JPS602697B2 - Information processing system switching method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switching method for an information processing system that can switch to a standby system in a short time when a failure occurs in the active system or for inspection without using a synchronous operation circuit.

Because online real-time systems such as electronic exchanges require high reliability, two identical systems were operated synchronously.

This was because the system hardware did not have sufficient reliability; one system's central processing unit had a verification circuit that constantly verified the operation of the other system, allowing for early failure detection. is possible, but
High-speed processing was difficult. Recently, the reliability of hardware has improved, so a standby system is used instead of the above-mentioned verification circuit. This is to keep one system in active use and the other in standby mode, and when a failure occurs in the active system, switch to the standby system. FIG. 1 is an explanatory diagram of this system, in which system #0 has a central processing unit CCO and a main memory MMO, and system #1 has a CCI and MMI, with a synchronous operation circuit SYC between them. and an emergency control circuit EMC. The synchronous operation circuit SYC is configured to distribute the same clock to both systems, compare the operations of both systems, and synchronize interrupts. When a failure occurs in the active system or when switching systems to discover a potential failure in the backup system, the above-mentioned synchronous operation circuit SYC is used to perform emergency control to ensure that the operations of both systems match. Circuit EMC confirmed this and activated the system switching circuit SEX, making the backup system the active system. Naturally, this switching must be performed while minimizing processing interruption time. In the conventional working/standby switching system, the standby system serves as a synchronous operating state cover with the working system, and then the working system is disconnected, which requires some switching time. Another drawback was that the synchronous operation circuit was complicated. SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and provide a system for switching to a standby system using emergency control means that matches the contents of the main memory without using a synchronous operation circuit.

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

FIG. 2 shows a configuration diagram of an embodiment of the present invention, in which SEC is a switching order control circuit, SST is an intersystem information transfer circuit, GO0, G
O1, GI0, GII are gates, CC0, CCI are processing units, MM0, MMI are main storage units, and EMC is an emergency control circuit. FIG. 3 shows an explanatory diagram of the operation of the apparatus shown in FIG. If #0 is operating as the active system and #1 as the standby system and system switching is required, the processing unit CCO
The inter-system information transfer circuit SST operates in response to a command from the system switching order control circuit SEC, controls the gate GIO, and causes writing to be performed also in the spare main memory device MMI. That is, the active processing unit CCO transfers the transferred data to the backup main memory MMO by executing a write command to the active main memory MMO.
It is transferred to the same location as MMO in MI to match the internal customers of both main memory disks. At that time, the emergency control EMC is also activated, and the system switching circuit SEX temporarily stops both systems.
Perform a reset and then switch to #1. Interrupt circuit I
The TP operates, issues an emergency processing program, and starts control. Since the emergency processing program is stored at a fixed address in the standby MMI, it is executed. A reset operation of the emergency control circuit SEC is commanded in the emergency processing program, and the switching is completed. Note that the gates are controlled to open predetermined gates because they are used as appropriate depending on the location of failure in the main storage device/processing device for system switching operations.

In this way, according to the present invention, system switching can be performed without using a synchronous operation circuit, so it is economical without using a particularly complicated circuit, and the processing interruption time for switching can be completed in microseconds. Therefore, it is particularly effective when used in telephone switching systems.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a conventional standby system, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a diagram illustrating the operation of FIG. 2. CC0, CC1... Processing device, MM0, MM1
...Main memory, EMC...Emergency control circuit, S
EX...Skin system switching circuit, SEC...System switching order control victory, SST...Intersystem information transfer circuit, GO0, G
O1, GI0, GI1...Gate, ITP...
interrupt circuit. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 In the switching method of an information processing system in which two systems of processing units, each equipped with a main memory device and a peripheral device, are switched to the active system and standby system, when switching from the active system to the standby system, both systems a switching order control circuit that temporarily stops and resets the switching order control circuit; an emergency control means that obtains the output of the switching order control circuit and allows the spare system to execute a program from a fixed address in the main memory of the spare system; intersystem information transfer means for writing and controlling information to the storage device, and when switching to the backup system, the intersystem information transfer means makes the contents of the main storage devices of both systems match, and then the emergency control means transfers the contents to the backup system. A switching method for an information processing system characterized by switching to a system.