Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Reexamination Certificate
1999-02-16
2002-04-23
Shin, Christopher B. (Department: 2182)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
C710S104000, C714S006130, C714S013000
Reexamination Certificate
active
06378021
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to various types of computers such as a personal computer (PC), a work station (WS), a server machine, an office computer, a minicomputer, and a mainframe, and more particularly to an information processing apparatus for data transfer via a crossbar switch in a multiprocessor configuration.
2. Description of the Related Art
A tightly coupled multiprocessor configuration which shares a main storage is prevailing among server machines and high end PC and WS. Improvements on the performance and function of a data transfer system for connecting a plurality of CPU's, and a main storage, and a plurality of I/O devices are becoming an important issue. A configuration using crossbar switch connection is one of such data transfer system configurations. In a tightly coupled multiprocessor system, even if one CPU among a plurality of CPU's becomes defective, the whole system runs down. In order to improve the reliability of the whole system, the whole system is multiplexed by using a hot standby configuration or the like. Multiplication of the whole system uses a general method by which a plurality of systems are prepared and used as active and standby partition. For a configuration using crossbar switch connection, a method is known by which the connection of the crossbar switch is logically divided into a plurality of groups each group running as an independent system to provide both the active and standby partition in a single system. In any of the above methods, information necessary for exchange between the active and standby partition is stored in a non-volatile external storage device such as a hard disk.
The method by which a plurality of systems are prepared and used as active and standby partition is described, for example, in JP-A-7-60399. The method by which the connection of a crossbar switch is logically divided into a plurality of groups each group running as an independent system to provide both the active and standby partition in a single system is described, for example, in “Technical White Paper: The Ultra Enterprise 10000 Server”; Sun Microsystems, Inc.; 1997 (appearing on the home page of Sun Microsystems, Inc. in the USA: http://www.sun.com/). With the above-described method of conventional techniques by which the connection of a crossbar switch is logically divided into a plurality of groups each group running as an independent system, it is necessary to reboot the whole system in order for an individual system to change settings of the division configuration.
For a so-called massively parallel type multi-processor system, a method of improving the system reliability regarding a CPU failure is provided by which a defective CPU is logically disconnected from CPU's of a processor array and the system is dynamically reconfigured. Techniques regarding this are disclosed, for example, in U.S. Pat. No. 5,129,077.
With the conventional techniques for the above-described massively parallel multiprocessor system, a defective CPU is logically disconnected and the system is dynamically reconfigured. This method is based upon that each CPU constituting the massively parallel type multiprocessor system is provided with input/output interface compatible with the function described above. There arises therefore a problem that these techniques cannot be applied to server machines and high end PC and WS which use commercially available CPU's not compatible with such a function.
Conventional techniques used for server machines and high end PC and WS multiplex the whole system in order to improve the system reliability. For example, if the system is doubled, the cost is at least double if the method is incorporated by which a plurality of systems are prepared and used as active and standby partition. Also with the method by which the connection of a crossbar switch is logically divided into a plurality of groups and each system is provided with both the active and standby partition, it is necessary to reboot the whole system in order for an individual system to change settings of the group division configuration. Therefore, in order to avoid a reboot during an ordinary operation of the system, the system is required to exchange the active partition with a standby partition without changing the group division configuration. It is therefore necessary for the standby partition to prepare in advance all system resources other than the system resources of the active partition. Namely, the standby partition is required to prepare additional important system resources such as CPU's and a main storage having the same scale as those of the active partition. There arises therefore a problem that although the frame, power source and the like can be shared, the cost of the important system resources such as CPU's and a main storage is doubled so that the cost of the whole system becomes very high.
With the above-described conventional techniques by which the connection of a crossbar switch is logically divided into a plurality of groups, the system cannot change the group division configuration during the ordinary operation of the system. Therefore, if the system is to be provided with auxiliary system resources, each group is required to independently have the auxiliary system resources. There arises therefore a problem that the cost of the auxiliary system resources becomes high.
SUMMARY OF THE INVENTION
It is an object of the present invention: to suppress an increase in cost of an information processing apparatus having a crossbar switch configuration, such as servers and high end PC and WS, wherein each system changes the division configuration of groups without rebooting the whole system, and in a hot standby system, system resources used by an active partition are included in a standby partition when the active partition is exchanged with the standby system; and to improve a system reliability to a level equal to multiplication, i.e., to a level allowing to exchange an active partition with a standby partition of a scale equal to that of the active partition when a fault occurs in the active partition, while an increase of the cost is suppressed.
It is another object of the present invention to shorten an exchange time required for each system to change from an active partition to a standby partition in a hot standby system of information processing apparatus having a crossbar switch configuration.
It is another object of the present invention to provide a system having a plurality of groups with standby system resources capable of being included in an arbitrary group.
It is another object of the present invention to provide a multiprocessor system with a crossbar switch connection capable of changing the group division configuration during an operation of the system without rebooting the whole system.
In order to achieve the above objects of the invention, in an information processing apparatus with a crossbar switch connection, when the connection of the crossbar switch is logically divided into a plurality of groups, the apparatus changes the group division configuration without affecting the logical operation other than the operation of the crossbar switch of the apparatus. Namely, the logical division is set to registers in LSI constituting the crossbar switch, and the apparatus interrupts all transfers through busy control or the like in a sync state of the whole crossbar switch to thereby make the operation other than that of the crossbar switch stand and to change the setting in the registers of LSI during the interruption.
More specifically, according to the present invention, the apparatus has two sets of registers for setting the group configuration of logical division, and setting values of one of the two sets of registers are always used, and the values of the other set are neglected. The apparatus also has a change instruction register for instructing a change in the group configuration of logical division, and the apparatus changes the group configuration of lo
Okada Yasuyuki
Okazawa Koichi
Tarui Toshiaki
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Shin Christopher B.
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