Modern operating systems use abstraction layers to describe data input/output interfaces. Operating systems based on these principles conform to the POSIX standard, which describes syntax and semantics of system calls. However, use of standards alone does not guarantee the consistency of used software components and correctness of designed algorithms. This article describes several logical errors which are typical for complex systems, different parts of which were developed independently of each other. An analysis of the described errors allows us to state that definition of the detailed models for software components and their subsequent formal verification and application for code testing can significantly improve robustness of the created operating systems and applications.