Andrew File System(AFS)

Q. Short Note on Andrew File System(AFS) (December 16) (10 Marks)

Ans -

1. Distributed network file system which uses a set of trusted servers to present a homogeneous, location transparent file name space to all the client workstation
2. Distributed computing environment developed at Carnegie Mellon University (CMU) for use as a campus computing and information system [Morris et al. 1986].
3. Intention is to support information sharing on a large scale by minimizing client-server communication
4. Achieved by transferring whole files between server and client computers and caching them at clients until the servers receives a more up-to-date version.

Features of AFS

• Uniform namespace
• Location-independent file sharing
• Client-side caching
• Secure authentication
• Replication
• Whole-file serving
• Whole-file caching

Working

Implemented as 2 software components that exists as UNIX processes called Vice and Venus

Vice: Name given to the server software that runs as a user level UNIX process in each server computer.

Venus: User level process that runs in each client computer and corresponds to the client module in our abstract model. Files available to user are either local or shared

Local files are stored on a workstation's disk and are available only to local user processes.

Shared files are stored on servers, copies of them are cached on the local disk of work stations.