JPS6336025B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic computer system, and particularly to a multi-computer system in which data is transferred via an input/output bus shared by a plurality of computers.

In a computer system using a loop-shaped input/output bus, the same signal passes through all the input/output devices, so the same information can be transferred to all the input/output devices at the same time. This is so-called broadcast transfer. However, by adding multiple computers to the loop bus in parallel,
There is also a computer system in which a plurality of input/output devices are added in parallel and a loop bus is shared. However, all linkages with the loop bus are done through the station. At this time, the correspondence between the computer and the input/output device is arbitrary, and they enter into a specific correspondence relationship with each other according to instructions from the computer. Therefore, when there is a correspondence between a specific computer and a specific input/output device,
In other words, when a specific input/output device is occupied by a specific computer, if another computer issues a broadcast transfer instruction, the broadcast transfer will be performed even to the occupied input/output device. information will be transferred. The occupied input/output device is unrelated to the computer that performed the above-mentioned broadcast transfer, and cannot originally be the target of the broadcast transfer. Therefore, broadcast transfer cannot be directly adopted in computer systems such as those described above. An example of the contents of a command during broadcast transfer is to reset all input/output devices occupied by a computer, and leave other input/output devices that are not occupied in the same state without resetting them. There is a specific input/output device reset method. When resetting a specific input/output device, if broadcast transfer cannot be used as described above, a method is adopted in which a reset command is transferred to each input/output device individually. However, the overall processing time increases due to the fact that the reset command has to be transferred repeatedly, and that each input/output device needs to take it in, determine it, and perform reset processing on the receiving side. It has a drawback that increases as the number of output devices increases.

An object of the present invention is to provide a multi-computer system in which it is possible to reset corresponding input/output devices by broadcast transfer.

The gist of the present invention is to extend the function of determining the source of information on the loop bus to each station and determining whether or not to process this information effectively.
The point is that the input/output device was reset.

The details will be explained below. In the present invention, at least the station on the input/output device side is provided with an occupied computer table that displays occupied computers. The configuration is such that the upstream computer can send the reset command by broadcast transfer.
The station on each input/output device side detects the broadcast transfer and checks whether the upstream computer is the computer that has occupied the input/output device itself by searching the above table. If the reset command is from a self-occupied computer, the contents of the table are reset, and the input/output devices linked to the station are reset. Unless the reset command is from a computer that has occupied itself, it passes as is and no reset operation is performed.

Furthermore, the present invention is also applied to efficient combinations with error control methods. The details will be explained below.

Information on the loop bus is generally transferred on the loop bus in a fixed frame format, and error control schemes are used to increase the reliability of the information. For example, a station that receives a frame checks the frame for errors, and then
If it is correct, response information reflecting the state of the own station is returned to the sender; if it is incorrect, the received frame is treated as invalid. On the other hand, the transmitting station uses a method in which it detects that no response has arrived within a certain period of time, retransmits the same frame, and repeats this a certain number of times. here,
In order to prevent a retransmitted frame from being received twice, each frame is assigned a consistent number. This is managed individually between any two stations on the loop bus. Therefore, when a station starts up (for example, turns on the power), all stations in the loop bus (or stations that have the possibility to transfer information with that station) connect to and from that station. It is necessary to initialize the frame consistency number.
Since the object of the present invention is a computer system, we focused on the fact that information is transferred only between a certain computer and a certain input/output device. Stations that have as many frame consistency number management tables as the number of stations to which input/output devices are connected need only have as many frame consistency number management tables as the number of stations to which computers are connected. Furthermore, since the source of the transfer start is always the computer side, the initialization of these consistency numbers is based on instructions from the computer.

In the present invention, the frame consistency number is initialized by broadcast transfer, and all stations connected to input/output devices receive this frame at the same time, and initialize the frame consistency number management table corresponding to the frame transmission source. do. After such initialization, the station to which the computer to which the input/output device is connected is connected is stored in the aforementioned occupied computer table, and if the source of the frame matches this, It also has the function of resetting input/output devices.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram to which the present invention is applied. CPU1, 2, 3, and I/O4, 5,
6 is connected to a loop bus 7 via a station 8. The station 8 has a function of transmitting information to the loop bus 7 and transmitting received information to the CPU or I/O connected to the station 8. On the other hand, information exchange on the loop bus 7 is generally sent as a series of information called frames. FIG. 2 shows an example of a frame, which is compliant with, for example, high-level data transmission control (HDLC). SA is the frame source station address, C is the command,
DA indicates the receiving station address, G# is I/O control management information, DC is the frame length (for example, the number of bytes), FCS is the frame error check code, and F is the synchronization indicating the start and end of the frame. It is a code.

FIG. 3 shows a configuration diagram of a station 8 to which input/output devices are connected, which is an embodiment of the present invention. FIG. 4 shows the processing flow of the station control unit 17, and
The contents of tables 20 and 19 are shown in FIG.
The station 8 includes a receiver 9 that receives signals on the loop bus 7 and a transmitter 1 that sends signals to the loop bus 7.
0, shift register 11 that stores serial information from the loop bus, own station address register 12, common (global) address register 13, comparator 14, which detects address coincidence.
5. OR circuit 16 that takes the logical sum of the outputs of the comparators;
A station control unit 17 that controls the reception of frames for its own station, data exchange with input/output devices, etc., and an occupied station address table 19 corresponding to the aforementioned occupied computer table, corresponding to the station to which the computer is connected. , frame consistent number management table 20
It is composed of a control memory 18 having a.

Frames received from the loop bus 7 via the receiver 9 are sequentially stored in the shift register 11, and first, the DA at the beginning of the frame is input to the comparators 14 and 12. In the comparator, register 12
is compared with its own station address or the global address of the register 13, and if they match, the output of the OR circuit 16 is input to the station control section 17, which starts receiving the frame FL. It is assumed that the station control section 17 consists of a microprocessor. A flowchart of the frame FL receiving operation at this time is shown in FIG.

First, a frame is received and a check is made to see if there is a frame consistency number initialization command in command C. When performing data transfer with a normal input/output device, it is determined that the command is not the above-mentioned initialization command, and the rationality of various frames is checked.
At this time, a unique station address is designated as DA. The above rationality check uses the frame consistency number in the command C and the SA in the frame consistency number management table 20 in the control memory 18.
This means a check such as a comparison with the contents corresponding to the SA, or a comparison between the occupied station address table 19 and the SA. Here, the frame consistent number management table 20 is shown in FIG. 5, where addresses 1, 2, .
indicates the frame consistency number. This frame consistency number SR-i is a number held on a one-to-one basis by the transmitting station and the receiving station, and is added to the frame by the transmitting station, and is incremented by 1 upon normal completion. The receiving station checks for a match when receiving, and adds 1 if the reception has been completed normally. FIG. 5 shows that a consistent number is uniquely given and updated for each transmitting station on each computer side. The station number as an address in FIG. 5 is given by the sending station number SA, and the receiving station that has received the sending station number SA searches the table 20,
Reads the contents of the corresponding address (SA compatible), checks whether it matches the sent frame consistency number, and when it matches, determines normal reception, +1
do. This ends the rationality check for the consistent number.

If everything is normal as a result of the rationality check,
Data is transferred to and from the corresponding input/output device of the station.

The above is a case of executing data transfer with a normal input/output device. Next, the transfer of an initialization frame and its processing will be explained.

When a certain computer starts up and resets (initializes) the input/output devices related to the computer, the corresponding contents of the frame consistent number management table shall also be reset, and the frame at that time shall be Number initialization frame. A global address is set in the DA in the frame and sent. All stations receive this frame in the same manner as described above. After receiving the information, the station control section 17 performs processing according to the flowchart of FIG.

First, command C is checked to see if it is a frame consistency number initialization command. In the present example, it is determined that it is an initialization command. Then,
Search the frame consistent number management table 20,
Searches for the SA-compatible address in the received frame and resets (initializes) its contents. Therefore, if any consistency number has been set as the consistency number, it will be reset to "0".

Next, the occupied station address table 19
Search for the number of the occupied computer (in terms of station number, send station number SA)
and the SA in the received frame. If they match, it can be seen that the corresponding input/output device of the receiving station is occupied by the computer that sent the initialization frame. still,
In FIG. 6, table 19 can be formed by one register, code C1 indicates either reserved (occupied) RSV or free FREE, and SA ₁ indicates the occupied station number. By the combination of SA and SA ₁ , RSV is reset to FREE and SA ₁ is reset (initialized) to "0". After this initialization, the station performs a reset of the corresponding (linked) input/output device. For stations that do not match, the contents of the occupied station address table 19 are not reset, and the linked input/output devices are not reset either, maintaining the current status.

According to this embodiment, when initializing frame consistency numbers using broadcast transfer, it is possible to simultaneously perform a comparison with the occupied station address table and reset the input/output devices. In the system, the overhead of startup processing for individual computers can be greatly reduced. On the other hand, this frame can be sent several times from the computer side, but in this case,
Even if the station that executed the reset receives the same frame next time, the occupied station address table has been initialized, so there is no need to perform the reset process again, and the processing load on the station control unit (microprogram processing load) is reduced. can be made minimal.

FIG. 7 shows a station control section 17 configured with hardware instead of a microprocessor.
The configuration is shown below. This station control section 17 is
It consists of a buffer register 30, a decoder 31, a write/read circuit 32 for the table 20, a write/read circuit 33 for the table 19, and a rationality check circuit 34. In addition, there is hardware for data transfer between the input/output device and the computer, but it is omitted because it is not directly related.

The buffer 30 temporarily stores the frame FL. The decoder 31 takes in the frame FL and OR
It takes in the output 16A of the circuit 16, performs a predetermined decoding of the frame FL (this also includes a comparison to see if SA matches), and creates various necessary timings. The write/read circuit 32 initializes the consistent number of the corresponding SA in the table 20 when decoding the initialization command of the decoder 31. At other times, necessary write/read instructions are given to the table 20 to perform processes such as updating the consistency number. Read/write circuit 33
is the value of table 19 after initialization of table 20 is completed.
If it matches SA, reset the table.
Further, the read/write circuit 33 sets the occupied station in the table 19 when the command is not an initialization command. Furthermore, after completing the above series of initialization operations, the decoder 31 issues a reset command to the linked input/output device (I/O) to reset it. The rationality check circuit 34 sequentially takes in the frame data of the buffer 30 when there is no initialization command and performs a necessary rationality check. Part of the rationality check is also performed by the read/write circuits 32,33. This is an SA confirmation such as SA match confirmation.
This is a check regarding. As a result of the check, if it is reasonable, data is transferred to and from the input/output device.

Each of the above embodiments was based on the frame consistency number initialization command, but in addition to this initialization command, the table 19 can be initialized by an occupied station initialization command. Table 20 may be initialized by other commands, or table 20 may be initialized by other instructions.
Even in systems that do not have 0, initialization using the occupied station initialization command is preferable. Also,
This embodiment can also be applied to an open bus instead of a loop bus.

According to the present invention, when initializing a frame consistency number using broadcast transfer, it is possible to simultaneously perform a comparison with the occupied station address table and reset the input/output device. In this way, the overhead of startup processing for individual computers can be greatly reduced. On the other hand, this frame can be sent several times from the computer side, but in this case,
Even if the station that executed the reset receives the same frame next time, the occupied station address table has been initialized, so there is no need to perform the reset process again, and the processing load on the station control unit (microprogram processing load) is reduced. can be made minimal.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the computer system of the present invention, FIG. 2 is a frame configuration diagram, FIG. 3 is a diagram of an embodiment of the station of the present invention, FIG. 4 is a flowchart of the station control section, and FIG. FIG. 6 is a block diagram of the table, and FIG. 7 is a diagram of another embodiment of the station control section. 1, 2, 3... CPU, 4, 5, 6... Input/output device, 8... Station, 17... Station control unit, 18... Control memory.

Claims (1)

[Claims] 1. A common bus, a plurality of computers, a plurality of input/output devices, and a computer corresponding to each computer and each input/output device that link the plurality of computers, the plurality of input/output devices, and the common bus. The station corresponding to the input/output device has a frame consistent number table memory corresponding to the station corresponding to the computer, and an occupied station number for storing the computer number (or station number corresponding to the computer) occupying the input/output device. When a frame consistent number initialization command is sent from the computer via a broadcast transfer via the common bus, the station corresponding to each input/output device decodes the broadcast transfer and executes the broadcast transfer. Forwarding When the sender computer is registered in its own frame consistent number table, initializes the frame number corresponding to the sender computer, and displays the sender computer as being occupied in its own occupancy state memory. A multi-computer system configured to check whether the station is occupied, reset the display of the occupied state memory when the station is occupied, and initialize the input/output device corresponding to the station. 2. The multi-computer system according to claim 1, wherein the common bus is a loop bus. 3 In addition to decoding broadcast transfers, the station compatible with the input/output device described above has the function of decoding transfers addressed to its own station alone, and when decoding frame consistent number initialization command transfers addressed only to its own station, When the sending computer of the transfer is registered in its own frame consistency number table, initializes the frame consistency number corresponding to the sending computer, and assumes that the sending computer is occupying its own occupied state memory. Check whether it is displayed or not.
The multi-computer according to claim 1 or 2, wherein when the station is occupied, the display of the occupied state memory is reset, and the input/output device corresponding to the station is initialized. system.