Abstract: Advocates the philosophy that operating systems are of indispensable significance to make applications trusled. Elaborates the concept of Trust Base in Operating System (TBOS) with a focus on Web applications. Discusses research methods for modeling the TI30S with a longing for ensuring that the TBOS is trusted. Proposes the TBOS archilecture that consists of three main parts, which are the Trust Monitoring Core Engine, the In-Kernel Trust Monitor and the Out of-Kernel Trust Monitor. Proposes a research guideline that is to exploit the potential of hardware and reduce the size of software. States key issues and key technictues in modeling the TBOS. Establishes the methodology foundalion of modeling the TBOS from the aspects of model construction method, trust monitoring method, inter-domain collaboration method, protection-by-isolation method, hardware features abstraction method and software size minimization method.

Key words: Operating system, Trust base, Modeling, Methodology, Model, Hardware