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Real Time Operating Systems: A Visual Simulator

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2004 Annual Conference


Salt Lake City, Utah

Publication Date

June 20, 2004

Start Date

June 20, 2004

End Date

June 23, 2004



Conference Session

Computed Simulation and Animation

Page Count


Page Numbers

9.1042.1 - 9.1042.11



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Paper Authors

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Daniel Pack

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Steven Barrett

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Real-Time Operating Systems: A Visual Simulator

Steven F. Barrett1 , Daniel J. Pack2 , Charles Straley1 , Lew Sircin1 , George Janack1 1 Department of Electrical and Computer Engineering University of Wyoming 2 Department of Electrical Engineering United States Air Force Academy, Colorado


A Real-Time Operating System, or RTOS, is an operating environment where multiple events called tasks compete for precious processor operating time of a single processor. The processor must prioritize tasks depending on system requirements to ensure that all tasks complete their required activities. Due to its complex nature, a RTOS is a difficult subject to teach in undergraduate institutions. Often it is difficult for the students to visualize the intricacies and inter-relationships between component parts of the system To help students to ‘see’ the operations, we have developed a visual hardware simulator that interfaces to an embedded controller. In our application, we use the popular Motorola HCS12 microprocessor as the simulator’s host system. The simulator can be easily interfaced with other processor families. The simulator provides a visual display of the status of up to 16 competing tasks. The simulator also provides a keypad for the user to interject new status and a LCD display to illustrate key RTOS activities.


The subject of Real-Time Operating Systems (RTOS) and their associated concepts are difficult for students to learn. The concepts are quite complex and involve multiple abstract data types such as multiple stacks and linked lists dynamically handing off information to one another in a quickly changing scenario. We developed a visual simulator to help the student view these rapidly changing events. The simulator consists of a hardware board that displays the status of up to 16 different tasks in a RTOS environment. The board was designed to be used with a HCS12-based evaluation board readily available from a number of manufacturers. In this paper we begin with a review of some basic RTOS concepts followed by the inherent complexities involved in effectively teaching these concepts. We then describe in detail the board developed to teach these concepts in a visual environment and suggest scenarios that may be used to illustrate RTOS concepts. “Proceedings of the 2004 American Society for Engineering Education Annual Conference and Exposition Copyright 2004, American Society for Engineering Education”

Pack, D., & Barrett, S. (2004, June), Real Time Operating Systems: A Visual Simulator Paper presented at 2004 Annual Conference, Salt Lake City, Utah. 10.18260/1-2--13843

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