Dynamic adding system for memory files shared among hosts, dynamic adding method for memory files shared among hosts, and computer-readable medium recording dynamic adding program for memory files shared among hosts
First Claim
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1. A dynamic adding system for memory files shared among hosts comprising:
- an external memory unit providing a shared memory file comprising a plurality of data blocks of equal size;
hash tables each comprising a plurality of entries, each entry being associated with one of said plurality of data blocks;
a plurality of host computers for hashing an identifier of the data, determining the associated entry in the hash table based on the result of the hashing and storing the data into the data block associated with the entry, when data are stored into each of said data blocks; and
an inter-host locking means for exclusively controlling access to said hash tables possessed by said host computers, whereinsaid external memory unit further includes a control file for storing information based on association between data blocks in said shared memory file and entries in said hash table,each of said host computers has a shared memory file access means which, if a first host computer is actuated before other host computers, then said first host computer;
i) exclusively controls with said inter-host locking means access by said other host computers to said hash tables of said other host computers,ii) acquires the whole number of data blocks in said shared memory file,iii) prepares said hash table comprising entries no less than the number of the data blocks,iv) stores into said control file information based on association between the entries in the hash table and the data blocks in said shared memory file, andv) releases with said inter-host locking means the exclusive control on access by said other host computers to said hash tables possessed by said other host computers, andif said first host computer is actuated after any of said other host computers, then said first computer;
i) exclusively controls with said inter-host locking means access by said other host computers to said hash tables of the respective other host computers,ii) reads said associating information out of said control file,iii) prepares said hash table within said first host computer on the basis of said associating information, andiv) releases with said inter-host locking means the exclusive control on access by said other host computers to said hash tables possessed by said other host computers.
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Abstract
In response to an extension request to a shared memory file 104, shared file adding means 111 allocates an (additional) memory file 110; inter-host locking means 103 locks a hash table 106; hash table updating means 108 checks the number of data blocks in the (additional) shared memory file, and updates the hash table 106 to alter one of the data block addresses, out of those stored in entries in the hash table 106, pointing to the same data block in the shared buffer 104 so as to point to a data block in the (additional) shared memory file 110; and the added shared memory file 110 is thereby made available for shared use.
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Citations
9 Claims
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1. A dynamic adding system for memory files shared among hosts comprising:
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an external memory unit providing a shared memory file comprising a plurality of data blocks of equal size; hash tables each comprising a plurality of entries, each entry being associated with one of said plurality of data blocks; a plurality of host computers for hashing an identifier of the data, determining the associated entry in the hash table based on the result of the hashing and storing the data into the data block associated with the entry, when data are stored into each of said data blocks; and an inter-host locking means for exclusively controlling access to said hash tables possessed by said host computers, wherein said external memory unit further includes a control file for storing information based on association between data blocks in said shared memory file and entries in said hash table, each of said host computers has a shared memory file access means which, if a first host computer is actuated before other host computers, then said first host computer; i) exclusively controls with said inter-host locking means access by said other host computers to said hash tables of said other host computers, ii) acquires the whole number of data blocks in said shared memory file, iii) prepares said hash table comprising entries no less than the number of the data blocks, iv) stores into said control file information based on association between the entries in the hash table and the data blocks in said shared memory file, and v) releases with said inter-host locking means the exclusive control on access by said other host computers to said hash tables possessed by said other host computers, and if said first host computer is actuated after any of said other host computers, then said first computer; i) exclusively controls with said inter-host locking means access by said other host computers to said hash tables of the respective other host computers, ii) reads said associating information out of said control file, iii) prepares said hash table within said first host computer on the basis of said associating information, and iv) releases with said inter-host locking means the exclusive control on access by said other host computers to said hash tables possessed by said other host computers. - View Dependent Claims (2, 3)
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4. A dynamic adding method for memory files shared among hosts comprising:
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a step of providing data stored in each of a plurality of data blocks of the same size to constitute a shared memory file to be used by the plurality of host computers; a data storing step during which each of a plurality of host computers hashes an identifier of the data to determine the associated entry in a hash table comprising a plurality of entries each associated with one or another of said data blocks, and stores the data into the data block associated with the entry; a hash table preparing step at which each of said host computers, when a first host computer is actuated before other host computers, said first host computer; i) exclusively controls access by said other host computers to said hash tables of said other host computers, ii) acquires the whole number of data blocks in said shared memory file, iii) prepares said hash table comprising entries no lees than the number of the data blocks, iv) stores into the control file, shared by said host computers, information associating the entries in the hash table with the data blocks in said shared memory file, and v) releases the exclusive control on access by said other host computers to said hash tables possessed by the said other host computers; and when said first host computer is actuated after any of said other host computers, said first host computer; i) exclusively controls access by said other host computers to said hash tables of said other host computers, ii) reads said associating information out of said control file, iii) prepares said hash table within said first host computer on the basis of said associating information, and iv) releases the exclusive control on access by said other host computers to said hash tables possessed by said other host computers. - View Dependent Claims (5, 6)
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7. A computer-readable medium storing a program to cause:
each of a plurality of host computers to perform; when data are stored into each of a plurality of data blocks of equal size constituting a shared memory file to be shared by said host computers, storage processing to hash an identifier of the data to determine the associated entry in hash tables each comprising a plurality of entries each associated with one of said data blocks, and store the data into the data block associated with the entry; hash table preparation processing to exclusively control by a first host computer, when said first host computer is actuated before any other host computer; i) access by said other host computers to said hash tables possessed by the said other host computers, ii) acquire the whole number of data blocks in said shared memory file, iii) prepare said hash table comprising entries no less than the number of the data blocks, iv) store into a control file shared by said host computers information on association between the entries in the hash table and the data blocks in said shared memory file; and v) release the exclusive control on access by any of said other host computers to said hash tables possessed by the said other host computers; and when said first host computer is actuated after said other host computers, to exclusively control by said first host computer; i) access by said other host computers to said hash tables of the respective said other host computers, ii) read said associating information out of said control file, iii) prepare said hash table within said first host computer on the basis of said associating information, and iv) release the exclusive control on access by said other host computers to said hash tables possessed by the said other host computers. - View Dependent Claims (8, 9)
Specification