System for opening cache file associated with designated file of file server only if the file is not subject to being modified by different program
First Claim
1. A method for caching data transferred to a client computer over a network pathway from a file server, said method comprising, in combination, the steps of:
- providing a cache storage unit connected to said client computer for persistently storing cache files,executing a program on said client computer which issues file open and file read requests directed to a designated file on said file server, andproviding a redirector program on said client computer for performing the steps of;
responding to each of said file open requests by;
opening said designated file on said file server, andopening a cache file associated with said designated file on said cache storage unit only if said designated file while open on said file server is not subject to being modified by a different executing program, andresponding to each file read request for specified data in said designated file by;
transferring said specified data to said client computer from said designated file on said file server for use by said program if there is no open cache file corresponding to said designated file which contains said specified data, andotherwise transferring said specified data to said client computer from said open cache file when said open cache file contains said specified data.
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Accused Products
Abstract
A network cache system includes a shared cache server and a conventional file server connected to a computer network which serves a plurality of client workstation computers. Each client computer may additionally include a local non-volatile cache storage unit for caching data transferred to the client from a network server or from the shared cache server. Each client computer further includes a resident redirector program which intercepts file manipulation requests from executing application programs and redirects these requests to either the shared network cache or the local non-volatile cache when appropriate.
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Citations
20 Claims
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1. A method for caching data transferred to a client computer over a network pathway from a file server, said method comprising, in combination, the steps of:
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providing a cache storage unit connected to said client computer for persistently storing cache files, executing a program on said client computer which issues file open and file read requests directed to a designated file on said file server, and providing a redirector program on said client computer for performing the steps of; responding to each of said file open requests by; opening said designated file on said file server, and opening a cache file associated with said designated file on said cache storage unit only if said designated file while open on said file server is not subject to being modified by a different executing program, and responding to each file read request for specified data in said designated file by; transferring said specified data to said client computer from said designated file on said file server for use by said program if there is no open cache file corresponding to said designated file which contains said specified data, and otherwise transferring said specified data to said client computer from said open cache file when said open cache file contains said specified data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A network data cache system comprising, in combination,
a data transmission network, a file server connected to said network for storing identifiable files of information, a client computer connected to said network for accessing said files stored on said file server, a non-volatile cache storage unit connected to said computer for persistently storing data, at least one application program executable on said client computer for issuing file open requests and file read requests, a redirector program executable on said client computer for intercepting said file open requests and said file read requests, said redirector program including: -
means responsive to a given file open request from said application program which specifies a designated file on said file server for opening said designated file on said file server, status check means responsive to said given file open request for determining whether said designated file, as opened on said file server, can be modified while open, means responsive to said status check means for opening a first cache file on said cache storage unit corresponding to said designated file if said designated file cannot be modified while open, and means responsive to a given file read request from said application program to read specified data from said designated file for transferring said specified data to said application program from said cache file instead of from said designated file when said specified data is present within an open cache file. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification