The table driven executive controls operational software via a set of fixed tables containing the subroutines to be called in the order in which they are called. With the advant of multimode radar on the technological...
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The table driven executive controls operational software via a set of fixed tables containing the subroutines to be called in the order in which they are called. With the advant of multimode radar on the technological doorstep, a table driven executive having ability to dynamically change its tables is highly desirable. Such an executive has been developed at Westinghouse and has been found to be versatile as well as cost effective when applied to a multimode system. This paper describes the operation of the dynamic table driven multimode executive in detail and provides examples of its versatility and cost effectiveness.
The paper identifies the differences between real time software and other software and suggests a design approach based upon the concept of a network of processes and data areas. A modular approach to the construction...
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The paper identifies the differences between real time software and other software and suggests a design approach based upon the concept of a network of processes and data areas. A modular approach to the construction, operation and test of software based upon this concept and known as MASCOT is then described. The approach leads to the abolition of the concept of global data and replaces the 'program' by the subsystem as the unit of software construction. Asynchronous data communication strategies between parallel processes introduces the 'access procedure' concept and the need for a small and very efficient kernel.
Performance of a virtual memory computer system operating in multiprogramming environment, critically depends upon the optimal sizing of the various levels in the memory hierarchy as well as on optimally controlling t...
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Performance of a virtual memory computer system operating in multiprogramming environment, critically depends upon the optimal sizing of the various levels in the memory hierarchy as well as on optimally controlling the level of multiprogramming. The main input to the system is the program behavior of the typical programs to be run on the machine. The program behavior of a program is adequately represented by the relationship between E denoting the average uninterrupted processor execution time and S, denoting the main memory space alloted to the program. An S-shaped curve typically characterizes this relationship. A queueing model representing the input/output (I/O) activity as a function of the size of the main memory is developed for a memory system with two memory levels. It is assumed that I/O requests generated at the central processing unit (C. P. U. ) are uniformly distributed among the auxiliary memory units. A closed solution for the C. P. U. idle time is obtained and the effect of main memory size, the level of multiprogramming and the number of auxiliary memory modules, on the C. P. U. idle time is studied.
Presented are a description and analysis of a task scheduling algorithm which is applicable to third generation computersystems. The analysis is carried out using a model of a computer system having several identical...
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Presented are a description and analysis of a task scheduling algorithm which is applicable to third generation computersystems. The analysis is carried out using a model of a computer system having several identical task processors and a fixed amount of memory. The algorithm schedules tasks having different processor-time and memory requirements. The goal of the algorithm is to produce a task schedule which is near optimal in terms of the time required to process all of the tasks. An upper bound on the length of this schedule is the result of deterministic analysis of the algorithm. computer simulations demonstrate the applicability of the algorithm in actual systems, even when some of the basic assumptions are violated.
The paper introduces the first complete programming framework for coarse grain dynamically reconfigurable accelerators and their application development. It includes a general model for cooperating host/accelerator pl...
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ISBN:
(纸本)0818682558
The paper introduces the first complete programming framework for coarse grain dynamically reconfigurable accelerators and their application development. It includes a general model for cooperating host/accelerator platforms and a parallelizing compilation technique derived from it. The paper is ail introduction illustrating these techniques and their principles by examples: a machine architecture (briefly), and its application development framework performing a "software-only" accelerator implementation (synthesis). The paper's focus is to explain the exploitation of four different levels of parallelism during this compilation process for achieving optimized speedups and hardware resource utilization.
This paper presents a technique for recovering the high level design of legacy software systems according to user defined architectural plans. Architectural plans are represented using a description language and speci...
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This paper presents a technique for recovering the high level design of legacy software systems according to user defined architectural plans. Architectural plans are represented using a description language and specify system components and their interfaces. Such descriptions are viewed as queries that are applied on a large data base which stores information extracted from the source code of the subject legacy system. Data mining techniques and a modified branch and bound search algorithm are used to control the matching process, by which the query is satisfied and query variables are instantiated. The matching process allows the alternative results to be ranked according to data mining associations and clustering techniques and, finally, be presented to the user.
A collection of CDC Fortran and Compass routines has been developed for code conversion from IBM 360 to CDC 6000/7000 system. These routines interface with standard CDC software to provide capabilities similar to thos...
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A collection of CDC Fortran and Compass routines has been developed for code conversion from IBM 360 to CDC 6000/7000 system. These routines interface with standard CDC software to provide capabilities similar to those available on an IBM system. With this package, up to 64 levels of overlay with multiple entry points and parameters can be supported, the IBM form of subprogram entry points can be handled, I/O buffers can be dynamically allocated as needed, and most other minor Fortran differences can be resolved. Thus, CDC compatible code can be produced with only a few simple Fortran modifications required.
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.
This paper examines the needs of the small country or small organization wanting to start a software industry or even a single software project. One of the initial needs is to import software tools, but the ultimate a...
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This paper examines the needs of the small country or small organization wanting to start a software industry or even a single software project. One of the initial needs is to import software tools, but the ultimate aim must be to be self-sufficient in software. A short survey of methods for software portability is given, and these are related to the above needs.
A nonhomogeneous Poisson process is used to model the occurrence of errors detected during functional testing of command and control software. The parameters of the detection process are estimated by using a combinati...
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A nonhomogeneous Poisson process is used to model the occurrence of errors detected during functional testing of command and control software. The parameters of the detection process are estimated by using a combination of maximum likelihood and weighted least squares methods. Once parameter estimates are obtained, forecasts can be made of cumulative number of detected errors. Forecasting equations of cumulative corrected errors, errors detected but not corrected, and the time required to detect or correct a specified number of errors, are derived from the detected error function.
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