This is the first of several articles on data correlation programs for programmable calculators. It presents a program for finding a relationship between one dependent and one independent variable. In this system it i...
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This is the first of several articles on data correlation programs for programmable calculators. It presents a program for finding a relationship between one dependent and one independent variable. In this system it is possible to use functions of the independent variable other than those written into the program, and there is provision for correcting data entries before the program is run. The discussion is presented under headings: basis of program MULTFIT (the correlation coefficient);the MULTFIT program;nitric acid example;crude-oil example;final remarks.
The article presents the principal features of the POLYP (Problem-Oriented Language for sYstem software programming) system intended for mathematical system software programming and, in particular, for operating syste...
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The article presents the principal features of the POLYP (Problem-Oriented Language for sYstem software programming) system intended for mathematical system software programming and, in particular, for operating systems. The system has been developed in 1973 in the Federal Republic of Germany by the Scientific Control systems (SCS) Company for IBM/370 and Siemens 4004 computers.
The ISI Delta Experiment is an effort to specify and verify a piece of real software of moderate complexity and size (roughly 1000 lines). This preliminary report describes (1) the Delta function, managing the editing...
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The ISI Delta Experiment is an effort to specify and verify a piece of real software of moderate complexity and size (roughly 1000 lines). This preliminary report describes (1) the Delta function, managing the editing of a single file by several users within an operational message processing system; (2) the formal specification of the Delta function in prose and in algebraic axioms; (3) the verification methodology in levels of (a) prose for the system interface level, (b) algebraic axioms for abstract data types, (c) recursive functions for major operations, (d) implementation of the recursive functions in PASCAL with the abstract data types, and (e) implementation of the PASCAL programs in BLISS; and (4) the experience gained in this experiment, both in specification and verification.
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.
An approach to the analysis of concurrent software is discussed. The approach, called anomaly detection, involves the algorithmic derivation of information concerning potential errors and the subsequent, possibly non-...
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An approach to the analysis of concurrent software is discussed. The approach, called anomaly detection, involves the algorithmic derivation of information concerning potential errors and the subsequent, possibly non-algorithmic determination of whether or not the reported anomalies are actual errors. Overviews are given of algorithms for detecting data-usage and synchronization anomalies and discuss how this technique may be integrated within a general software development support system.
A queueing analysis is presented of a pre-emptive, priority driven, timesliced dispatcher algorithm, typical of those found in many timesharing systems. A distinctive feature of the system being modeled is that a pree...
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A queueing analysis is presented of a pre-emptive, priority driven, timesliced dispatcher algorithm, typical of those found in many timesharing systems. A distinctive feature of the system being modeled is that a preempted task, when re-admitted to the dispatcher, is re-allocated a full timeslice rather than the residual. The combination of pre-emption, timeslice renewal and class dependent arrival and service rates, places the analysis beyond that of the well-known FB//N algorithms. The model is used to predict the behavior of the dispatcher algorithm under various workloads.
An in-place reversible sorting algorithm is used following a fast Walsh transform to sort coefficients into increasing sals followed by decreasing cals. This separation of the coefficients into those arising from odd ...
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An in-place reversible sorting algorithm is used following a fast Walsh transform to sort coefficients into increasing sals followed by decreasing cals. This separation of the coefficients into those arising from odd sinelike time functions and those from even cosinelike functions is useful in signal processing applications. A second sort routine generates a relocating set for a remap sequency sorting. To be valid for all N this sort routine is done out-of-place. The separation of the transform and sort functions has resulted in simple implementations for each. To demonstrate the differences in the sort routines, transform results and their inverses are made on a linear ramp. For this application the transform results with sal-cal sorting has all zeros beyond the mid-point showing that, with the exception of the large d. c. term, the linear ramp is composed entirely of Walsh odd time functions.
A methodology using attributed grammars representing the formal specification of distributed computing system software design is developed. This methodology provides a formal expression for synchronization, concurrent...
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A methodology using attributed grammars representing the formal specification of distributed computing system software design is developed. This methodology provides a formal expression for synchronization, concurrent processing and interprocess communication in the design of distributed computing system software using productions of attributed grammars. These productions can express sequencing, selection, recursion and concurrency in the system's activities, and can be used for expressing stepwise refinement of the design. The control flow of the software system is governed by the productions and the attributes of the symbols in the productions in the grammar. The formal specification of distributed computing system software design can also be used for consistency checking of the design and validation of implementation at run-time. An example is given to demonstrate this methodology.
Effective management and control of the development, operation and maintenance of software has been the weakest link over the thirty years of the evolution of the internally stored digital program. Improved management...
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Effective management and control of the development, operation and maintenance of software has been the weakest link over the thirty years of the evolution of the internally stored digital program. Improved management practices and controls have been shown to significantly reduce costs, improve reliability, and provide for easier maintainability. It is time for today's software managers, even at upper levels, to realize that to be effective they must involve themselves in the details of software development and they must understand the software that they are managing. Software engineering is a rapidly emerging field providing insights into software development. The results of several software engineering research projects applicable to software management are described.
A new modelling scheme capable of representing parallel systems with dynamic structure is discussed. An example is presented illustrating the model's use in studying correctness of process interaction is complex s...
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A new modelling scheme capable of representing parallel systems with dynamic structure is discussed. An example is presented illustrating the model's use in studying correctness of process interaction is complex software systems whose structure may change during system execution.
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