Exemplary methods, apparatuses, and products are described for creating a behavioral model of a hardware device for use in a simulation environment. The behavioral model is created by an iterative process that includes receiving in a simulated hardware device from a simulated device under test (‘DUT’) a stimulus waveform. The stimulus waveform includes data representing a number of stimuli. In response to receiving the stimulus waveform, the simulated hardware device presents a recorded response waveform from a recorded response file to the DUT. The stimulus waveform is also recorded. The recorded stimulus waveform is presented to the hardware device. A response waveform that results from presenting the recorded stimulus waveform to the hardware device is recorded in the recorded response file.