Data access management system in distributed processing system
First Claim
1. A data access management system in a distributed processing system comprising:
- a plurality of computers connected to each other under a network environment; and
a shared disk,wherein each of said computers has an access control subsystem capable of retaining a write-only token which specifies an area in the shared disk and represents authority to exclusively write data onto a specified area in the shared disk, and a read-only token which specifies an area in the shared disk and represents authority to non-exclusively read data from a specified area in said shared disk, said access control subsystem writes, when retaining a write-only token, data on the area specified by the write-only token, and said access control subsystem reads, when retaining a read-only token, data from the area specified by the read-only token,wherein any one of said computers has a management subsystem for uniquely generating a write-only token for every area in the shared disk, respectively issuing the generated write-only tokens for an access control subsystem requesting a write-only token, and generating a read-only token for an area for which no write-only token has been issued and issuing the generated read-only token to an access control subsystem requesting a read-only token, said management subsystem recording which access control subsystem is issued with a write-only token and which area is specified by the same write-only token, andwherein at least one of said computers has a standby management subsystem for eliciting, if said management subsystem is incapable of continuing the process, from each of said access control subsystems whether or not it retains a write-only token and which area is specified by its retaining write-only token, generating a write-only token for an area which is specified by no write-only token responded from any access control subsystem and recording which access control subsystem is issued with a write-only token and which area is specified by the same write-only token based on a response to the elicitation from an access control subsystem.
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Accused Products
Abstract
A data access management system in a distributed processing system capable of immediately restoring the system as a whole, has computers connected to each other via LAN, and a secondary storage device to which the computers are connected via data transfer paths. An access control subsystem for executing a data access to the secondary storage device is executed on each of the computers. A file management subsystem for giving an authority for writing the data to each access control subsystem, is executed on specified computer. When the file management subsystem transmits, to a certain access control subsystem, access control information indicating the authority for writing the data to a specified block on the secondary storage device, the same access control information is saved in the transmitted-side access control subsystem, and its record is retained in the file management subsystem. If the file management subsystem falls into a process-down, a standby file management subsystem is determined to become a new file management subsystem. Then this standby file management subsystem requests each of the access control subsystems to notify of the access control information saved by each of the access control subsystems.
54 Citations
8 Claims
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1. A data access management system in a distributed processing system comprising:
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a plurality of computers connected to each other under a network environment; and a shared disk, wherein each of said computers has an access control subsystem capable of retaining a write-only token which specifies an area in the shared disk and represents authority to exclusively write data onto a specified area in the shared disk, and a read-only token which specifies an area in the shared disk and represents authority to non-exclusively read data from a specified area in said shared disk, said access control subsystem writes, when retaining a write-only token, data on the area specified by the write-only token, and said access control subsystem reads, when retaining a read-only token, data from the area specified by the read-only token, wherein any one of said computers has a management subsystem for uniquely generating a write-only token for every area in the shared disk, respectively issuing the generated write-only tokens for an access control subsystem requesting a write-only token, and generating a read-only token for an area for which no write-only token has been issued and issuing the generated read-only token to an access control subsystem requesting a read-only token, said management subsystem recording which access control subsystem is issued with a write-only token and which area is specified by the same write-only token, and wherein at least one of said computers has a standby management subsystem for eliciting, if said management subsystem is incapable of continuing the process, from each of said access control subsystems whether or not it retains a write-only token and which area is specified by its retaining write-only token, generating a write-only token for an area which is specified by no write-only token responded from any access control subsystem and recording which access control subsystem is issued with a write-only token and which area is specified by the same write-only token based on a response to the elicitation from an access control subsystem. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification