention] Since the computer system using the conventional common memory interface is configured as described above, when the basic processing unit 3 wants to write data only to its own common memory device 5, the common It is necessary to turn off the electricity electrically by manually operating the switch 14 of the memory interface 6, and if you forget this operation, the common memory device 1 of the other system 2
There were problems such as writing data that you did not want to write to 0.

[0011] This invention was made in order to solve the above-mentioned problems, and its purpose is to obtain a computer system that can prohibit writing to a common memory device from basic processing without operating a switch. There is.

0012

[Means for Solving the Problems] A computer system according to the present invention is capable of switching whether or not data can be written from another system to a common memory device of the own system using software of the basic processing unit of the own system. It is.

[0013]

[Operation] In the computer system according to the present invention, writing of data from the basic processing unit of another system to the common memory device of the own system is prohibited by an instruction of the basic processing unit of the own system.

[0014]

[Example] Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, numerals 15 and 16 are switches for switching between enable and disable writing to the common memory in the common memory interfaces 6 and 11.

In FIG. 2, 17 is a push button switch that changes the connection of the common memory interface bus 13 each time it is pressed, and the switches 12 and 13 are push button switches 17.
Alternatively, the connection of the common memory interface bus 13 can be made by software commands from the basic processing units 3 and 8.
This is a switch that changes to the states of , ■, and ■.

When the basic processing units 3 and 8 wish to prohibit data in their own common memory devices 5 and 10 from being rewritten by the other system, they set their own switches 15 and 16 to the common memory interface bus disabled state. It has software that switches to the state.

Next, the operation will be explained.

When writing data from the basic processing unit 3 to the common memory device 5, the same data can also be written to the common memory device 10 via the common memory interface 6, common memory interface bus 13, and common memory interface 11 at the same time. can. At this time, if the common memory writing enable/disable switch 16 of the common memory interface 11 is turned off by a software command from the basic processing unit 8, writing from the basic processing unit 3 to the common memory device 10 is prohibited. . Similarly, writing from the basic processing device 8 to the common memory device 5 is prohibited by turning off the common memory write enable/disable switch 15 of the common memory interface 6.

The OFF state of the switches 15 and 16 corresponds to setting the switches 15 and 16 in FIG. 2 to the common memory interface bus disabled state in accordance with a software command from their own basic processing units 3 and 8.

In the above embodiment, the switch 15 of the common memory interface 6 prohibits writing from the basic processing unit 8 of the other system 2.
The switch 16 of the common memory interface 11 may prohibit writing from the basic processing device 8 to the common memory device 5 of the own system 1.

[0022]

[Effects of the Invention] As described above, according to the present invention, it is possible to change the switch in the common memory interface by a command on the software of the basic processing unit, and to prohibit writing from other systems to the common memory of the own system. If you do not want the data in the common memory device to be rewritten by another system, you can create software to turn off the above switch, which will automatically prohibit writing. This has the effect of saving you the trouble of forgetting to prohibit writing, which occurs when prohibiting .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a computer system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a switch used in the system.

FIG. 3 is a block diagram of a conventional computer system.

FIG. 4 is a configuration diagram of a switch used in the system.

[Explanation of symbols]

1 Local system 2 Other system 3 Basic processing unit 5 Common memory device 6 Common memory interface 13 Common memory interface bus 15 Common memory write enable/disable switch Note that in the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Claim 1: A common memory interface that communicates data with other systems through a common memory interface bus, a switch that changes the communication state of the common memory interface, and a common memory device that writes data received from the other systems. ,
A computer system comprising: a basic processing unit having software that switches the state of the switch so as to prohibit writing of data received from the other system into the common memory device as necessary.