Ths article discusses a number of techniques that can be used in designing parallel programs when such programs are represented by means of non-deterministic programs. Parallelism in the components of a program is sim...
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Ths article discusses a number of techniques that can be used in designing parallel programs when such programs are represented by means of non-deterministic programs. Parallelism in the components of a program is simpler the few interactions occur between these components. The article considers a method that makes it possible to derive from a given program an 'equivalent' program in which the necessary interactions are separated as far as possible from other operations, so that they do not unnecessarily restrict the possibilities of parallel execution of the program. In designing parallel programs it is necessary to ensure that no dealocks can occur in their execution. The article introduces a method that makes it possible, on the basis of a program that might give rise to deadlocks, to systematically derive a program that is guaranteed to be free from deadlock.
A guide is furnished to assist managers in the establishment of policies and procedures for effective preparation, distribution, control, and maintenance of documentation which will aid in re-use, transfer, conversion...
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A guide is furnished to assist managers in the establishment of policies and procedures for effective preparation, distribution, control, and maintenance of documentation which will aid in re-use, transfer, conversion, correction and enhancement of computer programs. Such documentation, together with the computer programs themselves, will provide software product packages which can be transferred and used by people other than the originators of the programs. ″Software″ and ″documentation″ are defined, some documentation problems are discussed, and policies, procedures, and applicable standards are outlined. Appendices provide checklists in support of documentation policies and procedures, and references to relevant guidelines, standards, and the literature. A glossary of terms is included.
The authors deal with the use of structured analysis just prior to system acceptance testing. Specifically, the drawing of data flow diagrams (DFDs) was done after integration testing. The DFDs provided a picture of t...
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The authors deal with the use of structured analysis just prior to system acceptance testing. Specifically, the drawing of data flow diagrams (DFDs) was done after integration testing. The DFDs provided a picture of the logical flow through the integrated system for thorough system acceptance testing. System test sets were derived from the flows in the DFDs. System test repeatability was enhanced by the matrix which flowed from the test sets.
The machine vision systems described in this paper are being successfully installed with and without robots in a variety of sorting and inspection tasks. Recent applications in part sortings, assembly verification, co...
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The machine vision systems described in this paper are being successfully installed with and without robots in a variety of sorting and inspection tasks. Recent applications in part sortings, assembly verification, cosmetic inspection and non-contact measurement are described. Guidelines for uses of machine vision in manufacturing are presented, including a discussion of the limitations of currently available vision systems in terms of processing speed, resolution and image contrast.
A programming notation is introduced to describe the behavior of groups of parallel processes, communicating with each other over a network of named channels. An assertion is a predicate with free channel names, each ...
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A programming notation is introduced to describe the behavior of groups of parallel processes, communicating with each other over a network of named channels. An assertion is a predicate with free channel names, each of which stands for the sequence of values which have been communicated along that channel up to some moment in time. A process invariantly satisfies an assertion if that assertion is true before and after each communication by that process. A system of inference rules is presented for proving that processes satisfy assertions, and their use is illustrated. The validity of the inference rules is established by constructing a model of the programming notation, and by proving each inference rule as a theorem about the model. Limitations of the model and proof system are discussed.
The history of memory management technology in IBM during the period between the 1950s and the early 70s is discussed in this paper. The paper concentrates on the programming and operating system aspects of the proble...
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The history of memory management technology in IBM during the period between the 1950s and the early 70s is discussed in this paper. The paper concentrates on the programming and operating system aspects of the problem, rather than the hardware technology involved.
A new algorithm to generate all topological sorting arrangements is presented. It is compared with other such algorithms and is found to be more efficient.
A new algorithm to generate all topological sorting arrangements is presented. It is compared with other such algorithms and is found to be more efficient.
A new scheduling algorithm is described for a multicomputer connected in a point-to-point fashion. The algorithm is both distributed (every processor runs the same algorithm) and stable (collective load balancing deci...
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A new scheduling algorithm is described for a multicomputer connected in a point-to-point fashion. The algorithm is both distributed (every processor runs the same algorithm) and stable (collective load balancing decisions will not cause unnecessary overloading of a processor in the network). It is assumed that process execution times are not known in advance and that inter-processor transfer times are non-trivial. Load is balanced by migrating suitable jobs after they have been run long enough to obtain an estimate of their required service time. The algorithm is suitable for job scheduling in a distributed time-sharing system implemented on a multicomputer. Performance of the algorithm is investigated through simulation.
By restricting attention to a particular class of parallel algorithms associated with the divide-and-conquer principle, and choosing an appropriate network topology, the authors have developed an attractive scheme whi...
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By restricting attention to a particular class of parallel algorithms associated with the divide-and-conquer principle, and choosing an appropriate network topology, the authors have developed an attractive scheme which they call ZAPP (Zero Assignment Parallel Processor) for 'buying speed' from VLSI in a programmable manner. The scheme supports variable grain exploitation of parallelism via a 'lazyflow' execution model, and appears particularly well suited for developing a high-performance personal computer which realizes the inherent parallelism in applicative languages.
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