1991 Reports

Service Interface and Replica Management Algorithm for Mobile File System Clients

Tait, Carl D.; Duchamp, Dan

Portable computers are now common, a fact that raises the possibility that file service clients might move on a regular basis. This new development requires rethinking some features of distributed file system design. We argue that existing approaches to file replica management would not cope well with the likely behavior of mobile clients, and we present our solution: a lazy "server-based" update operation. This operation facilitates fast, scalable, and highly fault-tolerant implementations of both read and write operations in the usual case. To cope with the weak semantics of the update operation, we propose a new file system service interface that allows applications to opt for "UNIX semantics" by use of a slower, less fault-tolerant read operation.