DECA is a computer program which is used in conjunction with a top-down dominated design methodology. The program organizes, validates, and produces a document depicting the design of a software system. The use of DEC...
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DECA is a computer program which is used in conjunction with a top-down dominated design methodology. The program organizes, validates, and produces a document depicting the design of a software system. The use of DECA significantly enhances the quality of the software design. The quality of the design in turn significantly benefits the quality of the implemented software system.
Software systems are increasingly required to be open and distributed. Research on software composition proposes to build such open and distributed systems by "gluing together" basic building blocks (compone...
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ISBN:
(纸本)0818682558
Software systems are increasingly required to be open and distributed. Research on software composition proposes to build such open and distributed systems by "gluing together" basic building blocks (components) using certain kinds of connections between them [16, 18]. Whereas work-in this area primarily focuses on more static aspects of composition. in order to ensure that given collections of components cooperate successfully, the aspect of dynamically changing compositions is less elaborated. In this paper, we pick up ideas from generative coordination for open systems [9] and develop the vocabulary of a composition language for modelling dynamic composition and re composition for which the term Generative Software Composition has been coined. We provide a formal semantics for our composition language which can be orthogonally integrated with the semantics of the Objective Linda coordination model [gamma]. We illustrate the expressiveness of our approach on an example.
Case based reasoning (CBR) retrieval operations with partial ordering similarity measures have been implemented in LINDA To extract generic operations and identify potential parallelism in CBR. Mapping and reduction o...
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ISBN:
(纸本)0818682558
Case based reasoning (CBR) retrieval operations with partial ordering similarity measures have been implemented in LINDA To extract generic operations and identify potential parallelism in CBR. Mapping and reduction operations, and constraint matching versions of all retrieval af operations were identified, then implemented in LINDA. Their operational semantics were expressed in terms of the CHAM for Liam (the LINDA Abstract Machine) and refined to produce the basis for efficient, parallel implementations of the operations as additional LINDA instructions. The implementation of the constraint matching operations suggests the Else of eva1 () to achieve process migration ill distributed systems, and default local tuple space interaction, ft as suggested that the constraint matching instructions replace the basic matching retrieval instructions, as they extend the functionality of the marching process by maintaining atomicity of matching and moving the constraint function from the program to the LINDA kernel.
A particular queueing process with three levels of priorities is considered as a model of a foreground-background system. A foreground job (class 1 or 2) has preemptive delay priority over background jobs. The mean nu...
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A particular queueing process with three levels of priorities is considered as a model of a foreground-background system. A foreground job (class 1 or 2) has preemptive delay priority over background jobs. The mean number of type 1 and 2 jobs at instant of service completion are derived, as well as a measure of the loss of efficiency due to preemptions. The results are discussed in the framework of the system which motivated this analysis.
The system described considered several subjective quality definitions: the extent to which object and source codes could be reduced via simple transformations or complete program restructuring and a ranked clarity of...
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The system described considered several subjective quality definitions: the extent to which object and source codes could be reduced via simple transformations or complete program restructuring and a ranked clarity of the program source. The principal method used was the manual grading of a sample, extraction of quantifiable independent variables, and the use of regression analysis to derive prediction formulas. Results included some tentative quality prediction formulas, correlations among the independent and dependent variables (e. g. , GOTOs and clarity), observtions about programming, and a host of newly-generated questions. There are indications that for two large program populations, a useful tool for automatically differentiating between good and bad programs has been derived.
The Chi/OS operating system, the latest large scale software effort of Chi Corporation, has had an excellent reliability record since its installation in November, 1973. Although the system design is vital to the reli...
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The Chi/OS operating system, the latest large scale software effort of Chi Corporation, has had an excellent reliability record since its installation in November, 1973. Although the system design is vital to the reliability of Chi/OS, several environmental factors are equally vital. After a brief presentation of the substantial work load supported by Chi/OS, this paper deals with those environmental factors which contribute to the reliability of the software.
This article suggests ways to effectively use a third generation operating system. Most of the examples used are from the most generalized and complicated of them all - IBM OS/360. Examination of operating systems beg...
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This article suggests ways to effectively use a third generation operating system. Most of the examples used are from the most generalized and complicated of them all - IBM OS/360. Examination of operating systems begins with the typical hardware resources of a computing plant and the OS response to those resources. A brief overview of the user tools supplied by the operating system is then presented, followed by discussions on bugs and debugging and other problems of performance.
The hardware and software needs of multiprogrammingsystems are presented. Various types of multiprogramming microcomputersystems are analyzed, and the key considerations for design and implementation are pointed out...
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The hardware and software needs of multiprogrammingsystems are presented. Various types of multiprogramming microcomputersystems are analyzed, and the key considerations for design and implementation are pointed out. Finally, the advantages and disadvantages of multiprogramming in the various types of microcomputersystems are weighed.
In order to meet the increasing need for more complex automated air terminal systems, Sperry Univac developed a unique failsafe-failsoft multiprocessor executive program that will serve as the software basis for enhan...
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In order to meet the increasing need for more complex automated air terminal systems, Sperry Univac developed a unique failsafe-failsoft multiprocessor executive program that will serve as the software basis for enhancements to present day ARTS III systems. The executive provides the overall control of the multiprocessor data processing subsystem, failure detection and recovery sequence, and the execution of the air traffic control tasks. Also described is the need for and background of the development of the multiprocessor executive; in addition, it presented failsafe-failsoft multiprocessor failure detection and recovery design.
Central processing unit (CPU) burst durations for several jobs were measured. The CPU burst exhibited patterns over time. A partially observable Markov process was used to model CPU burst generation. The model seems t...
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Central processing unit (CPU) burst durations for several jobs were measured. The CPU burst exhibited patterns over time. A partially observable Markov process was used to model CPU burst generation. The model seems to fit data reasonably well. A simulation study on general prediction schemes was carried out. A job's predicted burst was made to fall within a confidence region with a certain probability. The effect of the length of the confidence region and the probability of predicting within that region were studied. The device utilizations were remarkably insensitive to predictive accuracy. A pattern based predictor was developed and it yielded satisfactory schedules.
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