JPH04352264A - Input/output controller - Google Patents

Abstract

PURPOSE:To reduce the hardware quantity by providing an input/ output control part and an input/output switching part. CONSTITUTION:The input/output controller has the interface port for an input/ output device 7, the interface port for the other input/output controller, and input/output control parts 9 and 14 which performs input/output control over data, requests the switching with the other input/output controller, and permits the switching. Further, the controller has input/output switching parts 10 and 15 which switch the connections between the interface port for the input/output device 7 and input/output control parts 9 and 13, and the connections between the interface port for the input/output device 7 and the interface port for the other input/output controller under the control of the input/output control parts 9 and 14. Therefore, neither a conventionally necessary switching device dedicated to connection switching nor a device which sends a switching request to the switching device and waits for an answer is required when the input/output control parts 9 and 14 share the one input/output device 7, and then the hardware quantity is reducible.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input/output control device, and more particularly to an input/output control device that allows one input/output device to be shared by a plurality of input/output control devices.

0002

[Background Art] Conventionally, when one input/output device is shared by multiple input/output control devices, switching control of the input/output control devices connected to the input/output device is performed between the input/output devices and the input/output device. A switching request device was required to connect the switching device and to issue a switching request to the switching device.

FIG. 2 shows an example of the use of a conventional input/output control device. An input/output control device 31, a switching request device 35, and a main processing device 37 are connected to a system bus 39, and an input/output control device 32, a switching request device 36, and a main processing device 38 are connected to a system bus 40. When using the input/output device 34 from the input/output control device 31 connected to the same system bus 39 as the main processing device 37, first the main processing device 3
7 outputs a connection request with the input/output control device 31 from the switching request device 35 to the switching device 33. Switching device 33
If the main processing device 38 is not using the input/output device 34 more than the input/output control device 32, it connects the input/output device 34 and the input/output control device 31, and notifies the switching request device 35 of successful switching. , the switching process was completed.

0004

[Problems to be Solved by the Invention] In the conventional input/output control device described above, when one input/output device is shared by a plurality of input/output control units, a switching device dedicated to connection switching is required, and A device that performs switching control such as issuing a switching request to a device and waiting for a response is also required, which increases the amount of hardware.As the amount of hardware increases, costs also increase and reliability decreases. There are drawbacks.

[0005]

[Means for Solving the Problems] The input/output control device of the present invention has an interface port with the input/output device, an interface port with other input/output control devices, data input/output control, and communication with other input/output control devices. an input/output control unit that requests and permits switching between the input and output devices; an interface port with the input/output device and the input/output control unit; and an interface port with the input/output device and the other input/output control device. and an input/output switching section that switches the connection of the interface ports under the control of the input/output control section.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an input/output control device according to the present invention. The main processing device 3 uses the input/output device 7 from the input/output control device 1 connected to the same system bus 5, and the main processing device 4 uses the input/output device 2 from the input/output control device 2 connected to the same system bus 6.

Now, the input/output device 7 includes an interface cable 18 - interface port 11 - signal line 21 - input/output switching section 10 - signal line 22 - interface port 12
It is logically connected to the input/output control section 14 of the input/output control device 2 through the connections: - interface cable 19 - interface port 16 - signal line 23 - input/output switching section 15 - signal line 26 . When the main processing device 3 outputs data to the input/output device 7, the main processing device 3 gives a data output instruction to the input/output control device 1 via the system bus 5. A data output instruction from the main processing device 3 passes through a bus interface circuit 8 in the input/output control device 1 and reaches the input/output control section 9.

The input/output control section 9 receives a data output instruction from the main processing device 3, and first, the input/output switching section 10 switches the signal line 2.
1 is connected to the signal line 25 or the signal line 22. If the signal line 21 is connected to the signal line 25, it means that the input/output device 7 is also connected to the own device, and the process ends.

Now, since the signal line 21 is connected to the signal line 22, the input/output controller 9 detecting this connects the signal line to the input/output controller 14 of the input/output controller 2 via the interface cable 20. A switching request for switching the connection of 21 from the signal line 22 to the signal line 25 is output. When the input/output control unit 14 receives a switching request from the input/output control device 1 and is using the input/output device 7, the input/output control unit 14 sends a switching failure response to the input/output control device 1 via the interface cable 20. Let's do it. When the input/output control unit 9 receives a response indicating that switching is not possible from the input/output control device 2, it issues a switching request to the input/output control unit 14 of the input/output control device 2 until it receives a switching permission response from the input/output control device 2.

Next, when the input/output control device 2 finishes using the input/output device 7 while the input/output control device 1 is outputting a switching request, or 2 When the input/output control device 1 outputs a switching request, if the input/output control device 2 is not using the input/output device 7, the input/output control unit 14 of the input/output control device 2 that received the switching request is the signal line 23 for the input/output control unit 15.
After receiving the change instruction, the input/output switching section 15 switches the connection of the signal line 23 from the signal line 26 to the signal line 24.

Next, the input/output control unit 14 outputs a switching permission response to the input/output control device 1 via the interface cable 20. The input/output control unit 9 of the input/output control device 1 that received the switching permission response changes the connection of the signal line 21 to the input/output switching unit 10 from the connection to the signal line 22 to the signal line 2.
Upon receiving the change instruction, the input/output switching unit 10 switches the signal line 21 from the connection with the signal line 22 to the signal line 24.

With the above operation, the input/output device 7 connects the input/output control section 9 of the input/output control device 1 through the connection of the interface cable 18 - interface port 11 - signal line 21 - input/output switching section 10 - signal line 25. The main processing device 3 can output data to the input/output device 7.

Next, when the main processing device 4 outputs data to the input/output device 7, the above-described procedure is executed by replacing the input/output control device 1 and the input/output control device 2. The input/output device 7 is logically connected to the input/output control section 14 of the input/output control device 2, so that the main processing device 4 can output data to the input/output device 7.

[0015]

According to the present invention, when one input/output device is shared by a plurality of input/output controllers, a switching request is issued to a switching device dedicated to connection switching, which was conventionally necessary, and to the switching device. There is no need for a device that performs switching control such as waiting for a response, and the amount of hardware is reduced, and by reducing the amount of hardware, costs are reduced and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an input/output control device of the present invention.

FIG. 2 is a block diagram showing a case where one input/output device is shared by a plurality of conventional input/output control devices.

[Explanation of symbols]

1-2 Input/output control devices 3-4 Main processing devices 5-6 System bus 7 Input/output devices 8, 13 Bus interface circuits 9, 14
Input/output control section 10, 15 Input/output switching section 11-12, 16-17 Interface port 18-20 Interface cable 21-26
Signal lines 31-32 Input/output control device 33 Switching device 34 Input/output devices 35-36 Switching request device 37-38 Main processing device 39-40 System bus

Claims (1)

[Claims] [Claim 1] Input/output control for requesting and permitting switching between an interface port with an input/output device, an interface port with another input/output control device, data input/output control, and other input/output control devices. , the connection between the interface port of the input/output device and the input/output control section, and the connection of the interface port of the input/output device and the interface port of the other input/output control device. An input/output control device comprising: an input/output switching unit that performs control.