System for awarding token to client for accessing first data block specified in client request without interference due to contention from other client

摘要

A client/server computer system manages shared files. A client includes a data cache and an associated cache manager, and executes a client application that requests data from a shared file. In response to the request, the client cache manager determines if the data is currently stored in the data cache, and if so, grants the client access to the data in the cache. However, if the data is not currently stored in the cache, the client cache manager sends to the server a request for multiple consecutive blocks of data beginning with the first block containing the data requested by the client from the shared file. The server includes a token manager which receives the request, and in response (a) awards the token for a first data block specified in the request regardless of contention for the first data block and (b) awards tokens for all other consecutive blocks following the first block of the multiple blocks held by a client who also holds the token for the first block. However, if another client currently holds a contending token for one of the consecutive blocks other than the first block but does not also hold the token for the first block, then the token management process awards only the tokens for the first block and all blocks between the first block and the one block.