JPS60245346A - Reception controlling system - Google Patents

Abstract

PURPOSE:To prevent a central processor from generating a useless processing load by inhibiting a transfer of an information frame, when no information part exists in a receiving information frame, in a reception controlling system. CONSTITUTION:When a communication processor 20 has received an information frame having no I part which is substantial data, a circuit control part 23 is set to a state for waiting for a start flag of a new receiving frame. Also, as for the information frame which has been received already, it is not transferred at all to a central processor, and said part becomes a state for waiting for a reception of the next frame. The communication processor 20 transfers the receiving frame to the central processor or a prescribed buffer of its main storage device, only when an information part exists in the receiving frame, and inhibits a transfer of the receiving information, when it has been detected that no information part exists, therefore, a main storage device buffer 22 and its control information are set to the initial state, and it is possible to constitute this system so that processing of the central processor is not required at all.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a communication control device for a computer system, and more particularly to a reception control method in a communication control device.

(b) Background of the technology A communication control device is a device that controls communication lines connected to a computer system, and generally connects directly to a central processing unit.
Alternatively, the main purpose is to connect via a channel device or the like and transfer input/output data of the communication line to the main storage device based on input/output commands from the central processing unit.

(c) Prior art and problems When the communication control device receives a command to receive data from the central processing unit, it performs predetermined inspection and processing on the format of the received information, the content of control information, etc., and also performs transmission error control processing, etc. and transfers the correct received information to a buffer on the main storage device designated by the central processing unit.

Some of such received information is meaningless even if it is passed to the central processing unit. A corresponding example can be found, for example, in the widely used high-level transmission control procedure, the so-called information frame, which is an information format for conveying data.

FIG. 1 shows the general format of this information frame.

Here, F is a flag indicating a frame division, A is an address field, C is a control field, ■ is an information (data) field, and FCS is a check field.

Information such as messages to be transmitted to the other party is normally placed in the I part, but there is no limit to the length of the message etc. in the I part, and even if there is no I part (length is 0), due to transmission control procedures. is recognized as a legitimate information frame format.

Therefore, in conventional communication control devices, even if an information frame is missing, if it satisfies the normal frame format and there are no transmission errors, it is transferred to the main memory and left to the central processing unit to handle.

However, such information frames are not normally used, but can be used for testing transmission control procedures, and may occur if there is an error in the processing function of the originator.

In any case, it is not necessary for the central processing unit; rather, since the buffer in the main memory is used to pass this data to the central processing unit, the central processing This had the disadvantage of causing

(d) Object of the Invention In view of the above-mentioned situation, an object of the present invention is to process unnecessary information in a central processing unit, especially received information frames without an information section, without creating unnecessary processing load on the central processing unit. The aim is to provide a reception control method that can

(B) Structure of the Invention According to the present invention, the purpose is to provide a communication control device that is connected to a central processing unit and a communication line and has a function of transferring information frames received from the communication line to the device according to instructions from the device. In the apparatus, this can be achieved by a reception control method having means for suppressing the transfer of the received information frame when the received information frame does not have an information section.

That is, in the communication control device, the received information is transferred to the central processing unit or a predetermined buffer of its main storage device only when the received information frame has an information section, and when it is detected that there is no information section, the received information is transferred. Since transfer is inhibited, the main memory buffer and its control information are saved in their initial state, and can be used as they are for transferring the next received information frame that normally has the information section. It is possible to eliminate the need for any processing by the central processing unit.

(f) Embodiment of the invention FIG. 2 is a block diagram of a communication control device according to an embodiment of the invention. The communication control device 20 is connected to the channel device of the central processing unit by an input/output control unit 21, and receives commands transferred by executing input/output commands of the central processing unit, and receives commands from the main storage of the central processing unit and the storage of this device. Controls data transfer to and from the device 22, etc.

The line control unit 23 connects to a communication line, receives data from the line, transmits data to the line, and performs processing for identifying received data. These controls are performed by line control words placed on the storage device 22 corresponding to lines. The line control word of each line has the format shown in FIG.
, a counter section 31 that points to the buffer position, and a check addition section 36.

The main control unit 24 is composed of a necessary program storage and a processor that executes the program, and controls the entire apparatus by executing the program. The main control section usually starts specified processing in response to an interrupt from the input/output control section 21 or the line control section 23.

Processing by the reception control system of the present invention will be explained with reference to FIGS. 4, 5, and 6. FIG. 4 is a flowchart of processing related to reception by the line control unit 23, and FIGS. 5 and 6 are flowcharts of processing related to reception by the main control unit 24. In the following explanation, it is assumed that a control procedure equivalent to a high-level transmission control procedure is used to control the line, and an information frame in the format shown in FIG. 1 is received. Also, the processing unit of information is, for example, 8 bits, and parts A and C in FIG.
The FC3 part consists of 8 bits and the FC3 part consists of 16 bits.

When the input/output control section 21 receives a command from the central processing unit, it stores it in the storage device 22 and issues an interrupt request signal to the main control section 24 .

The main control unit 24 receives the interrupt (11, processing step 7
0 (5th M), it is determined whether the interrupt request source is the input/output control unit 21 or the line control unit 23, and in the case of the former, processing step 72;
The latter branches to processing step 8o.

In this case, the input/output control unit 21 is empty, so in processing step 72, the command stored in the storage device 22 is determined,
If the command is a receiving operation command, the process branches to processing step 73; otherwise, the process branches to processing step 76. A description of the processing after step 76 will be omitted below.

In processing step 73, the main control unit 24 sets sequence 5 (11), which specifies flag reception, in the sequence number field 30 (FIG. 3) of the line control word of the line specified by the command °. is used to specify the control mode of each line to the line control unit 23 and to classify the processing of the main control unit 24.

The line control unit 23 sequentially scans the lines to be connected using a known method, and receives a code of a predetermined number of bits (8 bits in this example) for each line in processing step 40 (FIG. 4). When the code is received, the code is processed based on the line control word of the corresponding line in processing step 41 and subsequent steps.

In processing step 41, the processing branch destination is classified according to the sequence of the relevant line, and if the sequence S is old, the process proceeds to processing step 42 to determine whether the received code is a flag. If the code is a flag, an interrupt request signal is issued to the main control unit 24.

The main control unit 24 receives and classifies the interrupt as described above, and since it is a request from the line control unit, processing step 8
Branch to 0.

In processing step 80, processing is classified according to the sequence of the line control word of the line specified by the interrupt, and since the sequence is SQI, the process proceeds to step 81, where the sequence number part 30 of the line control word is assigned to the address part (first Figure A part) Update to sequence SQ2 that specifies the reception mode.

When the line control unit 23 receives the next code, the process proceeds to step 44, where the line control word check addition unit 36 performs an operation using the code, and the code is stored in the buffer pointed to by the counter unit 31 (buffer O in this case). and requests an interrupt to the main control unit 24.

Here, the check addition may be, for example, a computation of a remainder polynomial in a known error detection code system.

The main control unit 24 receives the interrupt and processes step 83.
The process proceeds to step 84, where it is determined whether or not the received code in address 0 of the line control word indicates a predetermined address. Also, the sequence number part 3° of the line control word is updated to the sequence SQ3 received by the control unit (part 0 in FIG. 1). If the received code is not the expected address value, the process branches to other processes starting from process step 85, but since this has no direct relation to the present invention, further explanation will be omitted.

The line control unit 23 also performs SO2 in sequence SQ3.
The main control unit 2 operates in the same manner as above, processes the next received code, and
Interrupt to 4. The main control section proceeds to step 86-- and performs processing such as determining the type of frame being received based on the received code in buffer O of the line control word. If the received code is indicative of an information frame, then in processing step 87 the received code is held in a separate buffer following the previous received code for this line, and the sequence of line control words is stored in the general character receive sequence 5114. Update to.

When the line control unit 23 receives the next code in sequence 5 (14 and SO2 (described later)), it proceeds to processing step 47, and if the value of the line control word count 31 is less than 2, it branches to processing step 55, As before, perform the multiplication process using the received code, store the received code in the buffer pointed to by count 31 (buffer 0 in this case),
In processing step 57, the value of the count 31 is incremented by 1, and the process returns to waiting for the next received code. In this case, no interrupt request is made to the main control unit 24 as before.

When the next code is received, it is processed in the same way as in the case of "-". However, the received code is stored in buffer l, and the value of count 31 becomes 2 due to the increment.

When the next code and subsequent codes are received, the process branches to process step 48 based on the determination in process step 47, and the previously received two codes are checked by the information frame check section (F in FIG.
e2). That is, in processing step 48 it is determined whether the received code is a flag, and if it is not a flag, processing similar to the above-mentioned processing steps 55 to 57 is executed in processing steps 51 to 53, except that in processing step 54, the main controller 24 interrupt.

In this case, when the main control unit 24 accepts the interrupt, it proceeds to processing step 90 or 91 (FIG. 6), and if the count 31 of the line control word is greater than 2, it branches to processing step 94, The received code is processed by the central processing unit.
Start the transfer process. That is, in processing step 94, the code in buffer 0 of the line control word is saved to another Hanosoa following the previously received code, and in processing step 95, the code in buffer 0 is saved in buffer 1.2.
The received code at is shifted to buffer 0.1, and in processing step 9G, sequence number 30 is placed in SO2, and the value of count 31 is set to 2. Also processing step 97
Then, a command is given to the human output control unit 21 to transfer the received code saved in another buffer to the central processing unit-1.

In processing step 48 of the line control unit, if the received code is determined to be a flag, the immediately preceding two received codes are Fe2 in FIG.
Therefore, the process branches to processing step 49, and if it is determined that the value of the check addition unit 36 of the line control word is in a predetermined normal state (for example, 0) according to the error detection code method, the main control unit 24 interrupt. If the above determination indicates that a transmission error has occurred, a recovery process or the like is started, but since this is not directly related to the present invention, the explanation will be omitted.

The main control unit 24 receives the interrupt, and in the normal case, the sequence is already S[15, so the processing step 91
In this case, since the line control word count is 2, the process branches to process step 92, resets the sequence number part of the line control word to 0, puts it in a dormant state, and processes step 9.
At step 3, the reception end process such as sending a response back to the sender is started. The received code in buffer O1■ of the line control word is a code for monitoring transmission errors and is not data to be processed by the central processing unit, so it is not transferred.

As a result of the above reception control processing, if two reception codes and the following flag are immediately received after receiving the 0th part of the information frame shown in FIG. If the sequence S is received, the sequence S
Since the state is Q4, the process advances from processing step 90 to processing step 93, and the sequence number of the line control word is sent to SQL. Therefore, from now on, the line control unit 23 is set to wait for reception of the start flag of a new received frame. The main control unit 24 then performs reception termination processing in the same manner as described above in processing step 93.

Therefore, in this case, nothing about the currently received information frame is transferred to the central processing unit, and the system waits for reception of the next frame.

(g) Effects of the Invention As is clear from the above explanation, according to the present invention, unnecessary processing load on the central processing unit due to passing unnecessary received information to the central processing unit is eliminated, so that the electronic computer system It has a significant industrial effect of improving the processing efficiency.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a frame format in a high-level transmission control procedure, FIG. 2 is a configuration diagram of a communication control device according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram of line control words in the communication control device. FIG. 4 is a flowchart of processing by the line control section, and FIGS. 5 and 6 are flowcharts of processing by the main control section. In the figure, 20 is a communication control device, 21 is an input/output control unit, 22 is a storage device, 23 is a line control unit, 24 is a main control unit, 30 to 36 are each part constituting a line control word, and 40 to 98 are Processing step: F is a flag, A is an address section, C is a control section, 1 is an information section, and FCS is a check section. Figure 1, 4. Engraving of the drawings (no changes to the contents) Engraving of the drawings (no changes to the contents) Mushrooms fIt'j, i'r departure station 1 person f1gi
'l [God≦Yll1 prefecture Kawasaki Yamanaka 1jl': I', 'N
No. 1015 out of 11 J11. ! (522) H (U, Fujitsu Ltd. 4 Agent II: +'+r God≦・Kawasaki Yamanaka, Kawa Prefecture H: 1015, 1st grade Ill inside Fujitsu Ltd. - 5, Amendment order II I・[

Claims (1)

[Claims] In a communication control device that is connected to a central processing unit and a communication line and has a function of transferring an information frame received from the communication line to the device according to a command from the device, when the received information frame does not have an information section, A reception control system comprising means for inhibiting the transfer of the received information frame.