JPH0378659B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a communication system between a host and a terminal. It relates to a method of communication with a terminal device (hereinafter referred to as an actual terminal).

(Prior art) When constructing a network for communication between a host and multiple real terminals, when the distance between each node is long and the number of real terminals and therefore the number of lines is large, Generally, a relay processing device is introduced. In other words, the host and the relay processing device are connected via a high-speed line and communication control is performed at a speed that matches the processing speed of the host, and the relay processing device and the actual terminal are connected via a low-speed line to perform communication control at a speed that matches the processing speed of the actual terminal. We are trying to accommodate.

On the other hand, it is well known from experience that when adding or reforming software functions, the larger the base software, the more difficult the task is, and the more likely mistakes are to be made. Therefore, in order to deal with the diversification of real terminals that accompany the expansion of computer application operations, it is necessary to be aware of the attributes of real terminals, such as communication on the host side such as front-end processors. It is desirable to set virtual terminals so that they can be handled by a dedicated control processing section and the operating system can specify the address of a terminal to communicate with and send/receive data without being aware of the attributes of the real terminal.

In this type of conventional host-to-terminal communication method, the setting of a virtual terminal in one-to-one correspondence with a real terminal and the linking of the virtual terminal and an application program are performed on the host during system generation (SG). By the way, communication between the host and the real terminal is executed via this virtual terminal.

(Problems to be Solved by the Invention) In such a conventional method, it is necessary to configure as many virtual terminals as there are real terminals, which increases the configuration time and reconfiguration time when the host goes down, and the number of virtual terminals increases. As the number of buffers and tables created for each virtual terminal increases, the required resources on the host increase.Also, since the connection between virtual terminals and real terminals is fixed at SG time, it is difficult to connect real terminals by increasing the number of real terminals. There are many problems in that if there is a change in the configuration of the SG, it is necessary to redo the SG, and it is not possible to take various operational forms of the real terminal by dynamically linking the real terminal and the virtual terminal.

(Means for Solving the Problems) The method of the present invention is executed by a host and a host in a host-terminal communication method in which communication is performed between a host and a plurality of real terminals via a relay processing device. A virtual terminal with a one-to-one correspondence with an application program is set in advance in the relay processing device, and the real terminal waits for a request message specifying the application program and a permission message from the relay processing device in response to this request message. A communication message consisting of a terminal name and data is sent, and when the relay processing device receives the request message, it returns the above-mentioned permission message depending on the usage status of the corresponding virtual terminal, and also sends the above-mentioned communication message to the corresponding virtual terminal. The response message from the host to the communication message is transferred to the real terminal via the corresponding virtual terminal, and when the host receives the communication message, it processes it using the corresponding application program. It is characterized in that a response message with the actual terminal name attached is sent later.

(Example) Next, an example of the present invention will be described with reference to the drawings.

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

Referring to FIG. 1, this embodiment includes a host 10 that executes application programs AP1 and AP2, and a host 10 that executes application programs AP1 and AP2.
A host 20 running 3 and 9 real terminals 4
1, 42, 43, 44, 45, 46, 47, 48
and 49, and a relay processing device 30 that connects these real terminals 41 to 49 and the hosts 10 and 20 to perform relay processing.

In the relay processing device 30, there are four virtual terminals corresponding to a total of four application programs: application programs AP1 and AP2 executed on the host 10 and application programs AP1 and AP3 executed on the host 20. 31, 32, 33, and 34 are set at the time of SG, and these virtual terminals are dynamically associated with nine real terminals 41 to 49 by the switching means 35. Hosts 10 and 20 and relay processing device 30
The ○ mark in indicates an image of a virtual terminal or a real terminal within each device.

Next, referring to FIG. 2, which shows details of the relay processing device 30 together with real terminals and messages, in order to avoid complication of the drawing, in FIG. The illustration assumes an online computer system using A, B, C, and D.

The relay processing device 30 includes two tables 51 and 52 in one-to-one correspondence with the application programs AP1 and AP2, and four tables 53, 54, in one-to-one correspondence with the real terminals A, B, C, and D.
55 and 56 are provided.

In the tables 51 and 52, information for host management, such as data indicating whether the table is shared by a plurality of real terminals or dedicated to one host, is written at the time of SG.
In addition, information for terminal management is written in the tables 53, 54, 55, and 56 by telegrams from the real terminals A, B, C, and D, and the switching means 35 changes the table based on this written information. 53 to 56 are connected to either table 51 or 52.

Tables 53, 54, 55 and 56 are fixedly associated with real terminals A, B, C and D, respectively. On the other hand, tables 51 and 52 are SG
By writing either one of tables 51 and 52 into an application program correspondence table (not shown) on the host side, it is possible to associate the program with either application program AP1 or AP2.

Now, the actual terminal A and the application program
The operation of this embodiment will be explained using communication with the AP 2 as an example.

First, real terminal A sends the first message “$CON,AP
2” is sent. This first message requests communication with the application program AP2, and the control unit (not shown) of the relay processing device 30 checks the usage status of the table 52 corresponding to the application program AP2 and determines if it is empty. For example, a permission message is sent back to the actual terminal A, and the switching means 35 is controlled to connect the table 53 and the table 52.

In this way, the communication path between the real terminal A and the application program AP2 is set up, so when the real terminal A receives the above-mentioned permission message, it sends the second message "A, data". . This second message is communication data attached with the real terminal name of the sender, and is sent to the application program AP through the communication path set based on the first message.
2 for processing.

At this time, the application program AP2 on the host performs the process based on the actual terminal name in the message, and when this process is completed, the host sends the third message "A, response" to the second message "A. ,data"
is transmitted to the virtual terminal that received it, and delivered to the real terminal A through the above-mentioned communication path. This third message notifies the processing result of the application program AP2 for the second message,
When the real terminal A receives the third message, it transmits the fourth message "$DIS" or the second message "A, data" depending on the response content.

The retransmission of the second message "A, data" is due to malfunction of processing on the host side, but the fourth message "$DIS" announces the end of communication. The relay processing device 30
When receiving the message, the switching means 35 switches to the table 53.
and the table 52,
This ends the communication.

In order to simplify the explanation, the embodiment described above is a relatively small-scale system with only one relay processing device, but it is a relatively small-scale system with only one relay processing device. An embodiment including a relay processing device can also be easily implemented.

(Effect of the invention) According to the present invention, as explained above, the SG
The number of virtual terminals configured at the time should be the same as the total number of application programs running on each host, since this number is generally much smaller than the number of real terminals.
The time for setting up a virtual terminal and the time for resetting when a host goes down can be shortened, and the resources required on the host for setting up a virtual terminal can also be reduced.

In addition, since the connection between the virtual terminal and the real terminal is done dynamically using a message from the real terminal, there is no need to redo the SG even if the configuration of the real terminal changes, and one virtual terminal can be connected to multiple It is possible to dynamically adopt a variety of operational modes for real terminals, such as connecting multiple real terminals at the same time, or conversely, linking one real terminal to multiple virtual terminals.

In addition, since the host does not need to be aware of the communication route through which the message from the actual terminal came,
In a system with multiple relay processing devices, when a relay processing device fails, detour processing can be easily performed by simply connecting the actual terminal and another relay processing device with a switched line, and the line between the host and the relay processing device can be easily bypassed. In the event of a failure, bypass processing can be performed simply by connecting the relay processing device and another relay processing device using a switched line.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows a detailed diagram of this embodiment. 10, 20... host computer (host),
30... Relay processing device, 31, 32, 33, 34
...Virtual terminal, 35...Switching means, 41, 42,
43, 44, 45, 46, 47, 48, 49,
A, B, C, D...terminal device (actual terminal), 51,
52, 53, 54, 55, 56...table.

Claims (1)

[Scope of Claims] 1. In a host-terminal communication method in which communication is performed between a host computer and a plurality of terminal devices via a relay processing device, there is a one-to-one communication with an application program executed on the host computer. means for setting a virtual terminal corresponding to the relay processing device in the relay processing device; and a means for setting a virtual terminal corresponding to the application program in the terminal device and waiting for a request message specifying the application program and a permission message from the relay processing device in response to the request message; means for transmitting a communication message including a name and data; a means arranged in the relay processing device for replying the permission message according to the usage state of the virtual terminal when receiving the request message; means for transferring a response message from the host computer to the communication message to the corresponding host computer via the virtual terminal; and means for transferring a response message from the host computer to the communication message to the terminal device via the virtual terminal; A communication system between a host and a terminal, comprising means for transmitting the response message with the name of the terminal device after performing processing by the application program when receiving a communication message.