JPS62259156A - Input and output device - Google Patents

Abstract

PURPOSE:To avoid adverse influence against other input/output devices even in case an input/output device is forcibly removed, by forming a loop circuit to apply an active signal of a driver/receiver to an interface circuit. CONSTITUTION:The active and inactive states of input/output devices 2A and 2B of a magnetic disk device, etc. are controlled by a selection signal received from a controller 1. Then data are transferred between the controller 1 and both devices 2A and 2B via a driver/receiver 5. The active signal is applied to the driver/receiver 5 via the loops 4 of interface circuits 3 of both devices 2A and 2B. These loops 4 are formed in an application mode of power supply. When the power supply of the devices 2A and 2B is cut off, the loops 4 are opened. Thus no active signal is applied to the driver/receiver 5 and therefore both devices 2A and 2B become inactive. Furthermore, the active signal is cut off when a splice cable is forcibly removed between both devices 2A and 2B when the power supply is applied. Then the devices 2A and 2B are separated from a bus and therefore adverse influence is never given to other input/output devices.

Description

[Detailed Description of the Invention] [Summary] Equipped with input/output devices with a redundant configuration such as a duplex configuration, the control device The driver/receiver between the two is forcibly rendered inactive and disconnected from the bus so as not to adversely affect the other input/output device, thereby preventing system failure.

[Industrial application field]

The present invention relates to an input/output device having a redundant configuration such as duplex or triplex.

A system is known in which input/output devices such as a magnetic disk device, a magnetic drum device, or a printer are duplexed or triplexed to improve reliability. In such a redundant configuration of input/output devices, it is necessary to be able to select any input/output device and control its operation, and also to be able to maintain the selected input/output device.

(Prior Art) In a conventional example in which input/output devices such as magnetic disk drives have a redundant configuration, for example, as shown in FIG. The operation and non-operation of 42A and 42B are controlled, and the operation and non-operation of bidirectional buffers 43A and 43B between the control device 41 and the input/output devices 42A and 42B are also controlled by the selection signal. For example, when operating only one input/output device 43A, the buffer 43A is also controlled to be in the operating state by a selection signal from the control device 41, and data between the control device 41 and the input/output device 42A is is transferred via the buffer 43A. In that case, since the buffer 43B is in an inactive state, even if the power to the other input/output device 42B is turned off or the connection cable is removed, the input/output that is currently in operation will be transferred. This does not affect the device 42A. Therefore, maintenance work on the input/output device 42B becomes possible.

[Problem that the invention seeks to solve]

If the connection cable of either input/output device is removed while both input/output devices 42A, 42B are in operation and data is being transferred from the control device 41 to the input/output devices 42A, 42B, instability may occur. Since the signal is output from the buffer, it will affect the other input/output device and cause it to malfunction, and in the worst case, the system may go down.

An object of the present invention is to prevent other input/output devices from being adversely affected even when a redundant input/output device is forcibly removed.

[Means for solving problems]

The input/output device of the present invention has a loop circuit for adding a driver/receiver operable signal to an interface circuit of a redundant input/output device, and will be described with reference to FIG. The operation and non-operation of the input/output devices 2A, 2B such as magnetic disk and disk devices are controlled by selection signals from the control device 1, and data etc. between the control device 1 and the input/output devices 2A, 2B are controlled by a driver. - Transferred via receiver 5. The operable signal of the driver/receiver 5 is applied via the loop 4 of the interface circuit 3 of the input/output devices 2A and 2B, and this loop 4 is formed when the power is turned on.

[Effect]

When the power to the input/output devices 2A and 2B is turned off, the loop 4 is released, so the operable signal is no longer applied to the driver/receiver 5, and the loop 4 becomes inactive. Furthermore, if the connection cables of the input/output devices 2A and 2B are forcibly removed when the power is turned on, the operable signal applied to the driver/receiver 5 will be cut off, and the input/output devices 2
Since person 2B is disconnected from the bus, it will not adversely affect other input/output devices.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram of an embodiment of the present invention, in which 11 is a control device, 12A and 12B are input/output devices, 13 is an interface circuit, 14 is a loop circuit, 15 is a driver/receiver, and 16 to 24 are drivers/receivers. Receiver section, 25-30
31 and 32 are busses, 31 and 32 are selection signal lines that supply selection signals from the control device, 33 and 34 are operable signal lines, 35 is a processor, 36 is a magnetic disk control section, and 37 is a magnetic disk section.

The input/output devices 12A and 12B are magnetic disk devices, and include a magnetic disk unit 37 controlled by a magnetic disk control unit 36, an interface circuit 13, and a processor 35, and the interface circuit 13 includes a loop circuit 14. It is provided. This loop circuit 14 forms a loop when the input/output device is powered on.
It can be configured with transistors, relays, etc.

When a loop is formed by this loop circuit 14,
Operational signal! 33.34 to apply an enable signal to the driver/receiver 15. In addition, the input/output devices 12A and 12B are connected to selection signal lines 31 and 32 from the control device.
Operation or non-operation is controlled by a selection signal applied via the .

The buses 25 and 28 also connect the control device 11 and the magnetic disk unit 2.
The bus 26.29 is a bidirectional bus for transferring data between the control device 11 and the input/output device 12A,
This is a bus for transferring control signals that control the 12B.

The buses 27 and 30 are buses for transferring response signals and status signals from the input/output devices 12A and 12B to the control device 11.

The driver/receiver 15 is provided between the control device 11 and the input/output devices 12A, 12B, and is connected to the driver/receiver units 19 to 21 corresponding to the input/output device 212A and the input/output device 1.
2B compatible driver/receivers 22 to 24, and an operable signal consisting of a ground potential or a predetermined +■ potential formed in the driver/receiver 15.
The driver/receiver section 19.21 is connected to the operable signal line 33 via the loop circuit 14 of the interface circuit 13.
In addition to the driver/receiver sections 22 and 24, the operable signal line 34 also connects the driver/receiver section 19,
21, 22, and 24 are put into an operating state, and when the enable signal is turned off to put them into a non-operating state, they are disconnected from the bus. In addition, the driver/receiver section 20.2
Although it is possible to add an operation enable signal to 3 as well, since the control signal is sent from the control device 11, the case is shown in which it is always in the operating state.

A selection signal is applied from the control device 11 to the input/output devices 12A, 12B via the selection signal lines 31, 32, respectively, to bring them into an operating state, and when the input/output devices 12A, 12B are powered on, the loop circuit 14 is activated. A loop is formed,
An enable signal is applied to driver/receiver sections 19.21, 22.24 via enable signal line 33.34. A control signal is sent from the control unit fill, and the driver
When applied to the interface circuit 13 of the input/output devices 12A and 12B via the receiver 20.23 and the bus 26.29, the magnetic disk control unit 36 and the magnetic disk unit 37 are activated under the control of the processor 35, and the interface A response signal is sent from the circuit 13 to the control device 11.

The control device 11 transmits the response signal to the driver/receiver section 18.
When the data is sent out after being received by the controller, the data is added to the interface circuit 13 via the driver/receiver section 19.22 and the bus 25.28, and is written to the magnetic disk section 37 via the magnetic disk control section 36. .

That is, the same data is written from the control device 11 to the magnetic disk units 37 of the input/output devices 12A and 12B.

When reading data written to the magnetic disk unit 37, if the input/output device 12A is the active system, the magnetic disk unit 37 of the input/output device 12A is activated to read data, and the magnetic disk control is performed. from the bus 25 to the driver/receiver 1 via the interface circuit 13
9.16, the control device 11 processes the read data.

For example, when the power to the input/output device 12A is forcibly turned off, the loop of the loop circuit 14 is released, the operable signal applied to the driver/receiver section 19.21 is disconnected, and the driver/receiver section 19. .21 becomes inactive. Therefore, since the input/output device 12A is disconnected from the control device 11, it does not have any influence on the input/output device 12B, which is in an operating state when the power is turned on.

Also, if the connection cable of the input/output device 12A is forcibly removed, even if a loop is formed in the loop circuit 14,
The driver/receiver section 19 is connected via this loop circuit 14.
．． Since the operable signal applied to 21 is disconnected by disconnecting the connection cable, the driver/receiver unit 19.21 becomes inactive, and in this case as well, the input/output device 12B, which is powered on and in operation, is disconnected. It will not have any negative impact.

As for the input/output device 12'B, as described above, if the power is forcibly turned off during operation or the connection cable is forcibly removed, the other input/output device 12
It will not have any negative impact on A.

The input/output device 12A sends the operable signal via the aforementioned operable signal lines 33 and 34 to the control device 11.

When transferring it as 12B status information and indicating that it is operational,
It may also be possible to identify that the input/output devices 12A, 12B are in a normal state.

〔Effect of the invention〕

As explained above, the present invention provides interface circuits 3.13 for input/output devices 2A, 2B, 12A, and 12B with redundant configurations such as duplexing and triplexing that are activated by selection signals from the control device 1゜11. , loop 4 when the power is turned on
(loop circuit 14) and applies an operable signal to the driver/receiver 5.15 via this loop 4. When the power to an input/output device in operation is turned off, its input/output Since the loop 4 of the device interface circuit 3.13 is released and the operable signal is disconnected,
Control device 1. It will be in a state where it is separated from ll, and will not affect other input/output devices. Also, when the connection cable of the input/output device is forcibly removed while the power is on, the operation enable signal is no longer applied to the driver/receiver 5, 15, and the driver/receiver 5, 15 becomes disconnected from the control device 1.11, and the This will not affect other input/output devices. Therefore, even if an erroneous operation is performed during maintenance or the like, other operating input/output devices are not affected, so there is an advantage that the system will not go down.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a block diagram of a conventional example. 1.11 is a control device, 2A, 2B, 12A, 12B are input/output devices, 3.13 is an interface circuit, 4 is a loop, 14 is a loop circuit, 5.15 is a driver/receiver,
31 and 32 are selection signal lines, and 33 and 34 are operable signal lines.

Claims (1)

[Claims] In input/output devices (2A), (2B) with a redundant configuration that are activated by a selection signal from a control device (1), an interface of the input/output devices (2A), (2B) A loop (4) is formed in the circuit (3) when the input/output devices (2A) and (2B) are powered on;
a driver-receiver (5) between said control device (1) connected to said interface circuit (3) via a
An input/output device characterized by having a configuration for adding an operable signal to the input/output device.