ion Behavioral Abstraction (BA) described by Bates and Wileden [BW83] offers a new approach: "The basis for behavioral abstraction is viewing a system's activity, or behavior, as a stream of event occurences." Primitive events are basic actions in the system, e.g. process creation, message transmittance, etc. They can be clustered and filtered to represent higher-level events. The paper discusses how to detect complex events, and how to ignore "noise". The authors consider time too difficult to handle, even with global time algorithms the granularity will be too coarse. Events can be used for presentation to increase system understanding. An event can also be bound to a specified action, as normal breakpoints. 18.104.22.168 Evaluation LeBlanc and Mollor-Crummey [LMC87] see two disadvantages to BA systems: the user must before execution specify all interesting events, since further probing after discovering the error is not possible, and the information storage requirements quickly make..