JPS6156541B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a communication control system, and more particularly to a communication control system that reduces the load on a central processing unit when controlling unconnected devices connected by a shared line system.

When the central processing unit communicates with multiple terminal devices connected to one line (line), the central processing unit checks whether there is data to be sent to each terminal via the communication control device. Inquire by sending call data. If there is transmission data on the end device side, it responds to the inquiry from the central processing unit by sending the transmission data. If there is no data to be transmitted on the end device side, a negative response is returned to the central processing unit side. When the central processing unit receives a negative response from a terminal device, it sequentially sends call data to the next terminal device to make an inquiry.

In a conventional communication control device, the central processing unit sequentially sends out the call data group prepared on the main memory from the beginning to the end, and when negative responses are received from all terminal devices, the central processing unit requested intervention. For this reason, the central processing unit is essentially required to perform meaningless interrupt acceptance processing and call command restart processing, which is one of the causes of increased line control processing load.

The present invention does not make the above-mentioned invalid intervention request from the communication control device to the central processing unit, and when meaningful data is received from the terminal device to the central processing unit, or when the central processing unit instructs the central processing unit to stop calling. An object of the present invention is to issue an intervention request only when a problem occurs, thereby reducing the line control processing load on the central processing unit. In a communication control system in which call data to be sent to a line is fetched from a transmission buffer area in a storage device that is provided separately from the communication control device to the communication control device, the above-mentioned transmission buffer is provided in the communication control device. It is provided with means for holding the start address of the area, and means for instructing a transmission character storage address in the transmission buffer area, and sequentially fetches the call data from the transmission buffer address indicated by the transmission character storage address instruction means, and sends it to each terminal device. When a negative response is received from all of the terminal devices, the contents of the start address holding means are transferred to the sending character storage address indicating means, and the next call data to be sent is stored in the same sending buffer area again. It is characterized in that it performs a fetch from the source and sends it to the line.

Hereinafter, the present invention will be explained with reference to the drawings. The figure is a block diagram of a communication control system according to an embodiment of the present invention. In the figure, 1 is a communication control device, 2 is a main storage device, 3 is a central processing unit, 4 is a common bus, 5 is a character assembly circuit, and 6 is a block diagram of a communication control system according to an embodiment of the present invention. is a character processing circuit, 7 is a character transfer control circuit, 8 is a monitor circuit, 9 is a CCW address register (CCWA), 10 is an assembly buffer (AB), 11 is a character buffer (CB), 12
is a buffer start address holding register (BSA), 13 is an AND circuit, 14 is a buffer address holding register (BCA) for storing transmission characters, 1
5 is a buffer end address holding register (BEA), 16 is a reception command holding register (READ), 17 is a data buffer (DB), 18 is a channel command word (CCW), 19 is a transmission buffer, and 20 is a reception buffer.

The operation of the figure is as follows.

The software of the central processing unit 3 is stored in the main memory 2
Above, channel command word (CCW) 18 and
Send and receive buffers 19 and 20 associated with CCW are created. CCW includes the type of input/output command, designation of command chain, data chain, etc., start address and end address of sending and receiving buffers, etc. In the figure, it typically includes write command (WRITE), read command (READ), Only the buffer start address (BSA) and buffer end address (BEA) are shown.

Next, the central processing unit 3 stores data on the main memory 2.
After storing the CCW address in the CCW address register (CCWA) 9 in the communication control device 1, the communication control device 1 is activated.

The communication control device 1 receives the activation from the central processing device 3 through the monitor circuit 8 . The activated monitor circuit 8 fetches the CCW on the main memory address indicated by CCWA 9 and stores its contents in the corresponding register of the character transfer control circuit 7. In other words, among the CCWs 18 on the main storage device 2, BSA is
The BSA is stored in the BSA 12, and the BEA is stored in the BEA 15. At this time, the contents of the BSA are stored in the BCA 14. After this, the monitor circuit 8 is connected to the character processing circuit 6.
Send commands to and drive.

In the case of a calling command, the character processing circuit 6 detects transmission control characters in the transmitted and received characters, and also requests the character transfer control circuit 7 to transfer the transmitted characters from the transmission buffer 19.

The character transfer control circuit 7 transfers one character to be transmitted from the transmission buffer 19 of the main storage device 2 according to the transmission character storage destination buffer address holding register (BCA) 14, and stores it in a register (not shown) of the character processing circuit 6. After that, add +1 to the contents of BCA14.

When the character processing circuit 6 receives a negative response from the terminal device after sending the calling data, it performs the operation of sending the calling data to the next terminal device. If a negative response is still received from the terminal device after sending the final call data among the call data group prepared in the transmission buffer 19 of the main storage device 2, the character processing circuit 6 receives a negative response after the final call. The received signal is transmitted to the character transfer control circuit 7. As a result, in the character transfer control circuit 7, the AND circuit 13 is opened, the contents of the BSA 12 are transferred to the BCA 14, the contents of the BCA 14 are updated, and the start address of the transmission buffer 19 is held again. Therefore, the same call data group as the previously sent call data group will be sent to the circuit again. At this time, no intervention is made to the central processing unit, and all processing is automatically performed under control within the communication control unit.

In this way, unless data corresponding to an acknowledgment is received from the terminal device, and unless there is an instruction from the central processing unit, the communication control device continues to repeat and send out the paging data under internal control.

On the other hand, when data equivalent to an acknowledgment is received from the terminal device, or when a call stop instruction is issued from the software of the central processing unit, the monitor circuit 8 is instructed to terminate the command and fetch the next command. request. As a result, the monitor circuit 8 transfers the contents of the BCA 14 to the main memory 2.
Store it in the BEA section of CCW 18 and fetch the next command.

As described above, according to the present invention, the central processing unit sequentially sends the call data group addressed to each terminal device prepared in the transmission buffer from the beginning to the end, and receives negative responses from all of the terminal devices. If so, repeat the same process again from the beginning of the call data group without intervention from the central processing unit,
Since the central processing unit repeats calling and receiving operations in sequence until there is an instruction to stop calling from the central processing unit or until data corresponding to an acknowledgment is received from the terminal device, the central processing unit This eliminates the need for ineffective intervention, and reduces the line processing load on the central processing unit.

[Brief explanation of the drawing]

The figure shows a block diagram of a communication control system according to an embodiment of the present invention. In the figure, 1 is a communication control device, 2
is a main memory, 3 is a central processing unit, 4 is a common bus, 5 is a character assembly circuit, 6 is a character processing circuit, 7 is a character transfer control circuit, 8 is a monitor circuit, 12 is a buffer start address holding register, 14 is a buffer address holding register for storing transmission characters;
18 is a channel command word, and 19 is a transmission buffer.

Claims (1)

[Claims] 1 Controls multiple terminal devices connected by a shared line system, and fetches call data to be sent to a line prepared by the central processing unit from the transmission buffer area in the main memory to the communication control unit. In the communication control system, the communication control device is provided with a head address holding means for the transmission buffer area, and a transmission character storage address instruction means for the transmission buffer area, and a transmission specified by the transmission character storage address instruction means is provided. It fuses the call data from the buffer address and sends it to the end devices, and sends it to each end while sequentially updating the sending character storage address instruction means, and receives a negative response from all the end devices. In this case, the contents of the first address holding means are transferred to the sending character storage address indicating means, and the next call data to be sent is transferred to the same sending buffer area again without interrupting the central processing unit. A communication control method characterized by fetching data from the source and transmitting it to the line.