JPS6048637A - Priority control system of data transfer request - Google Patents

Abstract

PURPOSE:To improve the transmitting performance of data having high instantaneity by providing a priority level to a data transfer request from a terminal device in a data exchange device to identify and discriminate a priority level by a communication control section. CONSTITUTION:When the transfer request 1 of picture information is detected by a line control section 107, #1 after the start of scanning of the transfer request, a #1 address is set to a start point buffer 1060 and scanning is continued. Then the transfer of the control information of the transfer requests 1, 2 of the line control sections 107, #3, #5 to be detected is executed until the address of the scanning is restored to the line control section 107, #1. When the scanning is restored to the address #1, an interface section 106 confirms the presence of the transfer request again and picture information to the transfer request 1 is transferred. When the transfer is finished, the scanning is restarted and the transfer of the detected control information is executed until the transfer request 2 of the picture information is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data exchange system, and more particularly to a priority control system for data transfer requests in a system in which shifters are exchanged using a block multiplex transfer system.

A conventional general data exchange system will be explained with reference to FIGS. 1 to 5.

First, FIG. 1 shows an example in which data is exchanged using a channel device. The line control unit (CCU) 107 that controls the data terminal device 1109 scans the data transfer request set in the line control unit 107, reads data from the line control unit 107 where the data transfer request is set, and reads the data from the channel unit (11CH). ) 104 to the central control unit (ce)
A communication control interface unit (CIU) 106 that transfers data to the main memory unit (MM) 103 of a medium-φ processing unit t (CPU) 101 having a FILE) 111. Note that the reference numeral 105 in the figure is a communication control device (CCE).

In addition, FIG. 2 shows the central processing unit 10 without using a channel device.
1 and the interface 106 of the communication control device 105 are directly connected to a bus. In this case, the communication control interface section 106 also controls writing of data to the main storage section 103, but the line control section 107 and The data transfer control between is the same as in the case of FIG. 1.

In FIGS. 1 and 2, in order to increase the efficiency of data transfer by multiplexing data while scanning data transfer requests from the line control unit 107 in the communication limit interface unit 106, a block multiplex method is used. It is necessary to increase the data transfer unit (data block length) for one transfer request. However, when the data block length is increased, the conventional method of transferring data in the order in which transfer requests are detected by scanning often has the disadvantage that the transparency of data such as control signals that require immediacy deteriorates. That is, in FIG. 3, the line control section 1
The general data transfer request set to 07 is coded ■～■
, and control information that requires immediacy is indicated by the symbol ◎.
In addition, if the scanning position of the data transfer request detects ■, the data transfer for the transfer request of ■ is completed and then the data transfer for the transfer request of ■ is performed according to the scan.
The control information for ◎ is transferred only after the transfer requests for ■ to ■ have been processed. Therefore, as the data block length increases, the transparency of control information deteriorates (see FIG. 4). In particular, when exchanging messages between facsimile terminals, etc., the data length of image information etc. is larger than the data length of control information, and at the same time it is necessary to increase the data block length of image information etc. We need to improve our sexuality. FIG. 5 shows the facsimile communication procedure in T30 of the CCITT recommendation. For example, if the facsimile terminal is the calling party and the data exchange device is the called party, the data exchange device sends an MC to confirm the message within 3 seconds after the facsimile terminal sends an EOM signal indicating the end of the message.
It is necessary to tighten the F signal. In the figure, Dis
is a digital identification signal, DC8 is a digital command signal,
TcF is a training check signal, CF is a reception preparation confirmation signal, PIX is image information, and R'If'C is a control return signal.

An object of the present invention is to provide a priority level to a data transfer request set in a line control unit, and provide means for identifying the priority level of the data transfer request in the means for scanning the data transfer request. An object of the present invention is to provide a priority control method for data transfer requests that makes it possible to maintain transparency of data such as control information that requires immediacy even when the length is increased.

The present invention solves the problem that when increasing the data block length in order to improve data transfer efficiency in conventional data exchange technology, the delay time for transmitting information that requires immediacy such as control information increases. A priority level is set for transfer requests for data and control information from the line, and a means for identifying the priority level of the transfer request is provided in the communication control unit that monitors the line and controls block multiplex transfer. High priority level for sensitive data?
The present invention is characterized in that the block length of the transferred data can be increased without impairing the transparency of data transfer that requires immediacy.

Next, an embodiment of the present invention will be explained with reference to FIGS. 6 to 10.

First, FIGS. 6 to 8 show examples in which priority levels are set and scanned for transfer requests from the line side. In FIG. 6, a request to transfer general data with a large block length such as facsimile image information is set in #1, #2, and #4 of the line control unit 107, and $3. #
Considering the data exchange between facsimile terminals when a data transfer request such as control information requiring immediacy is set in 5, the following description will be made regarding two types of data: image information and control information. Now, as an initial value, the scan start address of the transfer request from the line control section 107 is set in the starting point buffer 1060 in the communication control interface section 106. After the scan of the transfer request starts, when the image information transfer request #1 is detected in #1 of the line control unit 107, the address of #1 of the line control unit 107 is set in the starting point buffer 1060, and the scan is continued. At this time, the image information is not transferred in response to the #1 transfer request from the line control unit 107.

Furthermore, the contents of the starting point buffer 1060 are held until the scan returns to the address set in the starting point buffer 1060. Next, the line control unit 107#3. which is detected before the scan address returns to the line control unit 107#1. Request for transfer of control information for $5 ◎1. ◎Execute the transfer of control information for 2 (see Figure 7).

Next, when the scan returns to the address (#1) of the line control unit 107 indicated by the origin buffer 1060, the communication control interface unit 1.06 again checks whether there is a transfer request,
Executes the image information transfer in response to the image information transfer request (3).

When a photon is transferred in response to the transfer request of the line control unit 107 $1, scanning of the transfer request is restarted, and transfers are sequentially executed in response to the control information transfer requests detected until the image information transfer request is detected, and the image information When a transfer request ■ is detected, the address (#2) of the line control unit 107 is set in the origin buffer 1060, and the control information transfer request (◎3) is sent until the transfer request scan returns to the address sent to the origin buffer 1060. (See FIG. 8). Similarly, by processing transfer requests for all other control information with priority before executing one transfer of image information, delays in transfer of control information can be avoided.

FIG. 9 shows the time relationship between the generation of the above-mentioned transfer request and the execution of data transfer. Referring to FIG. 9, the line control unit 107
#3. The maximum number of control information transfer requests set in #5 is 1
It can be seen that this is detected when the image information is transferred twice and the wait time for a maximum of one transfer request is detected.

In such a system, since the transfer priority control of the control information sent from the central processing unit 101 to the terminal device 109 can be controlled by upper-level software, there is no need to newly install a circuit. Furthermore, compared to a method that does not perform priority control for transfer of control information, the waiting time for scanning is longer, but it can be ignored compared to the waiting time for transferring data such as image information with a large data block length.

A first embodiment of a circuit installed in the communication control interface unit 106 for determining the priority level of a data transfer request is shown in the first embodiment.
Shown in Figure 0. In FIG. 10, in the initial state of the system, the VC sends a scan range instruction register (MAX) 502 to the last line control unit 10 within the range for which transfer request scanning is to be performed.
7 address is set, scan range instruction register (MINR) 503, starting point buffer (BUF) 506 .
The address of the first fat control unit 107 within the scan range is set in the scan address counter (CNT) 505. When a scan start instruction is issued from the central processing unit CPU, the data transfer control unit (TNS C0NT) 51
1 switches the gate of the selector circuit (SEL) 508 to the scan control unit side, and sends the address indicated by the scan address counter 505 to the bus connected to the line control unit CCU. Next, the line control unit CC indicated by that address
When the control information transfer request is detected by the scan control circuit (CONT) 510, the control information transfer request is all notified to the upper central processing unit CPU via the data transfer control unit 511. The central processing unit CPU thereby starts data transfer to the line control unit CCH at the address indicated by the scan address counter 505, and transfers the data to the data transfer control unit 51 of the communication control interface unit 106.
1. Selector circuit 508° interface circuit (FC)
After the transfer is completed, the scan control circuit 510 counts up the scan address counter 505 and moves the scan to the next line control. If an image information transfer control request is detected when reading the data transfer request, the value of the scan address counter 505 is set in the starting point buffer 506, the scan control circuit 510 counts up the scan address counter 505, and the next line control unit Move the scan to. Thereafter, scanning is performed sequentially, and when a request to transfer control information is detected, the control information is transferred until a scan completes one cycle and the value of the scan address counter 505 matches the value indicated by the starting point buffer 506, and when a request to transfer image information is detected. At this time, the data is not transferred and the scan is moved to the next one. When the address of the line control unit indicated by the scan range instruction register 502 matches the address of the line control unit indicated by the scan range instruction register 502, the scan control circuit 510 sets the contents of the scan range instruction register 503 in the scan address counter 505.
, 503 within the scan range specified. When the value of the scan address register 505 matches the value set in the starting point buffer 506.

The scan control circuit 510 includes a scan address counter 5
Reads the transfer request from the line control unit at the address indicated by 05,
If the image information transfer request is set, the image information is transferred in the same process as the control information transfer. When the transfer of the image information is completed, the scan address register 505 is counted up and scanning is moved to the next line control. Similarly, in the transfer request scan after image information transfer is completed, the address of the line control unit detected first is set to the starting point buffer 506.
, and the transfer in response to the control information transfer request is executed until the scan completes one cycle and matches the address indicated by the starting point buffer 506 . Image information is transferred by scanning or by going around the scan address counter 505 and starting point buffer 506.
This process is executed when the value of is 1 or more, and the control information is preferentially transferred without changing the starting point for sequentially transferring the image information.

As explained above, the present invention provides a priority level for a data transfer request from a terminal device, provides a means for identifying the priority level of the transfer request in the 1F3 control unit, and selects the priority level of the data transfer request from the terminal device. You can increase the block length and at the same time jtt
Transparency of highly temporal data such as control information can be increased.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing an example of a general data exchange method, and FIGS. 3 and 4 are diagrams showing a scanning method for data transfer requests in conventional pro-sock multiplex transfer.
FIG. 5 is a diagram showing a facsimile communication control procedure according to the CCI'l'T T30 recommendation as an example of a data transfer control procedure for data exchange, and FIGS. 6, 7, and 8 are data transfer methods according to the present invention. FIG. 9 is a diagram showing the time relationship between a data transfer request and data transfer execution in the present invention, and FIG. 10 is a diagram showing a specific configuration for realizing the present invention. be. 101...Central processing unit, 103...
Main memory. 105... Communication control device, 106...
Communication control interface section, 107... Line control section, 108... Line connection section, 109...
Data terminal equipment. 501...Scan control unit. (jji call side no (doukan 9a 41 @ Lila No. 50

Claims (1)

[Claims] In a data exchange device between terminal devices capable of data communication, a priority level is set for data transfer requests from the terminal devices, and data transfer requests from each line are monitored, and at the same time, data from the line where the data transfer request occurred is Data characterized in that a communication control unit that transfers data to a higher-level storage device using a block multiplex transfer method is provided with means for identifying the priority level of a data transfer request, and data transfer that requires immediacy is performed preferentially. Transfer request priority control method.