Coda2 encoding type7/30/2023 The original plan was that version of CODA after 1.2 would be version 2.0. Versions and were included in revisions and updates. Many lessons were learned during the use of the early CODA Efforts have been made to port Coda to Microsoft Windows, from the Windows 95/ Windows 98 era, Windows NT to Windows XP, by means of open-source projects like the DJGCC DOS C Compiler and Cygwin.The 1.x versions of CODA were based on code originally written on ULTRIX workstations starting in 1990 with the first useable version released within the lab in 1992. Subsequently, obsoleted there, an effort is under way to bring it back. Coda has extensive repair tools, both manual and automated, to handle and repair both types of conflicts.Ĭoda has been developed on Linux and support for it appeared in the 2.1 Linux kernel series. The former case is called a "local/global" conflict, and the latter case a "server/server" conflict. Optimistic replication can potentially cause concurrent updates to different servers on the same object, preventing replication. Disconnected operation's local updates can potentially clash with other connected users' updates on the same objects, preventing reintegration. These unique features introduce the possibility of semantically diverging copies of the same files or directories, known as "conflicts". Coda allows all servers to receive updates, allowing for a greater availability of server data in the event of network partitions, a case which AFS cannot handle. AFS uses a pessimistic replication strategy with its files, only allowing one read/write server to receive updates and all other servers acting as read-only replicas. Then it transitions back to normal connected-mode operation.Īlso different from AFS is Coda's data replication method. Upon network reconnection, the client moves to reintegration state it sends logged updates to the servers. This operating state is called disconnected operation. If the network connection is lost, the Coda client's local cache serves data from this cache and logs all updates. 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. Well defined semantics of sharing, even in the presence of network failureĬoda uses a local cache to provide access to server data when the network connection is lost.Continued operation during partial network failures in server network.Security model for authentication, encryption and access control.High performance through client-side persistent caching.Disconnected operation for mobile computing.The InterMezzo file system was inspired by Coda.Ĭoda has many features that are desirable for network file systems, and several features not found elsewhere. It descended directly from an older version of Andrew File System (AFS-2) and offers many similar features. Coda is a distributed file system developed as a research project at Carnegie Mellon University since 1987 under the direction of Mahadev Satyanarayanan.
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