Abstract: A method and apparatus for monitoring electrical signals within a system bus to compile statistics regarding the use of the bus by each of a plurality of circuit boards. The apparatus includes a trace memory for storing samples of the bus's electrical signals. A processor analyzes the samples to detect bus cycles, determines which of the circuit boards initiated the bus cycles, and prepares statistics regarding the use of the system bus by each circuit board. A display system prepares illustrations, such as graphs, which depict selected statistics. The apparatus also includes an application status register for storing information regarding the status of software executed by a processor board. The software sets a bit of the application status register to indicate that a specified event has begun and clears the bit to indicate that the specified event has terminated. The apparatus includes circuitry for reading the application status register to monitor the event.