Making paths explicit in the Scout operating system

This paper makes a case for paths as an explicit abstraction in operating system design. Paths provide a unifying infrastructure for several OS mechanisms that have been introduced in the last several years, including fbufs, integrated layer processing, packet classifiers, code specialization, and migrating threads. This paper articulates the potential advantages of a path-based OS structure, describes the specific path architecture implemented in the Scout OS, and demonstrates the advantages in a particular application domain---receiving, decoding, and displaying MPEG-compressed video. 1 Introduction Layering is a fundamental structuring technique with a long history in system design. From early work on layered operating systems and network architectures 12, 32, to more recent advances in stackable systems 27, 15, 14, 26, layering has played a central role in managing complexity, isolating failure, and enhancing configurability. This paper describes a complementary, but equally f...