A heterogeneous environment for hardware/software cosimulation is described. This environment permits a portion of an application's subsystems to be simulated using reconfigurable hardware while the remainder of t...
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A heterogeneous environment for hardware/software cosimulation is described. This environment permits a portion of an application's subsystems to be simulated using reconfigurable hardware while the remainder of the subsystems are simulated using software. An Aptix FPCB populated with Xilinx FPGAs serves as the hardware simulation platform while an IBM-compatible PC serves as the software simulation platform. The two platforms are connected using an Altera reconfigurable logic board which allows the development of a high-speed interface for communication. This paper focuses on the difficulties associated with designing and interfacing simulation entities in this heterogeneous environment. Strategies for designing hardware and software simulation entities are introduced. These strategies reduce the impact of size and performance constraints imposed by the cosimulation environment while addressing the issues of time management and synchronization. A simple queueing application is used to illustrate a design methodology which incorporates these design strategies.
parallel programming on loosely coupled distributedsystems is becoming a viable approach with the rapid increase in network speeds and availability of large amounts of unused CPU capacity on individual workstations. ...
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parallel programming on loosely coupled distributedsystems is becoming a viable approach with the rapid increase in network speeds and availability of large amounts of unused CPU capacity on individual workstations. parallel programs are often written for a specific configuration of the distributed system such as the number of nodes, their relative speeds and their network connections. These programs perform poorly when there is a change in the configuration or when they are taken to a system other than what they are intended for. We propose a new paradigm which can express the scale of a program as a part of the program itself. The scale of the program is specified in an abstract manner for an arbitrary number of nodes, their relative speeds and their network connections. The runtime system uses this information to decide the actual scale of program on a given distributed system.
In mobile collaborative applications, collaborating agents can move across heterogeneous networks. The collaborating agents also keep changing their roles depending on the work to be performed at that time. In such si...
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In mobile collaborative applications, collaborating agents can move across heterogeneous networks. The collaborating agents also keep changing their roles depending on the work to be performed at that time. In such situations, a simple and flexible handling of the transition between heterogeneous environments and roles is required. This paper proposes PolyConstraints, a design pattern to handle the generic problem of transitions across multiple network environments and roles.
Comprehensive distributed garbage collection in object-oriented distributedsystems has mostly been addressed via distributed versions of graph-tracing algorithms, a legacy of centralised garbage collection techniques...
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Comprehensive distributed garbage collection in object-oriented distributedsystems has mostly been addressed via distributed versions of graph-tracing algorithms, a legacy of centralised garbage collection techniques. Two features jeopardise the scalability of these approaches: the bottleneck associated with having to reach a global consensus before any resource can actually be reclaimed; and the overhead of eager log-keeping. This paper describes an alternative approach to comprehensive distributed garbage collection that entails computing the vector-time characterising the causal history of some relevant events of the mutator processes computations. Knowing the causal histories of these events makes it possible to identify garbage objects that are not identifiable by means of per-site garbage collection alone. Computing the vector-times necessary to identify garbage is possible without the unbounded space overheads usually associated with dynamically reconstructing vector-times of arbitrary events of distributed computations. Our approach integrates a lazy log-keeping mechanism and therefore tackles both of the aforementioned stumbling blocks of distributed garbage collection.
In order to generate local addresses for an array section A(l:h:s) with block-cyclic distribution, an efficient compiling method is required. In this paper, two local address generation methods for the block-cyclic di...
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ISBN:
(纸本)0780342291
In order to generate local addresses for an array section A(l:h:s) with block-cyclic distribution, an efficient compiling method is required. In this paper, two local address generation methods for the block-cyclic distribution are presented. One is a simple local address generation method that is modified from the virtual-block scheme. The other is a linear-time /spl Delta/M table construction method. The array elements of A(l:h:s) to be accessed at run-time build up a family of lines. By using the equation of the lines, a /spl Delta/M table can be generated in O(k) time. Experimental results show that a simple local address generation method has poor performance but a linear-time /spl Delta/M table generation method is faster than other algorithms in /spl Delta/M table generation time and access time for 10,000 array elements.
Existing reflective object-oriented real-time systems typically provide the programmer with a single mechanism or policy. With the advent of a new generation of application software with demand for (soft) real-time be...
Existing reflective object-oriented real-time systems typically provide the programmer with a single mechanism or policy. With the advent of a new generation of application software with demand for (soft) real-time behavior, this limited choice may not be sufficient. We propose a metalevel architecture, where an application can choose from different real-time mechanisms and policies, thereby configuring its real-time behavior dynamically at run-time. This allows the adaptation to requirements that are not anticipated during application development. An example from the field of multimedia systems motivates our approach. We achieve this adaptability by structuring our metalevel into separate entities concerned with the support of different areas such as active object models, scheduling, and synchronization. These entities implement a variety of different real-time mechanisms and policies. This metalevel architecture is implemented using standard reflective mechanisms such as metalevel interceptions and metaobject protocols. Some preliminary performance figures give an impression of the price that has to be paid when our approach is used. (C) 1996 Academic Press, Inc.
Lack of bandwidth has been shown to be a major impediment to achieving realism in large scale virtual worlds with many interacting entities. Recent projects that have addressed this problem have, for the most part, be...
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This paper describes the motivations for and main features of Tigger - a framework for the construction of a family of object-support operating systems that can be tailored for use in a variety of different applicatio...
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Lack of bandwidth and network latency are known to be major impediments to achieving realism in distributed virtual world (vw) applications with a large number of, potentially geographically dispersed, entities. This ...
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ISBN:
(纸本)9781450373395
Lack of bandwidth and network latency are known to be major impediments to achieving realism in distributed virtual world (vw) applications with a large number of, potentially geographically dispersed, entities. This paper describes a combination of techniques that we are using to overcome these twin problems. The techniques described are intended to reduce both the volume and frequency of communication between the entities that make up the virtual world and include the use of anonymous event-based communication with notify constraints, scoping of event propagation with zones, and use of predictive approaches to replica management. Each of these techniques is described in turn.
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