| 摘要 |
A data image management system (DIMS) that includes a local data image manager (LDIM), a remote data image manager (RDIM), and a remote persistent storage device (RPSD). The LDIM communicates with the RDIM through a direct communication link or through a communication network. The RDIM can store data on and retrieve data from the RPSD. In an environment where an LDIM has been installed in a computer having a "local" persistent storage device (LPSD), the DIMS allows for the storing of the LPSD's data image on the RPSD, with the LPSD serving as a persistent, consistent cache of the data image. The data image stored on the RPSD is referred to as the "master data image" and the data image cached on the LPSD is referred to as the "local data image" or "cached data image." The LDIM functions to intercept read/write requests that are intended to be received by the LPSD. The read/write requests specify an address of the LPSD. Upon intercepting a read request, the LDIM is programmed to determine whether the portion of the cached data image that is stored at the specified address is up-to-date. If it is up-to-date, the LDIM retrieves the requested data from the LPSD and passes the data back to the component or device from which it received the request. If it is not up-to-date, the LDIM transmits the read request to the RDIM. Upon receiving the read request, the RDIM locates and reads the requested data from the master data image stored on the RPSD and then transmits the data back to the LDIM.
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