1. Apparatus for acquiring data concerning the execution of software in a target system under test, which comprises: static event recognition means, comprising low-level event recognition detectors programmable to produce a first output signal upon the occurrence of a chosen pattern of signals received from the target system under test, and high-level event recognition detectors responsive to said first output signal programmable to produce a second output signal upon the occurrence of a chosen pattern of said first output signals; dynamic event recognition means comprising dynamic event recognition detectors programmable to produce a third output signal upon occurrence of a chosen pattern of signals received from the target system under test which represent actuation of a dynamic variable, at least one of said dynamic detectors being reprogrammable during the execution of the target system software to produce a fourth output signal upon the occurrence of a chosen pattern of signals received from the target system which represent access to a dynamically activated variable, and a dynamic sequencer responsive to said third output signal, which reprograms said dynamic detector, said dynamic sequencer also being responsive to said fourth output signal to produce a fifth output signal; acquiition memory which receives signals from the target system under test and stores selected signals; and a function generator responsive to said second output signals and to said fifth output signals to store data in said acquisition memory.