Sequential process event system analyzer tool

Information is provided about operation of a software library (22) accessed by an application program (21). Information about calls made by the application program (21) into the software library (22) is collected, for example, by capturing a trace of the calls. For a user selected portion of the calls a plurality of event streams (91-97) are displayed. Within the event streams (91-97), events are colored so that a color of each event displayed in each event stream (91-97) encodes information about a call associated with the event. A first call is represented as a separate event in each event stream (91-97) in the plurality of event streams (91-97) and coloring within each event stream (91-97) encodes different information about the first call.