Simulation-based debugging of soft real-time applications

We present a temporal debugger, capable of examining time flow of soft real time applications in Unix systems. The debugger is based on a simulator modelling an entire workstation in sufficient detail to run unmodified operating systems and applications. It provides a deterministic and non-intrusive debugging environment, allowing reproducible presentation of program time flow. The primary contribution of the paper is virtual machine translation, a technique necessary to debug applications in a simulated Unix system. We show how a virtual machine translator maps low-level data, provided by the simulator to data useful to a symbolic debugger. The translator operates by parsing data structures in the target operating system and has been implemented for the GNU debugger and simulated Linux systems.