JPH1131032A - Connection switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly and accurately switch connections between devices without being affected by the fault, state, etc., of devices before connection switching. SOLUTION: This device 101 is so constituted as to switch connections between host devices connected to host buses 111 (bus signal 1211) to 112 (bus signal 1212) and devices connected to a device bus 113 (bus signal 1221). A switch 261 for indicating a switching chance to a switching control part 221, a reset issue part 231 and a reset issue part 241 which issue reset signals to the host device and device sides under the control of the switching control part 221, and a bus signal switching part 251 which switches connections of the host buses 111 and 112 and device bus 113 are provided; and the reset signal is issued at the time of connection switching to initialize the host device and devices, thereby preventing malfunction caused by the trouble that obstacle before switching is carried forward beyond the switching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection switching technology, and more particularly to a technology effective when applied to a connection switching operation between a host device and a device in a configuration in which a plurality of host devices share a device under the control. .

[0002]

2. Description of the Related Art For example, in an information processing system or the like, from the viewpoint of improving the availability of devices and improving fault-tolerant performance, etc.
Multiple host devices and multiple subordinate peripheral devices
Are connected via a switching device or the like, and an arbitrary host device and an arbitrary device are selectively connected according to the operation status.

For example, Japanese Unexamined Patent Publication No. Hei 5-324525 discloses that a plurality of SCSI buses on a computer side and a plurality of SCSI buses on a magnetic tape unit side are connected in order to selectively connect one magnetic tape unit to SCSI buses of a plurality of computers. A switching device is interposed between the SCSI device and the SCSI bus, and a selection switch provided on the switching device is externally operated, whereby
A configuration for connecting one magnetic tape device to any one computer is disclosed.

[0004]

However, according to the above-mentioned prior art, for example, when a failure occurs before switching in a computer or a magnetic tape device, or when a failure occurs between a specific computer and a magnetic tape device. If a failure occurs due to connection switching during data transfer, the failure will be carried over after the switching operation, which may cause a failure in the I / O operation after switching or cause a malfunction. Technical problem.

[0005] Even if no failure occurs,
For example, if the connection is switched while the magnetic tape device is holding a command operation issued from a specific computer, then the magnetic tape device resumes the operation of the command whose operation was suspended, or the computer There is a concern that a malfunction of the switching procedure may cause malfunctions, such as continuing to wait for a response to an I / O command issued before the switching, or issuing an unnecessary I / O command from the computer after the switching to the magnetic tape device. Technical problem.

In order to avoid the latter technical problem, for example, after switching occurs, an operator manually operates each computer to transfer I / O processing among a plurality of computers. Complicated measures such as instructing the connection state of the magnetic tape device and separately providing communication means for notifying the occurrence of switching between the computers have been required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a connection capable of performing an accurate connection switching operation of a device group by reliably preventing a malfunction after connection switching due to a failure in each device before connection switching. It is to provide a switching technique.

Another object of the present invention is to provide a connection switching technique capable of smoothly and accurately transferring input / output processing at the time of connection switching according to the execution state of each device before connection switching. is there.

Another object of the present invention is to provide input / output processing at the time of connection switching according to the state of each device before connection switching without requiring complicated measures such as operator intervention or redundant communication means. An object of the present invention is to provide a connection switching technique capable of performing a smooth and accurate transfer.

[0010]

SUMMARY OF THE INVENTION The present invention resides between a first group of devices including at least one first device and a second group of devices including at least one second device, In a connection switching device for performing a switching operation of a connection between an arbitrary first device and an arbitrary second device, resetting at least one of a first device group and a second device group in conjunction with the switching operation. A reset signal generating means for issuing a signal is provided, and prior to the connection switching operation, each device to be connected after the switching is securely initialized.

Further, the present invention is provided between a first group of devices including at least one first device and a second group of devices including at least one second device, and includes an arbitrary first device. Device, and a connection switching device that performs a switching operation of a connection with an arbitrary second device, in conjunction with the switching operation,
A message information generating means for issuing a message information to a plurality of first devices of the first device group to perform a transfer operation of an input / output process between the first devices.

More specifically, as an example, for example,
When a plurality of host devices are connected to a plurality of subordinate shared devices, means for issuing a reset to the shared device in conjunction with the switching operation to guarantee the operation of the shared device after the switching, and a host in association with the switching. Means for allowing the host device to recognize that the connection of the device has been switched by issuing a reset or notification message to the device, and for transferring the I / O processing between the host devices; The system is provided with at least one of means for issuing a reset to the host device when a failure occurs in the host bus, thereby guaranteeing the host operation after switching.

[0013]

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

In the following description, as an example, a case where the connection switching device of the present invention is applied to an information processing system in which a plurality of subordinate devices are shared by a plurality of host devices will be described.

First, as a first embodiment, a connection switching device in a case where there is only one host device on the same bus will be described with reference to FIG. 1, FIG. 2, and FIG.

FIG. 1 is a conceptual diagram showing an example of the configuration of an information processing system provided with a connection switching device according to the present embodiment.

The connection switching device 101 includes a host bus 1
11 and a host bus 1
12 is connected to the device 106 and the device 1 connected to the device bus 113.
07 functions as a switching device for sharing.

FIG. 2 is a functional block diagram showing an example of the configuration of the connection switching device 101 of the present embodiment. In the figure, the connection switching device 101 includes a switch 261
, Switching control unit 221, bus signal switching unit 25
1, reset issuing unit 231 and reset issuing unit 241
It is composed of

The switch 261 is a switch for instructing the host device 102 and the host device 104 and the connection state of the devices 106 to 107 shared by them. The switch 261 may be manually operated by an operator or the like, or may be operated by software or the like.

The switching control unit 221 constantly monitors the state of the switch 261, and when switching is performed, uses the bus signal switching unit 251 to control the host buses 111 to 112.
And the device bus 113, issues a reset to each of the devices 106 to 107 using the reset issuing unit 241, and issues a reset to each of the host device 102 and the host device 104 using the reset issuing unit 231. .

Next, the host device 102 and the host device 10 in the information processing system of the present embodiment described above.
4 and the devices 106 to 10 shared by them
The operation of switching the connection of No. 7 will be described. FIG.
9 is a flowchart illustrating an example of a switching processing procedure performed by the connection switching device 101 according to the present embodiment.

When the power of the connection switching device 101 of this embodiment is turned on, the switching control unit 221 controls the bus signal switching unit 251 to connect the bus signal 1211 and the bus signal 1221 depending on the state of the switch 261 or The bus signal 1212 and the bus signal 1221 are connected (Step 300).

By this connection operation, any one of the host device 102 and the host device 104 and the devices 106 to 107 to which the connection is instructed by the switch 261 are connected to the I / O device.
Command operation can be performed.

Thereafter, the switching control section 221 constantly monitors the state of the switch 261 and waits for a connection switching instruction (step 305).

When switching is instructed by operating the switch 261, the switching control unit 221 switches the bus signals 1211 to 1212 on the host device side and the bus signal 1 on the device side.
221 (step 310),
The reset issuance unit 241 is controlled to issue a reset to the devices 106 and 107 (step 3).
15), controlling the reset issuing unit 231 to control the host device 1
A reset is issued to the host device 02 and the host device 104 (step 320). Thereby, the host device 10
2 to initialize the states of the host device 104 and the devices 106 to 107, and
A notification for transferring the I / O processing during the period 04 is issued.

Thereafter, the switching control section 221 controls the bus signal switching section 251 to connect the bus signal 1211 and the bus signal 1221 or the bus signal 1212 and the bus signal 1221 depending on the state of the switch 261 (step 3).
60) By doing so, one of the host devices 102 to 104 and the devices 106 to
7 enables an I / O command operation.

Thereafter, the process returns to the monitoring of the switch 261 (step 305), and the same processing is repeated.

In the embodiment having the configuration illustrated in FIG. 1, the host device 102 and the host device 104
Are independently connected to the connection switching device 101 via the respective host buses 111 and 112, so that the operation of notifying each of the host device 102 and the host device 104 of the occurrence of the connection switching is performed. Could simply be done by issuing a reset.

However, when there are two or more host devices on the same bus and the signal for transmitting the reset is shared between the host devices, the host device issues a reset as a means for notifying the device of initialization. The other host device has no means for identifying whether the reset is a reset from the connection switching device or a reset issued by the other host device, so the reset cannot be used as a notification that the switching has occurred.

Then, as a second embodiment,
4, 5, and 6, a case where the connection switching technique of the present invention is applied to a configuration in which a plurality of host devices exist on the same bus and a signal for transmitting reset is shared between the host devices. explain.

FIG. 4 is a conceptual diagram showing an example of the configuration of an information processing system including the connection switching device according to the second embodiment. The connection switching device 401 includes a plurality of host devices 402 and 403 connected on a common host bus 411 and a plurality of host devices 404 and host devices 40 connected on a common host bus 412.
5 is the device 40 connected on the device bus 413
6 and the device 407 are switched.

FIG. 5 is a functional block diagram showing an example of the configuration of the connection switching device 401 according to the second embodiment.

In the figure, the connection switching device 401
Include a switch 561, a switching control unit 521, a bus signal switching unit 551, a message issuing unit 535,
It comprises a reset issuing unit 531 and a reset issuing unit 541.

The switch 561 is connected to the host devices 402 to 40
3 and host devices 404-405 and devices 406-
A changeover switch 407 indicates a connection state.
The switching control unit 521 constantly monitors the state of the switch 561, and when the switching is performed, controls the connection between the host buses 411 to 412 and the device bus 413 by using the bus signal switching unit 551, and sets the reset issuing unit 541 to Issue a reset to each of devices 406-407 using
Using the message issuing unit 535, the host devices 402-4
05 is sent out.

As a method of sending a message to the host device by the message issuing unit 535, when the host buses 411, 412 and the device bus 413 are, for example, SCSI buses, the connection switching device 40 is used.
It is conceivable that an independent SCSI_ID is assigned to 1 and the message issuing unit 535 executes a reselection phase in the SCSI protocol for each host device using the SCSI_ID.

The message issuing unit 535 uses the bus signal switching unit 551 to change all the host devices 402 to 405.
Are sequentially connected, and a message is issued for causing the host devices 402 to 405 to recognize that the connection has been switched. If a failure occurs in the host buses 411 to 412 when a message is issued to the host devices 402 to 405, the host devices 402 to 405 are reset by using the reset issuing unit 531 as bus recovery means.

Next, an example of the operation of switching the connection between the host devices 402 to 405 and the devices 406 to 407 in the above information processing system will be described. FIG.
Is the connection switching device 40 according to the second embodiment.
13 is a flowchart illustrating an example of a switching processing procedure of FIG. When the power of the apparatus is turned on, the switching control unit 521 controls the bus signal switching unit 551 to change the bus signal 1511 and the bus signal 15 according to the state of the switch 561.
21 or the bus signal 1512 and the bus signal 1521 are connected (step 600).

With this connection operation, any one of the host devices 402 to 405 and the devices 406 to 407 to which the connection is instructed by the switch 561 can perform the I / O command operation.

Thereafter, the switching control section 521 constantly monitors the state of the switch 561 and waits for a connection switching instruction (step 605).

When switching is instructed by operating the switch 561, the switching control unit 521 controls the bus signal switching unit 551 to switch the bus signal 1511 and the bus signal 152.
1 or bus signal 1512 and bus signal 152
1 (step 610), and controls the reset issuing unit 541 to control the devices 406 and 40.
7 is reset (step 615) to initialize the states of the devices 406 and 407.

Next, a message is issued to all the host devices 402 to 405 by using the message issuing unit 535. That is, the message issuing unit 535 controls the bus signal switching unit 551 to control the bus signal 1511 (host bus 411) connected to the host device 402.
And the bus signal 1501 (step 620).
Thereafter, the host device 402 is connected (step 62).
5) By issuing a message notifying that the connection switching has occurred (step 630), a notification for transferring the I / O processing between the host devices is issued.

If a failure occurs in issuing a message to the host device 402 (step 635), the message issuing unit 535 uses the reset issuing unit 531 to send a bus signal 1501 and a connected bus signal 1511 to the host device 402. A reset is issued (step 640), and if the number of retries in the host device 402 is equal to or less than a predetermined value (step 642), the message is retried (step 630). If the number of retries exceeds a predetermined value, it is determined that a severe failure has occurred, and a connection switching device 40 is provided to notify an operator or the like of the occurrence of the severe failure.
A lamp (not shown) provided outside the first housing is lit (step 644), and the function of the connection switching device 401 is stopped (step 646).

If the message is successfully issued (step 635), the message is similarly issued to the host device 403 which is another host on the bus signal 1511 (host bus 411) (step 650), and the bus is issued. The issue of the message is completed to all the host devices 402 to 403 on the signal 1511 (host bus 411).

The series of operations from step 620 to step 650 as described above is also performed on all the host devices 404 and 405 on the host bus 412 (bus signal 1512) (step 655).

Thereafter, the switching control section 521 controls the bus signal switching section 551 to connect the bus signal 1511 and the bus signal 1521 or the bus signal 1512 and the bus signal 1521 depending on the state of the switch 561 (step 660). , Any one of the host devices 402 to 405 indicated by the switch 561 and the device 4
Each of 06 to 407 can perform an I / O command operation.

Thereafter, the process returns to the monitoring of the switch 561 (step 605), and the same processing is repeated.

As described above, by using the connection switching device of the present invention exemplified in each of the above-described embodiments, regardless of the state of each host device or device before switching and the timing of the connection switching operation, By automatically issuing resets to all devices, devices can be initialized before switching and faults can be automatically recovered.For example, malfunctions caused by device failure status being carried over after switching, etc. Generation can be reliably avoided.

Further, by issuing a message or reset to all the host devices, the host device can be surely recognized that the connection of the device has been switched. For example, an extra communication line or the like is provided. In addition, it is possible to smoothly and accurately transfer the I / O processing which has been put on hold at the time of switching between the host devices, and by issuing resets to all the host devices, Is initialized, the failure can be automatically and reliably recovered before the connection is switched, and the effect of reliably preventing the occurrence of a malfunction due to the fact that the failure of the host device is carried over after the connection is switched is obtained. .

Further, the operation of the information processing system including the connection switching device according to the present embodiment does not require any intervention by an operator or the like in the recovery of the failure of the host device or the device or the I / O transfer processing at the time of the connection switching. And the efficiency of operation work are improved.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say, there is.

[0051]

According to the connection switching apparatus of the present invention, it is possible to reliably prevent the occurrence of a malfunction after connection switching due to a failure or the like in each device before connection switching, and to perform an accurate connection switching operation of the device group. Can be performed.

Further, according to the connection switching device of the present invention, it is possible to smoothly and accurately transfer input / output processing at the time of connection switching according to the execution state of each device before connection switching. Can be

Further, according to the connection switching device of the present invention, it is not necessary to take complicated measures such as operator intervention or redundant communication means, and the connection switching device can be used at the time of connection switching according to the state of each device before the connection switching. The effect of being able to smoothly and accurately transfer input / output processing is obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an example of a configuration of an information processing system including a connection switching device according to a first embodiment of the present invention.

FIG. 2 is a functional block diagram illustrating an example of a configuration of a connection switching device according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating an example of a switching processing procedure of the connection switching device according to the first embodiment of the present invention.

FIG. 4 is a conceptual diagram illustrating an example of a configuration of an information processing system including a connection switching device according to a second embodiment of the present invention.

FIG. 5 is a functional block diagram illustrating an example of a configuration of a connection switching device according to a second embodiment of the present invention.

FIG. 6 is a flowchart illustrating an example of a switching processing procedure of the connection switching device according to the second embodiment of the present invention.

[Description of References] 101: connection switching device, 102: host device (first device)
Device), 104... Host device (first device), 106
… Device (second device), 107… device (second device), 111… host bus, 112… host bus, 1
13: Device Bus, 221: Switching Control Unit, 231
... Reset issuing unit (reset signal generating means), 241 ...
Reset issuing unit (reset signal generating unit), 251 bus signal switching unit, 261 switch, 401 connection switching device, 402 to 405 host device (first device), 406 to 407 device (second device) ), 41
DESCRIPTION OF SYMBOLS 1 ... Host bus, 412 ... Host bus, 413 ... Device bus, 521 ... Switching control part, 531 ... Reset issue part (reset signal generation means), 535 ... Message issue part (message information generation means), 541 ... Reset issue part (Reset signal generating means), 551: bus signal switching unit, 561: switch, 1211: bus signal, 12
12 bus signal, 1221 bus signal, 1501 bus signal, 1511 bus signal, 1512 bus signal, 15
21 Bus signal.

Claims (3)

[Claims] A first device including at least one first device;
And a second device group including at least one second device, and performs an operation of switching connection between any of the first devices and any of the second devices. A connection switching device, comprising: reset signal generation means for issuing a reset signal to at least one of the second devices in the second device group in conjunction with the switching operation. apparatus. 2. A first device comprising at least one first device.
And a second device group including at least one second device, and performs an operation of switching connection between any of the first devices and any of the second devices. A connection switching device, comprising: reset signal generating means for issuing a reset signal to at least one of the first devices in the first device group in conjunction with the switching operation. apparatus. 3. A first device comprising at least one first device.
And a second device group including at least one second device, and performs an operation of switching connection between any of the first devices and any of the second devices. A connection switching device, wherein message information is issued to a plurality of the first devices in the first device group in conjunction with the switching operation, thereby transferring input / output processing between the first devices. A connection switching device comprising a message information generating means for performing an operation.