This paper describes a first implementation of the executive for the Honeywell Experimental Distributed Processor (HXDP). HXDP has been built to investigate distributed, decentralized control in real time applications...
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This paper describes a first implementation of the executive for the Honeywell Experimental Distributed Processor (HXDP). HXDP has been built to investigate distributed, decentralized control in real time applications. The purpose of the implementation is to demonstrate the utility of, and to gain experience with the executive primitives in the area of interprocess communication.
The paper presents experiences in implementing a software quality assurance plan in a highly diversified avionics organization, whose products, until recently, contained little or no stored program computational compo...
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The paper presents experiences in implementing a software quality assurance plan in a highly diversified avionics organization, whose products, until recently, contained little or no stored program computational components.
This report presents a programmer's ″toolbox″ - an integrated set of software programs which facilitate various phases of microcomputersystems development and maintenance. The most important tools are the progr...
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This report presents a programmer's ″toolbox″ - an integrated set of software programs which facilitate various phases of microcomputersystems development and maintenance. The most important tools are the programming languages since they influence the overall software design and determine the effectiveness of the implementation. PLZ/SYS is a high-level language similar to Pascal, but designed specifically for efficient microcomputer systems programming tasks. PLZ/ASM is a structured assembly language with many of the features of PLZ/SYS, but based on machine-level primitives to allow complete access to a particular micro-processor architecture. The toolbox also contains a powerful macro processor program which is designed to be primarily a language enhancement tool, but can also be used as a stand-alone, general-purpose text manipulator or command interpreter.
computer programs are portable to the extent that they can be moved to new computing environments with much less effort than it would take to rewrite them. In the limit, a program is perfectly portable if it can be mo...
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computer programs are portable to the extent that they can be moved to new computing environments with much less effort than it would take to rewrite them. In the limit, a program is perfectly portable if it can be moved at will with no change whatsoever. Recent C language extensions have made it easier to write portable programs. Some tools have also been developed that aid in the detection of nonportable constructions. With these tools many programs have been moved from the pdp -11 on which they were developed to other machines. In particular, the unix * operating system and most of its software have been transported to the Interdata 8/32. The source-language representation of most of the code involved is identical in all environments.
Recent publications suggest that use of decision tables in analysing conventional computer programs. In this paper, it is argued that the classical decision table format is not well suited to represent flow-chart-like...
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Recent publications suggest that use of decision tables in analysing conventional computer programs. In this paper, it is argued that the classical decision table format is not well suited to represent flow-chart-like *** alternative decision table conventions are investigated. Finally, a basic distinction is made between the use of decision tables in the problem statement phase and in programming.
Three principles of optimality for multiprogramming derived from a general model of virtual memory computer system are presented. They state the existence of both an optimal multiprogramming degree and an optimal prog...
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Three principles of optimality for multiprogramming derived from a general model of virtual memory computer system are presented. They state the existence of both an optimal multiprogramming degree and an optimal program mixture in the multiprogramming set. The implementation of these principles is studied in a simulation model which permits, in contrast to analytical models, to relax assumptions on the workload submitted to the system. An appropriate dynamic control of the system is needed in order to achieve optimal performance. Proposed optimization takes into account such criteria as deadlines and priorities which are not directly related to system performance. The different results obtained on the system performance improvement are presented.
A finite state model for the specification and validation of communication protocols is considered. The concept of ″direct coupling″ between interacting finite state components is used to describe a hierarchical str...
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A finite state model for the specification and validation of communication protocols is considered. The concept of ″direct coupling″ between interacting finite state components is used to describe a hierarchical structure of protocol layers. The paper discusses different aspects of protocol validation, some verification tools based on the finite state formalism, and the basic limitations of the finite state modeling of protocols. An ″empty medium abstraction″ is proposed for reducing the complexity of the overall system description. The concept of ″adjoint states″ can be useful for summarizing the relative synchronization between the communicating system components. These concepts are applied to the analysis of a simple alternating bit protocol, and to the X. 25 call set-up and clearing procedures. The analysis of X. 25 shows that the procedures are stable in respect to intermittant perturbations in the synchronization of the interface introduced for different reasons, including occasional packet loss. However, on very rare occasions, an undesirable cyclic behavior could be encountered.
A multiprocessing model called software pipelining is introduced for which it is easy to guarantee determinancy of results. Design tools for general applications can be used to determine whether a design can cause int...
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A multiprocessing model called software pipelining is introduced for which it is easy to guarantee determinancy of results. Design tools for general applications can be used to determine whether a design can cause interference and hence, cause loss of data integrity and failure of the determinancy of results. The model is called automatic because the implementor does not need to supply the synchronization mechanism nor identify the points of synchronization. The linker can supply the synchronization mechanisms to prevent interference and yield determinancy results independent of the implementation language. In fact, only minor changes need to be made to existing compilers. No special synchronization statements need to be used and no changes to the implementation language need to be made, independent of which language is used.
The paper is devoted to testing the reliability of software embedded in military systems. Proposed reliability test criteria are discussed of large-scale software subsystems and approaches are recommended to software ...
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The paper is devoted to testing the reliability of software embedded in military systems. Proposed reliability test criteria are discussed of large-scale software subsystems and approaches are recommended to software reliability testing.
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