Larry L. Wear

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Assembly level instruction trace routines have been used for years by programmers as a debugging aid. However, most of these have the disadvantages that they are usually 1) very slow and 2) not amenable for use with operating system development. This paper shows how the standard ROM resident instruction set of the H-P 2100 was replaced by a new WCS resident(More)
The problems of determining the relative frequency of execution of instructions on a computer and finding the occurrences of patterns of instructions within programs have been investigated by a number of researchers in the past. The method most often used was to examine the object code and apply a method to count each type of instruction or group that(More)
We have looked at general descriptions and illustrations of several software development tools, such as tools for prototyping, developing DFDs, testing, and maintenance. Many others are available, and new ones are being developed. However, you have at least seen some examples of powerful CASE tools for systems development.
This paper describes an operating system (OS) simulator designed to be used as an instructional tool in the teaching of OS performance issues. Design criteria, assumptions used, development, and implementation of the model are discussed. The model provides a hands-on laboratory tool for experimentation with a layered, modular, multitasking, event driven OS.(More)
In this article, we looked at some decisions that apply to the design of reliable computer systems. We began with a discussion of several terms such as testability, then described some systems that call for highly reliable hardware and software. The article concluded with a discussion of methods that can be used to achieve higher reliability in computer(More)
This paper describes three methods that were used to investigate multiprocessor bus architectures. The models described were implemented in FORTRAN, GPSS, and SIMULA. Characteristics of the three implementations, such as program length, program memory requirements, execution time and ease of use are compared. Results of the simulation of a single bus system(More)
The two goals of this article are to give you a very brief overview of the evolution of computing and an introduction to the elements of a computer. The birth of the modern computer can be traced to John von Neumann. The model he proposed consisted of four major parts: the control unit, the arithmetic unit, the memory, and the input/output unit. His concept(More)
This paper reports the development of a probabilistic model of microprogram behavior and the application of this model to the measurement of some fundamental parameters of microprogram performance. The major parameters considered are: {a) the mean microinstruction reference time, (b) the degree of parallelism in microprograms, and (c) the effect of branch(More)