JPH0338757A - Terminal control system - Google Patents

Abstract

PURPOSE:To improve the operability of a work station by using an action control circuit which receives the information of the state change of a communication channel and controls the start/stop of an on-line program and the propriety for transmission/reception of data received from an off-line program. CONSTITUTION:A detection circuit 6 always monitors the state of a communication channel 4 and informs an action control circuit 8 of the changing state information when the state of the channel 4 changes. The circuit 8 instructs an on-line program 9 to stop temporarily its action and informs an off-line program 10 of the file access abnormality when the channel 4 is interrupted. When the circuit 6 reports the recovery of connection of the channel 4, the circuit 8 informs the program 9 of a restartable state of its action to control the action of the program 9 and at the same time attains the communication started from the program 10. Thus it is possible to flexibly cope with the recovery of the fault of a terminal equipment and to control the channel 4 despite the occurrence of a fault of the channel 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for a terminal device, that is, a workstation, which communicates with a host computer via a communication control device.

[Prior Art] Workstations connected to host computers via terminal control devices are becoming increasingly intelligent.
Online and offline multitasking is possible. In this case, since there is a local connection between the terminal control device and the terminal device, if a failure occurs in the line or terminal control device, the connection to the terminal device will be severed, and the workstation will be online from that point on. All offline tasks are in a stopped state. Additionally, restarting after failure recovery was not performed smoothly.

As a countermeasure against failures in terminal control devices in terminal devices, a method has been proposed to manage failures by providing an information transmission function between terminal devices, but when communicating with a host computer, this method is Fault management for terminal control devices is not functioning effectively. For example, in the method described in Japanese Patent Application Laid-Open No. 62-235669, even if a terminal control device goes down due to a failure, programs and data are exchanged between the terminal devices, so that the entire system remains unusable. I am trying to be able to do some work. However, the communication method between terminal devices described in the 2nd and 3rd publications is a distributed system in which the terminals communicate on an equal level, and the terminal control device has a small role in communication control. Therefore, this type of fault management is also functioning effectively. However, in order to communicate with a host computer, a terminal device connected via a terminal control device is a centralized terminal system that relies on the terminal control device to manage communications with the host. If a failure occurs, the operation of the terminal device alone becomes completely meaningless. As a result 1,
Fault management of terminal devices has rarely been considered important.

[Problems to be Solved by the Invention] As mentioned above, in the conventional system, the terminal control device has the communication management function for the host computer, and the relationship between the terminal control device and the terminal device is that the mask station and the slave station There was a relationship between In such a terminal system with a master-slave configuration, if the communication path between the terminal device and the terminal control device is disconnected, regardless of whether the terminal device has the function to reconnect to the communication path or not. Since the online program in the terminal device does not have a fault countermeasure function that activates the host-to-host communication management of the terminal control device, the terminal device had to stop the execution of the online program. Moreover, in order to restart the program of the terminal device at the time of recovery from a failure, a re-IPL or the like is required.

By the way, recent terminal devices have become capable of processing online and offline operations simultaneously as their functions have become more sophisticated, and even if a failure occurs in the communication path between the terminal device and the terminal control device, the terminal device It is necessary to continue offline operation, which can be handled by itself, or to recover online operation due to recovery from a communication path failure. Conventionally, there is no effective method, so the terminal device performs a re-IPL, etc. Problems included complexity and poor operational continuity.

The purpose of the present invention is to solve these conventional problems, improve the operability of a workstation, continue processing even in the event of a communication path failure, improve usage efficiency, and avoid downtime in the event of a failure. The objective is to provide a terminal control method that allows

[Means to solve the problem]

In order to achieve the above object, the terminal control method of the present invention (
b) Communication control for transmitting and receiving data of online programs and offline programs to and from the above control device via a communication path in a terminal device that is connected to a host device via a control device and executes online programs and offline programs. A detection circuit (6) that detects a change in the state of connection or disconnection of a communication path between the circuit (5) and the control device, and a detection circuit (6) that receives a notification of a change in the state of the communication path from the detection circuit and starts an online program. , an operation control circuit (8) that controls whether or not data can be sent and received by the communication control circuit according to requests from offline programs.
). (b) The operation control circuit (8) also stops the online program when the communication path with the control device is disconnected, and starts the online program when the communication path is connected. It has characteristics. (c) When the communication path with the control device is disconnected, the operation control circuit (8) does not activate the communication control circuit for communicating with the control device from the offline program, and Another feature of the present invention is that when the line is connected, the communication control circuit for communicating with the control device from an offline program is activated. Furthermore, (d) the operation control circuit (8)
) is activated at periodic timing, refers to the information in the memory set by the detection means, identifies a change in the state of the communication path with the control device, and operates according to the changed state. There are also characteristics.

[Function] In the present invention, even when a failure occurs in the communication channel,
It is possible to perform communication path control flexibly in response to failure recovery of the terminal device. That is, the detection circuit monitors the communication channel state from time to time, and when a change occurs in the state, it notifies the operation control circuit of the changed state information accordingly. When the operation control circuit receives this notification, it determines the information and, when the communication path is disconnected, notifies the online program to temporarily stop its operation, and also alerts the offline program to a file access error. Notice. Next, when the detection circuit notifies the operation control circuit that the connection of the communication path has been restored, the operation control circuit notifies the online program that its operation can be resumed, and controls the operation of the online program. At the same time, it also makes it possible to start communication from an offline program.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a terminal device showing one embodiment of the present invention.

A slave station (terminal device) 20 of the present invention is connected to a master station (terminal control device) 2 having a communication management function for a host computer via a communication path 4, and a mask station 2 is connected to a communication path 1. It is connected to a host computer (not shown) via. Mask station 2 has offline file 3
is connected and can also be accessed from the offline program 10 of the slave station 20.

In the slave station 20, a circuit newly provided in the present invention is a detection circuit 6 that detects the disconnection/connection state of the communication path 4 for the mask station, and based on the line information reported by this detection circuit 6, These are an operation control circuit 8 that instructs an online program to stop/start online operations for a host computer, and an interval circuit 7 that periodically activates this operation control circuit 8. These three circuits 6, 7.8 allow continued processing even if a communication path failure occurs between the mask station 2 and the slave station 20.

Communication between master and slave is performed via communication path 4, and this communication is controlled by communication control circuit 5. That is, information received from the mask station 2 is passed from the communication control circuit 5 to the operation control circuit 8. The operation control circuit 8 divides the received information into online data, which is information with the host computer, and offline data, which is information with the mask station 2 that is not related to the host computer, and the former data is sent to the online program 9. The latter data is passed to the offline program 10, respectively. The online program 9 and the offline program 1.0 perform appropriate processing using the received data, and then output the data to the CRT 14 via the online I10 memory 12 and the offline I/,0 memory 13. Display processing results.

Further, all information transmitted from the slave station 20 to the master station 2 is passed to the operation control circuit 8. That is, these pieces of information include the keyboard 15
data sent to the host computer input from etc.,
and online data from the online program 9, which is control information for notifying the mask station 2 that it is waiting for reception from the host computer, and the offline program 10 started from the keyboard 15, or does not exist in the offline file 11 of the own station. There is offline data etc. for requesting access to the offline file 3 on the mask station 2.

When the operation control circuit 8 receives each data, the detection circuit 6
The data is transmitted to the mask station 2 by referring to the line information of the communication path 4 detected by and activating the communication control circuit 5 according to the state. Further, the operation control circuit 8 gives information to the online program 9 and the offline program 10 by itself. The operation control circuit 8 is periodically activated by the interval circuit 7 and controls the online program 9 while referring to the communication channel information reported from the detection circuit 6.

FIG. 2 is a diagram showing an interface between the operation control circuit, the detection circuit 1, and the online program in FIG. 1.

The detection circuit 6 and the operation control circuit 8 are connected by a line information area that is accessible from both.

By detecting the state of the communication path 4, the detection circuit 6
When communication path 4 is connected, 'O'' is displayed in the line information area.
is written, and '1' is written when it is in the disconnected state.

Thereafter, the status of the communication path 4 can be referenced by accessing the line information area from the operation control circuit 8 and reading the contents.

Furthermore, the online program 9 and the operation control circuit 8 are also connected through an online status information area that is accessible from both. When the online program 9 is in an idle state, this online status information area displays 'o'.
o', 'oi' when busy,
Also, when in the stop state, '10' is written respectively. Thereafter, the status of the online program 9 can be referenced by accessing the online status information area from the operation control circuit 8 and reading its contents.

The operation control circuit 8 is activated periodically by the interval circuit 7, and refers to the contents of the line information area set by the detection circuit 6 and the online status information area set by the online program 9, and determines the processing method. Make changes. When the operation control circuit 8 is activated every cycle,
It makes a judgment based on the referenced line information and online status information, and instructs the online program 9 to start or stop its operation. Further, for the offline program 10, when the operation control circuit 8 is activated from the offline program 10, the line information area is referred to and the processing is changed.

FIG. 3 is a diagram showing the connection relationship of each block due to changes in the state of the communication path.

FIG. 3(1) shows a connected state, and when the communication path 4 between the master and slave is in the connected state, the communication control circuit 5 and the operation control circuit 8 are also connected. Further, FIG. 3(2) shows a disconnected state, and when the communication path 4 between the master and slave is in the disconnected state, the communication control circuit 5 and the operation control circuit 8 are disconnected.

When the detection circuit 6 detects the state of the communication path 4 and detects that the communication path has been disconnected, it writes '1' in the line information area, and the operation control circuit 8 refers to this content and immediately After disconnecting the communication control circuit 5, as shown in Fig. 3 (2).
state. The detection circuit 6 continues to monitor the communication path 4, and when it detects that the connection has been established again due to recovery from a fault, etc., the operation control circuit 8 writes r O+ in the line information area. Referring to FIG. 3, the communication control circuit 5 is reconnected to the state shown in FIG. 3 (1). In this way, the operation control circuit 8 controls access to the mask station 2.

FIG. 4 is a state transition diagram of the operation control circuit for online program management regarding the state of the communication path, and FIG. 5 is a state transition diagram of the operation control circuit for offline program management.

When the operation control circuit 8 is started from the online program 9 when it is not started from the online program 9, that is, when it is in the online idle state 41,
Transition to online busy state 42. In the online busy state 42, waiting for online completion continues. If "r disconnection" is detected in this state, wait for the online termination from the communication control circuit 5, issue a stop instruction to the online program 9, and enter the online stop state 4.
Move to 3. - After transitioning to the online stop state 43, the system does not directly transition to the online busy state 42, but always passes through the online idle state 41 before transitioning to the online busy state 42. Also,
If "r disconnection" is not detected while in the online busy state 42, the online process returns to the online idle state 41 again due to the online termination. If a "connection" is detected in the online stop state 43, a restart instruction is given to the online program 9, the state shifts to the online idle state 41, and waits for startup from the online program 9.

In FIG. 5, state transitions focusing on the control of the offline program 1015 are shown, and in this case there are only two states, a connected state 51 and a disconnected state 52. For the offline program 10, when the offline program 10 is started, in a connection state 51 in which "connection" is detected, the operation control circuit 8 starts the communication control circuit 5 and starts executing the program. Furthermore, in the disconnection state 52 where "disconnection" is detected at the time of activation from the offline program 10, the operation control circuit 8 automatically activates the offline program 10 without activating the communication control circuit 5. An abnormal termination is returned to the client. In this manner, in the transition to the offline program 10, either the connected state 51 or the disconnected state 52 is maintained depending on the state of the communication path 4.

FIG. 6 is a flowchart 1 of state transition when the operation control circuit is activated from the interval circuit.

When the operation control circuit 8 is activated by the interval circuit 7, it is classified into the following six types depending on the state at that time and the disconnected state of the line detected by the detection circuit 6. That is, (1) in the online idle state and the detection circuit 6 detects a connection; (11) in the online idle state and the detection circuit 6 detects a disconnection; (iji) in the online busy state and the detection circuit 6 detects a connection. (IV) When the online busy state and the detection circuit 6 detects a disconnection; (v) When the online stop state and the detection circuit 6 detects a connection; (vi) This is the case in the online stop state and when the detection circuit 6 detects disconnection.

In the case of (i) above, step 61.6'2°63.
64 and waits for startup (step 72). In addition, in the case of (11) above, steps 61, 62, 6
Online program 10 via 3,67.68
(step 69), and sets the online mode to the online stop state (step 7).
0). Then, the process continues to wait for startup (step 72). In addition, in the case of item 2 (iii), steps 61 and 62
, 63 and 64, and waits for startup (step 7
2). Further, in the case of (iv) above, step 61,
62, 63, 67, and 68, the online mode is set to a "connection" waiting state (step 71), and the system waits for startup (step 72). In the case of (V) above, the online program 10 is instructed to restart online via steps 61, 62, 63, and 64 (step 65), and the online mode is set to an online idle state (step 65). ). Then, the system waits for startup (step 72). In addition, in the case of (vi) above,
After passing through steps 61.6'2 and 63.67, the system waits for startup (step 72).

In this way, when the operation control circuit 8 is periodically activated by the interval circuit 7, the operation control circuit 8 refers to the line information area and
Although the transition order differs depending on whether the line is disconnected or the state of the operation control circuit 8 at that time, the online idle state becomes the online busy state or the online stop state, and the system waits for startup.

[Effects of the Invention] As explained above, according to the present invention, even if a failure occurs in the communication path between the workstation and the control device,
Since the workstation can be prevented from going down, offline operation is possible even in the event of a communication path failure, improving usage efficiency and re-IPLing when the communication path failure is recovered.
This simplifies the online program's response to failures and improves the workstation's operability.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a workstation showing an embodiment of the present invention, FIG. 2 is a diagram showing information exchange functions between the operation control circuit in FIG. 1 and other circuits, and FIG. Figures 4 and 5 are state transition diagrams for managing the online program and offline program of the operation control circuit, respectively. Figure 19-6 is the interval diagram of the operation control circuit. It is an operation flowchart at the time of startup. 1.4: Communication path, 2: Mask station (terminal control device), 20 Nislep station (terminal device), 3.
11: Offline file, 5: Communication control circuit, 6: Detection circuit, 7: Interval circuit, 8: Operation control circuit, 9
: Online program, lO; Offline program, 12: Online ■/○ memory, 13: Offline I
10 memory, 14: CRT, 15: keyboard. (1) Connection state diagram (2) Disconnection state

Claims (1)

[Claims] 1. In a terminal device that is connected to a host device via a control device and executes an online program and an offline program, data of the online program and offline program is exchanged with the control device via a communication path. a communication control means for transmitting and receiving information, a detection means for detecting a change in the state of connection or disconnection of a communication path between the control device, and receiving a notification of a change in the state of the communication path from the detection means;
1. A terminal control system comprising: operation control means for controlling whether or not data can be sent and received by the communication control means according to requests from the offline program and starting and stopping of an online program. 2. The operation control means according to claim 1, wherein the operation control means stops the online program when the communication path with the control device is disconnected, and starts the online program when the communication path is connected. terminal control method. 3. The operation control means does not activate the communication control means for communicating with the control device from the offline program when the communication path with the control device is disconnected, and when the communication path is connected. 3. The terminal control system according to claim 1, further comprising activating the communication control means for communicating with the control device from an offline program. 4. When activated at periodic timing, the operation control means refers to the information in the memory set by the detection means, identifies a change in the state of the communication path with the control device, and detects the changed state. 4. The terminal control system according to claim 1, 2 or 3, wherein the terminal control system operates according to the following.