Electrical computers and digital processing systems: multicomput – Multicomputer data transferring via shared memory
Reexamination Certificate
1998-12-09
2001-03-06
Vu, Viet D. (Department: 2758)
Electrical computers and digital processing systems: multicomput
Multicomputer data transferring via shared memory
C709S214000, C709S226000, C714S005110
Reexamination Certificate
active
06199105
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recovery system for system coupling apparatuses (hereinafter called MSCPs) and a recording medium recording a recovery program for use in a computer system including a plurality of processors (hereinafter called hosts) and inter-host shared resources for common use by the hosts, the system coupling apparatuses controlling access from each host to the inter-host shared resources.
2. Description of the Related Art
The Japanese Patent Application Laid-open No. Sho 61-221956 discloses a prior art recovery system for an access control apparatus for use in a computer system wherein, upon issuance of requests for exclusive access to a shared resource by a plurality of data processing units (counterparts to the hosts under the present invention), a single access control apparatus (counterpart to the MSCP under the invention) holds locking information for the shared resource and exclusively controls accesses to that shared resource, whereby, in the event of any failure in the access control apparatus, the lock information in the access control apparatus is recovered according to lock information held by each data processing unit in its control table after the restoration of the access control apparatus.
This prior art recovery system for access control apparatuses, however, involves a problem that the computer system cannot resume its operation until the access control apparatus in trouble is restored and the lock information in the access control apparatus is recovered according to the lock information held by each data processing unit.
SUMMARY AND OBJECTS OF THE INVENTION
An object of the present invention is to enable a computer system, consisting of a plurality of hosts and a plurality of MSCPs, to continue processing of an application program (AP), i.e. the operation of the computer system, in the event of failure of any of the MSCPs during the operation of the computer system, by causing lock information held by all the MSCPs including the one in trouble at the time of the occurrence of the failure to be held distributively among the other MSCPs, without having to wait for the restoration of the MSCP in trouble.
Another object of the invention is to provide the computer system with a reserve MSCP so that, in the event of failure of any of the MSCPs during the operation of the computer system, the performance of the MSCPs pertaining to lock processing before the failure can be maintained after the occurrence of the failure by causing lock information held by all the MSCPs including the one in trouble at the time of the occurrence of the failure to be held distributively among the other MSCPs and the reserve MSCP.
Still another object is to improve, where one MSCP is newly added to a computer system, the performance of the MSCPs pertaining to lock processing by distributing lock information, held by each MSCP before the addition, among the MSCPs whose total number is now greater by one than before and having them perform lock processing.
A first recovery system for system coupling apparatuses according to the invention comprises a plurality of hosts and a plurality of coupling apparatuses for holding lock information on inter-host shared resources for common use by the plurality of hosts, wherein: each of said plurality of hosts requests one of the system coupling apparatuses to lock one of the inter-host shared resources, and stores lock information notified by the system coupling apparatus having locked the inter-host shared resource in compliance with the request; each of said plurality of system coupling apparatuses locks an inter-host shared resource whose locking has been requested by one of the hosts, holds lock information indicating that the inter-host shared resource has been locked, and notifies the requesting host of the lock information; one of said plurality of hosts, when one of said plurality of system coupling apparatuses fails, causes lock information held by other normal system coupling apparatuses to be deleted; and each of said plurality of hosts requests one of said other normal system coupling apparatuses to lock an inter-host shared resource on the basis of lock information stored in the requesting host.
A second recovery system for system coupling apparatuses according to the invention comprises a plurality of hosts, a plurality of coupling apparatuses for holding lock information on inter-host shared resources for common use by the plurality of hosts, and a reserve system coupling apparatus wherein: each of said plurality of hosts requests one of the system coupling apparatuses to lock one of the inter-host shared resources, and stores lock information notified by the system coupling apparatus having locked the inter-host shared resource in compliance with the request; each of said plurality of system coupling apparatuses locks an inter-host shared resource whose locking has been requested by one of the hosts, holds lock information indicating that the inter-host shared resource has been locked, and notifies the requesting host of the lock information; one of said plurality of hosts, when one of said plurality of system coupling apparatuses fails, causes lock information held by other normal system coupling apparatuses to be deleted; and each of said plurality of hosts requests one of a plurality of system coupling apparatuses consisting of said other normal system coupling apparatuses plus said reserve system coupling apparatus to lock an inter-host shared resource on the basis of lock information stored in the requesting host.
A third recovery system for system coupling apparatuses according to the invention comprises a plurality of hosts, a plurality of coupling apparatuses for holding lock information on inter-host shared resources for common use by the plurality of hosts, and a reserve system coupling apparatus wherein: each of said plurality of hosts requests one of the system coupling apparatuses to lock one of the inter-host shared resources, and stores lock information notified by the system coupling apparatus having locked the inter-host shared resource in compliance with the request; each of said plurality of system coupling apparatuses locks an inter-host shared resource whose locking has been requested by one of the hosts, holds lock information indicating that the inter-host shared resource has been locked, and notifies the requesting host of the lock information; one of said plurality of hosts, when it recognizes that another system coupling apparatus has been newly connected, causes lock information held by previously provided system coupling apparatuses to be deleted; and each of said plurality of hosts requests one of a plurality of system coupling apparatuses consisting of said previously provided system coupling apparatuses plus said newly connected system coupling apparatus to lock an inter-host shared resource on the basis of lock information stored in the requesting host.
A fourth recovery system for system coupling apparatuses according to the invention comprises a plurality of hosts and a plurality of coupling apparatuses for holding lock information on inter-host shared resources for common use by the plurality of hosts, wherein: each of said plurality of hosts requests one of the system coupling apparatuses to lock one of the inter-host shared resources, and stores lock information notified by the system coupling apparatus having locked the inter-host shared resource in compliance with the request; each of said plurality of system coupling apparatuses locks an inter-host shared resource whose locking has been requested by one of the hosts, holds lock information indicating that the inter-host shared resource has been locked, and notifies the requesting host of the lock information and an identifier of its own; one of said plurality of hosts, when it recognizes that one of said plurality of system coupling apparatuses has failed, notifies other hosts of the failure; and each of said plurality of hosts, if it is holding lock information includ
Fuju Takashi
Soejima Yasushi
NEC Corporation
Vu Viet D.
Young & Thompson
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