Disconnected Operation for AFS

AFS plays a prominent role in our plans for a mobile workstation. The AFS client manages a cache of the most recently used files and directories. But even when the cache is hot, access to cached data frequently involves some communication with one or more file servers to maintain consistency guarantees. Without network access, cached data is soon rendered unavailable. We have modified the AFS cache manager to offer optimistic consistency guarantees when it can not communicate with a fileserver. When the client reestablishes a connection with the file server, it tries to propagate all file modifications to the server. If conflicts are detected, the replay agent notifies the user that manual resolution is needed. Our system brings the benefits of contemporary distributed computing environments to mobile laptops, offering a fresh look at the potential for nomadic computing.

[1]  John A. Kunze,et al.  A trace-driven analysis of the UNIX 4.2 BSD file system , 1985, SOSP '85.

[2]  William J. Bolosky,et al.  Mach: A New Kernel Foundation for UNIX Development , 1986, USENIX Summer.

[3]  Steve R. Kleiman,et al.  Vnodes: An Architecture for Multiple File System Types in Sun UNIX , 1986, USENIX Summer.

[4]  John H. Howard,et al.  On Overview of the Andrew File System , 1988, USENIX Winter.

[5]  Jeffrey I. Schiller,et al.  An Authentication Service for Open Network Systems. In , 1998 .

[6]  John L. Romkey,et al.  Nonstandard for transmission of IP datagrams over serial lines: SLIP , 1988, RFC.

[7]  Mahadev Satyanarayanan,et al.  Coda: A Highly Available File System for a Distributed Workstation Environment , 1990, IEEE Trans. Computers.

[8]  Mary Baker,et al.  Measurements of a distributed file system , 1991, SOSP '91.

[9]  David L. Mills,et al.  Network Time Protocol (Version 3) Specification, Implementation and Analysis , 1992, RFC.

[10]  John S. Heidemann,et al.  Primarily disconnected operation: experiences with Ficus , 1992, [1992 Proceedings] Second Workshop on the Management of Replicated Data.

[11]  Peter Honeyman,et al.  The LITTLE WORK project , 1992, [1992] Proceedings Third Workshop on Workstation Operating Systems.

[12]  Mahadev Satyanarayanan,et al.  Log-based directory resolution in the Coda file system , 1993, [1993] Proceedings of the Second International Conference on Parallel and Distributed Information Systems.

[13]  Mahadev Satyanarayanan,et al.  Disconnected Operation in the Coda File System , 1999, Mobidata.