JPH0783358B2 - Local area network control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a user task and a host on a personal terminal (having a personal terminal online connected to a host computer) connected by a local area network (LAN). The present invention relates to inter-task local area protocol control for command and response packet transfer between communication control tasks that controls online communication with a computer.

〔Overview〕

In a local area network in which multiple personal terminals are connected to the host computer by communication lines, command packets and response packets are sent and received between the communication control task connected to the host computer and the user task of each personal terminal. By controlling the transfer protocol between tasks and sharing the communication control task, data can be exchanged with the host computer from any personal terminal.

[Conventional technology]

Conventionally, when data is exchanged by online connection with a host computer using a communication line from a personal terminal connected by a local area network, the communication board (COMMUNICATION BOARD) for each personal terminal is used for online communication control.
Communication control device such as ARD), modem (MODEM), network control unit (NCU) is required, and only the user task on the personal terminal equipped with the communication control device can exchange data with the host computer through the communication control task. Met.

That is, conventionally, only a personal terminal equipped with an online communication control device can perform on-line communication with a host computer.

[Problems to be solved by the invention]

However, in the above-described conventional method, in order to perform online communication with the host computer by being connected to the host computer, the communication control of the communication board, the modem, the network control unit, etc. of the personal terminals connected by the local area network is required. Only the user task on the personal terminal having the device can start the communication control task and exchange data with the host computer. Therefore, the user tasks on all personal terminals connected by the local area network share the communication control device such as the communication board through the communication control task to exchange data with the host computer and access the database of the host computer. There was a big drawback that could not be done.

The present invention solves the above-mentioned problems, and a user task on all personal terminals shares a communication task for performing online communication control with a host computer, and a plurality of personal computers connected on a local area network. It is an object of the present invention to provide a local area network control method in which a terminal can access a database of a host computer and exchange data.

[Means for solving problems]

The local area network control method of the present invention is a communication control for controlling online connection between a user task on a personal terminal (which has a personal terminal connected online with a host computer) connected by a local area network and the host computer. Task, REQUEST (request), ANSWER (response), DATA
Controlling the inter-task local area network transfer protocol by setting the inter-task transfer protocol that consists of command packets (data) and READY (preparation) and less ounce packets (ACK) It is characterized by carrying out and sharing the communication control task.

[Action]

A command packet between a user task provided in the microcomputers of all personal terminals of a plurality of personal terminals connected to the local area network and a communication control task connected to the host computer and performing online communication control with the host computer. And the response packet is sent and received to set the inter-task transfer protocol. As a result, the user task on any personal terminal can exchange data with the host computer through the communication control task and access the database.

〔Example〕

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram of a local area network control system of the present invention. Multiple personal terminals 1
2, 13 ... are installed on the local area network respectively. Among them, the personal terminal 11 connected to the host computer is provided with a communication board for performing online communication control with the host computer, a communication control task, and a user task, and a disk device, a printing device, and a floppy disk device. It is equipped with. Other personal terminals are equipped with a user task, a printing device and a floppy disk device.

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

FIG. 2 shows a personal terminal 11 which is an embodiment of the present invention.
Task 3 by the Microprocessor on 12 and 12
3 illustrates an inter-task transfer protocol between the communication control task 4 and the communication control task 4. The flow of a command packet transfer protocol and a response packet transfer protocol is shown. When the user task 3 issues a transmission command, the command packet 9 (REQUEST) is transferred to the communication control task 4 through the local area network control board 5 and the local area network cable 6. When the buffer can be secured, the communication control task 4 transfers the response packet 10 (ACK) to the user task 3.
As a result, the user task 3 receives the command packet 9 (DAT
A) is transferred to the communication control task 4, and the communication control task 4 transmits the command packet 9 (DATA) to the host computer through the communication board 7 and the modem 8. When the transmission is completed, the communication control task 4 transfers the response packet 10 (ACK) to the user task 3, and if there is further information, the command packet 9 (DATA).
Transfer. When the communication control task 4 cannot secure the buffer for the command packet (REQUEST), that is, when it is being used by (REQUEST) from another user task, the response packet 10 (WAIT) is transferred to the user task 3. The user task 3 suspends the transmission process.

When data is received from the host computer, the communication control task 4 transfers the command packet 9 (ANSWER) to the user task 3, and when the user task 3 is ready for reception, it transfers a response packet 10 (ACK). As a result, the communication control task 4 transfers the received command packet 9 (DATA) to the user task 3, and the user task 3 transfers the response packet 10 (ACK) when the command packet 9 (DATA) has been captured. If there is data received from the host computer, the communication control task 4 executes the command packet 9
(DATA) is transferred.

FIG. 3 shows a command packet and response packet transfer protocol when a command packet is transferred from the user task 3 to the communication control task and data is transmitted to the host computer, and FIG. 4 shows a command packet retransmission protocol at the above time. Show. FIG. 5 is a response packet transfer protocol when the user task transfers a response packet to the communication control task for receiving data from the host computer.

In this way, the user task of each personal terminal shares the communication control task on the personal terminal equipped with the communication board connected to the host computer by the modem for online communication with the host computer, and the communication control from the plurality of personal terminals is performed. The task enables online communication with the host computer.

[Effects of the Invention] As described above, according to the present invention, "REQUEST" and "ANSWE" are provided between the user task on the personal terminal in the local area network system and the communication control task on the personal terminal connected to the host computer.
From a user task on any personal terminal in a local area network using inter-task transfer protocol control consisting of command packets of "R", "DATA" and "READY" and response packets of "ACK" and "WAIT" Also, there is an effect that a communication control device such as a communication board is shared through a communication control task to exchange data with a host computer, and a database can be accessed.

[Brief description of drawings]

FIG. 1 is a block diagram of a local area network system according to an embodiment of the present invention. FIG. 2 is a flow chart of a packet transfer protocol of commands and responses between the user task on the personal terminal and the communication control task. FIG. 3 is a control flow chart of command and response packets. FIG. 4 is a control flow chart of another command and response packet. FIG. 5 is a control flow chart of other command and response packets. 3 ... User task, 4 ... Communication control task, 5 ... Local area network control board, 6 ... Local area network cable, 7 ... Communication board, 8 ... Modem, 9 ... Command packet, 10
...... Response packet, 11 to 13 ...... Personal terminal, 11a to 13a ...... Floppy disk device, 11b ......
Printing device, 11c …… Disk device.

Claims (1)

[Claims] 1. A method of controlling a local area network in which a plurality of personal terminals including a microprocessor are connected by a communication line and the communication line is connected to a host computer, and the personal terminal is connected to the host computer and online with the host computer. A transfer protocol for transmitting and receiving command packets and response packets is set between the communication control task that performs communication control and the user task that controls communication of the microprocessor of each personal terminal. A local area network control method that is shared by all user tasks.