The framework of an approach to distributed computing system software design is presented. In this approach, the data and functional components are considered separately and all interactions among the functional compo...
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The framework of an approach to distributed computing system software design is presented. In this approach, the data and functional components are considered separately and all interactions among the functional components are allowed only through the access of shared resources. A precise description of all aspects of software design, including the data and functional components, their structural relations and interactions, is developed. A possible way of estimating the performance of the software design is suggested. Finally, a design example is given to illustrate this approach.
This paper describes the problems of writing large, rehostable support software systems. A methodology for attacking such problems is developed with examples of its successful use in a support software system.
This paper describes the problems of writing large, rehostable support software systems. A methodology for attacking such problems is developed with examples of its successful use in a support software system.
UDS**2 is a BCS developed prototype software design specification system consisting of a comprehensive, well-integrated system of automated design tools intended for a production environment. UDS**2 provides the softw...
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UDS**2 is a BCS developed prototype software design specification system consisting of a comprehensive, well-integrated system of automated design tools intended for a production environment. UDS**2 provides the software designer with a design specification language (SPECLE) and a set of automated tools which (1) generate documentation;(2) analyze the software design;and (3) at some point in the future, will generate source code directly from the SPECLE specification. UDS**2 is implemented on several large scale delivery systems and is currently being tested on several real-world projects.
The Finite Element Machine is a special purpose computer designed from 1024 microprocessors communicating by way of explicit word-serial channels. The algorithms for structural analysis using the finite element method...
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The Finite Element Machine is a special purpose computer designed from 1024 microprocessors communicating by way of explicit word-serial channels. The algorithms for structural analysis using the finite element method which have been proposed for this machine require both maximum and summation over a set of numbers stored one per processor. Three distinct types of sum and maximum algorithm making different use of the communications paths have been formulated and analyzed with respect to execution time. The results give some insight into the best way to use communications paths in a multiprocessor. The study demonstrated the need for a special hardware mechanism to support the global sum and maximum operations in this machine. The design of this hardware unit is also discussed.
The objectives of recent software standards efforts have been to reduce the cost and improve the reliability and quality of avionics software. These efforts have a significant influence on software quality assurance e...
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The objectives of recent software standards efforts have been to reduce the cost and improve the reliability and quality of avionics software. These efforts have a significant influence on software quality assurance efforts. Existing quality assurance (QA) and verification and validation (V&V) methods must be made compatible with and take advantage of the improvements resulting from these standards. This paper summarizes existing MIL-STDs, and Air Force Regulations applicable to both in-house QA efforts and independent V&V activities. The need for additional QA and V&V related standards is discussed and potential standards are suggested. The paper describes how standardization efforts in other areas will affect how QA efforts are conducted.
The development of software for microcomputers for use in educational environments is discussed. The suggestions presented should assist in the appropriate selection of the software and in being aware of the care nece...
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The development of software for microcomputers for use in educational environments is discussed. The suggestions presented should assist in the appropriate selection of the software and in being aware of the care necessary in presenting the material to a student.
This paper deals with the following mechanism for controlling the multiprogramming set in a demand paging system: processes are dynamically divided into several categories according to the number of page faults genera...
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This paper deals with the following mechanism for controlling the multiprogramming set in a demand paging system: processes are dynamically divided into several categories according to the number of page faults generated during their residence in main memory. A process is admitted into the multiprogramming set only if there is enough space free in the main memory to contain the number of pages corresponding to the current category of the process. Using a queueing network model of an interactive system with such a control mechanism the authors study the effectiveness of the control considered, and, more particularly, its ability to partition the memory space according to the locality of processes.
To eliminate incompleteness, redundancy, inconsistency or ambiguity in requirements specifications of real time computersystems, formal models are explored and a tool, called the Requirements Language Processor (RLP)...
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To eliminate incompleteness, redundancy, inconsistency or ambiguity in requirements specifications of real time computersystems, formal models are explored and a tool, called the Requirements Language Processor (RLP), is described in its concept and implementation. This is a multi-lingual table-driven requirements language compiler. The RLP produces a formatted requirements document, Petri nets, and test plan information to aid the customer, designer, and test team.
The problem of sorting in various models of magnetic bubble memory systems is studied. Three basic parameters are of interest, namely, the number of steps to sort, the number of switches required and the number of con...
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The problem of sorting in various models of magnetic bubble memory systems is studied. Three basic parameters are of interest, namely, the number of steps to sort, the number of switches required and the number of control states necessary for the switches. Several sorting algorithms are proposed.
A technique is presented for instrumenting Concurrent Pascal systems at the component level. The key technical problem is that of implanting in each component a unique index which can be matched to the name of the com...
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A technique is presented for instrumenting Concurrent Pascal systems at the component level. The key technical problem is that of implanting in each component a unique index which can be matched to the name of the component by the instrumentation package. The implantation technique requires two monitors for parent-parent synchronization and parent-offspring synchronization. An additional monitor provides percent utilization statistics by component and a report process periodically produces summary figures. The entire procedure can be automated. The source Concurrent Pascal System can be read by an instrumentation program and the Instrumented Source Program produced as output. No modifications are required to the Concurrent Pascal Compiler, hence the same compiler can be used to compile and run either the instrumented or uninstrumented version of the system.
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