A system for visualizing and animating program runtime histories

Program visualization and animation are well-known to be important in helping people understand computer programs. Researchers have investigated a variety of techniques and built many systems to this end. However, the use of program visualization and animation systems is limited in real programming environments due to a number of problems. Among others, these include lack of flexibility and poor user interaction resulting from the use of ad hoc techniques. This paper describes a programmable and integrated graphical system for visualizing and animating program runtime histories. It employs a special runtime system to automatically accumulate historical information about program execution and allows users to visualize it through multiple active views in a post-mortem style. Program animation is then integrated into these views by adding a time dimension. Underneath is an animation description language, using which we can specify all these views systematically. This paper describes the key features of the system, its primary design considerations and its implementation techniques.