JPH05143505A - Method for controlling terminal - Google Patents

Abstract

PURPOSE:To prevent system-down state information to data which is transmitted from a terminal to a terminal controller and taking-out and controlling the state information the terminal controller. CONSTITUTION:When the respective terminal 12 exchange communication data with a computer 2 by way of the terminal controller 10, state information is added to communication data 13 which is transmitted to the terminal controller 10 together with information adding a terminal address 14, etc. The state information is adopted as nearly one byte, for example. When the terminal controller 10 receives such data as this from the terminal device 12, communication data 13 is transferred to the computer 2 and state information 15 and the terminal device address 14 are fetched so as to be added in a state control table 20. Thus, state information of the terminal controller is normally updated into new state information even if a passing occurs in state information so that system-down, etc., is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal control method for managing the status of a terminal device in a computer system in which a plurality of terminal devices are connected.

[0002]

2. Description of the Related Art In a computer system in which a computer and a terminal device for using the computer are connected, an interface for connecting the computer and each terminal device has been standardized in recent years. Such a general-purpose interface has a feature that terminals of different models and different manufacturers can easily connect to each other. This includes, for example, IEEE-488 Standard4
88-1978 etc. are known. On the other hand, as the terminal device itself has become more intelligent, a terminal having both a listener / talker function is required rather than a terminal having only a listener function, such as a printer terminal device that is well known in the past. It has increased. For this reason, application programs for controlling such terminal devices have become complicated, and many of them dynamically switch the listener / talker state of the terminal device for use.

FIG. 2 shows a block diagram of a conventional general computer system. In the figure, this system is one in which a computer 2 and a bus line 3 are connected via a terminal control device 1, and a plurality of terminal devices 4 are connected to this bus line. The terminal controller 1 is composed of the IEEE-488 interface controller, and the bus line 3 is composed of an IEEE-488 bus. Here, the terminal control device 1 includes a state management table 5 for controlling the state of each terminal device 4.
The state management table 5 stores, for example, state information indicating whether each terminal device 4 is currently operating as a talker or a listener. Calculator 2
Performs various data exchanges with each terminal device 4 through such a terminal control device 1 and performs various controls while switching each terminal device to a talker or a listener as needed.

FIG. 3 shows a sequence chart of a conventional terminal control method. The procedure of the conventional state information control of each terminal device will be described with reference to this figure. First, the terminal control device 1 has a state management table 5 for managing each terminal device 4, and first, for a specific terminal device, sets the terminal to a listener (step S1). At the same time, the listener is designated for the terminal device 4 (step S2). The terminal control device 1 subsequently transmits data to the terminal device 4 (step S3). After that, the terminal control device 1 designates a talker for the terminal device 4 (step S4). Receiving this, the terminal device 4 transmits predetermined communication data to the terminal control device 1 (step S5). Upon receiving the necessary data, the terminal control device 1 cancels the talker designation of the terminal device 4 (step S6).

In the above control, the terminal control device 1 rewrites the state management table 5 according to its own control logic and manages it by its own judgment. FIG. 4 shows a sequence chart of another conventional terminal control method. In this method, while the state management table 5 is provided on the terminal control device 1 side,
The state management table 6 is also provided on the side of the terminal device 4. Then, the terminal control device 1 positively collects state information for state management from the terminal device by polling. That is,
When the corresponding terminal in the state management table 5 is set as a listener (step S1), the listener is designated for the terminal device 4 (step S2). Next, the terminal control device 1 transmits a status information request command to the terminal device 4 (step S3). Further, a talker is designated for the terminal device 4 (step S4). When the terminal device 4 receives the above command, it refers to its own status management table 6 and reads its contents (step S5). Then, the status information is transmitted to the terminal control device 1 (step S6). Terminal control device 1
When the status information is thus received, the contents are set in the status management table 5 (step S7). As a result, the latest state of the terminal device 4 can be recognized. The acquisition of the state information by such polling is repeatedly performed in a cycle of a constant time T as shown in the figure. Therefore, as compared with the case where the terminal control device 1 shown in FIG. 3 independently creates and manages the state management table 5, the method shown in FIG. 4 has the difference that the latest state information is obtained at regular time intervals. is there.

[0006]

However, the above-mentioned conventional methods have the following problems. First, in the system as shown in FIG. 3 in which the terminal control device manages the status information independently, for example, when a hardware failure occurs on the terminal device side or due to a software bug, etc. There may be a difference between the recognized state of each terminal device 4 and the actual state of each terminal device. For example, when the talker / listener function is dynamically switched for a plurality of terminal devices 4, the control program becomes complicated and software bugs are likely to occur. Therefore, for example, although the terminal control device 1 intends to switch the specific terminal device 4 to the talker, the command may not be transmitted normally, and the terminal device 4 may remain as a listener. In such a case, if the computer executes the processing assuming that the terminal device has become a talker, a system failure may occur due to the communication content or protocol. In addition, even if the system goes down due to such a failure, it is difficult for the computer to identify which terminal device is the failure, and it takes a lot of time for a specialist to solve the problem. ..

On the other hand, in the state management method by polling as shown in FIG. 4, since the state information of the terminal device is newly recognized every fixed time, there is an advantage that the occurrence of a failure of the terminal device is easy. However, in this method, since the status information of a plurality of terminal devices is read periodically at regular intervals, the load on the terminal control device increases as the number of connected terminal devices increases. This causes a problem that the original performance of the system is deteriorated. Further, there is a problem that such a system may not be realized depending on the application.

As another method, there is a method in which log data of each terminal is collected and analyzed after a failure occurs. However, this method has a problem in that log data is collected after the occurrence of a failure and therefore it is not useful for preventing the failure. Also, depending on the nature of the failure,
In some cases, even log data cannot be collected, and the system may be restarted only after the terminal device is initialized. It is impossible to collect accurate information. The present invention has been made in view of the above points, and an object thereof is to provide a terminal control method capable of performing accurate state management of each terminal device while suppressing the load on the terminal control device. Is.

[0009]

According to a first aspect of the present invention, in which a state of a terminal device is managed by a terminal control device via a communication line, the terminal device transmits to the terminal control device. State information of the terminal device is added to the communication data, and when the terminal control device receives the communication data from the terminal device, the terminal control device communicates with the communication data and the state added to the communication data. The present invention relates to a terminal control method characterized by incorporating information into a status management table for status management.

A second aspect of the present invention is to determine the state of the terminal device,
In a case where the terminal control device manages via a communication line, a state management table for state management is provided in both the terminal device and the terminal control device, transmitted from each terminal device, and received by the terminal control device together with communication data. Compared with the corresponding state information already stored in the state management table of the terminal control device, the state information of each terminal device that has been stored, if the two are different, the state information that has already received the stored state information The present invention relates to a terminal control method characterized in that

According to a third aspect of the present invention, the state of the terminal device is
In what is managed by a terminal control device via a communication line, the terminal device adds state information of the terminal device to communication data to be transmitted to the terminal control device, The present invention relates to a terminal control method, wherein the terminal control device requests the terminal device to transmit status information when communication data is not communicated for a predetermined time or more.

[0012]

In this method, the terminal device 12 adds the status information 15 to the communication data 13 for normal communication and transmits it to the terminal control device 10. The terminal control device 10 takes this state information 15 into the state management table 20. Therefore, as long as normal communication is performed, the terminal control device 10 can always collect the latest information regarding the terminal device 12. Information is collected by polling only when there is no communication of communication data. This reduces the load on the terminal control device and prevents the state management from passing each other.

[0013]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram of a computer system for implementing the method of the present invention. The system shown in FIG.
The computer 2 is connected to the bus line 11 via 0, and a plurality of terminal devices 12 are connected to the bus line 11. This terminal control device 10 is shown in FIG.
It is assumed that the bus line 11 is composed of the same IEEE-488 interface control device as described in the above, and the bus line 11 is composed of the IEEE-488 bus. Here, the terminal control device 10 includes a state management table 20 for controlling each terminal device 12. Further, each terminal device 12 is provided with a state management table 21, for example. The state management table 20 stores, for example, a state of each terminal device 12 being a talker or a listener, and a state for controlling other various devices in association with a terminal device name. And It is assumed that the state management table 21 provided in each terminal device 12 stores parameters indicating various operating states including the state of whether it is a talker or a listener.

In the method of the present invention, when each terminal device communicates with the computer 2 via the terminal control device 10, the communication data 13 to be transmitted to the terminal control device 10 is The state information 15 is added together with the information including the terminal device address 14 and the like. This status information is, for example, about 1 byte. Upon receiving such data from the terminal device 12, the terminal control device 10 transfers the communication data 13 to the computer 2 and incorporates the state information 15 and the terminal device address 14 into the state management table 20. .. As a result, the status information can be obtained from the terminal device without a special status information collecting operation.

The method of the present invention will be described more specifically.
FIG. 5 shows a sequence chart according to the method of the present invention. First, as shown in the figure, it is assumed that the terminal control device 10 manages, in the state management table 20, state information indicating that the terminal device 12 is a listener, for example. Further, it is assumed that the terminal device 12 holds in its own status management table 21 the status information that it is currently a listener.
Here, the terminal device 12 is connected via the terminal control device 10 to FIG.
When it is desired to perform data transmission to the computer 2 shown in (1), a transmission request is made to the terminal control device 10 (step S1). In the IEEE-488 interface, it is not possible to immediately recognize from which terminal device the transmission request is made even if such a transmission request is made. Therefore, the process for recognizing the request terminal device is executed (step S
2). Specifically, this is because a multi-line message is issued to all the terminal devices, and a polling operation in which the terminal controller 10 reads the status byte of each terminal device is executed. That is, the terminal control device 10 sequentially specifies a talker to each terminal device and requests the transmission of the status byte. In this way, when the terminal device in which the request flag in the status byte is turned on is recognized, the terminal control device 10 ends the polling operation.

Then, the talker is designated again for the corresponding terminal device (step S3). On the other hand, the terminal device 1
2 transmits communication data to the terminal control device 10, but reads its own state information from the state management table 20 prior to this (step S4). Then, the communication data and the state information are transmitted to the terminal control device 10 (step S5). When the terminal control device 10 receives this status information, the terminal control device 10 transcribes the contents in the status management table 20 or compares the two and checks them. After that, the terminal control device 10 releases the talker state of the terminal device 12 (step S7). As a result, regarding the terminal device 12 in which constant communication data communication is performed,
It becomes possible to collect the latest status information.

On the other hand, if there is a terminal device that does not become a talker for a certain period of time or more, the terminal control device 10 selects the terminal device and designates a talker (step S8). Then, the terminal device 12 has the state management table 21 at that stage.
Is read (step S9), and communication data and status information are sent to the terminal control device 10 (step S1).
0). In this way, the terminal control device 10 forcibly collects the state information, collates it with the state management table 20, and checks it. Here, the operation when a failure occurs in any of the terminal devices will be described.

FIG. 6 shows a sequence flowchart according to another method of the present invention. In the figure, the operation from step S1 to step S7 is exactly the same as that already described in FIG. Therefore, redundant description will be omitted. Here, as shown in the figure, it is assumed that some failure has occurred in the terminal device 12 and that the current state in the state management table 21 has changed to unlisten. In this case, when the terminal control device 10 designates a talker for the terminal device 12 (step S8), the terminal device 12 causes the state management table 2
The contents of No. 1 are read (step S9), and communication data and status information are transmitted (step S10). The terminal control device 10 receives this status information and checks the comparison with the status management table 20 in step S11. When a comparison error occurs in this case, the terminal control device 10 replaces the contents of the status management table with the newly received status information and sets it (step S12), recognizes a failure of the terminal device, and performs various processes. Run.

For example, when the talker / listener state switching is not normally transmitted, for example, the talker designation is forcibly issued again. As a result, the terminal side returns to the state that can be managed by the terminal control device, and normal system operation can be continued. In addition, when such status information has passed, detailed status information of the corresponding terminal is checked, and necessary log data is collected and analyzed to eliminate the failure early before the system goes down. You can also The present invention is not limited to the above embodiments. In the embodiment of the present invention, the state management table is provided for each terminal device, and it is described as the data having the table-like configuration in which the state information is stored. However, the state of each terminal device can be recognized. Any format of data can be used as long as it has the following contents. Further, the state information added to the communication data may be freely selected according to the system configuration such as the type and amount and the need thereof. The bus line may be composed of various communication lines for various data communication.

[0020]

According to the terminal control method of the present invention described above, the state information is added to the data transmitted from the terminal device to the terminal control device, and the terminal control device extracts and manages the state information. Therefore, even if the status information of the terminal device and the terminal control device pass each other, the status information of the terminal control device can always be updated to new status information, so system down etc. can be prevented beforehand. You can Further, since the terminal control device does not need to perform polling for collecting the state information specially for all the terminal devices, the load on the terminal control device is reduced and the system performance is not deteriorated.

Further, since the terminal device for which communication data has not been communicated for a certain period of time is forced to collect the state information, the latest state management of all the terminal devices can be performed. In addition, since the state of each terminal device can be checked at regular intervals during system operation, if any failure occurs in the terminal device, this can be detected before a complicated failure occurs. Therefore, there is also an effect that the failure analysis becomes easy and the system restoration becomes quick. In addition, when a new system is assembled and its performance is tested, software bugs can be found early, so the period until the system is put into full-scale operation can be greatly shortened.
In addition, when a terminal device is newly added to the system, an automatic state check is performed on the terminal device, so that stable operation can be easily and surely confirmed.

Further, with respect to a potential software bug that occurs only in a complicated control state or timing, the control information of the host side can be automatically rewritten and restored by the method of the present invention. It is possible to build a highly reliable system that does not lead to system down.
In addition, if automatic restoration is performed by automatically rewriting such a state management table, the system becomes large in scale, and even if a new terminal device is introduced, the reliability of the system does not deteriorate and the system can be expanded. You can do it with confidence. In addition, the status information of the terminal device can be collected while continuing the system operation, and by analyzing the control information of the terminal, it is possible to develop higher quality control software. is there.

[Brief description of drawings]

FIG. 1 is a computer system block diagram for implementing the method of the present invention.

FIG. 2 is a block diagram of a conventional general computer system.

FIG. 3 is a sequence chart of a conventional terminal control method.

FIG. 4 is a sequence chart of another conventional terminal control method.

FIG. 5 is a sequence chart according to the method of the present invention.

FIG. 6 is a sequence flowchart according to another method of the present invention.

[Explanation of symbols]

 2 computer 10 terminal control device 11 bus line 12 terminal device 13 communication data 15 state information 20, 21 state management table

Claims (3)

[Claims] 1. The terminal control device manages the state of the terminal device via a communication line, wherein the terminal device includes state information of the terminal device in communication data transmitted to the terminal control device. In addition, when the terminal control device receives the communication data from the terminal device, the terminal control device communicates with the communication data and loads the state information added to the communication data into a state management table for state management. A terminal control method characterized by the above. 2. A terminal control device manages the state of a terminal device via a communication line, wherein both the terminal device and the terminal control device are provided with a state management table for state management and transmitted from each terminal device. The status information of each terminal device received by the terminal control device together with the communication data is compared with the corresponding status information already stored in the status management table of the terminal control device. A terminal control method characterized by replacing the already-received status information with newly received status information. 3. The terminal control device manages the state of the terminal device via a communication line, wherein the terminal device includes state information of the terminal device in communication data transmitted to the terminal control device. In addition, when there is no communication data communication between the terminal control device and the terminal device for a certain period of time or more, the terminal control device requests the terminal device to transmit status information, ..