D. K. Gifford, R. M. Needham, and M. D. Schroeder. The Cedar File System. Communications of the ACM, 31(3):288--298, 1988.  Home/Search   Document Not in Database   Summary   ACM   TOC   Related Articles   Check

....required to determine allocated space from the data itself. Though the actual data and (possibly) filenames and filegroup names are encrypted and hidden, the list of physical blocks allocated is visible to the server for allocation decisions. There are several file systems such as Cedar [18], Elephant [41] Farsite [1] Venti [38] and Ivy [36] which treat file data as immutable objects. In a cryptographic storage file system with versioning, server verified writes are less important for security. Readers can simply choose to ignore unauthorized writes, and servers need worry only ....

D. Gifford, R. Needham, and M. Schroeder. The Cedar file system. In CACM, pages 288--298, March 1988.

....been written in the Cedar language. Status: Research on CFS is active and continues to be enhanced. CFS is still in use as an integral part of the Cedar Programming Environment. Contact: Michael D. Schroeder, DEC Systems Research Center, 130 Lytton Ave. Palo Alto, CA 94301 References: 84] [85], 86] 87] 88] 89] 90] 91] 92] 2.10 Charlotte Main Goal Charlotte is a distributed operating system developed at the Computer Sciences Department of the University of Wisconsin Madison providing location and access transparency. It is part of the Crystal project that was funded ....

D.K. Gifford, R.M. Needham, and M.D. Schroeder, "The Cedar File System", Communications of the ACM, 31(3):288--298, March 1988.

....that concern provision of utility programs to users or development libraries to programmers are examples of functionality in the convenience category. 3.3.1. Good roads Much work has been done in operating systems in general and distributed file systems in particular on caching and replication [Gifford et al. 1992; Reiher et al. 1994; Tbbicke 1994; Walker et al. 1992; Welch 1994] Caching involves keeping local client copies of information that logically resides on remote servers. Replication involves keeping copies of information that resides on one server at other servers. Most WWW browsers provide very ....

Gifford, D., Needham, R., & Schroeder, M. 1992. The Cedar file system. Distributed Computing Systems: Concepts and Structures. (ed. Ananda, A. & Srinivasan, B.) IEEE Computer Society Press, Los Alamitos, CA.

....The ability to control transmission or display rates. ffl Capacity: The number of supportable continuous media streams. 2. 1 The Etherphone System The Etherphone System [Swinehart83] employed a voice storage server [Terry88] which used a single large file on a dedicated Cedar File System [Gifford88]. An important observation was that, in terms of data throughput, voice services were beyond the capabilities of the general purpose Cedar File System and a discussion of the voice server implementation given in [Ades87] indicates that this intermediate 7 solution was adopted by the project to ....

D. Gifford, R.M. Needham, and M. D. Schroeder. The Cedar File System. Comm. of the ACM, 31(3), March 1988. (p 7)

....toolkit, standard workstation applications such as Exmh and Ical can easily be turned into mobile aware applications. Our research borrows from earlier work on replication for non mobile distributed systems. In particular, we borrow from Locus [44] type specific conflict resolving) and Cedar [45] (the check in check out model of data sharing) III. Mobile Aware Computing Using Rover The Rover toolkit is designed to support the construction of mobile aware applications and proxies. In this section we describe the issues that mobile application and mobile proxy designers face and how, ....

D. K. Gifford, R. M. Needham, and M. D. Schroeder, "The Cedar file system," Communications of the ACM, vol. 31, no. 3, pp. 288--298, Mar. 1988.

....a new file holding the updated data structure. In other words, we store files as sequences of versions. Note that as we do whole file transfer anyway, this puts no performance penalties on the file server. Version mechanisms have positive influences on caching, as reported in the Cedar File System [6], and on replication. It also presents the possibility of keeping versions on write once storage such as optical disks. The version mechanism is itself quite interesting, and is discussed in [7] For most applications this model works well, but there are some applications where different solutions ....

Gifford, D. K., Needham, R. M., and Schroeder, M. D., "The Cedar File System," Comm. ACM, pp. 288-298 (March 1988).

....to open a precise copy by specifying the version number in the name. However, a read may also request the latest version of the file, gaining some of the advantages (and problems) of mutable objects. Other Distributed File Systems Conventional distributed file systems are surveyed in [15] and [16]. These, like Jade and Cedar, are designed to be the primary filesystem used to store and retrieve files for everyday use. Commercial and experimental file systems in this category include Sun Network File System, Andrew File System, Sprite, and Locus. These systems typically employ a naming ....

Gifford, Needham, Schroeder, "The Cedar File System," Communications of the ACM, vol 31, no. 3, pp. 288-298, March 1988.

....distributed file systems[SGK 85, RFH 86, HKM 88, WPE 83] allow computers to share files transparently. A file server is a computer that provides other computers, called clients, access to its files. To ensure file consistency, distributed file systems can support immutable files[GNS88] whose modification results in the creation of new files, or they can use various caching policies[NWO88] 2.1.7 Summary File systems provide an abstract interface to support the storage, retrieval, organization, sharing, naming, and protection of persistent data. They can present various kinds ....

....scales smoothly[HKM 88] The Sprite File System[NWO88] is a distributed file system that caches data blocks on both client and server systems, provides the same level of data consistency as RFS, and scales as well as Andrew. The Cedar file system from Xerox uses immutable shared (remote) files[GNS88] and mutable private (local) files. Like Andrew, Cedar uses whole file copies and local disks on each client. Cedar also provides file versions. The LOCUS operating system[WPE 83] supports a locationtransparent distributed file system. The LOCUS file system extends the UNIX file system by ....

David K. Gifford, Roger M. Needham, and Michail D. Schroeder. The Cedar File System. Communications of the ACM, 31(3):288--298, March 1988.

....system with one server at DEC SRC that automatically dispatches tasks and collects results. The research described in this thesis borrows from early work on replication for non mobile distributed systems. In particular, we borrow from Locus [50] type specific conflict resolving) and Cedar [12] (check in, check out model of data sharing) Chapter 7 Conclusion Mobile aware applications are best suited to face the unique set of challenges faced by mobile computers. Mobile aware applications can excel even in the absence of high speed network connections. The Rover Toolkit supports ....

D. K. Gifford, R. M. Needham, and M. D. Schroeder. The Cedar file system. Communications of the ACM, 31(3):288--298, March 1988.

.... and materialized views and view indexes within the mediators [Roussopoulos: 86] Hanson:87] Sheth:88] 2 Rule bases for semantic query optimization [King:84] Chakravarthy:85] 3 data reorganization to follow dominant access demands [Fursin:86] 4 an ability to abandon ineffective object bindings [Gifford:88]. 5 Privacy protection for sensitive data through interface modules [Cohen:88] Sharing of these Techniques Artificial intelligence, logical, and systems techniques can of course be shared among the mediators. Only knowledge specific to the application needs to be local to each mediator. In the ....

D.K. Gifford, R.M. Needham, and M.D. Schroeder: "The cedar File System "; Comm. ACM, Vol.31 no.3, Mar.1988, pp.288--298.

....distributed and persistent object based system for the purpose of the replicated data storage and coordination service is an interesting future trend. The fundamental approach for the DSCS sub system borrows from work in distributed and replicated file systems like Locus [24] Coda [19] and Cedar [40] (check in check out model of data sharing) The Bayou project also defines an architecture for sharing data in a weekly consistent environment [23] However, propagation updates and conflict resolution is our main departure from these other approaches. The integration model between synchronous ....

Gifford,D.K., Needham,R., Schroeder,D., "The CEDAR File System", CACM,31 (3):pp. 288-298 (March 1988)

....was to create a convenient heterogeneous computing environment, we have chosen to implement a remote procedure call package at the user level. 2.1. 2 Remote Procedure Calls The idea of remote procedure calls derives from the seminal paper by Birrel and Nelson on the Cedar programming environment [19, 8]. This system was constructed for Dorado machines, and it provides a model where a client and server communicate via the networking services provided by the package. There is a run time library called RPCRuntime that handles the details of reliable data transmission, and the binding functions in ....

....be valid, there must be a set 14 percentage (quorum) of exactly matching entries from the sites holding replicas of the database. There are several variations of this protocol. One refinement of majority consensus voting involves assigning weights to each of the sites in the distributed database [19]. Weighting of sites depends upon the characteristics of the site. Another way of improving majority consensus voting is to create witnesses. Witnesses are not data objects; they are records of the state of the data object [33] A witness must be a part of the quorum when the voting entity reads ....

D. K. Gifford, R. M. Needham, and M. D. Schroeder. The Cedar file system. Communications of the ACM, 31(3):288--298, March 1988.

....model for the DSCS, in building a generic distributed and persistent object based system and coordination service is an interesting future trend. The fundamental approach for the DSCS sub system borrows from work in distributed and replicated filesystems like Locus [18] Coda [13] and Cedar [30] (check in check out model of data sharing) The Bayou project also defines an architecture for sharing data in a weekly consistent environment [17] However, propagation updates and conflict resolution is our main departure from these other approaches. 6. Future work The integration model ....

Gifford, D.K., Needham, R., Schroeder,D., "The CEDAR File System", CACM,31 (3):pp. 288-298, March 1988.

....languages and how such languages may impact operating system functionality, and specific considerations of distributed file systems. From the unique perspective of this paper, the third dimension is the more important one. The distributed file systems operate in one of the following three modes [GIFF88]: 1) remote 23 disk systems, which simply enable the sharing of unstructured remote disk blocks among a number of clients; 2) block level access systems, which enable the accessing of portions of remote files (called file blocks) and (3) file level access systems, which enable sharing of ....

D.K. GIFFORD, R.M. NEEDHAM, AND M.D. SCHROEDER. "The Cedar File System," Comm. ACM (March 1988), 31(3): 288-298.

....of invoked name spaces is B, C, E, F, H, I, G, and D. Since name spaces could be located anywhere in the internet, the search terminates whenever the desired name is found in one of the name spaces of this sequence in order to improve performance. 4. 6 Caching Entire Files The Cedar file system [Giff88] introduces the concept of caching entire files on a workstation s local disk. The Andrew file system has shown that in a large environment this approach, together with a call back mechanism, is superior in performance to the page access pattern used by the Network File System. In Jade, caching ....

Gifford, D. K., Needham, R. M., and Schroeder, M. D. The Cedar file system. Communications of the ACM, 31(3):288--299, March 1988.

....optimizations to store files contiguously in memory and transfer them in a single operation, Amoeba s file system would benefit from caching files in the memory of each processor. 2 Client caching of immutable files could be implemented in a natural fashion in Amoeba, as in the Cedar File System [Gifford et al. 1988], but caching of newly created files would be more difficult. 3.4 Process Management The final area of comparison is process management. Amoeba s process model was influenced by both the distributed nature of Amoeba applications and the use of a centralized 2 A higher level comparison of the ....

D. Gifford, R. Needham, & M. Schroeder. The Cedar file system. Communications of the ACM, 31(3):288--298, March 1988.

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D. K. Gifford, R. M. Needham, and M. D. Schroeder. The Cedar File System. Communications of the ACM, 31(3):288--298, 1988.

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D. K. Gifford, R. M. Needham, and M. D. Schroeder. The Cedar File System. Communications of the ACM, 31(3):288--298, 1988.

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D. K. Gifford, R. M. Needham, and M. D. Schroeder. The cedar file system. Communications of the ACM, 31(3), March 1988.

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D. K. Gifford, R. M. Needham, and M. D. Schroeder. The Cedar file system. Communications of the ACM, 31(3):288--298, March 1988.

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D. Gifford, R. Needham, and M. Schroeder, "The Cedar File System," Communications of the ACM, vol. 31, no. 3 (March 1988).

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D. K. Gifford, R. M. Needham, and M. D. Schroeder. The Cedar file system. Communications of the ACM, 31(3):288--98, March 1988.

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