Task time lines as a debugging tool

Debugging distributed programs is more difficult than debugging sequential ones. This paper describes a means of making this easier by presenting the user with a "time line" view of an Ada program. Each time line shows the successive states of an Ada task as easily recognisable symbols on a time axis. Communication and sychronisation between tasks is shown graphically by lines connecting the time lines. The paper shows how this representation can be used to depict typical Ada tasking activity, and describes a tool that provides a useful interface to the representation.