Visual representations of executing programs

Programmers have always been curious about what their programs are doing while it is executing, especially when the behavior is not what they are expecting. Since program execution is intricate and involved, visualization has long been used to provide the programmer with appropriate insights into program execution. This paper looks at the evolution of on-line visual representations of executing programs, showing how they have moved from concrete representations of relatively small programs to abstract representations of larger systems. Based on this examination, we describe the challenges implicit in future execution visualizations and methodologies that can meet these challenges.