A common interface (API) is provided which permits a single diagnostic
probe manager to communicate with and to control a plurality of
diagnostic probes. Through this interface the diagnostic probes are
enabled to pass information concerning dependencies between software
levels present in a hierarchical stack. This information is particularly
useful in that it permits the probe manager to direct diagnostic efforts
at the lowest desirable level so as to avoid the problems that occur when
problems are indicated at a high level but which are actually caused by
lower level software components.