JPH06105928B2 - Half-duplex line data transmission / reception method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a line scheduling means when a plurality of terminal devices are connected to a half-duplex line.

〔Overview〕

The present invention is a data transmission / reception method in which data is exchanged between a data terminal and an information processing device via a half-duplex line, and transmission / reception is performed with a limited amount of data transmission / reception, and temporary transmission / reception is performed for each data transmission / reception. By stopping the transmission and searching for the presence / absence of data from other terminals, the time from the request for transmission / reception from a plurality of terminals to the start of transmission / reception can be made evenly close.

[Conventional technology]

Conventionally, in the line scheduling method in the case where a plurality of terminal devices are connected to a half-duplex line, the receiving operation is executed when the data transmission process to the terminal device is completed or the transmission is suspended due to the terminal buffer busy.

[Problems to be solved by the invention]

In such a conventional half-duplex line scheduling means, when a plurality of input / output terminals, output terminals and input terminals are connected, if continuous transmission is performed to an output terminal such as a printer, the input terminal such as a CRT terminal However, there was a shortcoming that the data could not be received promptly. Further, there is a drawback that an even and efficient transmission service cannot be provided when there is data to be transmitted to a plurality of output terminals.

The present invention eliminates such drawbacks, and an object of the present invention is to provide a data transmission / reception system of a half-duplex line in which data transmission / reception between an information processing device and a terminal device is executed uniformly.

[Means for solving problems]

The present invention relates to an information processing apparatus, a plurality of data terminals that exchange data with the information processing apparatus via a half-duplex line, and a transmission request and / or a reception request to the information processing apparatus of the data terminals. In a data transmission / reception system of a half-duplex line having a management means for identifying a certain data terminal, a first control for limiting the amount of data transferred with one transmission or reception of the data terminal to a predetermined amount Means and
A second control means for temporarily stopping the transmission after the transfer of the predetermined amount and activating the management means, and one of the second control means when the management means identifies that another data terminal has a transmission request or a reception request. After the end of the transmission or reception of the data terminal, the third control means for starting the transmission or reception of the other data terminal is provided.

[Work]

For example, when a terminal that has a transmission request is searched by the management means, a certain amount of data is transmitted from this terminal, and the transmission operation is temporarily stopped each time, and the operation is switched to the reception operation with the terminal that has a reception request for a certain period of time. Receive operation. In this way, it is possible to provide an equal transmission / reception service to each terminal.

〔Example〕

 Hereinafter, a method according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the embodiment system of the present invention. As shown in FIG. 1, according to this embodiment, the information processing 1, the half-duplex line 2, the terminal control units 3 and 7 are used.
And terminal devices 4, 5, 6 and 8. here,
The terminal devices 4 and 8 are CRT terminals which are input / output terminals, the terminal device 5 is a printer terminal which is an output terminal, and the terminal device 6
Is the floppy disk terminal of the output terminal. The information processing device 1 is connected to a half-duplex line 2 and various terminal devices 4, 5, 6 are connected to the half-duplex line 2 via terminal control devices 3 and 7.
And 8 are connected.

The number of input resumes, the number of transmission requests that indicate the terminal that has data to be transmitted under the line, the current transmission terminal that indicates the terminal that is currently performing the transmission operation, and the transmission block that indicates the number of a certain amount of data that can be continuously transferred to the current transmission terminal. The number is stored in the line control block LCB. Further, the terminal control block TCB stores the maximum number of transmission blocks indicating the maximum number of blocks that can be continuously transferred.

When the output terminal under the line is scheduled, the number of output resumes in the line control block LCB is incremented and the resume flag in the corresponding output unit control block OUCB is turned on. When the input terminal under the line is scheduled, the number of input resumes in the line control block LCB is counted up, and the resume flag in the corresponding input unit control block IUCB is turned on. Line control block for input / output terminals
Count up both resume numbers in the LCB. When the terminal is scheduled, the open flag in the terminal control block TCB is turned on. When the number of transmission requests in the line control block LCB is "0" and the number of input resumes is "1" or more, the reception operation is executed as the reception schedule target. Further, when the number of transmission resumes in the line control block LCB is “1” or more and the number of transmission requests is “1” or more, the transmission operation is executed as the transmission schedule target.

FIG. 2 is a control block diagram corresponding to the system configuration shown in FIG. In Fig. 2, the line control block LCB stores information necessary for line control, the terminal control block TCB stores information necessary for terminal control, and the input unit control block IUCB stores when the terminal device has an input attribute. The information necessary for the input control is stored, and the output unit control block OUCB stores the information necessary for the output control when the terminal device has the output attribute.

In Fig. 2, all the terminal control blocks TCB, the input unit control block IUCB and the output unit control block OUCB under the line control block LCB can be searched,
A corresponding input unit control block IUCB and output unit control block OUCB are linked from each terminal control block TCB. All control blocks are provided in a part of the control memory in the information processing device 1. The line control block LCB shows the number of output resumes indicating the number of output devices subject to the line subordinate schedule and the number of input devices subject to the line subordinate schedule.

Next, the operation of the method according to the embodiment of the present invention will be described.

FIG. 3 is a block diagram showing the operation of this embodiment system. In FIG. 3, data sent to a plurality of terminal devices under the half-duplex line is handled by the mailbox control unit 9 as a message (a logical one transfer unit of a collection of data) for each terminal, that is, each terminal control block. It is queued in the output message waiting queue 13. For example, for terminal control block TCB-1, there is a send message M1, for terminal control block TCB-2 there is a send message M2,
There is a send message M3 for the terminal control block TCB-3.

When the message sent to the terminal is first queued in the output message waiting queue 13, that is, the send message in the output message waiting queue 13 is "0" to "1".
When it is counted up to 1, the mailbox control unit 9 notifies the schedule control unit 10 of the transmission request to this terminal. The schedule control unit 10 turns on a flag indicating that there is a transmission request in the terminal control block and the output unit control block corresponding to this terminal, and counts up the number of transmission requests in the line control block. When the number of transmission requests in the line control block is "1" or more, it becomes the target of the transmission schedule, the line state management unit 11 sets the line state to the transmission mode, and sets the number of transmission blocks in the line control block to "0". . Subsequently, the output unit control block that has a transmission request in the line control block is searched in the order specified by the system generation to determine the terminal to be transmitted, and the line control block is linked as the current transmission terminal. For example,
The current transmission terminal is the terminal control block TC
It is B-1. After this, control is transferred to the transmission control unit 12.

In order to obtain the data to be transmitted, the transmission control unit 12 requests the mailbox control unit 9 to read the transmission message to the output message waiting queue corresponding to the corresponding terminal control block. Data to be sent from the mailbox control unit 9 together with the send message read completion notification (a part of the message, for example, MB
1) Receives the stored pointer, transfers the data to the line buffer, executes the transmission operation, and counts up the number of transmission blocks in the line control block when the data transmission on the line is completed. When the transmission control unit 12 repeats this operation and the number of transmission blocks in the line control block matches the maximum number of transmission blocks in the terminal control block specified when the system was generated, control is returned to the line state management unit 11 and the corresponding terminal Control block eg terminal control block
Suspend the transmission operation to TCB-1. Next, the switching control unit 14 is requested by the timer by the value specified at the time of system generation, and the line state is set to the reception mode.
Transfer control to. For example, since the receiving operation is performed for a certain time in Fig. 3, the terminal control block TCB
It becomes possible to receive data from -4.

Upon receiving the timer completion notification from the switching control unit 14, the line state management unit 11 stops the reception operation and becomes the target of the transmission schedule again, sets the line state to the transmission mode, and sets the number of transmission blocks in the line control block to “0”. To Next, the output control block having a transmission request is searched from the next terminal linked to the current transmission terminal in the line control block to determine the terminal to be transmitted, and the current transmission terminal is rewritten. For example, the terminal control block TCB-1 is rewritten to the terminal control block TCB-2. Control is again transferred to the transmission control unit 12, and the same processing is repeated.

〔The invention's effect〕

As described above, according to the present invention, when there is data to be transmitted to a plurality of terminal devices under the control of a half-duplex line, a receiving operation is executed for a certain time each time a certain amount of data is transmitted to each terminal. Therefore, there is an effect that the reception service can be realized quickly. In addition, since the receiving operation for a certain period of time is completed and the next transmitting operation is switched to the terminal having the data to be transmitted, there is an effect that a uniform transmitting service is realized.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing the configuration of an embodiment system of the present invention. FIG. 2 is an operation explanatory diagram corresponding to the system configuration shown in FIG. FIG. 3 is a block diagram showing the configuration of the control means according to the embodiment of the present invention. 1 ... Information processing device, 2 ... Half-duplex line, 3, 7 ... Terminal control device, 4, 8 ... CRT terminal, 5 ... Printer terminal, 6 ... Floppy disk terminal, 9 ... Mail box Control unit, 10 ... Schedule control unit, 11 ... Line state management unit, 12 ... Transmission control unit, 13 ... Output message waiting queue, 14 ... Switching control unit, 15 ... Reception control unit, 16
…… Received data queue, 16 …… Line connection device, TCB ……
Terminal control block, IUCB ... input unit control block, OUCB ... output control block, LCB ... line control block.

Claims (1)

[Claims] 1. An information processing apparatus, a plurality of data terminals for exchanging data with the information processing apparatus via a half-duplex line, and a transmission request or a reception request to the information processing apparatus of the data terminals. In a data transmission / reception system of a half-duplex line having a management means for identifying a certain data terminal, a first control for limiting the amount of data transferred with one transmission or reception of the data terminal to a predetermined amount. Means, second control means for temporarily stopping the transmission of the data terminal or the information processing device after the transfer of the predetermined amount, and operating the management means for a predetermined time, and the management means for requesting or receiving transmission to another data terminal. When transmission from one data terminal or reception at one data terminal has been completed, transmission from this other data terminal or this Half-duplex line data transmission scheme, characterized in that a third control means for starting the transmission to the data terminal.