JP3291729B2 - Redundant computer system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a duplicated computer system connected to a communication line, and more specifically, the computer system has a communication interface unit connected to the communication line therein, and a failure of the communication interface unit. The present invention relates to a redundant computer system that allows easy diagnosis.

[0002]

[Prior art]

2. Description of the Related Art As one method for improving the reliability of a computer system, a duplex system has been conventionally used. In this case, each computer has a function for diagnosing whether or not its own operation is normal. When a failure is detected in the computer system in the operating state, each computer is in the standby state. Are switched to engage in actual work. Here, the functions of the self-diagnosis mainly include a memory access check (detection of a parity error and a no response), a calculation check, and an I / O response check.

FIG. 5 is a conceptual diagram showing the internal configuration of one computer system. In the figure, 1 is a processor unit, 2 is connected to the processor unit 1 via an internal bus BS1,
This is a communication interface unit connected to the communication line L1. The processor unit 1 includes a microprocessor 11 and a memory 12
And an interface 13 to the internal bus BS1.
The communication interface unit 2 has a line interface 21, a buffer memory 22, and an internal bus interface 23.

As described above, when the communication interface unit 2 is provided inside the computer system, it is necessary to diagnose this part. The diagnosis of the communication interface unit 2 is performed using
Regarding the internal bus interface 22 and the internal bus interface 23, specific data can be easily written, read out, and collated as in the case of diagnosis of the memory of the processor unit. On the other hand, the line interface 21 connected to the communication line L1 is diagnosed by a loopback method such as reading back data once output to the communication line L1.

However, in a system in which the communication line L1 has a bus structure and a plurality of computer systems are connected, while another computer system is using the communication line, the communication is interrupted, and loopback is performed. There is a defect that the test cannot be performed.

[0006]

[Problems to be solved by the invention]

The present invention has been made in view of such problems,
Its purpose is to perform a fault diagnosis of the communication interface of Shiraki without affecting the communication of other computer systems,
An object of the present invention is to realize a redundant computer system that can improve reliability.

[0007]

[Means for Solving the Problems]

The present invention that solves the above-mentioned problem is a redundant computer system connected to a baton-path communication line that performs a communication operation when a communication right (batton frame) is transmitted to itself. A baton detector for detecting the baton frame of the above, a baton reception counter for updating the content when the baton detector detects the baton frame, and a content of the reception counter for reading the content of the reception counter even if a predetermined time or more elapses. If the contents are not updated, a determination unit is provided for instructing switching of the duplexing control so that the computer system which has been in the standby state performs actual work, and each computer system is connected to the communication line via the coupler unit. In addition, a prohibition switch for instructing prohibition of the communication function is provided in the coupler unit. Under the condition that the switch does not instruct the prohibition of the communication function, if the content of the reception counter is not updated even after the lapse of a predetermined time, the computer system that has been in the standby state performs actual work. Thus, a redundant computer system is characterized by instructing switching of redundant control.

[0008]

[Action]

The communication right (batton frame) indicating that communication can be performed via the communication line is to sequentially circulate through each system connected to the communication line. If the communication interface unit is normal, the number of each system connected to the communication line is reduced. The baton bleed is detected by the baton detector at predetermined intervals. The baton reception counter receives the detection of the baton frame by the baton detection unit, and the customer is updated.

If the operation of the communication interface unit is normal, the contents of the baton reception counter are updated every time the baton frame is visited. The determining unit determines whether or not the communication interface unit has failed based on whether or not the content of the baton reception counter is updated every predetermined time. Further, under the condition that the prohibition switch does not instruct the prohibition of the communication function, if the content of the reception counter is not updated even after a predetermined time has elapsed, the computer system which has been in the standby state until then is not updated. Is instructed to switch the redundant control so as to perform the actual work.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a structural block diagram showing one embodiment of the present invention. In the figure, FC1 and FC2 are duplicated first and second computer systems, both of which are connected to a communication line L1 and have almost the same configuration. In the first and second computer systems FC1 and FC2, 1 is a processor unit, 2 is a communication interface unit for a communication line L1, and is connected to the processor unit 1 via an internal bus BS1.

In the communication line L1, each computer system connected to the communication line L1 and a system other than these computers sequentially carry a communication right that allows access to this communication line, and the communication right is given to itself. A baton pass (also called a token pass) system that executes communication when it arrives is adopted. In the processor section 1, 14 is a ready signal generating means for outputting a ready signal based on the content of the self-diagnosis, 15 is a duplex control section for receiving the ready signal and controlling whether the apparatus itself is in an operation state or a standby state, Reference numeral 16 denotes a determination unit which receives a signal from a reading unit 26 of the communication interface unit, which will be described later, and controls the operation of the ready signal generation unit based on the value.

In the communication interface unit 2, reference numeral 24 denotes a communication line.
A baton detector that monitors the signal on L1 and detects that a baton frame indicating the communication right of the communication line L1 has circulated to itself, and 25 is the content of the baton frame when the baton detector 24 detects the baton frame. Is increased by "1", the baton reception counter 26 reads the contents of the reception counter 25,
This is reading means for sending the data to the determination unit 16 via the internal bus BS1.

FIG. 2 shows the first and second computer systems in FIG.
FIG. 3 is a diagram showing a connection relationship between respective duplex control units 15 in FC1 and FC2. NAND circuits NG1, NDY for inputting ready signals RDY1, RDY2 from the ready signal generating means 14 to each computer system, respectively.
G2 is provided, and the output of each NAND circuit is connected so as to be applied to the input terminal of the NAND circuit of the other computer system, so that the two NAND circuits constitute a flip-flop circuit. As a result, the side that activated the ready signal earlier activates the control permission signal IOSE to acquire the control right and enters the operating state, and the other side performs the duplex switching operation such that it enters the standby state.

Next, the operation of the system configured as described above will be described. Here, it is assumed that the first computer system FC1 is in the operating state and the second computer system FC2 is in the standby state. In the first computer system, when a communication request occurs, when a baton frame is turned around, that is,
The communication operation can be performed when the baton detection unit 24 receives the baton frame. Then, when the communication operation is completed (when transmission is completed), a baton frame is transmitted to the next computer system. If a baton frame addressed to the white part is received when there is no data communication request, the baton frame is immediately transmitted to the next computer system.

Here, the computer system that has transmitted the baton frame, after transmitting the baton frame, has a failure in the communication interface unit 2 of the next computer system and cannot receive the transmitted baton frame, or the communication according to the communication request. An error such that the frame cannot be transmitted or the baton frame cannot be transmitted to the next computer system is detected by monitoring the signal on the communication line L1. In a place where such an error is detected, the computer system changes the baton frame transmission destination according to a predetermined rule, and retransmits the baton frame to a computer system that can correctly receive the baton frame.

In this way, when a failure occurs in each of the computer systems and other systems connected to the communication line L1, the computer system in which the failure has occurred is removed from the route of the baton frame circulation, and normal operation is performed. The baton frame will circulate between the computer system and other systems that are performing. In the normally operating computer system, the baton detection unit 24 detects the baton frame every time the baton frame circulates to itself, and updates the contents of the baton reception counter 25. The reading means 26 reads the contents of the baton reception counter 25 and sends the contents to the determination section 16 via the internal bus BS1.

The judging unit 16 monitors the contents of the sent baton reception counter 25, and if the customer is updated every predetermined time (the time required for one round of the baton frame),
It is determined that the operation of the communication interface unit 24 is normal. On the other hand, if the customer of the baton reception counter 25 is not updated for a time longer than the predetermined time, it is determined that the baton frame cannot be received or transmitted because the communication interface unit 2 has a failure. When it is determined that a failure has occurred in the communication interface unit 2, the determination unit 16 instructs the ready signal generation unit 14 to make the ready signal RDY1 to the duplex control unit 15 inactive.

When the ready signal RDY1 becomes inactive in the duplex control unit 15, the output of the NAND circuit NG1 is inverted, and the flip-flop circuit composed of the NAND rotations NG1, NG2 is inverted. As a result, the control permission signal IOSE to the second computer system FC2 becomes active, the side is switched to the operating state, and the communication function is restored. Note that, in the second computer system FC2 in the standby state, the operation of the determination unit 16 described above is not particularly performed. The diagnosis of the communication interface unit 2 on the standby side is performed by the communication interface unit 2 of the computer system in the operating state.
Under the condition that the operation is normal, the diagnostic frame is transmitted via the communication line L1, and the diagnostic frame is received again.

FIG. 13 is a diagram showing the main components of another embodiment of the present invention. In the embodiment shown in FIG. 1, redundant control units for performing switching control of a redundant computer system are provided in the first and second computer systems, respectively. The dual control unit DXC is provided. In this case, the redundant controller DXC receives ready signals RDY1 and RDY2 directly from the first and second computer systems FC1 and FC2, and determines which side is to be activated according to the state of these signals. , And outputs a control permission signal.

The determination unit 16 detects a failure of the communication interface unit 2 based on whether or not the content of the baton reception counter 25 is updated at predetermined time intervals. If a failure is detected, the duplexing control unit Deactivate the ready signal to DXC.
This operation is the same as in the embodiment shown in FIG.

FIG. 4 is a configuration block diagram showing still another embodiment of the present invention. In this embodiment, the communication interface unit 2 of each computer system is connected to the communication line L1 via the coupler unit 3, and this coupler unit 3 has a prohibition switch 4 for stopping the transmission / reception function at the time of maintenance or the like. Is provided. The status signal indicating the connection state of the prohibition switch 4 is applied to each of the determination units 16 in the first and second computer systems FC1 and FC2. The coupler unit 3 modulates or demodulates a transmission signal or a reception signal. The prohibition switch 4 is turned on (prohibited state), for example, when performing maintenance, and prohibits the transmission / reception operation in this state. Removed.

In this embodiment, when the status signal from the prohibition switch 4 does not indicate the prohibition state, the determination unit 16 determines whether or not the contents of the baton reception counter 25 are updated at predetermined time intervals. When the status signal from the prohibition switch 4 indicates a prohibition state, the operation of the baton detection unit 24 is determined to be normal even if the content of the reception counter 25 is not updated every predetermined time. According to this embodiment, even when a prohibition switch for stopping the transmission / reception function is provided for maintenance or the like, a failure in the communication interface unit can be accurately detected.

In the above description, it is assumed that there is only one type of baton frame that circulates through the communication line L1. However, in addition to the normal baton indicating the communication right, a diagnosis for automatically recovering a failed system is performed. Prepare a diagnostic baton to make
The present invention is also applicable to a system in which the diagnostic baton circulates at a constant cycle. That is, in the case of such a system, the baton detection section may leave the contents of the reception counter intact in the case of a diagnostic baton, and update the internal customers of the reception counter only when a normal baton is detected.

[0024]

【The invention's effect】

As described above in detail, according to the present invention, a system capable of detecting a failure of a communication interface unit without affecting the communication operation and quickly switching the duplexing even in the case of a failure of the communication interface unit. Can be provided. Also, when a prohibition switch for prohibiting the transmission / reception function is provided for maintenance, a failure of the communication interface can be detected without affecting the state of the switch.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a duplex control unit.

FIG. 3 is a configuration block diagram showing another embodiment of the present invention.

FIG. 4 is a configuration block diagram showing another embodiment of the present invention.

FIG. 5 is a conceptual diagram showing an internal configuration of one computer system in a conventional device.

[Explanation of symbols]

 FC1 First control unit FC2 Second control unit L1 Communication line 1 Processor unit 2 Communication interface unit 14 Ready signal generating means 15 Duplex control unit 16 Judgment unit 24 ... Baton detection unit 25 ... Baton reception counter 26 ... Reading means

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-55-166755 (JP, A) JP-A-54-133002 (JP, A) JP-A-63-282857 (JP, A) JP-A-63-1988 70344 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06F 11/16-11/20 G06F 13/00 G06F 15/16-15/177 H04L 12/40-12/437

Claims (1)

(57) [Claims] 1. A dual computer system connected to a baton path communication line that performs a communication operation when a communication right (batton frame) is transmitted to itself, wherein each computer system detects a baton frame addressed to itself. A baton detection unit, a baton reception counter that updates the content when the baton detection unit detects a baton frame, and a case where the content of the reception counter is not updated even after a predetermined time has elapsed after reading the content of the reception counter. A determination unit for instructing switching of the duplex control so as to cause the computer system which has been in the standby state to perform actual work, coupling each computer system to a communication line via a coupler unit, and Unit is provided with a prohibition switch for instructing prohibition of the communication function. If the contents of the reception counter are not updated even after a predetermined time has elapsed under the condition not instructed, an instruction is given to switch the duplexing control so that the computer system that was in the standby state until then performs actual work. A redundant computer system characterized by the following.