This paper deals with the statistics of estimating the software reliability of complex real-time systems where an electronic digital computer and associated computer programs are essential elements of system design an...
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This paper deals with the statistics of estimating the software reliability of complex real-time systems where an electronic digital computer and associated computer programs are essential elements of system design and function. Testing is conducted in the operating environment or a simulated environment related to the operating environment in some known way. The procedure is Bayesian so that improvement of reliability estimation is realized in a formal and convenient way as more and more test data are accumulated.
The application of the recovery block concept to parallel programs for ensuring increased reliability despite the presence of software bugs is considered. The basic idea of this technique is to include standby softwar...
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The application of the recovery block concept to parallel programs for ensuring increased reliability despite the presence of software bugs is considered. The basic idea of this technique is to include standby software components in the program which can be ″switched on″ in case the active component fails. However, before this could be done, the system must be rolled back to a consistent state. One of the goals in this rollback is to avoid undoing a large amount of computation. It is shown that the process interaction must be severely constrained in order to achieve this goal. Sufficient conditions for limiting the rollback in a system of process communicating via monitors are also presented.
The problem discussed is that of scheduling n unit-time jobs, with release times and deadlines which are arbitrary real numbers, on m identical parallel machines. An algorithm with running time O(n**3log n) which sche...
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The problem discussed is that of scheduling n unit-time jobs, with release times and deadlines which are arbitrary real numbers, on m identical parallel machines. An algorithm with running time O(n**3log n) which schedules all the jobs while minimizing the maximum job completion time is described.
A high level of integration of disciplines and use of a centralised computer data base and programming system were seen to offer advantages in a study of the marine and coastal environment of the Port Melbourne Author...
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In order to take full advantage of the capabilities of very large computers, it is important that data structure and coding practices be carefully selected to efficiently use the special hardware features. The data st...
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In order to take full advantage of the capabilities of very large computers, it is important that data structure and coding practices be carefully selected to efficiently use the special hardware features. The data structure must be designed to stage information from the high speed, relatively small devices, to the lower speed, relatively large capacity devices. Coding practices must consider instruction stacks, cache memories, and main memory structure, in order to drive the arithmetic units at maximum speed. For virtual memory machines, the real memory must be used in such a manner as to prevent thrashing. Large machines may provide for scalar processing in parallel with vector processing, and the arithmetic units may utilize either parallel or pipeline processing.
The success of high performance multiple processor systems depends upon the ability to decompose a program into small segments suitable for execution on one processor. It is argued that purely applicative languages ar...
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The success of high performance multiple processor systems depends upon the ability to decompose a program into small segments suitable for execution on one processor. It is argued that purely applicative languages are better suited for parallel processing because they offer considerable advantage over Fortran-like languages in program transformation and decomposition. A scheme for decomposing applicative programs is described through examples.
The DEC-10 administrative system of National Chiao-Tung University resulted from extending the original system provided by the DEC-10 manufacturer from the user-file-directory basis to the sub-file-directory basis to ...
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The DEC-10 administrative system of National Chiao-Tung University resulted from extending the original system provided by the DEC-10 manufacturer from the user-file-directory basis to the sub-file-directory basis to meet the special requirements of the computer center. A detailed description of this entension is presented: administrative control files, control file maintenance programs, administrative control programs, accounting processes, and fail-saving programs. Some of these are the result of modifying the original system;others are add-on's.
Standard implementations of conditional critical regions and monitors can lead to ″busy waiting″ if processes are allowed to wait on arbitrary boolean expressions. Techniques from global flow analysis may be employe...
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Standard implementations of conditional critical regions and monitors can lead to ″busy waiting″ if processes are allowed to wait on arbitrary boolean expressions. Techniques from global flow analysis may be employed at compile time to obtain information about which critical regions (monitor calls) are enabled by the execution of a given critical regions (monitor calls) are enabled by the execution of a given critical region (monitor call). This information may be used to obtain more efficient scheduling algorithms.
A multistage probabilistic decision model is formulated to determine the optimal batch size for computer jobs to be distributed to a series of time-share vendors. A recursive cost function is given for each stage in t...
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A multistage probabilistic decision model is formulated to determine the optimal batch size for computer jobs to be distributed to a series of time-share vendors. A recursive cost function is given for each stage in terms of the telecommunication cost, the actual processing cost, and a probability function giving the probability that a batch will be completed by a certain vendor. The probability function is studied from the viewpoint of a birth-death process and its estimate obtained as a function of the vendors' traffic patterns, buffer sizes and numbers of communication lines.
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