CS533 Concepts of Operating Systems Class 12 Micro-kernels (or Extensibility via Hardware-Based Protection)

CS533 - Concepts of Operating Systems 2 Questions  What is the motivation for modular operating systems? o Does this imply modules with hardware protection? o.. and what do I mean by hardware protection for modules?  What is the motivation for using hardware protection at module boundaries? o Does this imply message passing across module boundaries? o … what other alternatives do you have?  What is the motivation for using message-passing for inter-module communication?

CS533 - Concepts of Operating Systems 3 Questions  What is the structure of a pure emulation library- based OS above a micro-kernel? o How are system calls handled?  What is the structure of a single-server based OS above a micro-kernel? o How are system calls handled?  What is the structure of a multi-server based OS above a micro-kernel? o How are system calls handled?

CS533 - Concepts of Operating Systems 4 Questions  What are the main sources of overhead in micro- kernel based OSs compared to monolithic OSs?  How does L3 address these overheads? o Do these optimizations completely solve the problem?  What is the difference between L4 IPC and a protected control transfer (PCT)? o Would you expect a lot of difference in performance following extreme optimization of both?  What minimal abstractions should a kernel provide?

CS533 - Concepts of Operating Systems 5 Questions  What is extensibility and how does micro-kernel- based OS structure help? o What other approaches are there?