Automated verification of system requirements and software specifications Zusammenfassung: Many small to medium sized enterprises that specialise in electrical or communications engineering are challenged by the increasing importance of software in their – often safety critical – products. For this reason they have a strong interest in subcontracting competent partners for software development tasks. Yet many of those enterprises refrain from subcontracting because they assessthe associated risks as too high. This thesis presents a set of methods and tools based on formal methods that are useful in reducing those associated risks. We are concerned with software defined systems i.e. systems whose behaviour is solely controlled by a program and the input the program receives from the environment. We especially focus on systems whose controlling programaccesses its hardware via memory mapped I O.We present a method for validating requirements between stakeholders with different levels of expertise. Based on validated requirements we present the IRS method that reduces the problem of deciding whether a software defined system satisfies the requirements to the problem of whether the controlling program satisfies its specification. We show the feasibility of the IRS method through an industrial case study. The case study uses a class of state of the art tools for proving program correctness (deductive verifiers)