JPS6116355A - Bus switching device of data transfer system - Google Patents

Abstract

PURPOSE:To make an input/output controller other than the input/output controller whose power source is turned off transfer data normally, by providing bus switching devices, which have the function to by-pass an input/output bus, for input/output controllers connected to the input/output bus. CONSTITUTION:If a power source P of bus switching devices 10 and 11 is turned off, a coil RL of a relay is degaussed, and a relay circuit A is switched to a contact a2, and thereby, a transfer request signal line (REQ)201 and a transfer request acceptance signal line (ACK)102 are connected to an REQ101 and an ACK202 directly respectively without passing internal circuit elements 150 of an input/output device IOC2. Since bus switching devices 10, 11,... are provided, the REQ and the ACK do not pass the internal circuit of the IOC, whose power source is turned off, but skip over it to transfer data to the next IOC by functions of bus switching devices though the power source of the prescribed IOC is turned off, and a conventional trouble that data transfer is impossible does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a path switching device for a data transfer system in which a data channel device and a plurality of input/output control devices are connected by a set of input/output paths.

[Prior art and its problems]

An example of the configuration of a conventional data transfer system is shown in FIG.

In FIG. 1, for example, a transfer request signal line (hereinafter referred to as REQ) 301 issued from an input/output control device (hereinafter referred to as IOC) 4 is transmitted via internal circuit elements of 10C3 and 10C2 to REQ 201.

This becomes the REQIOI and is finally transmitted to the data channel device 1.

In addition, in response to the above REQIOI, the data channel device 1
The transfer request acceptance signal line (hereinafter abbreviated as ACK) 102 that is issued by l0c2. ACK 202 and ACK 302 in order via the internal circuit elements of l0C3,
Finally, it is transmitted to l0C4. Note that 110 is a data and address bus. Now, if we consider the case where the power supply to the internal circuit elements of IOC2 or IOC3 is turned off, there is a drawback that the data transfer operation of IOC4 becomes completely impossible in either case.

(Objective of the Invention) An object of the present invention is to provide a bus switching device for a data transfer system that eliminates the above disadvantages by preventing an IOC whose power is cut off from having an adverse effect on the data transfer operations of other IOCs. purpose.

[Structure of the invention]

To avoid this, the configuration of the present invention connects a data channel device and a plurality of input/output devices with a set of input/output buses, and a transfer request signal line output from the input/output control device and a response of the transfer request signal line. A transfer request acceptance signal line outputted from the data channel device as a transfer request reception signal line transfers data via circuit elements inside a plurality of input/output control devices connected between the input/output control device and the data channel device. In the data transfer system, a bus switching device is provided between each input/output control device and the transfer request signal line and the transfer request acceptance signal line, and power supply to circuit elements inside the input/output control device is cut off. In this state, the transfer request signal line and the transfer request acceptance signal line are bypassed within the bus switching device without passing through the input/output control device.

[1 Example of the invention] Next, one embodiment will be described with reference to the drawings.

FIG. 2 is a circuit configuration diagram of a data transfer system to which an embodiment of the bus switching device of the data transfer system according to the present invention is applied, and FIG. 3 is a circuit configuration diagram of the bus switching device.
In each figure, the same parts as in FIG. 1 are given the same reference numerals, and their explanations will be omitted.

In the figure, a transfer request signal line (REQ) 101, a transfer request acceptance signal line (ACK) 102, REQ 201,
A bus switching device 10 of an input/output control device (IOC) 2 is provided between the ACK 202 and the switching device 10 and the l0C2.
Connect to 06.

Similarly, REQ 201, ACK 202 and RE
Another bus switching device 11 is provided between Q301 and ACK 302, and the switching device 11 and l0C3 are connected to REQ2.
03, 205 and ACK 204, 206.

The IOCs after 10C4 are also connected in the same way, but are omitted from the diagram.

Here, the bus switching devices 10.11 and the bus switching devices connected to the IOCs after 10C4, which are omitted in the figure, are all the same.

In FIG. 3, the bus switching device 10 is composed of a relay coil RL controlled by a power supply P supplied to an internal circuit element 150 of the l0C2, and relay circuits A and B controlled by the coil RL. Ru.

When the power supply P is on, the relay coil RL is energized, the relay circuit A falls to the al side, and REQ201 becomes RE
Q 105 and IOC2 (7) are transmitted to the data channel device l via the internal circuit element 150 as REQ 103 and REQ 101.

At the same time, relay circuit B falls to the bl side, and ACK102 becomes A.
CK 104 , the internal circuit element 151 of IOC2 is transferred to subsequent IO as ACK 106 , ACK 202
It is transmitted to C.

When the power supply P is off, the coil RL of the relay is demagnetized, the relay circuit A falls to the a2 side, and the relay circuit B falls to the b2 side, so that REQ 201, AC
K 102 is directly REQ 101 without passing through the internal circuit element 150 of l0C2.

Connected to ACK202.

According to K, bus switching devices 10, 11 . ... is provided, so even if the power to a given IOC is cut off, the function of the path switching device will allow fi REQ and ACK to be processed without going through the internal circuits of the IOC whose power was cut off. Data can be skipped and transferred to the next IOC, and the inconvenience of being unable to transfer data unlike the conventional example does not occur.

(Effects of the Invention) As explained above, according to the path switching device of the data transfer system according to the present invention, the path switching device has the function of bypassing the input/output path of the input/output control device connected to the input/output bus. By providing this, the effect is that input/output control devices other than the input/output control device whose power has been cut off can normally transfer data.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a conventional data transfer system;
The figure is a circuit configuration diagram of a data transfer system to which an embodiment of the path switching device of the data transfer system according to the present invention is applied, and FIG. 3 is a circuit configuration diagram of the path switching device. 1°°゛Data channel device 2.3.4... Input/output control device (IOC) 10.11
...Path switching device 110...Data and address bus 150.151...Internal circuit element R of input/output control device
L...Relay coil A, B...Relay circuit

Claims (1)

[Claims] A data channel device and a plurality of input/output control devices are connected by a set of input/output buses, and a transfer request signal line output from the input/output control device and a transfer request signal line output from the data channel device in response to the transfer request signal line are connected. In a data transfer system in which a transfer request reception signal line transfers data via circuit elements inside a plurality of input/output control devices connected between the input/output control device and the data channel device, each input/output control A bus switching device is provided between the device and the transfer request signal line and the transfer request acceptance signal line, and the bus switching device is provided between the transfer request signal line and the transfer request acceptance signal line when the power supply supplied to the circuit elements inside the input/output control device is in a disconnected state. A bus switching device for a data transfer system, characterized in that the transfer request reception signal line is configured to be bypassed within the bus switching device without passing through the input/output control device.