The operating system kernel as a secure programmable machine

Abstract

Operating systems should provide only minimal embedded kernel functionality. Exokernels achieve this minimalist goal by presenting to applications the features supported by the underlying hardware resources. Applications customize the operating system by extending the exokernel interface. Code inspection, inlined cross-domain procedure calls, and secure languages are used to allow programmable yet safe additions to the supervisor-mode execution environment. These additions enable applications to benefit from full hardware functionality and performance. To test and evaluate exokernels and their customization techniques a prototype system, Aegis, is being developed.