System and method for accessing remote files in a distributed networking environment
First Claim
1. A system for accessing a file residing in a server processing system at a server node by at least one client processing system at least one client node, said system comprising:
- at least one client cache in the at least one client processing system caching blocks of the file at the at least one client node;
means for generating a file synchronization mode for the file, said file synchronization mode being dependent upon how many and which processes in the network have the file open, and whether the file is open for read only or write access; and
means for managing said at least one client cache through the file synchronization mode.
1 Assignment
0 Petitions
Accused Products
Abstract
A distrbuted services program installed on each of a plurality of data processing systems in a network allows the processors to access data files distrbuted across the various nodes of the network.
To reduce the network traffic overhead when files at other nodes are accessed, and to preserve the file system semantics, i.e. the file integrity, the accessing of the various files are managed by file synchronization modes. A file is given a first synchronization mode if a file is open at only one node for either read or write access. A file is given a second synchronization mode if a file is opened for read only access at any node. A file is given a third synchronization mode if the file is open for read access in more than one node, and at least one node has the file open for write access.
If a file is in either the first or second synchronization mode, the client node, which is the node accessing the file, uses a client cache within its operating system store the file. All read and writes are then sent to this cache.
If a file is in the third mode, all read and write requests must go to the server node where the file resides. The node accessing the file does not use the cache in its operating system to access the file data during this third mode.
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Citations
21 Claims
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1. A system for accessing a file residing in a server processing system at a server node by at least one client processing system at least one client node, said system comprising:
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at least one client cache in the at least one client processing system caching blocks of the file at the at least one client node; means for generating a file synchronization mode for the file, said file synchronization mode being dependent upon how many and which processes in the network have the file open, and whether the file is open for read only or write access; and means for managing said at least one client cache through the file synchronization mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method, in a data processing system having at least one node, for accessing a file residing in a server processing system at a server node by at least one client processing system at least on client node, said method comprising the steps of:
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generating at least one synchronization mode for the file, said synchronization mode being dependent upon how many and which processes in the network have the file open, and whether the file is open for read only or write access; and caching the file at the at least one client node in at least one client cache as determined by said generated synchronization mode; and managing access to said at least one client cache as determined by said generated synchronization mode. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for accessing a file residing in a server processing system at a server node by at least one client processing system at least one client node, said system comprising:
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means for creating at least one client cache in the at least one client processing system for caching blocks of the file at the at least one client node; means for classifying said file dependent upon which of a plurality of nodes have the file open, and which of a plurality of processes at each of said nodes have the file open for writes, and which of the processes at each of said nodes have the file open for reads; means for accessing said file from said at least one client cache in response to a first classification of said classifying means; and means for accessing said file from said server processing system in response to a second classification of said classifying means.
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20. A method for accessing a file residing in a server processing system at a server node by at least one client processing system at least one client node, said method comprising:
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creating at least one client cache in the at least one client processing system for caching blocks of the file at the at least one client node; classifying said file dependent upon which of a plurality of nodes have the file open, and which of a plurality of processes at each of said nodes have the file open for writes, and which of the processes at each of said nodes have the file open for reads; accessing said file from said at least one client cache in response to a first classification of said classifying means; and accessing said file from said server processing system in response to a second classification of said classifying means.
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21. A computer program product having a computer readable medium having a computer program recorded thereon for accessing a file residing in a server processing system at a server node by at least one client processing system at least one client node, said computer program product comprising:
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means for creating at least one client cache in the at least one client processing system for caching blocks of the file at the at least one client node; means for classifying said file dependent upon which of a plurality of nodes have the file open, and which of a plurality of processes at each of said nodes have the file open for writes, and which of the processes at each of said nodes have the file open for reads; means for accessing said file from said at least one client cache in response to a first classification of said classifying means; and means for accessing said file from said server processing system in response to a second classification of said classifying means.
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Specification