JPH0667771A - Switchover control system - Google Patents

Abstract

PURPOSE:To prevent logic abnormality from occurring in a main body device and an interface fault due to an unknown cause by a switching operation on the middle way of data transfer from occurring in an information processing system using plural main body devices and one peripheral unit by switching. CONSTITUTION:A switching operation control circuit 22 is provided in a switching device 20, and also, an unconnection pattern transmission circuit 24 which sends out a specific signal pattern set in an unconnected state and a selection circuit 25 which selects an input/output signal from a connected device or a signal from the pattern transmission circuit are provided at each of ports 41-4n connected to the main body devices 1-n. Furthermore, a pattern detection circuit 12 which detects the signal from the unconnection pattern transmission circuit 24 and outputs an interruption signal to a host CPU 11 is provided in each of the main body devices 1-n, and a connection state with the peripheral unit 30 is outputted until an unconnected pattern is re-connected after separation is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a switching control system, especially
The present invention relates to a switching control method in an information processing system in which one peripheral device is switched and shared with a plurality of main devices by a switching device.

[0002]

2. Description of the Related Art In the conventional switching control system of this kind, a changeover switch in a changeover device is changed by an operation,
When the selection of the connection destination port of the data switching circuit is changed by the instruction from the switching operation control circuit and the signal route between the peripheral device and the main unit is switched, the connection / disconnection operation is performed and the main unit of the host device is connected. The status has not been notified.

[0003]

In the above-mentioned conventional switching control system, since only the switching operation of connecting / disconnecting the interface between one peripheral device and N main units is controlled, one main unit is controlled. Is connected to the peripheral device, and the peripheral device is disconnected if the switching operation is performed and the connection is changed while there is no data transfer, but the main unit (CPU) that is the higher-level device has no notification that it has been disconnected. May be abnormal. Further, if a switching operation is performed during data transfer with a peripheral device, an interface failure may occur, resulting in an unknown failure.

[0004]

A method of the present invention is a switching control method in an information processing system in which one peripheral device is switched and shared by a plurality of main devices by a switching device. A switching operation control circuit for executing a switching operation by a switch is provided, and an unconnected pattern transmission circuit for transmitting a specific signal pattern in an unconnected state for each port connected to the main body device, and a peripheral device. And a selection circuit for selecting a signal from the unconnected pattern transmission circuit are provided, and a signal from the unconnected pattern transmission circuit is detected in the main body device, and the upper central processing unit is detected. A pattern detection circuit for outputting an interrupt signal is provided, and when the connection destination is changed by the changeover switch, an instruction of the changeover operation control circuit is given. After the port is disconnected completed connection between the peripheral device is disconnected Ri, characterized in that it operates as unconnected pattern is outputted until reconnection.

[0005]

1 is a block diagram of a switching device to which a switching control system according to a first embodiment of the present invention is applied.

The switching device 20 is composed of a common part for performing switching control and ports 41 to 4n each having an interface with the n main devices 1 to n. The common section includes a changeover switch 21, a changeover operation control circuit 22 that performs sequence control of a changeover operation of the present changeover device 20 by a changeover signal from the changeover switch 21, and a peripheral device 30 by a signal from the changeover operation control circuit 22. It is composed of a data switching circuit 23 that connects the interface to the ports 41 to 4n. Each of the ports 41 to 4n is an unconnected pattern transmitting circuit 24 that outputs an unconnected pattern when its own port is not connected to the peripheral device 30 via the data switching circuit 23,
It has a selection circuit 25 for selecting the signals of the data switching circuit 23 and the connection pattern transmission circuit 24.

Each of the main units 1 to n comprises a pattern detecting circuit 12 for detecting input / output data and an output pattern from the selecting circuit 25 in the switching device 20 and a CPU 11.

Next, the operation of this embodiment will be described.

At present, the peripheral device 30 is in a state of being connected to the main body device 1 via the switching device 20. When the changeover switch 21 is changed from the changeover state 0 to the changeover state 1 by operation, a changeover operation start signal is output to the changeover operation control circuit 22. Upon receiving the operation start signal, the switching operation control circuit 22 changes the selection signal output to the data switching circuit 23 from 0 to 1, and the unconnected pattern transmission circuit 24 selects the selection circuit 25 in the alarm and 41. The selection signal is output as described above. By this operation,
Before the switching operation is executed, the peripheral device 30 connected to the main body device 1 becomes a state in which it is not connected to all the main body devices 1 to n.

Next, a selection signal is output to the selection circuit in the port 42 so that the signal of the data switching circuit 23 is output to the main body device 2 with respect to the port 42 constituted by the same circuit as the port 41. After this operation is completed, the peripheral device 30 is connected to the main body device 2 through the port 42. On the other hand, in the port 41, the signal output from the unconnected pattern transmitting circuit 24 is output to the main body device 1 via the selecting circuit 25. This signal will be output until the switching state is changed again from 1 to 0 by the operation.
When the pattern detection circuit 12 in the main body device 1 detects a signal, the pattern detection circuit 12 outputs an interrupt signal 1 to the CPU 11. The CPU 11 can recognize that the peripheral device 30 has been disconnected by detecting this interrupt signal.

When the switching state is changed from 1 to 0, which is the reverse of this operation, the operation is the reverse of that described above, and the pattern detection circuit 12 in the main unit 1 receives the unconnected pattern,
It detects the disconnection of the peripheral device and interrupts the CPU 11. The pattern detection circuit 12 detects that the signal indicating the non-connection of the peripheral device from the port 41 disappears, and outputs an interrupt signal to the CPU 11. By detecting this interrupt signal, the CPU 11 can recognize that the peripheral device 30 has been reconnected.

FIG. 2 is a block diagram of a switching device to which the switching control system of the second embodiment of the present invention is applied. The switching device 50 includes the ports 4 in the switching device 20 shown in FIG.
A connection interrupt circuit 26 and a disconnection interrupt circuit are provided in place of the unconnected pattern transmitting circuit 24 in 1 to 4n. The other parts have the same structure as in the first embodiment.

The connection interrupt circuit 26 is provided in the data switching device 2
When the peripheral device 30 is disconnected via the data switching device 23, the disconnection interrupt circuit 27 generates an interrupt for a fixed period when the peripheral device 30 is connected via the data switching device 23.

Next, the operation of this embodiment will be described.

The peripheral device 30 is currently connected to the main unit 1 via the switching device 20. When the changeover switch 21 is changed from the changeover state 0 to the changeover state 1 by operation, a changeover operation start signal is output to the changeover operation control circuit 22. Upon receiving the operation start signal, the switching operation control circuit 22 changes the selection signal output to the data switching circuit 23 from 0 to 1 and the port 41.
A selection signal is output to the selection circuit 28 therein so that the disconnection interrupt circuit 7 is selected. By this operation, the peripheral device 30 connected to the main device 1 before the switching operation is not connected to all the main devices 1 to n.

Next, the selection signal is output to the selection circuit 28 in the port 42 formed of the same circuit as the port 41 so that the connection interrupt signal is output for a certain period, and then the signal from the data switching circuit 23 is selected. Output the selection signal. After this operation is completed, the peripheral device 30 is connected to the main body device 2 through the port 42. On the other hand, port 41
The signal output from the disconnection interrupt circuit 27 is output to the main body device 1 via the selection circuit 8 for a certain period. Main unit 1
When the internal pattern detection circuit 12 detects an interrupt signal, the pattern detection circuit 12 outputs an interrupt signal 1 to the CPU 11. By detecting this interrupt signal 1, the CPU 11 can recognize that the peripheral device 30 has been disconnected.

When the switching state is changed from 1 to 0, which is the reverse of this operation, the operation is opposite to that described above, and the pattern detection circuit 12 receives the disconnection interrupt signal and detects the disconnection of the peripheral device 30. Interrupt the CPU 11. The pattern detection circuit 12 detects the connection interrupt signal from the port 41 for a certain period and outputs the interrupt signal 2 to the CPU 11. The CPU 11 can recognize that the peripheral device 30 is reconnected by detecting the interrupt signal. Then, in response to an instruction from the switching operation control circuit 22, the port 4
Since the signal from the selection circuit 28 data switching circuit 23 in 1 is selected, after the CPU 11 recognizes the connection of the peripheral device 30, the actual peripheral device can be reconnected.

[0018]

As described above, according to the switching control system of the present invention, one main unit is in a connected state with the peripheral device, and the switching operation is performed to change the connection while the data transfer is not performed. Although the device is disconnected, the main unit, which is a higher-level device, has received a notification that the device has been disconnected, which can prevent a logical error, and if a switching operation is performed during data transfer with peripheral devices, an interface failure occurs. Even if the error occurs, it is possible to prevent an unknown failure due to the disconnection / connection information of the trace information peripheral device of the interrupt in the main device.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a block diagram of a second embodiment of the present invention.

[Explanation of symbols]

 1 to n Main unit 11 CPU 12 Pattern detection circuit 20, 50 Switching device 21 Changeover switch 22 Switching operation control circuit 23 Data switching circuit 24 Unconnected pattern transmission circuit 25 Selection (SEL) circuit 26 Connection interrupt transmission circuit 27 Disconnection interrupt transmission circuit 28 selection circuit 30 peripheral circuit 41 to 41n port

Claims (2)

[Claims] 1. A switching control method in an information processing system in which one peripheral device is switched and shared with a plurality of main devices by a switching device, and a switching operation control is executed in the switching device by a switching switch. A circuit is provided, and for each port connected to the main unit, an unconnected pattern transmission circuit that sends out a specific signal pattern in an unconnected state, an input / output signal from a peripheral device, and the unconnected pattern transmission. A selection circuit for selecting a signal from a circuit is provided, and a pattern detection circuit for detecting a signal from the unconnected pattern transmission circuit and outputting an interrupt signal to a higher-level central processing unit is provided in the main body device. When the connection destination is changed by the changeover switch, the connection state with the peripheral device is disconnected according to an instruction from the changeover operation control circuit. A switching control method that operates so that the port to be released is output until the unconnected pattern is reconnected after disconnection is completed. 2. A connection interrupt circuit for transmitting an interrupt for a change from an unconnected state to a connected state, and a disconnection for transmitting an interrupt for a change from a connected state to an unconnected state instead of the unconnected port transmitting circuit. An interrupt circuit is provided.
Switch control method described.