CODA FILE SYSTEM.pptx

It's all about CODA and its working and security

1. CODA FILE SYSTEM A.GURUCHARAN 2003339

2. WHAT IS CODA ? Coda (constant data availability)  is a distributed file system developed as a research project at Carnegie Mellon University since 1987 under the direction of  Mahadev Satyanarayanan . It descended directly from an older version of Andrew File System (AFS-2) and offers many similar features. 2

3. FEATURES OF CODA Disconnected operation for mobile computing . Freely available source code High performance through client side persistent caching Server replication Security model for authentication, encryption and access control Continued operation during partial network failures in server network Network bandwidth adaptation Good scalability Well defined semantics of sharing, even in the presence of network failure 3

4. Working of CODA Application Prog . KERNAL VFS CODA Client Disk VENUS SERVER kernel mode to user mode

5. Cont.. 5 Coda uses a local cache to provide access to server data when the network connection is lost. During normal operation, a user reads and writes to the file system normally, while the client fetches, or Hoards, all of the data the user has listed as important in the event of network disconnection. If the network connection is lost, the Coda client’s local cache serves data from this cache and logs all updates. This operating state is called disconnected operation. Upon network reconnection, the client moves to reintegration state; it sends logged updates to the servers . Then it transitions back to normal connected-mode operation.

6. Coda Security 6 Basically the security in Coda falls into two parts : 1. Authentication and secure connections: Coda’s RPC2 package has a mechanism for security authenticating clients to servers and vice versa and setting up encrypted channels between them. A key element of this scheme is passwords for Coda users. 2. Access control and protection databases: The files on Coda servers are protect with directory access control lists. Such lists grant permissions to users or groups and the structure of these is stored in a Coda protection database.

7. 7 THANK YOU..