JP2000172482A - High reliability display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a display device which has a dual CPU system to hold the screen display before fault occurrence even within the switching time of the CPU systems. SOLUTION: Display switching is carried out while a CPU A1 system is a master system and a CPU B2 system is a slave system. A frame memory A4 for display is normally stored with digital video A104 of a video adapter A3 and the memory contents are read out to a switch part 7 and displayed on the screen of a display device 8. If the CPU A1 becomes faulty, the CPU B2 continuously operates the display device with a monitor signal 101. At this time, the CPU B2 forcibly stops the update of the frame memory A5 with an update stop signal B107 and the contents which are not updated are read out of the frame memory A5 continuously. Once the CPU B2 system finishes the continuous process, the CPU B2 outputs a switch signal B109 to the switch part 7 to display the contents of the frame memory B6 on the display device 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device which always displays a stable screen by switching the connection of the display device by a duplex computer.

[0002]

2. Description of the Related Art Display devices used for monitoring and control applications such as air traffic control and command and control are continuously operated at all times and are required to have high reliability. In general, a display device required for such an application is provided with a spare display device and a method of increasing the reliability of the system by duplicating a host server. For example, JP-A-8-2
Japanese Patent Application Publication No. 72740 discloses a display device in which connection switching of a display device to a duplex computer is simplified and display can be switched instantaneously. That is, two displays, two server processes for switching the display screens of these displays, and two client processes for requesting screen display to these server processes are provided, and the display is performed by a server-client system. The connection of the screen is switched. Thus, highly reliable display switching can be performed.

Further, for such a purpose, as a method of improving the reliability of the display device itself, for example, a display device as shown in a block diagram in FIG. 2 is known. According to this display device, the CPU or the like in which a failure is most likely to occur is duplicated, and when a failure occurs, switching is performed by the switching unit to stabilize the display screen.

[0004] The display device shown in FIG.
A CPUA1 system for transmitting a screen signal from the switching unit 7 to the display device 8 via the PUA1 and the video adapter A3, and a CP for transmitting a screen signal from the switching unit 7 to the display device 8 from the storage device 9 via the CPUB2 and the video adapter B4.
It is configured to operate with, for example, one CPUA system as a main system and two CPUB systems as a backup system. In this way, the CPU system for controlling the display screen is duplicated to increase the reliability.

That is, a drawing command A1 from the CPU A1
02 is output to the video adapter A3.
In accordance with 102, drawing to the drawing frame memory inside the video adapter A3 is performed. Then, in synchronization with the TV scanning, the digital video A104 output from the video adapter A3 is sent from the switching unit 7 to the display device 7, and the display device 8 performs display. When a failure occurs in the CPU A1, the monitoring signal 1 is sent from the CPU A1 to the CPU B2.
01 is transmitted to the CPU B2 to perform a handover process, and the switching unit 7 switches the system to the system of the CPU B2 and the video adapter B4 and displays the system on the display device 8. Even when the CPUB2 system is the main system and the CPUA1 system is the backup system, the processing is performed by the same signal flow as described above.

FIG. 4 shows a display device of FIG.
Takeover operation of CPUB2 when A1 fails;
6 is a flowchart showing a relationship between display states on the display device 8. Hereinafter, referring to the flowchart of FIG.
The switching operation of the conventional display device shown in FIG.

First, when the CPU A1 is operating normally (step S1, hereinafter, "step" is omitted), the target on the display device 8 is normally updated (state A).
1. Hereinafter, "state" is omitted). Here, when a failure occurs in the CPU A1 (S2), the display screen on the display device 8 disappears (A2), and the takeover process is immediately started by the CPU B2 (S3). Then, the CPU is switched by the switching unit 7.
The system is switched to the system of B2, and the takeover processing screen is displayed on the display device 8 (A3). Eventually, when the handover process of the CPU B2 is completed (S4), the target on the display device 8 is updated again normally (A4), and the CPU 2 enters the normal operation (S5). In this way, even if the CPU A1 breaks down while displaying the screen from the CPU A1 system,
The screen is taken over by the two PUB systems, and the screen display is continued on the display device 8.

[0008]

However, in the conventional display device as shown in FIG. 2, until a failure occurs in one system of CPUA and the system is switched to two systems of CPUB, it usually depends on the situation of the failure. Problems such as the disappearance of the display screen on the display device 8 occur. Further, there is also a problem that the startup status of the OS being used is displayed until the application program is started even after switching to the CPUB2 system according to the duplex system. Such a problem is described in Japanese Patent Application Laid-Open No. 8-272740.
The same applies to the technology disclosed in Japanese Patent Application Publication No. However, in recent years,
Even when a failure occurs in the display device, there is a demand for so-called minimum continuity of operation, which keeps the screen state immediately before the failure occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a dual-purpose CPU, video adapter, and the like, even within the CPU system switching time. It is an object of the present invention to provide a highly reliable display device capable of retaining a screen display in a state before a failure occurs.

[0010]

SUMMARY OF THE INVENTION A high reliability display device of the present invention is a display device using a TV scanning system in which a CPU, a video adapter and the like are duplicated in order to improve reliability. A frame memory for switching and displaying is provided in a subsequent stage of the video adapter. As a result, the screen state immediately before the occurrence of the failure can be maintained even when any one of the CPU systems has failed and is being switched.

That is, the high-reliability display device according to the first aspect transmits at least two computer systems for controlling image signals, switching means for switching each computer system, and the computer system switched by the switching means. And a display means for displaying a screen based on the image signal obtained, wherein each of the computer systems includes a display storage means for storing an image signal to be transmitted to the display means. The switching means reads out the image signal stored in the display storage means, causes the display means to display a screen, and when the computer system transmitting the image signal breaks down,
Until the processing of transferring the image signal to another computer system to be switched is completed and the switching unit switches the other computer system to the display unit, the display storage unit belonging to the failed computer system updates the memory contents. Is forcibly stopped, and the display means displays a screen based on the image signal before the failure of the failed computer system.

According to a second aspect of the present invention, in the high reliability display apparatus according to the first aspect, when a computer system fails, the failed computer system transmits an image signal to another computer system to be switched. While transmitting the continuation signal to continue, the other computer system sends an update stop signal to the display storage unit belonging to the failed computer system, and forcibly stops updating the memory content of the display storage unit. It is characterized by making it.

According to a third aspect of the present invention, there is provided a high reliability display device according to the first or second aspect.
The display storage means is a display frame memory for storing digital video information output by the video adapter.

According to a fourth aspect of the present invention, in the high reliability display apparatus according to the second aspect, the display storage means is a drawing frame memory provided in a video adapter for outputting digital video information. In this case, the updating of the memory contents is forcibly stopped by controlling the drawing command to the drawing frame memory by the update stop signal.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high reliability display device according to an embodiment of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a block diagram of a highly reliable display device according to an embodiment of the present invention. First, the configuration of the display device will be described. The same parts as those of the prior art in FIG. 2 are denoted by the same reference numerals.

The high-reliability display device of this embodiment has a C
CPUA1 system consisting of PUA1 and video adapter A3, CPUB consisting of CPUB2 and video adapter B4
In contrast to the prior art composed of two systems, the output frame of each system has a display frame memory A5.
And a display frame memory B6 connected to the switching unit 7 to transmit a display signal to the display device 8.

That is, the storage means 9 is shared and the CP
UA1, video adapter A3 and display frame memory 5
And a CPUB comprising a CPUB2, a video adapter B4 and a display frame memory 6.
The CPU system is duplicated by the two systems. The switching unit 7 switches between the CPUA1 system and the CPUB2 system, and a display signal is transmitted to the display device 8. The method of duplexing the CPU and the like is a well-known technique, and is not directly related to the technique of the present invention.

Next, the operation will be described.
Description will be made assuming that one PUA system operates as a main system and two CPUB systems operate as a backup system. of course,
The CPUB2 system may be operated as a main system, and the CPUA1 system may be operated as a backup system.

When the drawing instruction A102 from the CPU A1 is output to the video adapter A3, the drawing instruction A102
, Drawing is performed in the drawing frame memory inside the video adapter A3. Then, in synchronization with the TV scanning, the digital video A output from the video adapter A3 is output.
104 is written into the display frame memory A5.
Further, the display frame memory A5 reads the memory contents to the switching unit 7 in accordance with the TV scanning timing. The switching unit 7 receives the read signal and performs display on the display device 8.

Here, if a failure occurs in the CPU A1,
In response to the monitoring signal 101 from the CPU A1, the CPU B2 starts a takeover process for continuing the operation of the reliable display device. At that time, the CPU B2 sends the update stop signal B1
07, the updating of the display frame memory A5 is forcibly stopped. Therefore, the display frame memory A5 continues to read the content that is not updated. As a result, the display screen before the failure of the CPU A1 is continuously displayed on the display device 8.

Then, the CPUB2 and the video adapter B
At the point in time when all the handover processes of Step 4 have been completed, the CPU B2 outputs a switching signal B109 to the switching unit 7, switches from the display frame memory A5 to the contents of the display frame memory B6, and displays the contents on the display device 8. It goes without saying that the same operation is performed even when the CPU A1 system is a backup system.

That is, normally, the display frame memory A
Numeral 5 stores the digital video A104 of the video adapter A3, and reads the memory contents to the switching unit 7 in accordance with the TV scanning timing. Then, the switching unit 7 receives the read signal and performs display on the display device 8. And C
When a failure occurs in the PUA1, the monitoring signal 101 causes the CPUB2 to continuously operate the display device. At this time, the CPU B2 forcibly stops updating the display frame memory A5 by the update stop signal B107. Therefore, the display frame memory A5 continues to read the content that is not updated.

Then, the CPU B2 and the video adapter B
At the point in time when all the continuation processes of Step 4 have been completed, the CPU B2 outputs the switching signal B109 to the switching unit 7 and displays the contents of the display frame memory B6 on the display device 8. Therefore, C
Even if a failure occurs in the PUA1, the display is continued without stopping the update, and the update is restarted after the continuation process by the CPUB2 is started, without the display screen disappearing or displaying during the switching process. The effect is obtained.

Next, the relationship between the takeover operation of the CPU B2 and the display state on the display device 8 when a failure occurs in the CPU A1 in the high reliability display device of this embodiment will be described with reference to the flowchart of FIG. I do. The operation of this high-reliability display device will be described on the assumption that it is used for target display such as monitoring control.

When the CPU A1 is operating normally (S
11), the target on the display device 8 has been normally updated (A11). Then, when a failure occurs in the CPU A1 (S12), the monitoring signal 101 immediately causes the CP to fail.
The takeover process is started by UB2 (S13). In this case, the CPU B2 forcibly stops updating the display frame memory A5 by the update stop signal B107. Therefore, the display of the target on the display device 8 is continued while the update is stopped (A12). That is, CPUB
Normally, it takes about one minute to complete the takeover process of No. 2, but during this time, the display of the target is kept stopped and the display is continued.

When the CPUB2 completes the handover process (S14), the CPUB2 sends a switching signal B to the switching unit 7.
109 is output and the display device 8 is switched from the display frame memory A5 to the contents of the display frame memory B6.
To be displayed. As a result, the CPU 2 enters the normal operation (S
15), the target on the display device 8 is updated normally again (A13). In this way, the display of the CPUA1 system is continued even when the CPUA1 is switching the failure, and the CPUB1 is switched to the CPUB2 at the time when the handover process of the CPUB2 system is completed.
The display switches to B2 system.

The embodiment described above is an example for explaining the present invention, and the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the invention. is there. For example, the basic configuration is the same as that of the above-described embodiment, but it is also possible to use three or more CPU systems. Also in this case, when a failure occurs in the CPU system in operation, the screen display before the failure can be continued during the switching time to another CPU system by the same operation as the above-described embodiment.

If the number of stages up to the switching section of the display frame memory is increased, it is of course possible to more reliably hold the screen display before the failure. Also, without using the switching display frame memory,
A method is also possible in which a drawing command to the drawing frame memory inside the video adapter is controlled by an update stop signal. However, in this case, the contents of the drawing frame memory inside the video adapter may be partially updated depending on the timing of the occurrence of the failure of the CPU.

[0029]

As described above, according to the high-reliability display device of the present invention, when the CPU, the video adapter and the like are duplicated, the switching display frame is provided at the subsequent stage of the video adapter. With memory, CPU in operation
Even if a failure occurs, the screen display before the failure can be continued at a minimum. Furthermore, since the switched CPU switches the display on the display device after the end of the handover process, the user may feel that the updating of the screen display is momentarily delayed, but the continuity of the normal operation is not sufficient. Can be satisfied.

[Brief description of the drawings]

FIG. 1 is a block diagram of a highly reliable display device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional display device.

FIG. 3 is a block diagram of the high reliability display device of FIG.
9 is a flowchart showing a relationship between a takeover operation of the CPU B2 and a display state on the display device 8 when a failure has occurred in the display device 8;

4 is a flowchart showing a relationship between a takeover operation of a CPU B2 and a display state on a display device 8 when a failure occurs in a CPU A1 in the display device of FIG.

[Explanation of symbols]

1 CPUA, 2 CPUB, 3 video adapter A,
4: Video adapter B, 5: Display frame memory A, 6
... Display frame memory B, 7 ... Switching unit, 8 ... Display device, 9 ... Storage means

Continued on the front page F term (reference) 5B069 AA01 BA01 BB11 BC02 KA06 5C080 AA01 AA18 BB05 DD09 DD30 EE01 EE17 FF09 GG02 GG12 JJ02 JJ07 5C082 AA12 AA37 BA02 BA12 BB15 BB22 BB26 CA81 CB00

Claims (4)

[Claims] At least two computer systems for controlling an image signal, switching means for switching each of the computer systems, and a screen based on an image signal transmitted by the computer system switched by the switching means. A high-reliability display device based on a multiplexed computer system, comprising: display means for displaying; and each of the computer systems includes display storage means for storing an image signal to be transmitted to the display means. Reading the image signal stored in the display storage means and displaying a screen on the display means, when the computer system transmitting the image signal fails, the image to another computer system to be switched to When the signal transfer processing is completed, the switching means sets the other computer system in front. Until switching to the display means, the display storage means belonging to the failed computer system is forcibly stopped updating the contents of the memory, and the display means is provided with an image signal before the failure of the failed computer system. A highly reliable display device characterized by displaying a screen based on the information. 2. When the computer system fails,
The failed computer system transmits a continuation signal for continuing the image signal to another computer system to be switched, and the other computer system sends an update stop signal to a display storage unit belonging to the failed computer system. 2. The high-reliability display device according to claim 1, wherein the update of the memory contents of the display storage means is forcibly stopped. 3. The high-reliability display device according to claim 1, wherein the display storage means is a display frame memory for storing digital video information output by a video adapter. 4. The display storage means is a drawing frame memory provided in a video adapter that outputs digital video information, and controls a drawing command to the drawing frame memory by the update stop signal. 3. The highly reliable display device according to claim 2, wherein updating of memory contents is forcibly stopped.