This paper describes three computer-based simulators developed to support an undergraduate computer architecture course. Using a hypermedia authoring package, a simulator was created for each of the three course content areas: (1) introduction of the hypothetical computer structure--contains a tutorial, a quiz, and a simple program that presents background information and introduces the architecture of the hypothetical machine and the first 11 fundamental machine instructions; (2) presentation of the microsequence operations--includes a quiz section which tests student understanding of concepts; and (3) actual programming of the hypothetical computer--allows students to write and execute programs using a graphical presentation of the program. Results from research on the class indicated that students' responses were favorable to the incorporation of the simulators in the class; students showed lower levels of frustration and a higher level of understanding of abstract materials; students shifted from lecture and classroom questioning on specific items as a means of obtaining information to the consultation of the appropriate simulator to obtain the answer; and the class showed significant improvements. Two figures illustrate sample screens from Simulators One and Two. (ALF)