Method and device for analyzing an execution of a predetermined program flow on a physical computer system

The functionality of simulated, virtual hardware units is varied during the execution of a program flow on the virtual hardware units, for example via an interface device of a simulation device, in such a manner that the execution behavior changes of a program flow can be identified by using at least one faulty, physical hardware unit. A method and a device are used for analyzing an execution of a predetermined program flow on a physical computer system. The method and the device are used to determine execution behavior changes of software products which changes are due to faulty hardware components. The method and device allow execution behavior changes to be identified systematically, using an operating system and eliminates the need for expensive, physical hardware components and for modifications to a physical computer system.