Policy/mechanism separation in Hydra

摘要: The extent to which resource allocation policies are entrusted user-level software determines in large part the degree of flexibility present an operating system. In Hydra determination separate mechanism and policy is established as a basic design principle implemented by construction kernel composed (almost) entirely mechanisms. This paper presents three such mechanisms (scheduling, paging, protection) examines how external manipulate them may be constructed. It shown that decisions remain embedded exist for sole purpose arbitrating conflicting requests physical resources, then only guaranteeing fairness.