On the Correctness of Operating System Kernels

The Verisoft project aims at the pervasive formal verification of entire computer systems. In particular, the seamless verification of the academic system is attempted. This system consists of hardware (processor and devices) on top of which runs a microkernel, an operating system, and applications. In this paper we define the computation model CVM (communicating virtual machines) in which concurrent user processes interact with a generic microkernel written in C. We outline the correctness proof for concrete kernels, which implement this model. This result represents a crucial step towards the verification of a kernel, e.g. that in the academic system. We report on the current status of the formal verification.