Extending the Coda File System to handle cache misses on isolated clients

For mobile information access, client caching is widely used for coping with server unavailability due to temporary disconnection of the network. Cache-miss is the most visible phenomenon to users caused by the disconnection. When multiple clients are isolated from servers, cache-miss happening on a client can be fulfilled using cache contents on other clients. Using a mechanism called disconnected operation, clients of the Coda File System can continue to work without contacting servers; however, clients cannot pass files between them by themselves. This paper presents the design and implementation of two mechanisms: import/export and session server. These mechanisms add read-sharing capability for clean objects to clients disconnected from Coda servers with reasonable response time.