707,934 research outputs found
Dynamic Choreographies - Safe Runtime Updates of Distributed Applications
Programming distributed applications free from communication deadlocks and
races is complex. Preserving these properties when applications are updated at
runtime is even harder. We present DIOC, a language for programming distributed
applications that are free from deadlocks and races by construction. A DIOC
program describes a whole distributed application as a unique entity
(choreography). DIOC allows the programmer to specify which parts of the
application can be updated. At runtime, these parts may be replaced by new DIOC
fragments from outside the application. DIOC programs are compiled, generating
code for each site, in a lower-level language called DPOC. We formalise both
DIOC and DPOC semantics as labelled transition systems and prove the
correctness of the compilation as a trace equivalence result. As corollaries,
DPOC applications are free from communication deadlocks and races, even in
presence of runtime updates.Comment: Technical Repor
Distributed and parallel Ada and the Ada 9X recommendations
Recently, the DoD has sponsored work towards a new version of Ada, intended to support the construction of distributed systems. The revised version, often called Ada 9X, will become the new standard sometimes in the 1990s. It is intended that Ada 9X should provide language features giving limited support for distributed system construction. The requirements for such features are given. Many of the most advanced computer applications involve embedded systems that are comprised of parallel processors or networks of distributed computers. If Ada is to become the widely adopted language envisioned by many, it is essential that suitable compilers and tools be available to facilitate the creation of distributed and parallel Ada programs for these applications. The major languages issues impacting distributed and parallel programming are reviewed, and some principles upon which distributed/parallel language systems should be built are suggested. Based upon these, alternative language concepts for distributed/parallel programming are analyzed
Dynamic Choreographies: Theory And Implementation
Programming distributed applications free from communication deadlocks and
race conditions is complex. Preserving these properties when applications are
updated at runtime is even harder. We present a choreographic approach for
programming updatable, distributed applications. We define a choreography
language, called Dynamic Interaction-Oriented Choreography (AIOC), that allows
the programmer to specify, from a global viewpoint, which parts of the
application can be updated. At runtime, these parts may be replaced by new AIOC
fragments from outside the application. AIOC programs are compiled, generating
code for each participant in a process-level language called Dynamic
Process-Oriented Choreographies (APOC). We prove that APOC distributed
applications generated from AIOC specifications are deadlock free and race free
and that these properties hold also after any runtime update. We instantiate
the theoretical model above into a programming framework called Adaptable
Interaction-Oriented Choreographies in Jolie (AIOCJ) that comprises an
integrated development environment, a compiler from an extension of AIOCs to
distributed Jolie programs, and a runtime environment to support their
execution.Comment: arXiv admin note: text overlap with arXiv:1407.097
Building distributed heterogeneous smart phone Java applications an evaluation from a development perspective
The advances in mobile phone technology have enabled such
devices to be programmed to run general-purpose applications
using a special edition of the Java programming language. Java is designed to be a heterogeneous programming language targeting different platforms. Such ability when coupled with the provision of high-speed mobile Internet access would open the door for a new breed of distributed mobile applications. This paper explores the capabilities and limitations of this technology and addresses the considerations that must be taken when designing and developing such distributed applications. Our findings are
verified by building a test client-server system where the clients in this system are mobile phones behaving as active processing elements not just mere service requesters
Orchestrating Tuple-based Languages
The World Wide Web can be thought of as a global computing architecture supporting the deployment of distributed networked applications. Currently, such applications can be programmed by resorting mainly to two distinct paradigms: one devised for orchestrating distributed services, and the other designed for coordinating distributed (possibly mobile) agents. In this paper, the issue of designing a pro-
gramming language aiming at reconciling orchestration and coordination is investigated. Taking as starting point the orchestration calculus Orc and the tuple-based coordination language Klaim, a new formalism is introduced combining concepts and primitives of the original calculi.
To demonstrate feasibility and effectiveness of the proposed approach, a prototype implementation of the new formalism is described and it is then used to tackle a case study dealing with a simplified but realistic electronic marketplace, where a number of on-line stores allow client
applications to access information about their goods and to place orders
Distributed semantic networks and CLIPS
Semantic networks of frames are commonly used as a method of reasoning in many problems. In most of these applications the semantic network exists as a single entity in a single process environment. Advances in workstation hardware provide support for more sophisticated applications involving multiple processes, interacting in a distributed environment. In these applications the semantic network may well be distributed over several concurrently executing tasks. This paper describes the design and implementation of a frame based, distributed semantic network in which frames are accessed both through C Language Integrated Production System (CLIPS) expert systems and procedural C++ language programs. The application area is a knowledge based, cooperative decision making model utilizing both rule based and procedural experts
Distributed expert systems for ground and space applications
Presented here is the Spacecraft Command Language (SCL) concept of the unification of ground and space operations using a distributed approach. SCL is a hybrid software environment borrowing from expert system technology, fifth generation language development, and multitasking operating system environments. Examples of potential uses for the system and current distributed applications of SCL are given
Functionally Specified Distributed Transactions in Co-operative Scenarios
Addresses the problem of specifying co-operative, distributed transactions in a manner that can be subject to verification and testing. Our approach combines the process-algebraic language LOTOS and the object-oriented database modelling language TM to obtain a clear and formal protocol for distributed database transactions meant to describe co-operation scenarios. We argue that a separation of concerns, namely the interaction of database applications on the one hand and data modelling on the other, results in a practical, modular approach that is formally well-founded. An advantage of this is that we may vary over transaction models to support the language combinatio
Reasoning About a Service-oriented Programming Paradigm
This paper is about a new way for programming distributed applications: the
service-oriented one. It is a concept paper based upon our experience in
developing a theory and a language for programming services. Both the
theoretical formalization and the language interpreter showed us the evidence
that a new programming paradigm exists. In this paper we illustrate the basic
features it is characterized by
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