Unix for Nomads: Making Unix Support Mobile Computing

Bender, Micheal; Davidson, Alexander; Dong, Clark; Drach, Steven; Glenning, Anthony; Jacob, Karl; Jia, Jack; Kempf, James; Periakaruppan, Nachiappan; Snow, Gale; Wong, Becky

doi:10.1007/978-0-585-29603-6_16

Cited by 12 publications

(5 citation statements)

References 6 publications

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“…The need for systems which support "disconnected operation" and "mobile computing" lead to several research projects [1,2,3,4,6] which deal with issues such as system integrity and consistency, scalability, performance, data replication as well as specific hardware and software requirements.…”

Section: Introductionmentioning

confidence: 99%

Experience with Connected and Disconnected Operation of Portable Notebook Computers in Distributed Systems

Huizinga

Heflinger²

1994

1994 First Workshop on Mobile Computing Systems and Applications

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DOC (Disconnected Operation Cache) is a two-level client caching system designed and implemented to support connected and disconnected operation of small form-factor, battery powered portable computers. This paper describes some design features of DOC, and our experiences with running it in the software engineering environment of AST Research. The uniqueness of the DOC project stems from the fact that it has been designed to completely support client caching and disconnected operation of currently existing portable notebook computers. The AST's local area network consisting of several Novell servers and top of the line notebooks running MS/DOS 6.2 as clients communicating via an Ethernet connection are used to support the system and perform experiments. DOC supports "connected", "partially disconnected", and "disconnected" modes of operation. The partially disconnected mode of operation has been designed to permit DOC to respond to requests on certain files that are not modified frequently, without server involvement. Results of our experiments indicate not only considerable performance gains for "connected" and "partially disconnected" system but also successful operation in the disconnected mode.

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Section: Introductionmentioning

confidence: 99%

Experience with Connected and Disconnected Operation of Portable Notebook Computers in Distributed Systems

Huizinga

Heflinger²

1994

1994 First Workshop on Mobile Computing Systems and Applications

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“…Several aspects of mobile computing and disconnected operation have been studied recently [1,[6][7][8][9][10][11][12]. While the focus of these studies is on various aspects of mobility such as application design [8,12], directory service [11], predictive caching [10] and power management [7]; three systems-Coda [1,6], Ficus [9] and DOC [13] -share some design goals with our project.…”

Section: Related Workmentioning

confidence: 99%

“…While the focus of these studies is on various aspects of mobility such as application design [8,12], directory service [11], predictive caching [10] and power management [7]; three systems-Coda [1,6], Ficus [9] and DOC [13] -share some design goals with our project. Similar to Coda and DOC, the unified cache design is based on a client-server model with client caching as a basis for disconnec-ted operation.…”

Section: Related Workmentioning

confidence: 99%

Disconnected operation for heterogeneous servers: A practical approach

Huizinga

Mann

1997

Personal Technologies

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This paper describes an implementation of a client caching system which supports disconnected and partially connected modes of operation while preserving the traditional role of client caching (improved response time) in the fully connected mode. The system is designed to facilitate various server-dependent verification protocols. The need for the heterogeneous server support stems from the fact that the mobile user is likely to access various network services, transfer data between them and use the data in the local unit application programs. The unique feature of this project is its implementation which does not require modification of the native system's kernel source code. The paper shows that an installable file system is a viable mechanism for providing such file system extensions without source code modifications. The results of our preliminary experiments indicate efficiency of the design and the feasibility of the implementation mechanism used.

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“…And while NFS must be installed as a file system (in the kernel) in order to catch file system operations as they arrive, FR needs no particular operating system support and it runs entirely in user space. This also makes our system stand out against efforts where system integration is in focus [1].…”

Section: Related Workmentioning

confidence: 99%

“…When a file is replicated, the servers will maintain consistency between the replicas by means of 1 The term copy has to do with distribution in space, while version implies changes over time. Replication ensures that all copies of a file has the same version, and a replica is a copy which is kept up-to-date.…”

Section: File Repositorymentioning

confidence: 99%

User controlled sharing in a variable connected distributed system

Stabell-Kulø

Fallmyr²

Proceedings Seventh IEEE International Workshop on Enabling Technologies: Infrastucture for Collaborative Enterprises (WET ICE

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This paper describes the design and implementation of a distributed file repository that supports data sharing in a variable connected environment. Our design is based on the observation that it is difficult to make a clean cut between the various choices for important issues like consistency and concurrency control when the system is designed. Hence, we make it possible for the user to choose whether to adopt an optimistic or a pessimistic approach, rather than embedding it into the system; that is, the user is placed in the decision loop. Unlike many contemporary systems, our repository treats the optimistic and pessimistic approach uniformly and allows users to select them on a per-file basis. Furthermore, even if a file has to be managed pessimistically, the advantage of the optimistic approachhigh availability-is retained. The file repository has been implemented, and it is our research vehicle.

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Unix for Nomads: Making Unix Support Mobile Computing

Cited by 12 publications

References 6 publications

Experience with Connected and Disconnected Operation of Portable Notebook Computers in Distributed Systems

Experience with Connected and Disconnected Operation of Portable Notebook Computers in Distributed Systems

Disconnected operation for heterogeneous servers: A practical approach

User controlled sharing in a variable connected distributed system

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