A mechanism for synchronizing shared objects in a distributed system based on persistent, typed objects is presented. Synchronization constraints are expressed as separate control clauses and are factorized for a clas...
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ISBN:
(纸本)0818621443
A mechanism for synchronizing shared objects in a distributed system based on persistent, typed objects is presented. Synchronization constraints are expressed as separate control clauses and are factorized for a class of objects. the interference of this mechanism with inheritance and transactions is examined and solutions are proposed. Examples of synchronized objects are provided, and a semaphore-based implementation of the mechanism is described.
Techniques are proposed for computing a global virtual time (GVT), which is the minimum local virtual time of processes in Time Warp. the algorithm computes a conservative estimate of GVT using an approach which is co...
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ISBN:
(纸本)0818621443
Techniques are proposed for computing a global virtual time (GVT), which is the minimum local virtual time of processes in Time Warp. the algorithm computes a conservative estimate of GVT using an approach which is considerably simpler than previous algorithms for computing GVT. this algorithm does not require a global synchronization of processors. An inherent problem in GVT computation relates to handling messages in transit. Several alternatives are proposed for solving the transient message problem. the algorithm is suitable for distributed shared memory machines such as the BBN Butterfly and message passing machines with a variety of interconnection networks.
An approach to dynamic reconfiguration in online distributed applications based on a data sharing model is presented. the data sharing model consists of facets, objects, and processes, with facets as the unit of shari...
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ISBN:
(纸本)0818621443
An approach to dynamic reconfiguration in online distributed applications based on a data sharing model is presented. the data sharing model consists of facets, objects, and processes, with facets as the unit of sharing. the primary contribution of this work is the addition of important special cases of dynamic reconfiguration, without resorting to general dynamic allocation. A metaphor consistent with PROFIT's data sharing model for expressing dynamic reconfiguration facilities within the programming language is proposed.
distributed automatic garbage collection of objects possessing their own thread of control is discussed. the relevance of garbage collection and concurrent objects to distributed applications is briefly discussed, and...
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ISBN:
(纸本)0818621443
distributed automatic garbage collection of objects possessing their own thread of control is discussed. the relevance of garbage collection and concurrent objects to distributed applications is briefly discussed, and the specific model of concurrent objects used is explained. the collector comprises a collection of independent local collectors, one per node, loosely coupled to a distributed global collector. the mutator (application), the local collectors, and the global collector run concurrently. the synchronization necessary to achieve correct and efficient concurrent operation between the collectors is presented. One interesting aspect of the distributed collector is the termination algorithm.
Clouds Lisp distributed Environments (CLIDE) is a distributed, persistent object-based symbolic programming system being implemented on the Clouds distributed operating system. LISP environment instances are stored as...
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ISBN:
(纸本)0818621443
Clouds Lisp distributed Environments (CLIDE) is a distributed, persistent object-based symbolic programming system being implemented on the Clouds distributed operating system. LISP environment instances are stored as large-grained persistent objects, enabling users on many machines to share the contents of these environments through interenvironment evaluations. CLIDE provides a comprehensive research environment for distributed symbolic system language, invocation and consistency semantics, and an implementation vehicle for the construction of the symbolic processing portions of complex megaprogrammed systems.
A distributed processor level fault diagnosis algorithm is proposed where every processor will come up with its own conclusion about the status of other processors and also the links connecting it to its neighboring p...
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ISBN:
(纸本)0818621443
A distributed processor level fault diagnosis algorithm is proposed where every processor will come up with its own conclusion about the status of other processors and also the links connecting it to its neighboring processors. Performance is improved by considering a dynamic testing strategy where each processor is assigned a small number of processors to test it, ideally two. then, when some processors or links fail, a new testing assignment is made among the processors. Simulation results are presented to show that the proposed algorithm is effective in reducing the testing overhead.
the roles of processor allocation and job scheduling in achieving good performance on hypercube computers are compared. It is shown that the choice of job scheduling discipline has a dramatic effect on performance. A ...
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ISBN:
(纸本)0818621443
the roles of processor allocation and job scheduling in achieving good performance on hypercube computers are compared. It is shown that the choice of job scheduling discipline has a dramatic effect on performance. A family of scheduling disciplines, called Scan, with particular performance advantages is proposed. Furthermore, it is shown that if Scan scheduling is used, the choice of processor allocation strategy has negligible effect on performance. As a result, complex allocation strategies can be replaced by a simple O(n) strategy.
A versatile scheme for implementing fault-tolerant queues in a distributed system is proposed. Based on the combination of two simple concepts, by distributing replications of a queue and conducting intelligent-sequen...
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ISBN:
(纸本)0818621443
A versatile scheme for implementing fault-tolerant queues in a distributed system is proposed. Based on the combination of two simple concepts, by distributing replications of a queue and conducting intelligent-sequential probe (DRISP), the backbone of this work is unsophisticated, yet powerful. A description is presented of the protocols for handling a replicated and distributed queue, which is different from a replicated file in the sense that FIFO order should be maintained in a queue. the replicated distributed queue supported by these algorithms provides dynamic fault tolerance, high availability, and uniform load balancing with small storage space requirements and low communication cost. It is also adaptable to environment changes. Consistency is guaranteed.
Implementation of a kernel-level consistency control mechanism called invocation-based consistency control (IBCC) is presented. IBCC supports general-purpose persistent object-based distributedcomputing. IBCC provide...
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ISBN:
(纸本)0818621443
Implementation of a kernel-level consistency control mechanism called invocation-based consistency control (IBCC) is presented. IBCC supports general-purpose persistent object-based distributedcomputing. IBCC provides mechanisms that support a range of powerful, well-defined consistency semantics. IBCC mechanisms can also be used to implement custom recovery and synchronization. An operating-system-level implementation of IBCC as part of the Clouds distributed operating system that uses memory faulting to initiate locking and intermediate version creation is also given. Performance aspects are discussed, as well as the overhead incurred by supporting IBCC in terms of additional data structures needed in the operating system, and the additional amount of required code.
A two-level hierarchical model is proposed to analyze the availability of distributed systems as perceived by their users. At the higher level (user level), the availability of the tasks (processes) is analyzed in ter...
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ISBN:
(纸本)0818621443
A two-level hierarchical model is proposed to analyze the availability of distributed systems as perceived by their users. At the higher level (user level), the availability of the tasks (processes) is analyzed in terms of the availability of the system components. At the lower level (component level), detailed Markov models are developed to analyze the component availabilities. these models take into account the hardware/software failures, congestion and collisions in communication links, allocation of resources, and the redundancy level. Also presented is the availability analysis of some of the services provided by the Unified Workstation Environment (UWE) currently being implemented at AT&T Bell Laboratories.
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