JP3422271B2 - High reliability display device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for constantly displaying a stable screen by connecting and switching display devices by means of a dual computer.

[0002]

2. Description of the Related Art A display device used for surveillance / control applications such as air traffic control and command control is continuously operated at all times and is required to have high reliability. A display device required for such an application is generally provided with a spare display device, and a method of increasing system reliability by duplicating a host server is adopted. For example, JP-A-8-2
Japanese Patent Publication No. 72740 discloses a display device in which connection switching of the display device to the duplex computer is simplified and the 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 display is performed by the server / client method. The screen connection is switched. This makes it possible to perform display switching with high reliability.

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 of FIG. 2 is known. According to this display device, the CPU that is most prone to failure is duplicated, and when a failure occurs, the switching unit switches the display screen to stabilize the display screen.

The display device shown in FIG. 2 has a storage means 9 to C.
CPUA1 system that transmits a screen signal from the switching unit 7 to the display device 8 via the PUA1 and the video adapter A3, and a CP that transmits a screen signal from the storage unit 9 to the display device 8 via the CPUB2 and the video adapter B4.
It is composed of a UB2 system, for example, a CPUA1 system as a main system and a CPUB2 system as a backup system. In this way, the CPU system that controls the display screen is duplicated to improve reliability.

That is, the drawing command A1 from the CPU A1
02 is output to the video adapter A3, and the drawing command A
In accordance with 102, drawing is performed in the drawing frame memory inside the video adapter A3. Then, in synchronization with the TV scanning, the digital video A104 which is the output of the video adapter A3 is sent from the switching unit 7 to the display device 7, and the display of the display device 8 is performed. If a failure occurs in CPUA1, CPUA1 sends a monitoring signal 1 to CPUB2.
01 is transmitted and the handover process is performed to the CPU B2, and at the same time, the switching unit 7 switches to the system of the CPU B2 and the video adapter B4 and is displayed on the display device 8. Even if 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 CPU of the display device of FIG.
The takeover operation of CPUB2 when a failure occurs in A1,
7 is a flowchart showing a relationship of display states on the display device 8. Hereinafter, with reference 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, the following "step" is omitted), the target on the display device 8 is normally updated (state A).
1, hereinafter "state" is omitted). Here, if a failure occurs in the CPU A1 (S2), the display screen on the display device 8 disappears (A2), and immediately the CPU B2 starts the takeover process (S3). Then, the switching unit 7 causes the CPU
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 takeover process of the CPUB2 ends (S4), the target on the display device 8 is normally updated again (A4), and the CPU2 enters the normal operation (S5). In this way, even if the CPUA1 fails while displaying the screen from the CPUA1 system, the C
The screen is handed over to the PUB2 system, 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 the CPUA1 system and the system is switched to the CPUB2 system, it usually depends on the status of the failure. Problems such as the display screen on the display device 8 disappearing occur. Further, depending on the duplexing method, there is also a problem that even after switching to the CPUB2 system, the startup status of the OS being used is displayed until the application program is started. Such a problem is caused by Japanese Patent Laid-Open No. 8-272740.
The same applies to the technique disclosed in the publication. However, in recent years
Even when a failure occurs in the display device, there is a demand for so-called minimum continuity of operation in which the screen state immediately before the failure occurs is retained.

The present invention has been made in view of the above circumstances, and an object thereof is to make a CPU, a video adapter, etc. redundant, even within the switching time of the CPU system. An object of the present invention is to provide a highly reliable display device capable of holding the screen display in the state before the failure occurs.

[0010]

The 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 display is provided in the latter part of the video adapter. As a result, even if one of the CPU systems has failed and is being switched, the screen state immediately before the failure can be retained.

That is, the high-reliability display device according to claim 1 transmits by at least two computer systems for controlling an image signal, switching means for switching each computer system, and computer systems switched by the switching means. In a highly reliable display device using a multiplexed computer system that includes a display unit that displays a screen based on the generated image signal, each computer system includes a display storage unit that stores the image signal to be transmitted to the display unit. 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 fails,
Until the switching means switches the other computer system to the display means after the transfer processing of the image signal to the other computer system to be switched is completed, the display storage means belonging to the faulty 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.

The high reliability display device according to a second aspect is the high reliability display device according to the first aspect, wherein when the computer system fails, the faulty computer system sends an image signal to another computer system to be switched. At the same time as transmitting the continuation signal for continuing, the other computer system forcibly stops the update of the memory contents of the display storage means by transmitting the update stop signal to the display storage means belonging to the faulty computer system. It is characterized by

A high reliability display device according to claim 3 is the high reliability display device according to claim 1 or 2, wherein
The display storage means is a display frame memory that stores digital video information output by the video adapter.

A high-reliability display device according to a fourth aspect is the high-reliability display device according to the second aspect, wherein the display storing means is a drawing frame memory provided in a video adapter for outputting digital video information. It is characterized in that 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]

BEST MODE FOR CARRYING OUT THE INVENTION A highly reliable display device according to an embodiment of the present invention will be described in detail below 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 this display device will be described. The same parts as those in the prior art shown in FIG. 2 are designated by the same reference numerals.

The high-reliability display device of this embodiment is C
CPUA1 system consisting of PUA1 and video adapter A3, and 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, which are 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
A CPUA1 system consisting of a CPUB2, a video adapter B4, and a display frame memory 6
The CPU system is duplicated by the two systems. Then, the CPU A1 system and the CPU B2 system are switched by the switching unit 7, and the display signal is transmitted to the display device 8. Note that the duplication method of the CPU and the like is a well-known technique and is not directly related to the technique of the present invention, and therefore description thereof will be omitted.

Next, the operation will be described. Here, C
It is assumed that the PUA1 system operates as a main system and the CPUB2 system operates as a backup system. of course,
It is also possible to operate the CPUB2 system as the main system and the CPUA1 system as the backup system.

When the drawing command A102 from the CPU A1 is output to the video adapter A3, the drawing command A102 is output.
Accordingly, 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 in 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 displays the display device 8.

Here, if a failure occurs in CPUA1,
The monitor signal 101 from the CPU A1 causes the CPU B2 to start a takeover process for continuing the operation of the high reliability display device. At that time, the CPU B2 sends the update stop signal B1.
07, the display frame memory A5 is forcibly stopped from being updated. Therefore, the display frame memory A5 continues to read the contents that are 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 CPU B2 and the video adapter B
When all the takeover processes of No. 4 are completed, the CPU B2 outputs the switching signal B109 to the switching unit 7, switches the contents of the display frame memory A5 to the contents of the display frame memory B6, and displays the contents on the display device 8. Needless to say, the same operation is performed even when the CPU A1 system is a backup system.

That is, the display frame memory A is usually used.
Reference 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 displays the display device 8. And C
When a failure occurs in PUA1, CPUB2 continues the operation of this display device by monitoring signal 101. At that time, the CPU B2 forcibly stops the update of the display frame memory A5 by the update stop signal B107. Therefore, the display frame memory A5 continues to read the contents that are not updated.

Then, the CPU B2 and the video adapter B
When all the continuation processes of 4 are 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 PUA1, the screen is not stopped or the switching process is not displayed, the screen display is continued with the update stopped, and the update process is restarted after the continuous process by CPUB2 is started. The effect of doing is obtained.

Next, the relationship between the takeover operation of the CPUB2 and the display state on the display device 8 when a failure occurs in the CPUA1 in the high reliability display device of this embodiment will be described with reference to the flowchart of FIG. To do. The operation of this high-reliability display device will be described on the assumption that it is used for target display such as surveillance control.

When CPUA1 is operating normally (S
11), the target on the display device 8 has been updated normally (A11). Then, when a failure occurs in the CPU A1 (S12), the CP is immediately sent by the monitoring signal 101.
The takeover process is started by the UB2 (S13). In this case, the CPU B2 forcibly stops the update of the display frame memory A5 by the update stop signal B107. Therefore, the display on the target on the display device 8 is continued while the update is stopped (A12). That is, CPUB
Normally, it takes about 1 minute until the takeover process of No. 2 is completed, but during that time, the update of the target is stopped and the display is continued.

Then, when the handover process of the CPUB2 is completed (S14), the CPUB2 sends the switching signal B to the switching unit 7.
109 is output, and the contents of the display frame memory A5 are switched to the contents of the display frame memory B6 to switch the display device 8
To display. This causes the CPU 2 to enter the normal operation (S
15), the target on the display device 8 is normally updated again (A13). In this way, the display of the CPUA1 system is continued even when the failure of the CPUA1 is being switched, and when the takeover process of the CPUB2 system is completed, the CPU
The display switches to the 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 can be made within the scope of the gist 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 operating CPU system, the screen display before the failure can be continued during the switching time to another CPU system by the same operation as that of the above-described embodiment.

Further, if the number of stages up to the switching unit of the display frame memory is increased, it goes without saying that the screen display before the failure can be held more reliably. Also, without using the switching display frame memory,
A method of controlling a drawing command to a drawing frame memory inside the video adapter by an update stop signal is also possible. 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 failure occurrence of the CPU.

[0029]

As described above, according to the high-reliability display device of the present invention, when the CPU, the video adapter, etc. are duplicated, a frame for switching display is provided in the latter part of the video adapter. Since the memory is provided, the CPU in operation
Even if a failure occurs in, for example, at least the screen display before the failure can be continued. Further, after the switched CPU finishes the takeover process, the display on the display device is switched, so although the user may feel that the screen display has been updated for a moment, the continuity of normal operation is sufficient. Can be satisfied.

[Brief description of 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 illustrating a CPUA in the high reliability display device of FIG.
6 is a flowchart showing 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 first device.

4 is a flowchart showing a relationship between a takeover operation of CPUB2 and a display state on display device 8 when a failure occurs in CPUA1 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

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Claims (4)

(57) [Claims] 1. A computer system of at least two systems for controlling an image signal, a 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. In a high-reliability display device by a multiplex computer system including display means for displaying, each of the computer systems includes display storage means for storing an image signal to be transmitted to the display means, and the switching means is , The image to another computer system that is switched when the computer system transmitting the image signal is read out by reading the image signal stored in the display storage unit and displaying a screen on the display unit When the signal takeover processing is completed, the switching means is set in front of the other computer system. Until switching to the display means, the display storage means belonging to the failed computer system is forcibly stopped from updating the memory contents, and the display means displays the image signal before the failure of the failed computer system. High-reliability display device characterized by displaying a screen based on it. 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 causes the display storage means belonging to the failed computer system to stop updating. 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 by transmitting the message. 3. The high reliability display device according to claim 1, wherein the display storage unit is a display frame memory that stores digital video information output by a video adapter. 4. The display storage means is a drawing frame memory provided in a video adapter for outputting digital video information, and by controlling a drawing command to the drawing frame memory by the update stop signal. 3. The high reliability display device according to claim 2, wherein the updating of the memory contents is forcibly stopped.